1502343_DOS_2.10_Reference_Sep83 1502343 DOS 2.10 Reference Sep83

User Manual: 1502343_DOS_2.10_Reference_Sep83

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Personal Computer
Computer Language
Series

Disk
Operating
System
by Microsoft Corp.

First Edition (September 1983)
Version 2.10
International Business Machines Corporation provides this manual
"as is" without warranty of any kind, either express or implied,
including, but not limited to the implied warranties of
merchantability and fitness for a particular purpose. IBM may make
improvements and or change in the product( s) and or the program( s)
described in this manual at any time and without notice.
Products are not stocked at the address below. Requests for copies
of this product and for technical information about the system
should be made to your authorized IBM Personal Computer Dealer.
This publication could contain technical inaccuracies or
typographical errors. Changes are periodically made to the
information herein; these changes will be incorporated in new
editions of this pUblication.
A Reader's Comment Form is provided at the back of this
publication. If this form has been removed, address comments
to: IBM Corp., Personal Computer, P.O. Box 1328-W, Boca
Raton, Florida 33432. IBM may use or distribute any of the
information you supply in any way it believes appropriate without
incurring any obligations whatever.
©

Copyright International Business Machines Corp. 1983

Preface

Read This First

This manual explains how to use the IBM Personal
Computer Disk Operating System Version 2.10 (DOS).
Information is also given on how to prepare DOS and
your fixed disk for use, and how to use the features
of DOS Version 2.10.
This book together with the IBM DOS Technical
Reference can be used by experienced programmers
when using developed application programs.
Information is provided on how to issue commands to
DOS to create, edit, link, debug, and execute programs.

First Time Users
Before using your DOS diskette for the first time read
the sections "About Diskettes" and "Backing Up Your
DOS Diskettes" in the IBM Disk Operating System
User's Guide.

Experienced DOS Users
Experienced application programmers will find the IBM
DOS Technical Reference helpful.

iii

About Your DOS Diskettes
DOS Version 2.10 is shipped on two diskettes. The first
labeled "DOS" contains the DOS programs and
commands. It is referred to as the DOS diskette in this
manual. The second diskette labeled "DOS
Supplemental Programs" contains the LINK Utility,
EXE2BIN, DEBUG, and several BASIC sample
programs (see the IBM Personal Computer BASIC
book for information about the sample programs).

Terms Used
The terms "disk," "diskette," and "fixed disk" are used
throughout this book. Where "diskette" is used, it
applies only to diskette drives and diskettes. Where
"fixed disk" is used, it applies only to the IBM
nonremovable fixed disk drive. Where "disk" is used, it
applies to both fixed disks and diskettes.

iv

Considerations for Using
Applications

If you have any of the following applications, please
note there are different storage requirements when using
these applications with DOS Version 2.10. Refer to
Appendix D.

•

Accounting Packages by BPI Systems, Inc.

•

Accounting Packages Version 1.00 by Peachtree
Software, Inc.

•

Accounting Packages Version 1.10 by Peachtree
Software, Inc.

•

Arithmetic Games 1 and 2

•

Asynchronous Communications Support
Version 1.00

•

Asynchronous Communications Support
Version 2.00

•
•
•
•
•

EasyWriter Version 1.10
Fact Track
MUltiplan 1.00
pfs:FILE
pfs:REPORT

v

•

SNA 3270 Emulation and RJE Support
Version 1.00

•

The Dow Jones Reporter Version 1.00

•

Typing Tutor

•

VisiCalc Version

•

3101 Emulator Version 1.00

Organization of This Manual
This manual has 8 chapters and 6 appendixes.
Chapter 1 is an introduction to the commands you can
issue to DOS. These commands enable you to manage
files, maintain disks, create programs, and execute
programs.
Chapter 2 gives a detailed description of each
command, which is listed in alphabetical order. Each
description contains the purpose, format, and type of
each command. Examples are given where appropriate.
Chapter 3 gives detailed instructions on how to use the
fixed disk.
Chapter 4 tells you how to configure your system.
Chapter 5 describes how to use tree-structured
directories.
Chapter 6 tells you how to use the Line Editor
(EDLIN) program to create, alter, and display source
language files and text fiJes.
Chapter 7 describes the use of the linker (LINK)
program to link programs together before execution.

vi

Chapter 8 describes the uses of the DEBUG program in
providing a controlled test environment so you can
monitor and control the execution of a program to be
debugged. This is done by altering, displaying, and
executing object files.
Appendix A lists messages generated by the programs
described in this manual.
Appendix B describes how to run compilers and the
macro assembler with fixed disk.
Appendix C explains how to run the Pascal compiler
with fixed disk.
Appendix D contains important information about the
application programs.
Appendix E gives a brief description of all the
enhancements from DOS 1.10 to DOS 2.00 and 2.10.
Appendix F discusses the editing keys you use with
DOS.

vii

viii

Contents

Chapter 1. Using DOS ...................
Introduction .............................
Redirection of Standard Input and Output
Devices ................................
Piping of Standard Input and Output .......
DOS Filters .............................
Invoking a Secondary Command
Processor ...............................
Types of DOS Commands ................
Format Notation .........................
DO S Command Parameters ...............
Reserved Device Names ...............
Global Filename Characters ............
Information Common to All DOS
Commands .............................
DOS Version 2.10 Features ................
Automatic Program Execution ..............
Chapter 2. DOS Commands ..............
Introduction .............................
ASSIGN (Drive) Command ..............
BACKUP (Fixed Disk) Command .........
Batch Commands ........................
The AUTOEXEC.BAT File ...........
Creating a .BAT File With Replaceable
Parameters .........................
Executing a .BAT File With Replaceable
Parameters .........................
ECHO Subcommand ..................
FOR Subcommand ...................
GOTO Subcommand .................
IF Subcommand ......................
PAUSE Subcommand.................
REM (Remark) Subcommand ..........
SHIFT Subcommand .................

1-1
1-3
1-5
1-8
1-10
1-11
1-13
1-15
1-16
1-19
1-20
1-23
1-26
1-27
2-1
2-5
2-6
2-9
2-13
2-15
2-1 7
2-19
2-20
2-22
2-23
2-24
2-28
2-29
2-30

ix

BREAK (Control Break) Command .......
CHDIR (Change Directory) Command ....
CHKDSK (Check Disk) Command. ..... ..
CLS (Clear Screen) Command ............
COMP (Compare Files) Command ........
COpy Command ........................
CITY Command ( Change Console) .......
DATE Command ........................
DEL Command ..........................
DIR (Directory) Command ...............
DISKCOMP (Compare Diskette)
Command ..............................
DISKCOPY (Copy Diskette) Command ...
ERASE Command .......................
EXE2BIN Command ....................
FDISK Command .......................
FIND Filter Command ...................
FORMAT Command .....................
GRAPHICS (Screen Print) Command .....
MKDIR (Make Directory) Command ......
MODE Command .......................
MORE Filter Command ..................
PATH (Set Search Directory) Command ...
PRINT Command .......................
PROMPT (Set System Prompt)
Command ..............................
RECOVER Command ....................
RENAME (or REN) Command ...........
RESTORE (Fixed Disk) Command .......
RMDIR (Remove Directory) Command ....
SET (Set Environment) Command .........
SORT Filter Command ...................
SYS (System) Command .................
TIME Command .........................
TREE (Display Directory) Command ......
TYPE Command .........................
VER (Version) Command .................
VERIFY Command ......................
VOL (Volume) Command .................
Summary of DOS Commands .............

x

2-33
2-35
2-38
2-42
2-44
2-48
2-61
2-63
2-65
2-66
2-73
2-77
2-81
2-83
2-86
2-87
2-89
2-96
2-98
2-100
2-107
2-108
2-110
2-116
2-119
2-122
2-124
2-127
2-128
2-131
2-133
2-134
2-136
2-139
2-141
2-142
2-144
2-145

Chapter 3. Preparing Your Fixed Disk .... .
Introduction ............................ .
Fixed Disk Drive Letters ................. .
Preparing Your Fixed Disk ............... .
Setting Up the DOS Partition ............ .
Partitioning Your Fixed Disk ............. .
Creating the DOS Partition (Option 1) .. .
Changing the Active Partition
(Option 2) ......................... .
Deleting the DOS Partition
(Option 3) ......................... .
Displaying Partition Data (Option 4) ... .
Selecting Next Fixed Disk Drive
(Option 5) ......................... .
Chapter 4. Configuring Your System .......
Introduction .............................
Configuration Commands .................
BREAK Command ...................
BUFFERS Command .................
DEVICE Command ..................
FILE S Command ....................
SHELL Command ....................
Chapter 5. Using Tree-Structured
Directories .............................
Introduction .............................
Directory Types ..........................
The Current Directory ....................
Specifying the Path To a File ..............
Directory Commands .....................
Creating a Subdirectory ................
Deleting a Directory ..................
Displaying and Changing the Current
Directory ...........................
Displaying the Directory Structure ......
Where DOS Looks for Commands and
Batch Files .............................

3-1
3-3
3-5
3-6
3-9
3-13
3-15
3-19

3-20
3-22
3-23
4-1
4-3
4-3
4-4
4-5
4-8
4-9
4-10

5-1
5-3
5-5
5-6
5-7
5-10
5-10
5-10
5 -11
5-11

5-12

xi

xii

Chapter 6. The Line Editor (EDLIN) ......
Introduction .............................
How to Start the EDLIN Program .........
Editing an Existing File ................
Editing a New File ....................
The EDLIN Command Parameters ........
The EDLIN Commands ..................
Information Common to All EDLIN
Commands .........................
Append Lines Command ..................
Copy Lines Command ....................
Delete Lines Command ...................
Edit Line Command ......................
End Edit Command ......................
Insert Lines Command ...................
List Lines Command .....................
Move Lines Command ....................
Page Command ..........................
Quit Edit Command ......................
Replace Text Command. . .. . . . . . . . . . . . . . . .
Search Text Command. . . . . . . .. . . .. . . . . . . .
Transfer Lines Command .................
Write Lines Command ....................
Summary of EDLIN Commands ..........

6-1
6-3
6-5
6-5
6-6
6-7
6-9
6-9
6-11
6-12
6-13
6-1 7
6-20
6-21
6-25
6-30
6-31
6-32
6-33
6-37
6-41
6-42
6-43

Chapter 7. The Linker (LINK) Program ...
Introduction .............................
Files ....................................
Input Files ...........................
Output Files .........................
VM.TMP (Temporary File) ............
Definitions ..............................
Segment .............................
Group ..............................
Class ...............................
Command Prompts .......................

7-1
7-3
7-4
7-4
7-5
7-5
7-6
7-6
7-7
7-7
7-8

Detailed Descriptions of the Command
Prompts ................................
Object Modules [.OBJ]: ...............
Run File [filename.EXE]: ..............
List File [NUL.MAP]: ................
Libraries [.LIB]: ......................
Linker Parameters ....................
How to Start the Linker Program ..........
Before You Begin .....................
Option 1 - Console Responses ..........
Option 2 - Command Line .............
Option 3 - Automatic Responses ........
Example Linker Session ..................
How to Determine the Absolute
Address of a Segment ................
Messages ................................
Chapter 8. The DEBUG Program .........
Introduction .............................
How to Start the DEBUG Program ........
The DEBUG Command Parameters........
The DEBUG Commands .................
Information Common to All DEBUG
Commands .........................
Assemble Command ......................
Compare Command ......................
Dump Command .........................
Enter Command .........................
Fill Command ...........................
Go Command ............................
Hexarithmetic Command .................
Input Command .........................
Load Command..........................
Move Command .........................
Name Command .........................
Output Command ........................
Quit Command ..........................
Register Command .......................

7-10
7-10
7-11
7-12
7-13
7-14
7-18
7-18
7-18
7-19
7-21
7-23
7-26
7-28
8-1
8-3
8-4
8-7
8-13
8-13
8-15
8-19
8-20
8-23
8-27
8-28
8-31
8-32
8-33
8-36
8-37
8-39
8-40
8-41

xiii

Search Command .........................
Trace Command ..........................
Unassemble Command ....................
Write Command ..........................
Summary of DEBUG Commands ...........

8-47
8-49
8-51
8-55
8-60

Appendix A. Messages ...................
Introduction ............................
Responses ..............................
Device Error Messages ...................
Other Messages .........................

A-I
A-I
A-2
A-3
A-9

Appendix B. Running Compilers and
Assembler ..............................
Using Compilers and Assemblers
With Fixed Disk ....................
Exceptions ..........................
Appendix C. Running the Pascal
Compiler ............ . . . . . . . . . . . . . . . . . . .
Using Pascal Hex Patch With Fixed
Disk. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix D. Considerations for Using
Applications ...........................
Accounting Packages by BPI
Systems, Inc. ...........................
Accounting Packages Version 1.00 by
Peachtree Software, Inc. .................
Accounting Packages Version 1.10 by
Peachtree Software, Inc. .................
Arithmetic Games 1 and 2 ................
Asynchronous Communications Support
Version 1.00 ............................
The Procedure .......................
Asynchronous Communications Support
Version 2.00 ............................
The Procedure ..................... ".
EasyWriter Version 1.10 ..................
Fact Track ..............................
Multiplan 1.00 ..........................
xiv

B-1
B-1
B-2
C-I
C-I
D-I
D-2
D-2
D-2
D-3
D-3
D-4
D-6
D-7
D-9
D-ll
D-12

'"

pfs:FILE ...............................
Using pfs:FILE with the IBM Fixed
Disk ..............................
Error Conditions .....................
Running the pfs:FILE Program from
a Fixed Disk .......................
Changing Settings When Using the
Fixed Disk .........................
, pfs:REPORT............................
Using pfs:REPORT with the IBM
Fixed Disk .........................
Error Conditions .....................
Running the pfs:REPORT Program from
a Fixed Disk .......................
Changing Settings When Using the
Fixed Disk .........................
The Dow Jones Reporter Version 1.00 .....
SNA 3270 Emulation and RJE Support
Version 1.00 ............................
The Procedure .......................
Typing Tutor ............................
VisiCalc by VisiCorp .....................
Putting DOS 2.10 on Your Program
Diskette ...........................
3101 Emulator Version 1.00 ..............
The Procedure .......................

D-13
D-13
D-15
D-16
D-16
D-17
D-17
D-20
D-21
D-21
D-21
D-22
D-22
D-23
D-24
D-24
D-25
D-26

Appendix E. DOS Version 2.00 and 2.10
Enhancements ........................... E-l
For All Users ......................... E-l
New Commands ...................... E-5
Enhanced Commands .................. E-9
For Programmers ...................... E-12
Appendix F. Some Keys You Use
with DOS ...............................

F-l

xv

xvi

Chapter 1. Using DOS

Contents
Introduction

1-3

Redirection of Standard Input
and Output Devices ......................

1-5

Piping of Standard Input and Output ........

1-8

DOS Filters .............................. 1-10
Invoking a Secondary Command
Processor ................................ 1-11
Types of DOS Commands .................. 1-13
Format Notation .......................... 1-15
DO S Command Parameters ................
Reserved Device Names ................
Global Filename Characters .............
The? Character ...................
The * Character ...................
Examples of Ways to
Use? and * ......................
Example 1 .......................
Example 2 .......................
Example 3 .......................

1-16
1-19
1-20
1-20
1-21
1-22
1-22
1-22
1-22

Information Common to All
DOS Commands ......................... 1-23
DOS Version 2.10 Features ................ 1-26
Automatic Program Execution .............. 1-27

1-1

1-2

Introduction

This chapter explains how to use the DOS commands.
Chapter 2 lists the commands in alphabetical order and
gives a detailed description of each command.
You can use DOS commands to:
•

Compare, copy, display, erase, rename files, and
format fixed disks and diskettes.

•

Execute system programs, such as EDLIN and
DEBUG, plus your own programs.

•

Set various printer and screen options.

•

Request DOS to pause.

•

Transfer DOS to another diskette.

•

Cause printer output to be directed to the
Asynchronous Communications Adapter.

•

Recover a specific file from a damaged disk, or
recover the entire disk or diskette.

•

Print the contents of a graphics display screen on a
printer.

•

Print files on the printer while the system is doing
other work.

•

Backup and restore files on a fixed disk.

•

Define a remote device as your primary console.

1-3

•
•

.,l

•
•
•
•

1-4

Sort text data.
Search files for occurrences of specified strings of
text.
Display a screen full of data at a time.
Set new system prompt.
Set the system environment.
Convert .EXE files to .COM files.

Redirection of Standard Input and
Output Devices

The DOS standard input and output device redirection
feature allows a program to receive its input from a
source other than the (standard input device), or direct
its output to a device other than the (standard output
device).
DOS provides internal functions that programs can use
to receive input and display or print output. These
devices are called standard input devices and standard
output devices.
When you first start DOS, the standard input device is
the IBM Personal Computer keyboard, and the
standard output device is the display unit (screen).
However, DOS 2.10 lets you specify input and output
devices other than the keyboard and the screen. Refer to
the CTTY command, described later on in this chapter,
to see how you can specify a remote terminal as the
standard input and output device instead of the
keyboard and screen.
DOS handles the mapping of the logical (standard input
and output) devices to the real devices in a way that is
transparent to the application program. The application
program does not need to be aware of the physical
device that is actually being used for the standard input
(STDIN) and standard output (STDOUT) device.

1-5

This means that you can run your application program
using the keyboard and screen for your input and output
device, and then run your application another time using
a remote terminal for your input and output device. You
do not have to change the application program, which
continues to talk to STDIN and STDOUT. DOS goes
to the correct physical device on behalf of the
application program.
The standard input and output devices can be redirected
to or from files or other devices by the following DOS
command line parameters:

> [d:] fpath ]filename
Causesfilename to be created (or truncated to
zero length) and then assigns standard output to
that file. All output that would normally have gone
to the screen from the command is placed in the
file.

>> [d:]fpath ]filename
Causesfilename to be opened (created if
necessary) and positions the write pointer at the
end of the file so that all output is appended to the
file.

<[d: ]fpath ]filename
Causes standard input to be assigned tofilename.
All input to the program comes from this file
instead of from the keyboard.

1-6

CAUTION
When using this method of providing input to a
program, be sure all of the program's input is in the
file. If the program attempts to obtain more input
after end-of-file is reached, DOS is unable to supply
the input, and processing will stop. You can return
to the DOS prompt by entering Ctrl-Break.
Note: If an application does not use DOS
function calls to perform standard input and/or
output (for example, you put text directly into the
video buffer), then redirection will not work for
that application.

Example:

In this example, the output of the DIR command is
sent to the printer:
DlR >PRN

In this example, the output of the DIR command is
sent to file DIRLIST:
DlR >OIRLlST

In the following example, program MYPROG will
receive its input from file INPUT. TXT, instead of
from the keyboard:
MYPROG FILE
If you wish the file to contain only the directory entries
for sub-directories, you could enter:
DIn: FIND G'DlR" :SORT>FILE

1-9

DOS Filters

A filter is a program or command that reads data from a
standard input device, modifies the data, then writes the
result to a standard output device. Thus, the data has
been "filtered" by the program. For example, one of the
filters on your DOS diskette is called SORT. SORT
reads input from the standard input device (normally the
keyboard), sorts the lines of data, then writes the sorted
results to the standard output device (normally the
screen). With the redirection capabilities described
earlier in this chapter, you can cause SORT to receive
its input from some other source, and to send its output
to a different destination. For example,
SORT RESULT

will cause SORT to read the file MYFILE, sort the
lines within it, and write the sorted output to file
RESULT.
By using the piping feature, you can cause a filter to
receive its input from the output of another command,
or to send its output to the input of another command.
F or example,
DlH: SORT

Causes the output listing from the DIR command to be
used by SORT as its input. The listing will be sorted
and the result displayed on the standard output device.

1-10

There are three filters on your DOS diskette, and they
are described as individual commands in Chapter 2.
They are:
SORT

Sorts text data.

FIND

Searches files for occurrences of specified
strings of text.

MORE Displays a screen full of data at a time, then
pauses with the message -More-.
You can easily add your own filter to the filters that
have been supplied; just write a program that reads its
input from the standard input device, and writes its
output to the standard output device.
Note: If an application does not use DOS
function calls to perform standard input
and/or output (for example you put text directly
into the video buffer), then filters will not work for
that application.

Invoking a Secondary Command
Processor
If you wish to invoke a secondary command processor,
the following syntax should be used:
COMMAND [d:](path] [/P] lIe string]

Where d.path will be the directory searched for the
command processor to be loaded, /P causes the new
copy to become permanent in memory, and / C string
allows you to pass a command line (string) as a
parameter. The command line will be interpreted and
acted upon as if you had entered it as a normal
command. For example: COMMAND
/C DIR B: causes a secondary command processor to
be loaded, and it executes the command DIR B:.
1-11

Issuing COMMAND without any parameters causes a
new copy of the command processor to be loaded, and
this new copy will inherit the environment known to the
previous level of the command processor. If you use the
SET command to change the environment known to the
secondary command processor, that change is known
only to the secondary copy. Exiting back to the primary
command processor causes a resumption of the
environment that the primary command processor knew
before the secondary copy existed. Here's an example.
Let's assume that the primary command processor used
the normal DOS prompt of A>. If you invoke a
secondary copy of the command processor, the
secondary copy "inherits" that prompt. If you change
the secondary's prompt to something else, and then you
exit back to the primary, the primary's prompt will still
be A>.
When a secondary command processor has been
loaded, you can cause it to return to the previous level
of command processor by issuing the special command
EXIT. If you use the /P parameter, it will not return
to the previous level.
Note: Application programmers. Please refer to
Chapter 7 of IBM DOS Technical Reference for
additional information.

1-12

Types of DO S Commands

There are two types of DO S commands:
•

Internal

•

External

Internal commands execute immediately because
they are built-in to DOS.
External commands reside on disk as program
files; therefore, they must be read from disk before
they execute. This means that the disk containing
the command must already be in a drive, or DOS
is unable to find the command. For example, if
you entered the command:
B:GRAPHICS

You must be sure that the diskette containing
GRAPHICS.COM is in drive B. If you entered:
GRAPHICS

Then DOS will look on the default drive (the one in
your system prompt) for the GRAPHICS command.

1-13

Any file with a filename extension of .COM or .EXE is
considered an external command. This allows you to
develop your own unique commands and add them to
the system. (For example, programs such as FORMAT
.COM and COMP.COM are external commands.)
When you select an external command, do not include
the filename extension.
For Application Developers: DOS Version 2.00 and
2.10 have provisions that allow you to cause execution
of DOS commands from within your application.
Note: Application developers may find IBM
DOS Technical Reference helpful. Please refer to
Chapter 7 for details.

1-14

Format Notation

We will use the following notation to indicate how the
DOS commands should be entered:
•

You must enter any words shown in capital letters.
These words are called keywords and must be
entered exactly as shown. You can; however, enter
keywords in any combination of uppercase and
lowercase letters. DOS automatically converts
keywords to uppercase.

•

You must supply any items shown in lowercase
italic letters. For example, you should enter the
name of your file whenfilename is shown in the
format.

•

Items in square brackets ([ ]) are optional. If you
want to include optional information, you do not
need to type the brackets, only the information
inside the brackets.

•

Items separated by a bar ( I) mean that you can
enter one of the separated items. For example:

ON IOFF
Means you can enter ON or OFF, but not both.
•

An ellipsis ( ... ) indicates that you can repeat an
item as many times as you want.

•

You must include all punctuation ( except square
brackets and vertical bars) such as commas, equal
signs, questions marks, colons, slashes, or
backslashes where shown.

1-15

DO S Command Parameters

Parameters are items that you can include in your DOS
command statements. They are used to specify
additional information to the system. Some parameters
are required in your commands, others are optional. If
you do not include some parameters, the system
provides a default value. Default values that the system
provides are discussed in the detailed descriptions of the
DOS commands.
Use the following parameters in your DOS command
statements:
Parameter

Definition

d:

Denotes when you should specify a drive.
Enter a drive letter followed by a colon to
specify the drive. For example, A: represents
the first drive on your system, B: represents
the second. If you omit this parameter, DOS
assumes the default drive.

1-16

Parameter
path

Definition
[\][dirname ][\dirname[ ... ]]

Denotes a path of directory names. Enter the
directory names, separated by backslash
characters. If a filename is also to be
appended, it should be separated from the last
directory name by a backslash. For example:
\DIR1\DlR2\FILEl

The first backslash is optional. If used, it tells
DOS to begin with the root directory. If
omitted, the directory path is assumed to
begin with the current directory. Global
filename characters are not allowed in path
specifications. The longest path allowed by
DOS (from root directory to the last level) is
63 characters.
filename

Diskette filenames are 1-8 characters in
length, and can be followed by a filename
extension.
The following characters can be used for
filenames:
A-Z 0-9 $ & # @ !
%"()-

{ }

-/\

Any other characters are invalid. An invalid
character is assumed to be a delimiter, in
which case the filename is truncated.
Refer also to "Reserved Device Names" in
this chapter for more information about
filenames.

1-17

Parameter

Definition

. ext

The optional filename extension consists of a
period and 1-3 characters. When used,
filename extensions immediately follow
filenames.
The following characters can be used for
filename extensions:
A-Z 0-9 $ & # @ !
%"()-

{}

-/\

Any other characters are invalid.
Remember to include the extension when you
refer to a file that has a filename extension;
otherwise, DOS will be unable to locate the
file.

filespec

[d: lfilename[ .ext]
Examples:
B:myprog.COB
A:yourprog
DATAFILE.pas
cobfile

1-18

Reserved Device Names
Certain names have special meaning to DOS. DOS
reserves the following names as system devices:

Reserved N arne

Device

CON

Console keyboard/screen. If used as an
input device, you can press the F6 key;
then press the Enter key to generate an
end-of-file indication, which ends CON as
an input device.

AUX
or
COMI

First Asynchronous Communications
Adapter port.

COM2

Second Asynchronous Communications
Adapter port.

LPTI
or
PRN

First Parallel Printer (as an output device
only).

LPT2
or
LPT3

Second Parallel Printer

NUL

Third Parallel Printer
Nonexistent (dummy) device for testing
applications. As an input device,
immediate end-of-file is generated. As an
output device, the write operations are
simulated, but no data is actually written.

1-19

Notes:
1.

Since these are reserved names, you cannot
create files with these names.

2.

When using a device name, you should
assure that the device actually exists; using
the name of a nonexistent device can cause
unpredictable errors in DOS operation.

3.

The reserved device names can be used in
place of a filename.

4.

Any drive specifier or filename extension
entered with these device names will be
ignored.

Global Filename Characters
Two special characters ? and * can be used within a
filename and its extension. These special characters
give you greater flexibility with the DOS commands.

The? Character
A ? in a filename or in a filename extension indicates
that any character can occupy that position. For
example,
OUt AB?DE.XYZ

lists all directory entries on the default drive with
filenames that have five characters, begin with AB, have
any next character, are followed by DE, and have an
extension of XYZ.

1-20

Here are some examples of the files that might be listed
by the DIR command:
ABCDE XVl
ABIDE XVl
ABODE XVl

The * Character
An * in a filename or in a filename extension indicates
that any character can occupy that position and all the
remaining positions in the filename or extension. For
example,
DlR AB*.XYZ

lists all directory entries on the default drive with
filenames that begin with AB and have an extension of
XYZ. In this case, the filenames may be from 2-8
characters in length.
Here are some example files that might be listed by the
DIR command:
ABCDE
ABC357
ABIDE
ABIIOU
ABO$$$

AB

XVl
XVl
XVl
XVl
XVl
XVl

1-21

j

Examples of Ways to Use? and

*

Example 1
To list the directory entries for all files named INPUT
on drive A (regardless of their filename extension),
enter:
DlR A:INPUT.???

or
DIR A:INPUT.*

Example 2
To list the directory entries for all files on drive A
(regardless of their filenames) with a filename extension
of XYZ, enter:
DIR A:????????XYZ

or
DlR A:*.XYZ

Example 3
To list the directory entries for all files on drive A with
filenames beginning with ABC and extensions beginning
with E, enter:
DIR A:ABC?????E??

or
DlR A:ABC*.E*

1-22

Information Common to all DOS
Commands

This section gives a description of how to use the
commands presented in Chapter 2. The commands
appear in Chapter 2 in alphabetical order; each with its
purpose, format, and type. Examples are provided
where appropriate.
The following information applies to all DOS
commands:
•

The normal prompt from the command processor
is the default drive letter plus > , such as A>
unless changed by the PROMPT command.

•

When a command completes, the system prompt
will reappear on the screen. If no error messages
are displayed before the system prompt reappears,
the command has been successfully completed.

•

Commands are usually followed by one or more
parameters.

•

Commands and parameters may be entered in
uppercase or lowercase, or a combination of both.

•

DOS will search the current directory of the
specified or default drive to find a command or
batch file whose name you have entered. If not
found, DOS will continue its search in each of the
directories listed in the PATH command.

1-23

v

•

Most commands allowing you to enter filenames
will also accept a path (directory) name ahead of
the filename. If you do not plan to create
directories of your own, you may disregard all
references to path names. This will greatly simplify
the command syntax for you.

•

Commands and parameters must be separated by
delimiters (space, comma, semicolon, equal sign,
or the tab key). The delimiters can be different
within one command. For example, you could
enter:
COPY oldfile.rel;newfile.rel
RENAME,th~sfile thaUUe

1-24

•

The three parts of filespec (d:filename.ext) must
not be separated by delimiters. The colon (:) and
period (.) already serve as delimiters.

•

In this book, we usually use a space as the
delimiter in the commands for readability.

•

Also in this book, when we say "Press any key",
we mean "Press any character key."

•

Files are not required to have filename extensions
when you create or rename them; however, you
must include the filename extension when referring
to a file that has a filename extension.

•

You can end commands while they are running by
pressing Ctrl-Break. Ctrl-Break is recognized only
while the system is reading from the keyboard or
printing characters on the screen, unless you have
used BREAK=ON in your configuration file or
have issued a BREAK=ON command. Thus, the
command may not end immediately when you
press Ctrl-Break.

•

Commands become effective only after you press
the Enter key.

•

Global filename characters and device names are
not allowed in a command name. You may only
use them in command parameters.

•

F or commands displaying a large amount of
output, you can press Ctrl-Num Lock to suspend
the display of the output. You can then press any
character key to continue the display.

•

You can use the control keys and the DOS editing
keys described in DOS User's Guide while
entering DOS commands.

•

Drives will be referred to as source drives and
target drives. A source drive is the drive you will
be transferring informationJrom. A target drive is
the drive you will be transferring information to.

•

When an external command is entered, DOS first
looks for it in the current directory of the default or
specified drive. If not found, DOS continues
searching for it in the directories listed in the most
recent PATH command.

•

If the characters <, >, or : appear anywhere in
the command line you enter, DOS will act upon
them as described in "Redirection of Standard
Input and Output" and "Piping of Standard Input
and Output Device" described in this chapter.

Thus, the command:
REM this is

ill

I test

would pipe the output of the REM command (none) to
a program named "test". If the program "test" does not
exist, this message appears:
Bad command or filename

1·25

DOS Version 2.10 Features

DOS Versions 2.00 and 2.10 contain several features
for more efficient programming. These features include
automatic program execution, using batch files, and
enhancements from prior versions of DOS. For more
information on DOS enhancements refer to
Appendix E. DOS Versions 2.00 and 2.10 contain the
same functions.
By using automatic program execution you may start a
specific program every time you start DOS. The
concept of automatic program execution is explained on
the following page.
A batch file is a file containing one or more commands
that DOS executes one at a time. Batch files allow you
to set up a group of commands or procedures that
automatically go into effect when the batch file is
executed. For more information on batch files refer to
"Batch Commands" in Chapter 2.
We recommend that you take the time to review the
information in Appendix E, whether you are an
experienced DOS user or are about to use DOS for the
first time.

1-26

Automatic Program Execution

You may want to start a specific program every time
you start DOS. You can do this with the DOS
command processor by using automatic program
execution.
Every time you start up DOS, the command processor
searches for a file named AUTOEXEC.BAT in the
root directory on the disk that DOS was started from.
This filename is special because it refers to a batch file
that is automatically executed whenever you start the
system. With this facility, you can execute programs or
commands immediately every time you start DOS.
If the system finds the AUTOEXEC.BAT file, the file
is immediately executed by the command processor.
The date and time prompts are bypassed.
If DOS does not find the AUTOEXEC.BAT file, DOS
issues the date and time prompts. Refer to "Batch
Commands" in Chapter 2 for details on how to create
an AUTOEXEC.BAT file.

1-27

Chapter 2. DO S Commands

Contents
Introduction

2-5

ASSIGN (Drive) Command ..............

2-6

BACKUP (Fixed Disk) Command .........

2-9

Batch Commands ........................
TheAUTOEXEC.BATFile ...........
Creating a .BA T File with
Replaceable Parameters ..............
Executing a .BAT File with
Replaceable Parameters ..............
ECHO Subcommand ..................
FOR Subcommand ...................
GOTO Subcommand .................
IF Subcommand ......................
PAUSE Subcommand.................
REM (Remark) Subcommand ..........
SHIFT Subcommand .................

2-13
2-15

2-19
2-20
2-22
2-23
2-24
2-28
2-29
2-30

BREAK (Control Break) Command .......

2-33

CHDIR (Change Directory) Command ....

2-35

CHKDSK (Check Disk) Command ........

2-38

CLS (Clear Screen) Command ............

2-42

CaMP (Compare Files) Command ........

2-44

COpy Command ........................

2-48

CITY Command ( Change Console)

2-61

.......

2-1 7

2-1

,j

DATE Command ........................

2-63

DEL Command ..........................

2-65

DIR (Directory) Command ...............

2-66

DISKCOMP (Compare Diskette)
Command ..............................

2-73

DISKCOPY (Copy Diskette)
Command ..............................

2-77

ERASE Command .......................

2-81

EXE2BIN Command ....................

2-83

FDISK Command .......................

2-86

FIND Filter Command ...................

2-87

FORMAT Command .....................

2-89

GRAPHICS (Screen Print) Command .....

2-96

MKDIR (Make Directory) Command ......

2-98

MODE Command ....................... 2-100
MORE Filter Command .................. 2-107
PATH (Set Search Directory)
Command .............................. 2-108
PRINT Command ....................... 2-110
PROMPT (Set System Prompt)
Command .............................. 2-116
RECOVER Command .................... 2-119

2-2

RENAME (or REN) Command ........... 2-122
RESTORE (Fixed Disk) Command

2-124

RMDIR (Remove Directory)
Command .............................. 2-127
SET (Set Environment) Command ......... 2-128
SORT Filter Command ................... 2-131
SYS (System) Command ................. 2-133
TIME Command ......................... 2-134
TREE (Display Directory) Command ...... 2-136
TYPE Command ......................... 2-139
VER (Version) Command ................. 2-141
VERIFY Command ...................... 2-142
VOL (Volume) Command ................. 2-144
Summary of DOS Commands ............. 2-145

2-3

2-4

Introduction

This chapter presents a detailed description of the
DOS commands. The commands appear in
alphabetical order. The description includes the
purpose, format, and type of each command.
Examples are provided where appropriate.
Note: If you have not yet done so, we suggest
you read "Chapter 1. Using DOS" before
continuing.

2-5

ASSIGN (DRIVE)
Command

Purpose:

Instructs DOS to use a different drive from the one
that was specified for disk operations.

Format:

ASSIGN [x y [ ... ]]

Type:

Internal External

***
Remarks:

Use this command to tell DOS to route all requests
for a disk drive to a different drive.
The first drive letter x is internally converted by
DOS to the second drive letter y. This command
does not require you to enter a colon after the drive
letter. Entering ASSIGN with no parameters causes
all drive reassignments to be reset so that normal
drive assignments will resume.

Example:

This example causes DOS to route all requests for
drive A to drive C. Thus, if you issue DIR A: DOS
will display the directory that is on physical drive C:
ASSIGN A=C

2-6

ASSIGN (DRIVE)
Command

In this example, any requests for drive A or drive B
are routed by DOS to drive C:
ASSIGN A=C B=C

The command:
ASSIGN

will undo the reassignment so that requests for drive
A will again go to physical drive A, etc.
Note: This command has been included to
assist you with applications that were designed
to perform their disk operations specifically on
drives A and B (those applications that do not
allow you to specify a drive). By using a
command such as:
ASSIGN A=C B=C

Those applications can be made to use drives
other than A and B, such as a fixed disk.

2-7

ASSIGN (DRIVE)
Command

Reassignment of drives should only be used
when necessary for these cases. It should never
be used with the PRINT command or when
running DOS in normal operations, because it
can hide the true device type from commands
and programs that require actual drive
information. Also note that DISKCOPY and
DISKCOMP will ignore any drive
reassignments.
If you will be developing an application program we
recommend that you avoid using specific drive
assignments within your program. Instead, allow the
user to specify the drive( s) to be used.

2.. 8

BACKUP (Fixed Disk)
Command

Purpose:

Backs up one or more files from a fixed disk to
diskettes.

Format:

BACKUP d:fpath ] [filena me[ .ext]]
d:[!S][/M][/ A ][/D:mm-dd-yy]

Type:

Internal

External

***
Remarks:

Use DOS formatted diskettes only. The first
parameter you specify is the fixed disk file you want
to back up. The second parameter is the backup
diskette drive. Files are backed up from the current
directory if you do not specify a path. If you do not
specify a filename or extension, then all files in the
directory will be backed up.
Global filename characters are allowed in the
filename. They cause all files matching the filename
to be backed up onto diskettes. For example,
entering:
BACKUP C:*.DAT A:

Causes each file from the current directory of fixed
disk drive C that has an extension of .DAT to be
backed up onto the diskette in drive A.

2·9

BACKUP (Fixed Disk)
Command

The parameter /S causes the files in all
sub-directories to be backed up in addition to the files
in the specified directory itself. This includes subdirectories at all levels beyond the specified
directory.
The parameter /M indicates that only files that have
been modified since the last backup should be backed
up. Use this parameter to avoid backing up files that
never change. The BACKUP command can tell
which files have been changed because of an
indicator in each file's directory entry that is set by
DOS whenever the file is written to.
The parameter / A indicates that backed up files
should be added to the files on the backup diskette
already in the specified drive. If this parameter is
omitted, then you will be warned that all previously
existing files on the diskette will be erased.
The parameter /D can be used to back up files
written only on or after the specified date. See the
description of the DATE command for valid date
formats.
The following example backs up all of the files on
fixed disk drive C:
BACKUP C:\ A: /S

2-10

BACKUP (Fixed Disk)
Command

The next example backs up three different files from
the default fixed disk drive onto the same set of
backup diskettes:
BACKUP \level1\filel.dat A:
BACKUP \level1\leveI2\file2.dat A: IA
BACKUP \level1\leveI3\file3.dat A: IA

The next example backs up all files in the current
directory that have changed since the last backup:
BACKUP *.* A: 1M

After you enter the BACKUP command, you will be
prompted to insert a diskette (unless you specified the
fA parameter). Use DOS formatted diskettes only.
BACKUP will erase existing files on the diskette
before it starts backing up the fixed disk file, unless
you have used the fA parameter. After BACKUP
fills up a diskette, it will prompt you to insert a new
diskette. You should label each diskette and record
the date and diskette number.
BACKUP displays the name of each file as it backs
it up. If you want a printed copy of this list, you can
use redirection of output to the printer. Refer to
"Redirection of Standard Input and Output Devices"
in Chapter 1 for additional information.

2-11

BACKUP (Fixed Disk)
Command

The BACKUP command sets the exit code as
follows:

o

Normal completion

1

No files were found to backup

3

Terminated by user (Ctrl-Break)

4

Terminated due to error

These codes can be used with the batch processing
IF subcommand.
Note: The files on the backup diskettes are
unusable in normal processing, and should only
be used by the RESTORE command.

2-12

Batch
Commands

Purpose:

Executes the commands contained in the specified
file from the current directory of the designated or
default drive. If the batch file is not found in the
current directory, DOS searches for it in the
directories listed in the PATH command.

Format:

[d: ]filename [parameters]

Type:

Internal

External

***
Remarks:

A batch file is a file containing one or more
commands that DOS executes one at a time. All
batch files must have a filename extension of .BAT.
You can pass parameters to the filename .BAT file
when the file executes. Therefore, the file can do
similar work with different data during each
execution.
You create a batch file by using the Line Editor
(EDLIN), or by using the COPY command directly
from the standard input device.
Notes:
1.

Do not enter the name BATCH (unless the
name of the file you want to execute is
BATCH.BAT).

2-13

Batch
Commands

2.

Only the filename must be entered to run
the batch file. Do not enter an extension.

3.

The commands in the file named
filename .BA T are executed.

4.

There are seven subcommands that can be
used to control batch processing: ECHO,
FOR, GOTO, IF, SHIFT, PAUSE, and
REM. They are explained in the following
pages.

5.

If you press Ctrl-Break while in batch
mode, this prompt appears:
Terminate batch job (Y/N)?

If you press Y, the remainder of the
commands in the batch file are ignored and
the system prompt appears.
If you press N, only the current command
ends and batch processing continues with
the next command in the file.
6.

2-14

If you remove a diskette containing a batch
file being processed, DOS prompts you to
insert it again before the next command
can be read.

Batch
Commands

7.

The last command in a batch file may be
the name of another batch file. This allows
you to invoke one batch file from another
when the first is finished.

8.

DOS will remember which directory your
batch file was started from. Therefore, the
commands within the batch file may
change the current directory at will, and
the batch file will continue executing.

The AUTOEXEC.BAT File
The AUTOEXEC.BAT file is a special batch file.
When you start or restart DOS, the command processor
searches for the AUTOEXEC.BAT file. If this file is
present in the root directory of the drive DOS was
started from, DOS automatically executes the file
whenever you start DOS.
For example, if you want to automatically load BASIC
and run a program called MENU, create an
AUTOEXEC.BAT file as follows:
1.

Enter:
COPY CON: AUTOEXEC.BAT

This statement tells DOS to copy the information
from the standard input device into the
AUTOEXEC.BAT file on the default drive.

2-15

Batch
Commands

2.

Now, enter:
BASIC MENU

and press Enter.
This statement goes into the AUTOEXEC.BAT
file. It tells DOS to load BASIC and to run the
MENU program whenever DOS is started.
3.

Press the F6 key, then press the Enter key to end
copying from the standard input device to the file.
The MENU program will now run automatically
whenever you start DOS.

To run your own BASIC program, enter the name of
your program in place of MENU in the second line of
the example. Remember, you can enter any DOS
command, or series of commands, in the
AUTOEXEC.BAT file.
Note: If you use AUTOEXEC.BAT, DOS does
not prompt you for the current date and time
unless you include DATE and TIME commands
in the A UTOEXEC.BA T file.

2-16

Batch
Commands

Creating a .BAT File With Replaceable
Parameters
Within a batch file you may include dummy parameters
that can be replaced by values supplied when the batch
file executes.
F or example, enter:
A>CoPV con: ASMFILE.BAT
Copy % 1.MAC 0/o2.MAC
Type 0/02.PRN
Type %O.BAT

Press Enter after entering each line.
Now, press F6; then press Enter.
The system responds with this message:
1 File(s) copied
A>_

The file ASMFILE.BAT, which consists of three
commands, now resides on the diskette in the default
drive.

2-17

Batch
Commands

The dummy parameters %0, %1, and %2 are replaced
sequentially by the parameters you supply when you
execute the file. The dummy parameter %0 is always
replaced by the drive designator, if specified, and the
filename of the batch file.
Notes:

2-18

1.

Up to 10 dummy parameters (%0 - %9) can
be specified within a batch file, more than 10
parameters can be specified on a command
line (see SHIFT subcommand).

2.

If you want to use % as part of a filename
within a batch file, you must specify it twice.
For example, to specify the file ABC%.EXE
you must enter it as ABC%%.EXE in the
batch file.

Batch
Commands

Executing a .BAT File With Replaceable
Parameters
To execute the ASMFILE.BA T file and pass
parameters, enter the batch filename followed by the
parameters you want sequentially substituted for % 1,
%2, etc.
F or example, you can enter:
ASMFILE A:PROGl B:PROG2

ASMFILE is substituted for %0, A:PROG 1 for % 1,
and B:PROG2 for %2.

The result is the same as if you entered each of the
three commands (in the ASMFILE.BAT file) from the
console with their parameters, as follows:
Copy A:PROG1.MAC B:PROG2.MAC
Type B:PROG2.PRN
Type ASMFILE.BAT

Remember that the dummy parameter %0 is always
replaced by the drive designator, if specified, and the
filename of the batch file.

2-19

Batch
Commands

ECHO Subcommand
Purpose:

The ECHO batch processing subcommand allows or
inhibits the screen display of DOS commands
executed from a batch file. It does not interfere with
messages produced while the commands are
executing.

Format:

ECHO [ONIOFFlmessage]

Type:

Internal

External

***
Remarks:

Batch commands are normally displayed on the
screen as they are read from the batch file. ECHO is
ON after power-on or system reset. ECHO ON
displays all the commands on the standard output
device as they are executed. ECHO OFF stops the
display of commands on the screen (including the
REM command).
Echo message displays message on the standard
output device regardless of the current ON or OFF
state. In this way, you can cause specific messages to
be displayed even when ECHO has been turned off.
If ECHO is issued with no parameters, the current
ECHO state (ON or OFF) is displayed.

2-20

Batch
Commands

Example:

In this example, the batch file contains the following:
echo off
rem *U command display is off

dir a:/w
echo on
dir a:/w

Upon execution of the above batch file, the following
display will occur:
echo off
Volume on drive A has no
Directory of A\

II)

filenamel.ext filename2.ext
2 file(s)

xxx xx bytes free

dir a:/w
Volume in drive A has no 10
Directory of A: \

filenamel.ext filename2.ext
2 fUels)

xxxxx bytes free

In the above example, the ECHO OFF is displayed.
The rem command and dir a:/w are not displayed
because ECHO is OFF, but the output of the dir is
not inhibited.

2-21

Batch
Commands

FOR Subcommand
Purpose:

The FOR batch processing subcommand allows
iterative execution of DOS commands.

Format:

FOR %%variable IN (set) DO command

Type:

Internal

External

***
Remarks:

The % % variable is sequentially set to each member
of set and then the command is evaluated and
executed. If a member of set is an expression
involving * and/or?, then the %%variable is set to
each matching filename from disk.

Example:

In this example, if you enter the command:
FOR %%1 IN (progl.asm prog2.asm prog3.asm) DO dir
1

0/0 0/0

The result is
dir prog1.asm
dir prog2.asm
dir prog3.asm

Note: FOR subcommands cannot be nested;
that is, only one FOR subcommand can be
specified on a command line. Also, path names
are not accepted with filenames.
2-22

Batch
Commands

GOTO Subcommand
Purpose:

The GOTO batch processing subcommand transfers
control to the line following the one containing the
appropriate label. A label is inserted in a batch file as
a colon (:) followed by the label name.

Format:

GOTO label

Type:

Internal

External

***
Remarks:

The GOTO label causes commands to be executed
beginning with the line immediately after :label. If
:label is not defined, the current batch file terminates
with the message Label not found. A label in a
batch file is defined as a character string where the
first 8 characters are significant (make it different).

Example:

In this example, the following batch file produces an
indefinite sequence of rem looping ... and GOTO
LOO P messages on the screen:
:LOOP

rem looping ...
GOIO LOOP

Note that labels within a batch file are never
displayed while the batch file is executing. In the
example above, the line :LOOP would not be
displayed. Thus, unreferenced labels provide a handy
means for placing comments within your batch file
that are not displayed when the file is executed.
2-23

Batch
Commands

IF Subcommand
Purpose:

The IF batch processing subcommand allows
conditional execution of DOS commands.

Format:

IF [NOT] condition command

Type:

Internal

External

***
Remarks:

The condition parameter is one of the following:
ERRORLEVEL number
string! ==string2
EXIST filespec
When the IF parameter's condition is true, then the
DOS command is executed. Otherwise, the DOS
command is skipped, and the following command in
the file is executed.
ERRORLEVEL number is true if the previous
program had an exit code of number or higher. The
number is specified as a decimal value.

2-24

Batch
Commands

Stringl ==string2 is true when string 1 and string2
are identical.
Note: The corresponding characters of String 1
and String2 must both be uppercase or
lowercase to be identical.
EXIST filespec is true iffilespec is found on the
specified drive. Path names are not allowed with the
filespec.
NOT condition is true if the condition is false.

Example:

This example is for the IF EXIST filespec
command:
if exist filel goto abc

:abc
command

Execution of a batch file containing this command
would make the condition true providedfilel is found
on the default drive. The goto abc would be executed
causing the system to skip to the command following
the label :abc. Ifjilel is not found, the goto abc
would not be executed. Processing would then
continue with the next command in the batch file.

2-25

Batch
Commands

The following example is for the IF
stringl ==string2 command:
if

%

1 == Doug echo Doug was here!

Execution of a batch file containing this command
with Doug given as the % 1 parameter would make
the condition true. The ECHO batch command
would then be executed displaying Doug was here!.
If Doug was not given as the %1 parameter, the
condition would have been false. The ECHO batch
command would not have been executed. Processing
would continue with the next command in the batch
file.
The following example is for the IF ERRORLEVEL
number command:
myprogl
if errorlevel 1 echo myprogl failed - end batch file execution

The above two commands are in a batch file;
MYPROG 1 is a program that sets the errorlevel
when it completes its processing. In the simple case,
MYPROG 1 sets the errorlevel to 0 if it completed
processing successfully and sets errorlevel to 1 if
processing completed unsuccessfully. The batch file
conditional if errorlevel 1 echo ... tests for the
situation when MYPROG 1 failed. If MYPROG 1
completed processing unsuccessfully, the condition is
true and the ECHO batch command is executed. The

2-26

Batch
Commands

ECHO batch command displays the data (or
message) immediately following echo. If MYPROG 1
was successful, the condition would not be true and
the ECHO batch command would not be executed.
Processing would then continue with the next
command in the batch file.
The following example is for the IF NOT EXIST
filespec command:
if not exist a: % 1 copy b:% 1 a:
program

The above IF batch command demonstrates the
NOT condition. The batch file that this command is
in, is going to execute a program that requires a
particular file to be on drive A. The IF command is
executed prior to the program to make sure that the
required file is not on drive A. If the file does not
exist on drive A, the condition is true. The copy will
then be executed, copying the file from drive B to
drive A to satisfy the requirements of the program. If
the file does exist on drive A, the copy will not be
executed. Processing will then continue to execute
the batch file.
Note: At the present time, only BACKUP
and RESTORE commands set an
ERRORLEVEL that can be tested. The facility
is included to allow your own programs to set an
error code that can then be interrogated by the
IF ERRORLEVEL subcommand.

2-27

Batch
Commands

PAUSE Subcommand
Purpose:

Suspends system processing and displays the
message Strike a key when ready....

Format:

PAUSE [remark]

Type:

Internal

External

***
Remarks:

You can insert PAUSE commands within a batch file
to display messages and to give you the opportunity
to change diskettes between commands. To resume
execution of the batch file, press any key except CtrlBreak. (Ctrl-Break ends processing.)
If you include the optional remark, the remark is also
displayed. The optional remark can be any string of
characters up to 121 bytes long.

You can control how much of a batch file you want
to execute by placing PAUSE commands at strategic
points in the file. At each PAUSE command, the
system stops and gives you time to decide whether to
end processing. To end processing, press Ctrl-Break.
To continue processing, press any other key.
Example:

If you enter this PAUSE command in a batch file,
the following message is displayed:
A>PAUSE Change diskette in drive A
Strike a key when ready ... _

This PAUSE enables you to change diskettes
between commands.

2-28

Batch
Commands

REM (Remark) Subcommand
Purpose:

Displays remarks from within a batch file.

Format:

REM [remark]

Type:

Internal

External

***
Remarks:

The remarks are displayed when the batch execution
reaches the remark.
Remarks can be any string of characters up to 123
bytes long.
You can use REM commands without remarks for
spacing within your batch file, for readability.

Example:

If the following REM command is issued in a batch
file, this remark is displayed:
REM This is the daily checkout program

Note: See "Information Common to All DOS
Commands" in this Chapter 1 for
considerations in using the REM command.

2-29

Batch
Commands

SHIFT Subcommand
Purpose:

The SHIFT batch processing subcommand allows
command lines to make use of more than 10 (%0
through %9) replaceable parameters.

Format:

SHIFT

Type:

Internal

External

***
Remarks:

Replaceable parameters are numbered %0 through
%9. If you wish to use more than 10 parameters on a
command line, you can use SHIFT to get at
parameters past the tenth. All parameters on the
command line are shifted one position to the left,
with the %0 parameter being replaced by the % 1
parameter, etc. Each subsequent shift command
causes all the parameters to be shifted to the left by
one position. For example:
0/00 =:
0/01 =0/02 =
0/03 =

0/09

2-30

A
B
C
0

Batch
Commands

The SHIFT results are:
0/00 = B
0/01 = C
0/02 = 0

0/09

Example:

This example demonstrates how the SHIFT
subcommand can be used in a batch file. If a batch
file named MYFILE.BAT contains the following
commands, and the default drive is A:
echo
shift
echo
shift
echo
shift
echo
shift
echo

0/00

%

1 0/02 0/03

0/00

%

1 0/02 0/03

0/00

%

1 0/02 0/03

0/00

%

1 0/02 0/03

0/00

%

1 0/02 0/03

Invoke the batch file with the following parameters:
MYFILE PROGl

PROG2

PROG3

2-31

Batch
Commands

Produces the following results:
A>echo MYFILE PROGl
MYFI LE PROG 1 PROG2

PROG2
PROG3

A>shift
A>echo PROGl PROG2
PROGl PROG2 PROG3
A>shift
A>echo PROG2
PROG2 PROG3
A>shift
A>echo PROG3
PROG3
A>shift
A>echo
A>

2-32

PROG3

PROG3

PROG3

BREAK (Control Break)
Command

Purpose:

Allows you to instruct DOS to check for a control
break whenever a program requests DOS to perform
any functions (such as disk operations).

Format:

BREAK [ON I OFF]

Type:

Internal

External

***
Remarks:

Use this command to specify when DOS should
check for a Ctrl-Break being entered at the keyboard.
Normally, DOS only performs this check during
standard input, standard output, standard print
device, or auxiliary device operations.
Ctrl-Break allows you to breakout of a program that
performs few or no standard device operations (such
as a compiler).
The ON parameter causes DOS to begin checking
for Ctrl-Break whenever a program requests any
DOS function. Specifying OFF causes DOS to
check only during standard input, standard output,
standard print device, or Asynchronous
Communications Adapter operations.

2-33

BREAK (Control Break)
Command

You can also turn on the extended checking by using
BREAK=ON in your configuration file. Refer to
"Configuring Your System" in Chapter 4.
Entering BREAK with no parameter causes DOS to
display the current state (on or oft) of Ctrl-Break
checking.

2-34

CHDIR (Change Directory)
Command

Purpose:

Change the DOS current directory of the specified or
default drive, or to display the current directory path
of a drive.

Format:

CHDIR [[d: ]path]
or
CD [[d:]path]

Type:

Internal

External

***
Remarks:

The current directory is where DOS looks to find
files whose names were entered without specifying
which directory they were in. If you do not specify a
drive, the default drive is assumed. If you enter
CHDIR or CD with no parameters or with only ad:
parameter, the current directory path of the specified
or default drive is displayed.

Example:

In this example, the command will change the current
directory of the default drive to its root directory:
CHOIR \

2·35

CHDIR (Change Directory)
Command

In this example, the command will change drive B's
current directory to the path
"root-> LEVELl-> LEVEL2":
GD 8:\lEVEU\lEVH.2

In this example, the command will change drive B's
directory to the current directory path plus LEVEL3:
GO is: LHH:l3

Thus, if the second example had been used, the
resultant path would be:
root

>lEVEU --_. >lEVE12-

. >LEVEl3

The search for the LEVEL3 directory begins in the
directory that was current when the command was
issued, because no leading backslash (\) was used.
If the command is entered as:
GO B:\ LEVELJ

then DOS looks for the path:

root ··>lEVElJ
because the leading backslash (\) tells DOS to start
at the root directory.

2-36

CHDIR (Change Directory)
Command

DOS remembers the current directory for each drive
on the system and, if you don't specify a path, any
reference to a drive will access the current directory.
Example:

8>CD \LEVEl1\LEVEL2
8>CO A:\LEVEl1
B>COPY 8:JACK.COM A:

The file JACK.COM is copied from the
LEVELl\LEVEL2 directory on drive B to the
\LEVELI directory on drive A.

2-37

CHKDSK (Check Disk)
Command

Purpose:

Analyzes the directories and the File Allocation
Table on the designated or default drive and produces
a disk and memory status report.

Format:

CHKDSK [d: ] [filename [ .ext]][/F][/V]

Type:

Internal

External

***
Remarks:

If you specify a filename, CHKDSK will display the
number of non-contiguous areas occupied by the file
or files. Note that CHKDSK only looks in the
current directory for these files.
CHKDSK will not automatically correct errors
found in the directory or file allocation table. If you
want it to make the corrections, use the IF (fix)
parameter. If you do not specify the IF parameter,
CHKDSK continues to function as though it were
preparing to correct the disk so that you can analyze
the possible results of correction, but does not
actually write the corrections on the disk.
If you use the IV parameter, CHKDSK will display
a series of messages indicating its progress, and
provide more detailed information about the errors it
finds.

2-38

CHKDSK (Check Disk)
Command

After checking the disk, CHKDSK displays any
error messages, followed by a status report. A
complete listing of error messages can be found in
Appendix A.
Following is an example of the status report that is
displayed:
Volume MYDISK
179712
18944
512
26112
134144

Created AUG 12, 1983 10:00

bytes total disk space
bytes in 3 hidden files
bytes in 1 directories
bytes in 4 user files
bytes available on disk

196608 bytes total memory
170736 bytes free

Note that in this status report, three hidden files were
reported. These are the volume label, and the DOS
system files IBMBIO.COM and IBMDOS.COM,
that are hidden from the normal directory searches.
Some application programs also create hidden files.
CHKDSK does not wait for you to insert a diskette.
It assumes that the diskette to be checked is in the
specified drive. Therefore, on a single diskette-drive
system, it is especially important that the specified
drive is different from the default drive, unless you
are checking the DOS diskette itself.

2-39

CHKDSK (Check Disk)
Command

You should run CHKDSK occasionally for each
fixed disk and diskette to ensure the integrity of the
file structures.
Notes:
1.

All yes or no (YIN) prompts from
CHKDSK require you to press Enter after
entering Y or N, to prevent accidental
changes to your disk.

2.

If you specified a filename, the number of
non-contiguous areas occupied by the file
will be reported. Badly fragmented files
(many non-contiguous areas) can cause
system performance to slow down when
those files are accessed, since DOS can
not read them sequentially . You can
determine the extent of file fragmentation
by using *. * in the filename field of the
CHKDSK command.

3.

If CHKDSK finds lost allocation units
(clusters) on the disk, it asks if you wish to
recover the lost data into files. If you say
yes, and the IF parameter was used,
CHKDSK recovers each chain of lost
allocation units into a file whose name is in
the form:
FILEnnnn,CHK

2-40

CHKDSK (Check Disk)
Command

Where nnnn is a sequential number
starting with 0000. These files are created
in the root directory of the specified drive.
You can then look at these files to see if
they have any useful information. If not,
you can erase them.
4.

If you redirect CHKDSK's output to a file,
for example:
CHKDSK B:>FILE

it will report errors on that file. In this
case, be sure not to use the IF parameter.

2-41

CLS (Clear Screen)
Command

Purpose:

Clears the display screen.

Format:

CLS

Type:

Internal

External

***
Remarks:

2-42

This command clears the display on the standard
output device upon execution. If foreground and
background colors have been selected through the
"Extended Screen Control and Keyboard" functions
described in Chapter 2 of the Technical Reference
manual, the colors will remain unchanged.
Otherwise, the standard output device is set to white
characters on a black background.

COMP (Compare Files)
Command

Purpose:

Compares the contents of the first set of specified
files to the contents of the second set of specified
files. Usually, you would run COMP after a COpy
operation to ensure that the two sets of files are
identical.
Note: This command compares two sets of
files; the DISKCOMP command compares two
entire diskettes.

Format:

COMP [d: ][path ][filename [.ext]]
[d: ][path ][filename[ .ext]]

Type:

Internal

External

***
Remarks:

The first parameter you specify is the primary file.
The second parameter is the secondary file. The files
that you compare may be on the same drive or on
different drives. They can also be in the same
directory or different directories.

2-43

COMP (Compare Files)
Command

Global filename characters are allowed in both
filenames, and will cause all of the files matching the
first filename to be compared with the corresponding
files from the second filename. Thus, entering:
COMP A:*.ASM B:*.BAK

causes each file that has an extension of .ASM from
drive A to be compared with a file of the same name
(but with an extension of .BAK) from drive B.
If no parameters are entered with the CO MP
command, or if the second parameter is missing, you
are prompted for them. If either parameter only
contains a drive or a path with no filename, COMP
assumes a filename of *. *. You can enter a complete
path with either of the two filenames. For example,
the command:
COMP B:*.ASM C:

causes all .ASM files on drive B to be compared with
the files of the same names and extensions on drive
C.
It is also possible to compare all files in one directory
with all corresponding files in another directory. For
example:

COMP A:\LEVEL1 A:\LEVEL2

locates all the files in the LEVELl directory of drive
A and compares them with files of the same name
from the LEVEL2 directory on the same drive.
2-44

COMP (Compare Files)
Command

If no file matches the primary filename, COMP will
prompt you for both the primary and secondary
parameters again.
The paths and names of the files being compared are
displayed as the comparing process proceeds. An
error message will follow if a file matching the second
filespec cannot be found, or the files are different
sizes, or a specified directory path is invalid.
During the comparison, an error message appears for
any location that contains mismatching information
in the two files. The message indicates the offset into
the files of the mismatching bytes, and the contents of
the bytes themselves (all in hexadecimal), as follows:
Compare error at offset XXXXXXXX
File 1 = XX
File 2 = XX

In this example, File 1 is the first filename entered;
File 2 is the second filename entered.
After ten unequal comparisons, COMP concludes that
further comparing would be useless; processing ends;
and the following message is displayed:
10 Mismatches - ending compare

After a successful comparison, COMP displays:
Files compare OK

2-45

COMP (Compare Files)
Command

After the comparison of the two files ends, comparing
will proceed with the next pair of files that match the
two filenames, until no more files can be found that
match the first parameter. Then COMP displays:
Compare more files (YIN)? __

You now have the option to compare two more files or
to end the comparison. If you want to compare two
more files, enter Y. You will be prompted for new
primary and secondary filenames.
If you want to end COMP processing, enter N. You
will return to the DOS prompt. In all compares, COMP
looks at the last byte of the files being compared to
assure that it contains a valid end-of-file mark (Ctrl-Z,
which is the hexadecimal character 1A). If found, no
action is taken by COMPo If the end-of-file mark is not
found, COMP produces the message:
EOF mark not found

This is done because some products produce files whose
sizes are always recorded in the directory as a multiple
of 128 bytes, even though the actual usable data in the
file is usually a few bytes less than the directory size. In
this case, COMP may produce compare error
messages when comparing the few bytes beyond the last
real data byte in the last block of 128 bytes (COMP
always compares the number of bytes reflected in the
directory). Thus, the BOF mark not found message
indicates that the compare errors may not have
occurred in the usable data portion of the file.

2-46

COMP (Compare Files)
Command

Notes:
1.

The two sets of files you want to compare can
have the same path and filenames-provided
they are on different drives.

2.

If you only specify a drive for the second file,
it is assumed that the second filename is the
same as the first filename. But, the current
directory is to be used. That is, it is the same
as entering:
d'· •

3.

A comparison does not take place if the file
sizes are different.

4.

CaMP does not wait for you to insert a
diskette containing a file to be compared.
Therefore, if a file to be compared is not on
the same diskette as the CaMP command
itself, you should enter CaMP with no
parameters. When CaMP prompts for the
filenames, you can insert the desired diskette
and reply with the name of the file to be
compared.

2-47

COpy
Command

Purpose:

Copies one or more files to another disk and
optionally, gives the copy a different name if you
specify it in the COPY command.
COpy also copies files to the same disk. In this case,
you must give the copies different names unless
different directories are specified; otherwise, the copy
is not permitted. Concatenation (combining of files)
can be performed during the copying process.
You can also use COpy to transfer data between any
of the system devices. (An example of how to copy
information that you enter at the keyboard to a file is
provided at the end of the description of COpy.)

Format:

COPY [IA ][/B][d: ] [path )filename [ .ext][/A][/B]
[d: ] [path ] [filename [ .ext]][/AH/BH/V]
or
COpy [IA][/B][d:][path ]filename[.extH/ A][/B]

[+[d:] [path )filename [.ext][/ A ][/B]. .. ]

[d: ] [path ] [filename [ .ext]][/A ][/BH/V]

Type:

Internal

External

***
Remarks:

2-48

The first file specified is the source file. The second
file specified is the target file. If the second parameter
is a directory (path with no filename), files are
copied into that directory without changing their
names.

COpy
Command

The parameter IV causes DOS to verify that the
sectors written on the target diskette are recorded
properly. Although errors in recording data are very
rare, this option has been provided for those of you
who wish to verify that critical data has been
correctly recorded. This option causes the COpy
command to run more slowly, due to the additional
overhead of verification.
The IV parameter provides the same check as does
the VERIFY ON command. IV is redundant if the
VERIFY ON command has been executed
previously. The difference is that IV is effective only
during the duration of the COPY command. The
VERIFY ON command is in effect continually until
VERIFY OFF is entered.
The parameters IA and IB indicate the amount of
data to be processed by the COPY command. Each
applies to the filespec preceding it and to all
remaining filespecs on the command line until
another IA or IB is encountered. These parameters
have the following meanings:
When used with a source filespec:

I A Causes the file to be treated as an ASCII (text)
file. The file's data is copied up to, but not
including, the first end-of-file character (Ctrl-Z,
which is hex lA) found in the file; the remainder
of the file is not copied.

IB Causes the entire file (based on the directory file
size) to be copied.
2-49

COpy
Command

When used with a target filespec:
/A

Causes a Ctrl-Z character to be added as the
last character of the file.

/B

Causes no end-of-file character (Ctrl-Z) to be
added.

The default values are / A when concatenation is
being performed (see Option 3 below), and /B when
concatenation is not being performed (Options 1 and
2).
Notes:
1.

When copying to or from a reserved device
name, the copy is performed in ASCII
(/ A) mode. The first Ctrl-Z character
encountered will end the copy unless /B
was specified.

2.

When making a copy of a file that is
marked read-only, the copy will not be
marked read-only.

You can use the global characters? and * in the
filename and in the extension parameters of both the
original and duplicate files. If you enter a ? or * in the
sourcejilespec, the names of the files will be
displayed as the files are being copied. For more
information about global characters, refer to "Global
Filename Characters" in Chapter 1.

2-50

COpy
Command

The COpy command has three format options:
Option 1 - Copy With Same Name
Use this option to copy a file with the copied file
having the same filename and extension as the source
file. For example:
COpy

[d: ][path lfilename[ .ext]

or
COpy

[d: ][path lfilename[.ext] d:[path]

In the first example, we want to copy a file to the
current directory of the default drive. In the second
example, we specify the target drive and/or directory.
In both examples, because we did not specify the
second filename, the copied file will have the same
filename as the source file. Because we did not
specify a name for the second file, the source drive
and the target drive must be different unless different
directories were specified or implied; otherwise, the
copy is not permitted.

2-51

COpy
Command

F or example, assume the default drive is A. The
command:
COpy B: MYPROG

copies the file MYPROG from drive B, to the default
drive A, with no change in the filename. The
command:
COpy *.* B:

copies all the files from the default drive A to drive
B, with no change in the filenames or in the
extensions. The filenames are displayed as the files
are copied. This method is very useful if the files on
drive A are fragmented. The command:
COPY B:\MYPROG

B:\LEVELl

copies the file MYPROG from the root directory of
drive B to the directory path:
root->LEVEL 1

on the same drive. The copy has the same filename
as the original file. Note that the above example
assumes that directory \LEVELI exists on drive B.
If it did not, then the file MYPROG would have been
copied into a file named LEVELl in the root
directory of drive B. In other words, if the second
parameter specifies a directory that exists, the file (or
files) will be placed in that directory, keeping the
same filename. If the second parameter does not
specify a directory that exists, DOS will treat it as a
filename.

2-52

COpy
Command

Option 2 - Copy With Different N arne
Use this option when you want the copied file to have
a different name from the file that is being copied.
For example:

COpy [d: ][path lfilename[. ext] [path lfilename[.ext]
or

COpy [d: ][path lfilename[ .ext]
d:[path lfilename[ .ext]
In the first example, we copied a file (first file
specified), and renamed the copy (second file
specified). We did not specify a drive, so the default
drive was used. In the second example, we copied a
file and renamed the copy also. In this example, we
did specify the target drive. Because we changed the
name of the file, the source drive and the target drive
do not have to be different. The current directory can
be the same or different.
F or example:
COpy MYPROG.ABC B:*.XXX

copies the file MYPROG .ABC from the diskette in
the default drive to drive B, naming the copy
MYPROG .XXX .. The current directory of each
drive was used.

2-53

COpy
Command

You can also use reserved device names for the copy
operation. For example:
COpy
COPY
COpy
COpy
COPY
COpy
COpy
COPY

CON
CON
CON
fileA
fileB
fileC
AUX
AUX

fileA
AUX
LPTl
CON
AUX
LPT2
LPTl
CON

Also, NUL: can be used in any variation.
Refer to "Reserved Device Names" in Chapter 1 for
information about system devices.
This example shows how to use COpy to put what
you enter from the keyboard into a file:
A>COPY CON fileA
Type a line and press Enter.
Type your next line and press Enter.

•
•
•

Type your last line and press Enter.
Now, press F6 and then press Enter.

2-54

COpy
Command

When you press F6, and then press Enter, the COPY
operation ends and saves the information you
entered. In this example, the information is saved in a
file named fileA.
Note: This example assumes that you have
not altered the meaning of F6 through the
"Extended Keyboard Support" functions
described in Chapter 2 of the IBM DOS
Technical Reference manual. If you have, then
substitute the key that you have assigned Ctrl-Z
for F6 in this example.
Option 3 - Copy and Combine Files
Use this option when you want to combine files while
copying. That is, you can combine two or more files
into one file by adding the additional files to the end of
the first. The date and time recorded in the result file
directory are the current date and time. The message
indicating the number of files copied refers to the
number of result files created.
To combine files, list any number of source files,
separated by plus (+) signs in the COpy command.
Use the following format:
COpy [IA][/B][d: ][path lfilename[ .ext][/A ][/B]

[+[d: ][path lfilename[ .ext][/A ][/B]. .. ]
[d: ][path lfilename[ .ext]][/A][/B][/V]

2-55

COpy
Command

F or example:
COPY A.XYZ+B.ABC+B:C.TXT BIGFILE.TXT

This command creates a new file called
BIGFILE.TXT on the default drive. The combination
of A.XYZ, B.ABC, and B:C.TXT is put into
BIGFILE.TXT.
If you do not specify a result filename , the additional
files are added to the end of the first file, leaving the
result in the first file. For example:
COPY A.ASM+B.ASM

In this case, COPY appends B.ASM to the end of
A.ASM and leaves the result in A.ASM.
Note: Combining files is normally performed in
text (or ASCII) mode. That is, the first Ctrl-Z
(hex 1A) character in the file is interpreted as an
end-of-file mark. To combine binary files, use the
/B parameter to force COPY to use the physical
end-of-file (the file length shown in the DIR
command).
You can also combine ASCII and binary files by using
the following parameters:

2-56

•

ASCII-/A

•

Binary - /B

COpy
Command

For example:
COpy A.XYZ+B.COM/B+B:C.TXT/A BIGFILE.TXT

An / A or /B takes effect on the file it is placed after,
and it applies to all subsequent files on the command
line until another / A or /B is found. An / A or /B on
the result file causes a Ctrl-Z to be added (I A), or
not to be added (lB), as the last character in the
result file.
You can use the global characters ? and * in the
filenames of both the files to be combined and the result
file. For example:
COPY *.LST COMBIN.PRN

In this example, all files matching *.LST are combined
into one file called COMBIN.PRN::
COPY *.LST +*.REF COMBIN.PRN

This example combines all files matching *.LST and
then all files matching *.REF into one file called
COMBIN.PRN:
COpy *.LST +*.REF *.PRN

2-57

COpy
Command

In this example, each file matching *.LST is
combined with the corresponding .REF file, with the
result having the same name but with extension
.PRN. Thus, a file FILE t.LST would be combined
with FILEt.REF to form FILEl.PRN; XYZ.LST
would be combined with XYZ.REF to form
XYZ.PRN; etc. Note that in this case (when
multiple files are to be created), only one file from
each of the source filespecs is used to create a given
target file.
For more information about global characters, refer
to "Global Filename Characters" in Chapter 1.
It is easy to enter a COpy command to combine files

where one of the source files is the same as the
target, yet this often cannot be detected. For
example:
COpy *.LST ALL.LST

This would produce an error if ALL.LST already
existed. The error would not be detected, however,
until it was time for ALL.LST to be appended; by
this time,ALL.LST could already have been altered.

2-58

COpy
Command

COpy handles this situation as follows: As each
input file is found, its name is compared with the
target filename. If the names are the same, that one
input file is skipped, and the message Content of
destination lost before copy is displayed. Further
copying proceeds normally. This allows summing
files with a command like:
COpy ALL.LST

+

*.LST

This command appends all.LST files, except
ALL.LST itself, to ALL.LST. In this case, the error
message is suppressed, because this is a true physical
append to ALL.LST.
The following are special cases. Remember to use the
/B parameter whenever you use the plus (+) sign
with non-ASCII files:
COpy B:XYZ.ASM+

This command copies the file XYZ.ASM to the
default drive and gives it a new date and time. To
simply change the date and time, leaving the file in
place, you can use the following command:
COpy B:XYZ.ASM+" B:

Note that the two commas are necessary to define the
end of the source filename, because COPY normally
expects to see another filename after the plus (+)
sign.

2-59

COpy
Command

In these special cases, if global filename characters
are used in the filename or extension, then all of the
matching files will be appended together into the first
filename that matches. Thus, the command:
COPY B:*.*+" B:

will not update the dates and times of all files on
drive B, but will append all of drive B's files together
into a single file that will replace the first file found
on drive B.
Note: When combining files, COpy considers
the copying process to be successful if at least
one, but not necessarily all, of the named source
files is found. If none of the source files can be
found, you receive the message:

o file(s) copied

2-60

CTTY
( Change Console)
Command

Purpose:

Changes the standard input and output console to an
auxiliary console, or restores the keyboard and
screen as the standard input and output devices.

Format:

CTTY device-name

Type:

Internal

External

***
Remarks:

Defines the device to be used as the primary console.
Specifying AUX, COMl, or COM2 causes DOS to
use that device as the primary console. Specifying
CON resets the standard input and output device to
the primary console.

Example:

In this example, the command causes DOS to use the
A UX device for its standard input and output
operations:

em

AUX

2-61

CTTY
( Change Console)
Command

In this example, the command reverses the previous
assignment, causing DOS to switch back to the
standard screen and keyboard for its operations:

em eON
Notes:
1.

The CTTY command accepts the name of
any character-oriented device to allow you

to install your own device drivers, and to
specify their device names. You must be
certain that the named device is capable of
both input and output operations. For
example, you should not specify the name
of a printer, because DOS will attempt to
read from that device.
2.

2-62

The CTTY command is effective only for
programs that use DOS function calls.
Other programs, such as BASIC (that do
not use DOS function calls), will not be
able to use the CTTY command to change
the standard input and output devices.

DATE
Command

Purpose:

Permits you to enter a date or change the date known
to the system. The date is recorded in the directory
entry for any files you create or alter.

Format:

DATE [mm-dd-yy]

Type:

Internal

External

***
Remarks:

If you enter a valid date with the DATE command,
the new date is accepted, and the system prompt
appears. Otherwise, the DATE command issues the
following prompt:
Current date is day mm-dd-yy
Enter new date:_

The system displays the day of the week in the day
location.
Enter a new date in the form mm-dd-yy or
mm/dd/yy, where:

mm is a one- or two-digit number from 1-12
dd is a one- or two-digit number from 1-31
yy is a two-digit number from 80-99
(a leading 19 is assumed) or a four-digit
number from 1980-2099

2-63

DATE
Command

You can change the date from the standard input
device or from a batch file. Remember, when you
start the system, you are not prompted for the date if
you use an AUTOEXEC.BAT file. You may want
to include a DATE command in that file. For more
information about the AUTOEXEC.BAT file, refer
to "Batch Commands" in this chapter.
Notes:

Example:

1.

To leave the date as is, press Enter.

2.

The valid delimiters within the date are
hyphens (-) and slashes (/).

3.

Any date is acceptable as today's date, as
long as the digits are in the correct ranges.

4.

If you enter an invalid date or delimiter,
you receive an Invalid date message.

In this example, once you press Enter, the date
known to the system is 7/24/83.
A> DATE
Current date is Mon 1-18-1983
Enter new date: 7/24/83

2-64

DEL
Command

See "ERASE Command" in this chapter.

2-65

DIR (Directory)
Command

Purpose:

Lists either all the directory entries, or only those for
specified files. The information provided in the
display includes the volume identification and the
amount of free space left on the disk. The display line
for each file includes its size in decimal bytes and the
date and time the file was last written to. Entries that
name other directories are clearly identified with
 in the file size field.
Note: Directory entries for system files
IBMBIO.COM and IBMDOS.COM are not
listed, even if present.

Format:

DIR [d: ]fpath ] [filename ][ .extH/PH/W]

Type:

Internal

External

***
Remarks:

The /P parameter causes the display to pause when
the screen is full. When you are ready to continue
with the directory listing, press any key.
The /W parameter produces a wide display of the
directory, which lists only the filenames and directory
names. Each line displayed contains five names.
(This parameter is only recommended for 80-column
displays.)

2-66

DIR (Directory)
Command

You can use the global characters ? and * in the
filename and extension parameters. For more
information about the global characters, refer to
"Global Filename Characters" in this Chapter 1.
The D IR command has two format options (the IP
and IW parameters mHy be used with either option):
Option 1 - List All Files
Use this option to list all the files in a directory. For
example:
DIR [path]
or
DIR d:[path]
In the first example, we want to list all directory
entries on the default drive. In the second example,
we want to list all directory entries on the specified
drive. In both cases, if a path is specified, the listing
is of files in the specified directory. Otherwise, the
current directory is listed.

2-67

DIR (Directory)
Command

The directory listing might look like this:
A>dir
Volume in drive A is MYDISK

Directory of A:\

FILE1
flLE3

9X
LEVEL2
FILEl

A
A

10368
1613
31


7 ·20·83
5-27 83
8-17·82
9-09-82

2288

9·02-82

m

12:13p
12:14p
10:59a

12:10p
12:25p

5 File(s) 141312 bytes free

Note that if the directory being listed is not the root
directory, the above example would have included
two special entries. The first entry would contain a
period in place of a filename. The second would
contain two periods in place of a filename. The list of
files shown above would follow these two entries.
These special entries tell you that the directory being
listed is a subdirectory, rather than the root directory.

2-68

DIR (Directory)
Command

Option 2 - List Selected Files
Use this option to list selected files from a directory.
F or example:

DIR fpathlfilename.ext
or

DIR d:fpath ]filename. ext
If either filename or . ext is omitted, an * is assumed.
In the first example, we want to list all the files in the
named or current directory of the default drive that
have the specified filename and extension. In the
second example, we want to list all the files in the
named or current directory of the specified drive that
have the specified filename and extension.
U sing the previous example, if you enter:

dar file3.a
the screen might look like this:
A>dir file3.a
Volume in drive A is MYDISK
Directory of A:\
FILE3

A
1613
5 27·83
12:14p
1 FUe(s) 141312 bytes free
N

2-69

DIR (Directory)
Command

If you enter:
dir *.a

or
dir.a

(omission ofjilename defaults to *)

the screen might look like this:
A>dir *.a
Volume in drive A is MYDISK
Directory of A:\
FILEl
FILE3

A
10368
7·20·83
A
1613
5·27·83
2 File(s) 141312 bytes free

12:13p
12:14p

If you enter:
dir filel

the screen might look like this (omission of.ext
defaults to *):
A>dir filel
Volume in drive A is MYDISK
DireGtory of A:\
FILEl
FILEl

2-70

A

10368
7·20·83
2288
9-02-82
2 File(s) 141312 bytes free

12:13p
12:25p

DIR (Directory)
Command

To display only the entry for a file that has no
extension, enter the filename followed by a period. In
this case, the . ext does not default to *. For example,
dir filel

displays the entry for FILEt, but not for FILEl.A.
If you wish to display all the files in directory
LEVEL2 on the above drive, you can enter:
dir level2

The screen will look like this:
A>dir level2
Volume in drive A is MYDISK
Directory of A:\leveI2

9·09·82

9·09·82
MYPROG
COM
2463
7·30·82
3 File(s) 141312 bytes free

8:55a

Note that all files in directory LEVEL2 have been
listed, including the two special entries found in all
sub-directories. The entry marked with a single
period denotes the directory being listed (LEVEL2),
and the double period denotes this directory's parent
directory (in this case, the root directory). Thus, if
your current directory is LEVEL2 and you wish to
see the files in its parent directory, you can enter:
dir ..

2-71

DIR (Directory)
Command

The following screen is displayed:
A>dir ..
Volume in drive A is MYDISK
Directory of A:\
FILEl
FILE3
9X
LEVEL2
FILEl

2-72

7-20-83
5·27·83
8·17·82
9·09·82

9·02-82
2288
5 File(s) 141312 bytes free
A
A

10368
1613
31

12:13p
12:14p
10:59a
12:10p
12:25p

DISKCOMP (Compare Diskette)
Command

Purpose:

Compares the contents of the diskette in the first
specified drive to the contents of the diskette in the
second specified drive. Usually, you would run
DISKCOMP after a DISKCOPY operation to
ensure that the two diskettes are identical.
Notes:
1.

This command is used only for comparing
diskettes. If a fixed disk drive letter is specified,
an error message is displayed.

2.

This command compares two entire diskettes;
the COMP command compares twofiles.

Format:

DISKCOMP [d:] [d:] [/1] [/8]

Type:

Internal

External

***
Remarks:

You can specify the same drive or different drives in
this command. If you specify the same drive, a
single-drive comparison is performed. You are
prompted to insert the diskettes at the appropriate
time. DISKCOMP waits for you to press any key
before it continues.
'
The /1 parameter forces DISKCOMP to compare
only the first side of the diskettes, even if the
diskettes and drives are dual-sided.
2-73

DISKCOMP (Compare Diskette)
Command

The /8 parameter causes DISKCOMP to compare
only 8 sectors per track, even if the first diskette
contains 9 sectors per track.
DISKCOMP compares all tracks on a track-for-track
basis and issues a message if the tracks are not equal.
The message indicates the track number and the side
(0 or 1) where the mismatch was found.
After completing the comparison, DISKCOMP
prompts:
Compare more diskettes (Y/N)?_

If you press Y, the next comparison is done on the
same drives that you originally specified, after you
receive prompts to insert the proper diskettes.

To end the command, press N.
Notes:

2-74

1.

If you omit both parameters, a single-drive
comparison is performed on the default
drive.

2.

If you omit the second parameter, the
default drive is used as the secondary
drive. If you specify the default drive in the
first parameter, this also results in a
single-drive comparison.

DISKCOMP (Compare Diskette)
Command

3.

On a single-drive system, all prompts are
for drive A, regardless of any drive
specifiers entered.

4.

DISKCOMP usually does not issue a
Diskettes compare OK message if you try
to compare a backup diskette created by
the COpy command with the diskette you
copied from. The COPY operation
produces a copy that contains the same
information, but may place the information
at different locations on the target diskette
from those locations used on the source
diskette. In this case, you should use the
COMP command to compare individual
files on the diskettes.

5.

If a diskette error occurs while
DISKCOMP is reading the diskette, a
message is produced that indicates where
(track and side) the error occurred. Then
DISKCOMP continues to compare the
rest of the diskette. Because the remainder
of the data to be compared cannot be read
correctly from the indicated track and side,
you can expect to receive a Compare error
message.

2·75

DISKCOMP (Compare Diskette)
Command

6.

DISKCOMP automatically determines the
number of sides and sectors per track to be
compared, based on the diskette that is to
be read first (the first drive parameter
entered).
If the first diskette or drive can be read on
only one side, or if the /1 parameter is
used, only the first side is read from both
diskettes. If the first diskette contains 9
sectors per track, then DISKCOMP will
compare 9 sectors per track unless you
used the /8 parameter. If the first drive and
diskette are dual-sided, and /1 is not
specified, a two-sided comparison is done.
In this case an error message is produced if
either the second drive or the diskette is a
single-sided diskette.

2-76

DISKCOPY (Copy Diskette)
Command

Purpose:

Copies the contents of the diskette in the source drive
to the diskette in the target drive. The target diskette
is formatted if necessary, during the copy.
Note: This command is used only for copying
diskettes. If a fixed disk drive letter is specified,
an error message is displayed.

Format:

DISKCOPY [d:] [d:] [/1]

Type:

Internal

External

***
Remarks:

The first parameter you specify is the source drive.
The second parameter is the target drive.
The /1 parameter causes DISKCOPY to copy only
the first side of the diskette, regardless of the diskette
or drive type.
You can specify the same drives or different drives. If
the drives are the same, a single-drive copy operation
is performed. You are prompted to insert the
diskettes at the appropriate times. DISKCOPY waits
for you to press any key before continuing.

2-77

DISKCOPY (Copy Diskette)
Command

After copying, DISKCOPY prompts:
Copy another (Y/N)?_

If you press Y, the next copy is done on the same
drives that you originally specified, after you are
prompted to insert the proper diskettes.

To end the command, press N.
Notes:

2-78

1.

If the target diskette has not been
formatted with the same number of sides
and sectors per track as the source diskette,
DISKCOPY will format the target diskette
during the copy operation.

2.

If you omit both drive parameters, a
single-drive copy operation is performed on
the default drive.

3.

If you omit the second parameter, the
default drive is used as the target drive.

4.

If you omit the second parameter and you
specify the default drive as the source
drive, a single-drive copy operation is
performed.

DISKCOPY (Copy Diskette)
Command

5.

On a single-drive system, all prompts will
be for drive A, regardless of any drive
letter you may enter.

6.

Diskettes that have had a lot of file
creation and deletion activity become
fragmented, because diskette space is not
allocated sequentially. The first free sector
found is the next sector allocated,
regardless of its location on the diskette.
A fragmented diskette can cause degraded
performance due to excessive head
movement and rotational delays involved
in finding, reading, or writing a file. If this
is the case, we recommended that you use
the COpy command, instead of
DISKCOPY, to eliminate fragmentation.
F or example, place a freshly formatted
diskette in drive B, and the diskette you
wish to copy in drive A. The command:
COpy A:*.* B:

copies all the files from the diskette in
drive A to the diskette in drive B. The
resultant files (in drive B) are now copied
sequentially. You should get better
performance when you use these files from
now on.

2-79

DISKCOPY (Copy Diskette)
Command

7.

You can run DISKCOMP after a
successful DISKCOPY to ensure that the
diskettes are identical.

8.

If disk errors are encountered on either
diskette, DISKCOPY indicates the drive,
track, and side in error and proceeds with
the copy. In this case, the target diskette
(copy) mayor may not be usable,
depending on whether the affected diskette
location was to contain valid data.

9.

DISKCOPY automatically determines the
number of sides and sectors per track to
copy, based on the source drive and
diskette. If only the first side of the source
diskette can be read, then only the first side
can be copied. If the source drive and
diskette are dual-sided, both sides can be
copied (unless you override it with the /1
parameter). In this case, if the target drive
is single-sided, an error message will
indicate that the drives are incompatible.
If the source diskette has ever been
physically formatted with 9 sectors per
track, then all 9 sectors on each track will
be copied.

2-80

ERASE
Command

Purpose:

Deletes the file with the specified filename from the
specified directory on the designated drive, or deletes
the file from the default drive if no drive is specified.
If no path is entered, the file is deleted from the
current directory.

Format:

ERASE [d:][path][filename[.ext]]
or
DEL [d:] [path] [filename[.ext]]

Type:

Internal

External

***
Remarks:

The shortened form, DEL, is a valid abbreviation for
ERASE.
You can use the global characters ? and * in the
filename and in the extension. Global characters
should be used with caution, however, because
multiple files can be erased with a single command.
For more information about global characters, refer
to "Global Filename Characters" in Chapter 1.
To erase all files in the current directory, enter:
ERASE [d:]*.*

2-81

ERASE
Command

To erase all files in a specific directory, enter:
ERASE [d:]path

ERASE assumes a filename of*.* if no filename is
given.
Notes:
1.

The system files IBMBIO.COM and
IBMDOS.COM cannot be erased. Also,
the two special entries in each subdirectory (. and .. in place of filenames)
cannot be erased.

2.

If you use the filespec *.* to erase all of the
files in a directory or on a disk, DOS
issues the following message to verify that
you actually want to erase all files:
Are you sure (YIN)?

If you do want to erase all of the files on
the diskette, enter Y. Otherwise, enter N.
Then press the Enter key.

Example:

In this example, the file myprog.l will be erased
from the current directory of drive A.
A>ERASE A:myprog.l

2-82

EXE2BIN
Command

Purpose:

Converts .EXE files that have no segment fixup to a
form that is compatible with .COM programs. This
results in a saving of diskette space and faster
program loading.

Format:

EXE2BIN [d: )[path lfilename[ .ext]]
[d: )[path )[filename [.ext))

Type:

Internal

External

***
Remarks:

The file named by filespec is the input file. If no
extension is specified, it defaults to .EXE. The input
file is converted to .COM file format (memory image
of the program) and placed in the output file,
[d:]tilename[.ext). If you do not specify a drive, the
drive of the input file is used. If you do not specify an
output filename, the input filename is used. If you do
not specify a filename extension in the output
filename, the new file is given an extension of .BIN.
If you do not specify a path, the current directory is
used.
The input must be in valid .EXE format as produced
by the linker. The resident, or actual code and data,
part of the file must be less than 64K. There must be
no STACK segment.

2-83

EXE2BIN
Command

Two kinds of conversions are possible, depending on
the specified initial CS:IP:
•

If CS:IP is not specified in the program (the
.EXE file contains 0:0), a pure binary
conversion is assumed. If segment fixups are
necessary (the program contains instructions
requiring segment relocation), you are prompted
for the fixup value. This value is the absolute
segment at which the program is to be loaded.

In this case, the resultant program is usable only
when loaded at the absolute memory address
specified by a user application. The DOS
command processor will not be capable of
properly loading the program.
•

2-84

If CS:IP is specified as 0000: 100R, it is
assumed that the file is to be run as a COM file,
with the location pointer set at 100R by the
assembler statement ORG; the first IOOR bytes
of the file are deleted. No segment fixups are
allowed, as COM files must be segment
relocatable; that is, they must assume the entry
conditions explained in Chapters 1, 4, 5, 6, 7, 8,
and 9 of the IBMDOS Technical Reference
manual and Appendixes B, C, and D of this
manual. Once the conversion is complete, you
may rename the resultant file to a .COM
extension. Then, the command processor is
capable of loading and executing the program in
the same manner as the .COM programs
supplied on your DOS diskette.

EXE2BIN
Command

If CS:IP does not meet one of these criteria, or if it
meets the COM file criterion but has segment fixups,
the following message is displayed:
file cannot be converted

This message is also displayed if the file is not a valid
.EXE file.
To produce standard COM files with the assembler,
you must both use the assembler statement ORG to
set the location pointer of the file at lOOH and
specify the first location as the start address. (This is
done in the END statement.) Also, the program must
not use references that are defined only in other
programs. For example, with the IBM Personal
Computer MACRO Assembler:
DRG lDOH
START:

•
•
•
END START

EXE2BIN resides on your DOS Supplemental
Program diskette.

2-85

FDISK
Command

See Chapter 3, "Preparing Your Fixed Disk".

2-86

FIND Filter
Command

Purpose:

This filter sends to the standard output device all
lines from the filenames specified in the command
line that contain the specified string.

Format:

FIND [lV][/C][/N]string[[d: ][path lfilename[.ext] ... ]

Type:

Internal

External

***
Remarks:

The IV parameter causes all lines not containing the
string to be displayed.
The IC parameter causes FIND to display only a
count of the number of matching occurrences of
string in each file, without displaying the matching
lines from the file.
The IN parameter causes the relative line number of
each matching line to be displayed ahead of the line
from the file.
The string should be enclosed in double quotes. Two
quotes in succession are taken as a single quote.
Global filename characters are not allowed in the
filenames or extensions.

2-87

FIND Filter
Command

Example:

A>FIND "Fool's Paradise" bookl.txt book2.txt book3

will output all lines from the book1.txt, book2.txt,
and book3 (in that order) that contain the string
"Fool's Paradise". Or,
A>DlR B:

I FIND

IV

"OAT"

will output the names of all the files in the current
directory of drive B that do not contain the string
DAT.

2-88

FORMAT
Command

Purpose:

Initializes the disk in the designated or default drive
to a recording format acceptable to DOS; analyzes
the entire disk for any defective tracks; and prepares
the disk to accept DOS files by initializing the
directory, File Allocation Table, and system loader.
CAUTION
Please note that formatting destroys all data on
the disk. Because of this you should be very
careful before you decide to format any disk,
particularly a fixed disk. If you attempt to format
your fixed disk, please note that the entire contents
of any previously created DO S partition,
including all subdirectories and their contents, are
destroyed. If you are not certain which drive is the
default drive, do NOT enter FORMAT without a
drive letter. If you do not specify a drive letter, you
could unintentionally destroy all of the data on
whatever disk happens to be default. It's safer to
specify a drive letter.

Format:

FORMAT [d: ][/S][/1 ][/8][/V][/B]

Type:

Internal

External

***

2-89

FORMAT
Command

Remarks:

You must format all new diskettes (by using either
the FORMAT or DISKCOPY command) and fixed
disks (through FORMAT) before they can be used
by DOS.
A fixed disk must also be formatted again if you
change the size of its DOS partition through the
FDISK command.
If you specify /S in the FORMAT command, the
operating system files are also copied from the
default drive to the new disk or diskette in the
following order:
IBMBIO.COM
IBMDOS.COM
COMMANI1COM

If you specify /1, the target diskette is formatted for
single sided use, regardless of the drive type.
If you specify /8, the target diskette is formatted for
use at 8 sectors per track. FORMAT will default to 9
sectors per track usage if you do not specify /8. Note
that FORMAT always creates 9 physical sectors on
each diskette track, but that it instructs DOS to use
only 8 sectors per track if you use the /8 parameter.
The /1 and /8 parameters are valid only for diskettes.
If you specify IV, FORMAT will prompt you for a
volume label which will be written on the disk. We
strongly recommend that you use the /V parameter.
This will uniquely identify each disk.

2-90

FORMAT
Command

FORMAT does not allow you to enter 18 and IV at
the same time. This is because DOS will not
recognize a volume label on 8 sectored diskettes.
This maintains compatibility with DOS 1.10.
The volume label cannot be used in place of
filenames as input to any of the DOS commands.
The volume label is for your use in keeping track of
your diskettes.
The IB parameter causes FORMAT to create an 8
sector per track diskette with space allocated for the
IBMBIO.COM and IBMDOS.COM system
modules. It does not place the system modules or the
command processor on the diskette. This parameter
is used to create a diskette on which any version of
DOS (1.00, 1.10,2.00, or 2.10) can be placed
through that version's SYS command. If the IB
parameter is not used, only DOS Version 2.00 or
2.10 can be placed on the diskette through the SYS
command.
The IV and I S parameters cannot be used with the

IB parameter.
Notes:
1.

Formatting destroys any previously
existing data on the disk.

2.

During the formatting process, any
defective tracks are marked as reserved to
prevent the tracks from being allocated to a
data file.
2-91

FORMAT
Command

2-92

3.

Directory entries for IBMBIO.COM and
IBMDOS.COM are marked as hidden
files, and therefore, they do not appear in
any directory searches-including the DIR
command.

4.

FORMAT will prompt you to enter a
volume label (volume identification) if you
have used the /V parameter. The label can
consist of from 1 to 11 characters. All
characters acceptable in filenames are
acceptable in the volume label. Unlike
filenames, however, the volume label does
not contain a period between the eighth
and ninth characters.

5.

FORMAT produces a status report, that
indicates:
•

Total disk space

•

Space marked as defective

•

Space currently allocated to the DOS
system files (when /S is used)

•

Amount of space available for your
files

FORMAT
Command

6.

FORMAT determines the target drive type
and formats the disk or diskette
accordingly. For diskettes, if the diskette
can be successfully read and written on
only one side, the diskette is formatted for
single-sided use; it can be used in either
type of drive. If the target drive is
dual-sided and you do not use the /1
parameter, the diskette is formatted for
dual-sided use; it will not be usable in a
single-sided drive.

7.

Fixed disks are already physically
formatted (proper recording format) when
shipped by IBM. When formatting a fixed
disk, FORMAT checks all locations within
the DOS partition, but does not physically
format them again.

8.

If the / S parameter is used and the system
has insufficient available memory for
FORMAT to load all three system
modules, it will load as many modules as it
can, format the target disk and write the
modules that are in memory. It must then
read the remaining modules from the
source disk so they can be placed on the
target disk. If the source diskette has been
removed from the drive, an appropriate
message will prompt you to reinsert it
before FORMAT can continue.

2-93

FORMAT
Command

Example:

By issuing the following command, the diskette in
drive B is formatted and the operating system files
are also copied:
A>FORMAT B:/S/V

The system displays the following message:
Insert new diskette for drive B:
and strike any key when ready

After you insert the appropriate diskette and press
any key, the system displays this message:
Formatting ...

while the diskette formatting is taking place.
Once the formatting is complete, the system displays
this message:
Formatting ... Format complete
System transferred
Volume label (11 character, ENTER for none)? MYDISK
xxxxxx bytes total disk space
xxxxx bytes used by system
XXXXXX: Dyies avaiiabie on disk
Format another (Y/N)?n

2-94

FORMAT
Command

In the above example, note that MYDISK was
entered as the volume label.
Enter Y to format another diskette.
Enter N to end the FORMAT program.
When you format a fixed disk, you will see the
following message instead of the prompt to insert a
diskette:
Press any key to begin formatUng x:

The x is replaced by the drive letter you typed. Other
than this, the messages appear in the same manner.
Fixed disk formatting can take several minutes
because of the large size that is allocated to DOS, so
don't be alarmed if it takes some time before you are
prompted for the volume label. You can tell that
FORMAT is working by noting that your fixed disk
drive light is on.

2-95

GRAPHICS (Screen Print)
Command

Purpose:

Allows the contents of a graphics display screen
to be printed on an IBM Personal Computer
80 cps Graphics Printer when using a color/graphics
monitor adapter. This command increases the
resident size of DOS in memory by 736 bytes.

Format:

GRAPHICS

Type:

Internal

External

***
Remarks:

2-96

Press the Shift-PrtSc keys to print the screen
contents on the printer. If the screen is in text mode,
the text is printed in under 30 seconds. If the screen
is in the graphics mode, each time the PrtSc key is
pressed, the following things occur:
•

In the 320x200 color graphics mode (Screen 1),
the screen contents are printed in up to four
shades of gray.

•

In the 640x200 color graphics mode (Screen 2),
the screen is printed sideways on the paper. The
upper right comer of the screen is printed on the
upper left comer of the paper.

GRAPHICS (Screen Print)
Command

•

Printing may take as long as three minutes.

•

To invoke the screen print from a program, use
the following coding example:
PUSH BP
INT 5
POP UP

2-97

MKDIR (Make Directory)
Command

Purpose:

Creates a subdirectory on the specified disk.

Format:

MKDIR [d:]path
or
MD [d:]path

Type:

Internal

External

***
Remarks:

If you do not specify a drive, the default drive is

assumed.

Example:

In this example, the command creates an entry in the
root directory for a new subdirectory called
LEVEL2:
MD \LEVEl2

If you have done this and wish to add another
directory level, you can use either of the following
two examples.

2-98

MKDIR (Make Directory)
Command

Use this example if your current directory is the root
directory:
M0 \LEVEL2\LEVEL3

adds an entry for subdirectory LEVEL3 in the
LEVEL2 directory.
Use this example if your current directory is
LEVEL2:
MD LEVEL3

This command will do the same thing as the previous
example. Note that in the previous example, the first
backslash (\) tells DOS to begin its directory search
with the root directory. The absence of a leading \ in
the last example causes DOS to begin at the current
directory. Each directory may contain the names of
still other directories.
N ote: You can create as many subdirectories
as you wish, limited only by available disk
space. However, you should ensure that the
maximum length of any single path from the
root directory to the desired level is 63
characters, including imbedded backslashes.

2-99

MODE
Command

Purpose:

Sets the mode of operation on a printer or on a
display connected to the Color/Graphics Monitor
Adapter, sets options for an Asynchronous
Communications Adapter, or causes printer output to
be routed to an Asynchronous Communications
Adapter.
Technical Note: When used in Option 1, 3,
or 4, the MODE command causes printer and
Asynchronous Communications Adapter
intercept code to be made resident in memory.
This increases the size of DOS in memory by
approximately 256 bytes.

Format:

MODE LPT#:[n][,[m][,P]]
or
MODEn

or
MODE [n ],m[,T]
or
MODE COMn:baud[,parity[,databits
[,stopbits[,P]]]]

or
MODE LPT#:=COMn

2-100

MODE
Command

Type:

Internal

External

***
Remarks:

A missing or invalid n or m parameter means that the
mode of operation for that parameter is not changed.
The MODE command has four format options:
Option 1 (For the printer)
MODE LPT#:[n][,[m][,P]]
where:
# is 1, 2, or 3 (the printer number)
n is 80 or 132 (characters per line)
m is 6 or 8 (lines per inch vertical spacing)

P specifies continuous retry on time-out errors
For example:
MODE LPT1:132,8

sets the mode of operation of printer 1 to 132
characters per line and 8 lines per inch vertical
spacing. The power-on default options for the printer
are 80 characters per line and 6 lines per inch.
The retry loop can be stopped by pressing
Ctrl-Break. To stop time-out errors from being
continuously retried when you have entered P, you
must use MODE Option 1 without specifying P.

2-101

MODE
Command

Option 2

(For switching Display Adapters, and
setting the display mode of the Color/
Graphics Monitor Adapter)

MODEn

or
MODE [n ],m[,T]
where:

2-102

n

is 40,80, BW40, BW80, C040, C080, or
MONO

40

sets the display width to 40 characters per
line (for Color/Graphics Monitor
Adapter).

80

sets the display width to 80 characters per
line (for Color/Graphics Monitor
Adapter).

BW40

switches the active display adapter to the
Color/Graphics Monitor Adapter, and sets
the display mode to Black and White
(disables color) with 40 characters per line.

BW80

switches the active display adapter to the
Color/Graphics Monitor Adapter, and sets
the display mode to Black and White
(disables color) with 80 characters per line.

MODE
Command

C040

switches the active display adapter to the
Color/Graphics Monitor Adapter, enables
color, and sets the display width to 40
characters per line.

COSO

switches the active display adapter to the
Color/Graphics Monitor Adapter, enables
color, and sets the display width to 80
characters per line.

MONO switches the active display adapter to the
Monochrome Display Adapter (which
always has display width of 80 characters
per line).
m

is R or L (shift display right or left).

T

requests a test pattern used to align the
display.

F or readability, you can shift the display one
character (for 40 columns) or two characters (for 80
columns) in either direction. If you specify T in the
MODE command, a prompt asks you if the screen is
aligned properly. If you enter Y the command ends.
If you enter N the shift is repeated followed by the
same prompt. For example,
MODE 80,R,T

sets the mode of operation to 80 characters per line
and shifts the display two character positions to the
right. The test pattern is displayed to give you the
opportunity to further shift the display without having
to enter the command again.
2-103

MODE
Command

Option 3 (For Asynchronous Communications
Adapter)
MODE COMn :baud[ ,parity [,databits [ ,stopbits
[,P]]]]
where:
n

Either 1 or 2 (Asynchronous
Communications Adapter number)

baud

110,150,300,600, 1200, 2400, 4800, or
9600
Note: Only the first two characters
are required; subsequent characters
are ignored.

parity

Either N (none), 0 (odd), or E (even)(default = E)

databits Either 7 or 8 (default = 7)
stopbits

2-104

Either 1 or 2 (if baud equals 110,
default = 2; if baud does not equal 110,
default = 1)

MODE
Command

These are the protocol parameters. They are used to
initialize the Asynchronous Communications
Adapter. When you specify the protocol, you must
specify at least the baud rate. The other parameters
can be omitted, with the defaults accepted, by
entering only commas. For example:
MODE COM1:12,N,8,1,P

sets the mode of operation to 1200 baud rate, no
parity, eight databits, and one stopbit. To use the
defaults listed in the definitions above, you enter:
MODE COM1:12,m P

The parity defaults to even, the databits defaults to
seven, and the stopbits defaults to one.
The P option indicates that the asynchronous adapter
is being used for a serial interface printer. If you
enter the P, time-out errors are continuously retried.
You can stop the retry loop by pressing Ctrl-Break.
To stop the time-out errors from being continuously
retried when you have entered P, you must
reinitialize the asynchronous adapter without entering
the P.

2-105

MODE
Command

Option 4

(To redirect parallel printer output to
an Asynchronous Communications
Adapter)

MODE LPT#:=COMn
where:
#

Either 1, 2, or 3 (printer number)

nEither 1 or 2 (Asynchronous Communications
Adapter number)
All output directed to printer LPT# is redirected to
the Asynchronous Adapter n.
Notes:

2-106

1.

Before you can use MODE to redirect
parallel printer output to a serial device,
you must initialize the Asynchronous
Communications Adapter by using Option
3 (see above). If that serial device is a
printer, your serial initialization command
should also include the P parameter.

2.

MODE LPT#:[n][,m] disables
the redirection for the printer designated by
the #.

MORE Filter
Command

Purpose:

This filter reads data from the standard input device,
and sends one screen full of data to the standard
output device, and then pauses with the message
-More-.

Format:

MORE

Type:

Internal

External

***
Remarks:

Pressing any character key causes another screen full
of data to be written to the standard output device.
This process continues until all input data is read.

Example:

In this example, the command line will display the
contents of file TEST.ASM one screen full at a time.
When the screen is full, the message -Moreappears on the bottom line. You can press any key to
see the next screen full.
MORE " character.
The "<" character.
The " r" character.
The "=" character.
A backspace and erasure of the previous
character.
The ESCape character.
The CR LF sequence (go to beginning of
new line on the display screen).

PROMPT (Set System Prompt)
Command

Any other character is treated as a null characterno action is taken on it by the PROMPT command.

Example:

In this example, the command would set the normal
DOS prompt:
PROMPT $n$g

In this example, the command would set ABC as the
system prompt:
PROMPT ABC

In this example, the command would set a two line
prompt that displays:
Time = (current time)
Date = (current date)
PROMPT Time

=

$t$_ Date

=

$d

2-117

PROMPT (Set System Prompt)
Command

If you wish to create a prompt that begins with any of
the DOS command delimiters (such as semicolon,
blank, etc.), you can precede that character with a
null meta-string. The character will then be treated as
the first character of the prompt, rather than as a
delimiter between the word PROMPT and its
parameter. For example:
PROMPT $A;ABC

causes the PROMPT command to interpret the $A
as a null character because A is not one of the
defined characters in the above list. All characters
following the null character will become the new
system prompt.

2-118

RECOVER
Command

Purpose:

Recovers files from a disk that has developed a
defective sector . You can recover the file that
contains the bad sector (minus the data in the bad
sector), or all the files on the disk can be recovered if
the directory has been damaged.

Format:

RECOVER [d: ][path ]filename[. ext]
or
RECOVERd:

Type:

Internal

External

***
Remarks:

The file named by filename is the file to be
recovered. If you do not specify a drive, the default
drive is used. If you do not specify a path, the current
directory is used. The size of the recovered file is a
multiple of the DOS allocation unit size. In most
cases, this is larger than the original file size. Text
files will normally require re-editing to remove
unwanted data from the end of the recovered file
before they can be used for normal processing.

2-119

RECOVER
Command

In the second format shown, RECOVER assumes
the directory is damaged, and recovers all files on the
specified disk.
If the global filename characters * and ? are used in
the filename or extension, only the first file that
matches the filespec will be recovered. RECOVER
only recovers one file at a time when a filespec is
entered.

Example:

For this example assume the disk file to be recovered
is MYPROG:
RECOVER A:MYPROG

This command causes the disk file MYPROG on
drive A to be read sector-by-sector, skipping the bad
sectors. The bad sectors are allocated in a system
table, thus preventing future allocations of that
sector. The filename is not changed.
The following example shows how to recover the
contents of an entire disk from drive A:
RECOVER A:

This command causes the disk file allocation table on
drive A to be scanned for chains of allocation units.
A new root directory is created for each chain of
allocation units in the form:
FILEnnnn.REC

2-120

RECOVER
Command

Where nnnn is a sequential number starting with
0001. Each FILEnnnn .REC points to one of the
recovered files on the disk.
Note: This form of the RECOVER command
should only be used if the directory of the disk
becomes unusable. Because RECOVER has no
way of knowing whether the data in the
directory is valid or not, it must assume that the
entire directory is invalid, and therefore recovers
all files into filenames of the forms shown
above, including any files for which there may
still have been valid directory entries.

2-121

RENAME (or REN)
Command

Purpose:

Changes the name of the file specified in the first
parameter to the name and extension given in the
second parameter. If a valid drive is specified in the
second parameter, the drive is ignored.

Format:

REN[AME] [d:][pathlfilename[.ext] filename[.ext]

Type:

Internal

External

***
Remarks:

You can use the abbreviated form REN for the
REN AME command. You can also use the global
characters? and * in the parameters. For more
information about global characters, refer to "Global
Filename Characters" in Chapter 1. A path can be
specified only with the first filename; the file will
remain in the same directory after its name has been
changed.

Example:

The command:
RENAME B:ABODE HOME

renames the file ABODE on drive B to HOME.

2-122

RENAME (or REN)
Command

The command:
REN B:ABODE *.XY

renames the file ABODE on drive B to
ABODE.XY.
The command:
HEN

B~LEVEL2\MYPROG.COM

MYPROG1.COM

renames the file MYPROG .COM in directory
\LEVEL2 on drive B to filename
MYPROG I.COM.

2-123

RESTORE (Fixed Disk)
Command

Purpose:

Restores one or more files from diskettes to a fixed
disk.

Format:

RESTORE d: [d: ] [path ] [filename [ .ext]H/SH/P]

Type:

Internal

External

***
Remarks:

The files being restored must have been placed on the
diskettes by the BACKUP command. The first
parameter you specify is the backup diskette drive.
The second parameter is the fixed disk file you want
to restore.
Files are restored to the current directory if you do
not specify a path. If you do not specify a filename or
extension, then all files backed up from the directory
will be restored.
Global filename characters are allowed in the
filename, and cause all of the files matching the
filename to be restored. For example, entering:
RESTORE A: C:*.DAT

restores each file from the backup diskettes with an
extension of .DA T that had been backed up from the
current directory.

2-124

RESTORE (Fixed Disk)
Command

The parameter I S causes backed up files in all
subdirectories to be restored in addition to the files
in the specified directory itself. This includes
subdirectories at all levels beyond the specified
directory.
The parameter IP causes RESTORE to prompt you
before restoring files that have changed since they
were last backed up, or that are marked read-only.
You can then choose to restore the file or not.
Read-only is a file attribute that an application can
set by interfacing with DOS internally. The two DOS
system files (lBMBIO.COM and IBMDOS.COM)
are marked read-only when they are created by the
FORMAT and SYS commands.
The following example restores all files on the
backup diskettes to fixed disk drive C:
RESTORE A: C:\ /S

The next example restores three different files from
the backup diskettes to the default fixed disk drive:
RESTORE A: \level1\filel.dat
RESTORE A: \level1\leveI2\file2.dat
RESTORE A: \level1\leveI3\file3.dat

When RESTORE prompts you to insert the backup
diskette, make sure you insert the first diskette that
might contain the file you want to restore. If you are
not sure, insert backup diskette number one. If the
file is not on the diskette you inserted, RESTORE
will prompt you to insert the next diskette.

2·125

RESTORE (Fixed Disk)
Command

If you used global filename characters, RESTORE
prompts you to insert the next diskette after it has
restored all files on the backup diskette that match
the specified filename.
The RESTORE command sets the ERRORLEVEL
(see Batch Commands) as follows:

o

Normal completion

1

No files were found to restore

3

Terminated by user (Ctrl-Break or ESC)

4

Terminated due to error

These codes can be used with the batch processing
IF subcommand to control subsequent error level
processing.

2-126

RMDIR (Remove Directory)
Command

Purpose:

Removes a subdirectory from the specified disk.

Format:

RMDIR [d:]path
or
RD [d:]path

Type:

Internal

External

***
Remarks:

The directory must be empty before it can be
removed with the exception of the" ." and" .. "
entries. The last directory name in the path is the
directory to be removed.

Example:

In this example, the command:
RD B:\LEVEL2\LEVEL3

removes the entry for LEVEL3 from directory
LEVEL2.
Note: The root directory and the current
directory cannot be removed.

2-127

SET (Set Environment)
Command

Purpose:

This command inserts strings into the command
processor's environment. The entire series of strings
in the environment is made available to all
commands and applications.

Format:

SET [name=[parameter]]

Type:

Internal

External

***
Remarks:

The entire string (beginning with name) is inserted
into a block of memory reserved for environment
strings. Any lowercase letters in the name are
converted to uppercase letters when added to the
environment; the remainder of the line is inserted as
you entered it. If the name already existed in the
environment, it is replaced with the new parameter.
If the SET command is entered with no name
specified, then the current set of environment strings
will be displayed.
If a name is specified, but the parameter is not
specified, then the current occurrence of
name parameter is removed from the environment.

2·128

SET (Set Environment)
Command

The environment (series of names and parameters) is
made available to all DOS commands and
applications (see the "Program Segment Prefix"
description in Chapter 6 of the IBM DOS Technical
Reference) . You can display the current environment
contents by entering a SET command with no
parameters. You can select the strings in the
environment. For example, entering:
SET abc=xyz

will add the string ABC=xyz to the other strings
already in the environment (note the conversion of
abc to uppercase ABC). In this way, it is possible for
you to enter keywords and parameters that are not
meaningful to DOS, but can be found and interpreted
by applications that are designed to examine the
environment.

Example:

This example adds the string PGMS=\LEVEL2 to
the environment. When an application program
receives control, it could search the environment for
the name PG MS, and use the supplied parameter as
the directory name to use for its files:
SET PGMS=\LEVEL2

The following example would remove
PGMS=\LEVEL2 from the environment:
SET PGMS=

2-129

SET (Set Environment)
Command

Notes:

2-130

1.

DOS automatically adds any PROMPT or
PATH commands to the environment
when you enter them. You do not need to
use the SET command to add either of
these two commands to the environment.

2.

One of the strings in the environment
(placed there by DOS when it starts up)
will always be a COMSPEC = parameter.
That parameter describes the path that
DOS uses to reload the command
processor when necessary.

3.

If you have not loaded a program that
remains resident (such as MODE, PRINT,
GRAPHICS, etc.), DOS expands the
environment string area to hold additional
strings. If you have loaded a program that
remains resident, DOS is unable to expand
the environment area beyond 127 bytes or
if the environment area has already
expanded beyond 127 bytes when you load
a program that is to remain resident, DO S
is unable to expand the environment area
beyond that point. The message Out of
environment space appears if you issue a
SE T command that would cause the
combined environment strings to exceed
127 bytes.

SORT Filter
Command

Purpose:

This filter command reads data from the standard
input device, sorts the data, then writes the data to
the standard output device.

Format:

SORT [lR] [/+n]

Type:

Internal

External

***
Remarks:

Sorts are done using the ASCII collating sequence.
Tab characters are not expanded with blanks.
The IR parameter will reverse the sort, for example
make "Z" come before "A."
The 1+ n parameter is an integer that starts the sort
with column n. If no parameters are specified, the
sort starts with column 1. The maximum file size that
can be sorted is 63K.

2-131

SORT Filter
Command

Example:

In this example, the command line will read the file
UNSORT. TXT, do a reverse sort, then write the
output to file SORT. TXT:
A>SORT /R SORT.TXT

In the next example, the command line causes the
output of the directory command to be piped to the
SORT filter. The SORT filter will sort starting with
column 14 (this is the column the file size starts in),
then send the output to the console. Thus, a directory
sorted by file size will be the result:
A>OIR I SORT /+14

2·132

SYS (System)
Command

Purpose:

Transfers the operating system files from the default
drive to the specified drive.

Format:

SYS d:

Type:

Internal

External

***
Remarks:

The directory of the disk in the specified drive must
be completely empty, or the disk must have been
formatted by a FORMAT d:/S or FORMAT d:/B
command to contain directory entries for the DOS
files IBMBIO.COM and IBMDOS.COM. This is
necessary because DOS startup requires these files to
occupy the first two directory entries, and because
IBMBIO.COM must reside on consecutive sectors
on the disk.
Note: SYS lets you transfer a copy of DOS to
an application program diskette designed to use
DOS, but sold without it. In this case, the space
required for the DOS files has already been
allocated, although the DOS files are not
actually present. The SYS command will
transfer the files to the allocated space.

2-133

TIME
Command

Purpose:

Permits you to enter or change the time known to the
system. Whenever you create or add to a file, the
time is recorded in the directory. You can change the
time from the console or from a batch file.

Format:

TIME [hh:mm:ss.xx]

Type:

Internal

External

***
Remarks:

If you enter a valid time with the TIME command,

the time is accepted, and the system prompt appears.
Otherwise, the TIME command displays the
following prompt:
Current time is hh:mm:ss.xx
Enter new time: _

where:
is a one- or two-digit number from 0-23
(representing hours)
mm is a one- or two-digit number from 0-59
(representing minutes)
ss is a one- or two-digit number from 0-59
(representing seconds)
xx is a one- or two-digit number from 0-99
(representing hundredths of a second)
hh

2-134

TIME
Command

Notes:

Example:

1.

To leave the time as is, press Enter.

2.

If you enter any information (for example,
just the hours, and press Enter), the
remaining fields are set to zero.

3.

Any time is acceptable as long as the digits
are within the defined ranges.

4.

The valid delimiters within the time are the
colon (:) separating the hours, minutes, and
seconds, and the period (.) separating the
seconds and the hundredths of a second.

5.

If you specify an invalid time or delimiter,
you receive an Invalid time message.

In this example, once you press Enter, the time
known to the system is changed to 13:55:00.00.
A>TIME
Current time is 00:25:16.65
Enter new time: 13:55_

2-135

v

TREE (Display Directory)
Command

Purpose:

Displays all of the directory paths found on the
specified drive, and optionally lists the files in each
sub-directory .

Format:

TREE [d:][!F]

Type:

Internal

External

***
Remarks:

If no drive is specified, the default drive is assumed.
F or each directory found, its full path name will be
displayed, along with the names of any directories
defined within it (these are called subdirectories in
the output). If the IF parameter is used, the names of
all files in each subdirectory are also displayed.
To make the screen output pause, use the Ctrl-Num
Lock keys or pipe the output to the MORE filter.

Example:

In this example, the command:
TREE B:/F >TREE.LST

causes all directories on drive B to be listed. The
output will be placed in file TREE.LST in the
current directory of drive B, and will contain the
names of all subdirectories and files at each directory
level.

2·136

TREE (Display Directory)
Command

Following is an example of a directory path listing. If
the disk called MYDISK in drive A had the
following directory structure:

MYPROG1.ASM
MYPROG2.ASM

No files
lEVEL3
MYPROG1.EXE

2·137

L

TREE (Display Directory)
Command

Then TREE would display:
DIRECTORY PATH LISTING FOR VOLUME MYDISK
Path: \SOURCE
Subdirectories: None
Files:

MYPROGl .ASM
MYPROG2.ASM

Path: \LEVEL2
Subdirectories: LEVEL3
Files:

None

Path: \LEVEL2\LEVEL3
Subdirectories: None
Files:

MYPROGl .EXE

The following example lists all the subdirectories
and filenames from drive A on the printer:
TREE A:/F >PRN

2-138

TYPE
Command

Purpose:

Displays the contents of the specified file on the
standard output device.

Format:

TYPE [d:][pathlfilename[.ext]

Type:

Internal

External

***
Remarks:

The data is unformatted except that tab characters
are expanded to an eight-character boundary; that is,
columns 8, 16, 24, etc.
Notes:
1.

Press Ctrl-PrtSc if you want the contents
of a file to be printed as it is being
displayed. You can also redirect the output
to a file or the printer.

2.

Text files appear in a legible format;
however, other files, such as object
program files, may appear unreadable due
to the presence of nonalphabetic or
nonnumeric characters.

2-139

TYPE
Command

Example:

3.

You must specify a filespec.

4.

Global filename characters are not allowed
in the filename or extension. If global
filename characters are used in the
filename or extension, the message File
not found will appear.

In this example, the file MYPROG.ONE on the
diskette in drive B is displayed on the screen:
TYPE B:myprog.one

2-140

VER (Version)
Command

Purpose:

Displays the DOS version number that you are
working with on the display screen.

Format:

VER

Type:

Internal

External

***
Remarks:

The DOS version consists of a single-digit major
version number, followed by a period, followed by a
two-digit minor revision level.

Example:

A>VER
IBM Personal Computer DOS Version 2.10

2-141

VERIFY
Command

Purpose:

Verifies that the data written on a disk has been
correctly recorded.

Format:

VERIFY [ON I OFF]

Type:

Internal

External

***
Remarks:

VERIFY ON remains on until it is turned off through
the SET VERIFY System Call or a VERIFY OFF
command.
When ON, DOS performs a verify operation
following each disk write operation, to verify that the
data just written can be read without error. Because
of the extra time required to perform the verification,
the system runs slower when programs write data to
disk.
Entering VERIFY with no parameters causes DOS
to display the current state (on or off) of the verify
feature.

2-142

VERIFY
Command

Example:

This example causes the verify feature to be turned
on:
A>VERIFY ON

This example displays the current status:
A>VERIFY
VERIFY is on

A>

2-143

VOL (Volume)
Command

Purpose:

Displays the disk volume label of the specified drive.

Format:

VOL [d:]

Type:

Internal

External

***
Remarks:

If you do not specify a drive, the default drive is
assumed.

Example:

A>VO L
Volume in drive A is MYDISK

A>

2-144

Summary of DOS Commands

The following chart is provided for quick reference.
The section called "Format Notation" at the
beginning of Chapter 1 explains the notation used in
the format of the commands.
Note: In the column labeled Type, the I
stands for Internal and the E stands for
External.
Command

Type

Purpose

Format

(Batch)

I

Executes batch
file

[d: lfilename
[parameters]

ECHO

I

Inhibits screen
display

ECHO
[ON IOFFI
message]

FOR

I

Iterative
execution of
commands

FOR %%variable
IN (set) DO
command

GOTO

I

Transfers control
to line following
the label

GO TO label

IF

I

Conditional
execution of
commands

IF [NOT] condition
command

SHIFT

I

Shift command
lines

SHIFT

PAUSE

I

Provides a
system wait

PAUSE [remark]

Figure 1 (Part 1 of 2). DOS Batch Processing Commands

2-145

Command

Type

Purpose

Format

REM

I

Displays remarks

REM [remark]

Figure 1 (Part 2 of 2). DOS Batch Processing Commands

Format

Command

Type

Purpose

ASSIGN

E

Routes requests to ASSIGN [x=y [ ... ]]
a different drive

BACKUP

E

Backs up fixed
disk files

BACKUP
d:fpath]
[lilename[ .ext]] d:

[/SJ[/MJ[/AJ
[D:mm-dd-yy]

BREAK

I

Checks for
control break

BREAK
[ON (OFF]

CHDIR

I

Change current
directory

CHDIR [[d:]path]
or
CD [[d:]path]

CHKDSK

E

Checks disk and
reports status

CHKDSK
[d: ] [lilename[ .ext]]

[IF][/V]
CLS

I

Clears the
display screen

CLS

COMP

E

Compares files

COMP
[d: ][path ][filename
[. ext]]
[d: ][path ][filename
[. ext]]

Figure 2 (Part 1 of 6). DO S Commands

2-146

Command

Type

Purpose

Format

COpy

I

Copies files

COpy [I A][/B]
[d: ][path lfilename
[.ext][/ A][/B]

[d: ][path ][filename
[.ext]][/ A][/B][/V]
or
COpy [I A][/B]
[d: ][path lfilename
[.ext][/ A][/B]

[+[ d: ][path ]
filename[. ext]
[/ A][/B] ... ]
[d:] [path] [filename
[. ext]][/ A ][/B][/V]
CTTY

I

Change standard
CTTY device-name
input and standard
output device.

DATE

I

Enter date

DATE [mm-dd-yy]

DIR

I

Lists filenames

DIR [d:][path]
[filename][ .ext]
[lP][/W]

DISKCOMP E

Compares
diskettes

DISKCOMP
[d:] [d:]
[11][/8]

DISKCOPY E

Copies diskettes

DISKCOPY [d:]
[d:] [/1]

Figure 2 (Part 2 of6). DOS Commands

2-147

Command

Type

Purpose

Format

ERASE

I

Deletes files

ERASE
[d: ][path ][filename
[.ext]]
or
DEL
[d: ][path ][filename
[.ext]]

EXE2BIN

E

Converts .EXE
files to .COM
format

EXE2BIN
[d: ][path lfilename
[. ext]]

[d:] [path] lfilename
[.ext]]
FIND

E

Searches files for
strings of text

FIND
[/V][/C][/N] string
[[ d: ][path ]
filename[ .ext] ... ]

FORMAT

E

Formats diskette

FORMAT [d:][/S]
[/1 ][/8][/V][/B]

GRAPHICS

E

Prints graphics
display screen

GRAPHICS

MKDIR

I

Creates a
subdirectory

MKDIR [d: ]path
or
MD [d:]path

Figure 2 (Part 3 of6). DOS Commands

2-148

Command

Type

Purpose

Format

MODE

E

Sets mode on
printer/ display

MODE LPT#:[n]
[,[ m] [,P]]
or
MODEn

or
MODE [n],m[,T]
or
MODECOMn:
baud[,parity
[,databits[ ,stop bits
[,P]]] ]

or
MODE LPT#:=
COMn
MORE

E

Displays a screen
full of data

MORE

PATH

I

Searches
directories for
commands or
batch files

PATH
[[ d: ]path[ [;[ d:]
path] ... ]]

PRINT

E

Queues and
prints data files

PRINT
[[ d: ][filename[. ext]]
[IT][/C][/P] ... ]

Figure 2 (Part 4 of 6). DOS Commands

2-149

Command

Type

Purpose

Format

PROMPT

E

Set new prompt

PROMPT
[prompt-text]

RECOVER

E

Recovers files
from disk or
diskette

RECOVER
[d:] [path lfilename
[.ext]
or
RECOVERd:

RENAME

I

Renames files

REN[AME]
[d:] [path lfilename
[. extlfilename[. ext]

RESTORE

E

Restores diskette
files to fixed disk

RESTOREd:
[d: ][path ][filename
[.ext]][/S][/P]

RMDIR

I

Removes a
subdirectory

RMDIR [d:]path
or
RD [d:]path

SET

I

Inserts strings
into the command
processor's
environment

SET [name=
[parameter] ]

SORT

E

Sorts text data

SORT [lR] [I+n]

SYS

E

Transfers DOS

SYS d:

TIME

I

Enter time

TIME
[hh:mm:ss.xx]

Figure 2 (Part 5 of6). DOS Commands

2-150

Command

Type

Purpose

Format

TREE

E

Displays all
directory paths

TREE [d: H/F]

TYPE

I

Displays file
contents

TYPE
[d: ][path lfilename
[. ext]

VER

I

Displays version
number

VER

VERIFY

I

Verifies data

VERIFY
[ON I OFF]

VOL

I

Displays volume
identification

VOL [d:]

Figure 2 (Part 6 of6). DOS Commands

2-151

2-152

Chapter 3. Preparing Your Fixed
Disk

Contents
Introduction

3-3

Fixed Disk Drive Letters ...................

3-5

Preparing Your Fixed Disk .................

3-6

Setting Up the DO S Partition

..............

3-9

Partitioning Your Fixed Disk ...............
Creating the DOS Partition
(Option 1) ...........................
Changing the Active Partition
(Option 2) ...........................
Deleting the DOS Partition
(Option 3) ...........................
Displaying Partition Data
(Option 4) ...........................
Selecting Next Fixed Disk Drive
(Option 5) ...........................

3-13
3-15
3-19
3-20
3-22
3-23

3-1

3-2

Introduction

If your IBM Personal Computer has a fixed disk, there
are several facts you need to know, and several steps to
take before DOS is able to use it. If you try to use your
fixed disk before you take the following steps, you will
get the error message:
Invalid drive specification

The first section in this chapter, "Fixed Disk Drive
Letters" describes how drive letters are used with the
fixed disk. The remaining sections describe how to
prepare your fixed disk for DOS.
Note: If your fixed disk is in an expansion unit
(not in the system unit), the expansion unit must
be turned on before you turn on the system unit.
A fixed disk can be divided up into separate areas
called partitions. There can be from one to four
partitions on a fixed disk. These partitions can be
different sizes. Each partition is set up through a Fixed
Disk Setup Program (called FDISK) provided by the
operating system that will use it.
You will use the DOS Fixed Disk Setup Program to set
up the DOS partition. Fixed disk drives are referred to
in the same way you refer to diskette drives, using the
fixed disk drive specifier when you want to read from or
write to the fixed disk.

3-3

If DOS is the only operating system that you intend to
use with the fixed disk, you will want to assign all of the
fixed disk space for use with DOS. Follow the steps in
" Preparing Your Fixed Disk" to assign all of the fixed
disk space to the DOS partition.
If you do intend to use part of the fixed disk with other
operating systems, then you will need to divide up the
available fixed disk space among them. Follow the steps
in "Partitioning Your Fixed Disk" to assign a specific
amount of disk space to DOS.
If you are not sure whether you will be using any other
operating system with the fixed disk, you should go
ahead and assign all of the fixed disk space to DOS as
described in "Preparing Your Fixed Disk." If you
decide later to use another operating system, you can
use the BACKUP command to backup your files in
your DOS partition, reassign the DOS partition, and
then use the RESTORE command to restore your files
from diskettes. After you have followed the instructions
in "Preparing Your Fixed Disk" or "Partitioning Your
Fixed Disk," you will need to follow the instructions in
"Setting Up the DOS Partition" in order to make the
partition you have created useable by DOS.
The menus and screens that make up the Fixed Disk
Setup Program have been designed to make it easy for
you to set up your fixed disk. When the Fixed Disk
Setup Program asks you to enter something, it displays
a default answer for you. If that is the answer you want,
you need merely press the Enter key. If you want to
enter something else, simply type in the entry you want
and then press the Enter key.

3-4

Fixed Disk Drive Letters
You already know that if you have two diskette drives
on your system, they are known to DOS as A and B. If
you have only one diskette drive on your system, there
are still two diskette drives (A and B) known to DOS.
But in this case, they are simulated on the same
physical drive. (If you are not yet familiar with this
concept, please refer to "How to Use DOS With One
Diskette Drive" in Chapter 1 of the DOS User's Guide
before you continue.)
When DOS starts, it first assigns letters to all of the
diskette drives it knows about, then assigns the
following letters to your fixed disks. For example, if you
have one or two diskette drives, and one fixed disk, the
letters A and B apply to the diskettes, and your fixed
disk is known to DOS as C (if you had a second fixed
disk, it would become D).

3-5

Preparing Your Fixed Disk

If DOS is the only operating system that you intend on
using with your fixed disk, follow the instructions in this
section. All of the fixed disk space will be assigned for
use with DOS.
If you intend to use part of the fixed disk with another
operating system, then you should go to "Partitioning
Your Fixed Disk" in this chapter.
In order to prepare the fixed disk for use with DOS, you
must first use the FDISK command as follows:
1.

With your DOS diskette in drive A and the DOS
prompt (A» on the screen, type:
FDiSK

and press Enter. The following screen appears:
IBM Personal Computer
Fixed Disk Setup Program Version 1.00
(C)Copyright IBM Corp. 1983
FDiSK Options
Current Fixed Disk Drive: 1
Choose one of the following:

1.
2.
3.
4.
5.

Create DOS Partition
Change Active Partition
Delete DOS Partition
Display Partition Data
Select Next Fixed Disk Drive

Enter choice: [1]

3-6

The current fixed disk drive and option 5 will only
be shown if your system has more than one fixed
disk drive. If you want to set up the DOS partition
on the next drive, type:
5

and press Enter. The Fixed Disk Setup Program
will allow you to create an active partition on a
fixed disk other than the first fixed disk. However,
DOS can only be started from the first fixed disk
(refer to "Changing the Active Partition" in this
chapter to change the partition status). You will
see the drive number change on the screen after
you press Enter.
2.

Type:

and press Enter to set up the fixed disk for use
with DOS. If the fixed disk has not already been
set up for DO S or another operating system, then
the following screen appears:
IBM Personal Computer
Fixed Disk Setup Program Version 1.00
(C)Copyright IBM Corp. 1983
Create DOS Partition
Current Fixed Disk Drive: 1

Do you wish to use the entire fixed disk
for DOS (yiN) ..................... ? [Y]

If your fixed disk has already been set up, then you
will see a different screen that shows how the fixed
disk partitions have been assigned, and you will get
a different prompt. If this happens, you should
follow the steps in "Partitioning Your Fixed Disk"
in this chapter.

3-7

3.

You should press Enter since you want to use the
entire fixed disk for DOS. The Fixed Disk Setup
Program will then assign the fixed disk to DOS,
and display the following message:
Insert DOS diskette in drive A:
Press any key when ready ...

4.

You must now restart DOS so that it will
recognize your fixed disk and assign a drive letter
to it. With your DOS diskette in drive A, press
any key to restart DOS.

Your fixed disk has now been set up with a DOS
partition. But before DOS can use it, DOS needs to
create a directory and other information in the partition.
To do this, follow the instructions in "Setting Up the
DOS Partition."

3-8

Setting Up the DOS Partition

The DOS fixed disk partition must be formatted by the
DOS FORMAT command before it can be used. You
should only follow these instructions if the DOS
partition has been created, but has not already been
formatted and used to store data. This is because any
data in the partition will be destroyed by the format
operation.
1.

Make sure your DOS diskette is in drive A and the
DOS prompt (A» is on the screen.
If DO S is to be started from the fixed disk, enter:

FORMAT d:/S/V
If the partition is not to contain a copy of DOS

(not to be automatically started), enter:
FORMAT d:/V

In either case, substitute the correct fixed disk
drive letter for the d in the command (for example,
if you have 1 or 2 diskette drives, you would enter
C, as shown in the following screens). This prompt
now appears:
Press any key to begin formatting drive C:

3-9

2.

Press any key. The red light on your fixed disk
drive will light up, and the message:

C
__

F_or_m_a_t_ti_n_g,_,,_____________________________)

appears on the screen. Do not be alarmed if
several minutes go by before you see any more
messages. DOS is checking the data in every
location in the DOS partition and it takes several
minutes. You will see the message:

C
__

F_D_rm_a_t_c_o_m_p_l_et_e__________________________)

and, if you used IS in your FORMAT command,
you also see the message:

C
__

S_y_st_e_m__
tr_a_ns_f_e_rr_e_d__________________

~____)

This tells you that a copy of DOS has been placed
on the fixed disk.
Then the following message appears:
Volume label [11 characters, ENTER for name)?

3.

Enter a 1-11 character volume label (for example,
MYFIXEDDISK) that is used to identify the
fixed disk when DIR and CHKDSK displays
information. If you do not want to label the fixed
disk, just press Enter; however, please note that
you cannot add a volume label later , so we
recommend entering one now.
FORMAT then displays the disk space statistics
and the DOS prompt:

A>

3-10

Your fixed disk is now completely usable by DOS.
If you have placed a copy of DOS on the fixed
disk, we recommend that you do the following two
steps:
4.

With your DOS diskette still in drive A, enter:
COpy

*.* d:

Remember to use a correct fixed disk letter for
your system. This copies all the programs on the
DOS diskette to your fixed disk. Once these
programs are copied, all DOS commands can be
run from the fixed disk -and your DOS diskette can
be stored away in a safe place.
Also, remember to copy the programs from your
DOS Supplemental Program diskette in the same
manner, if you will be using these programs.
5.

Remove the DOS diskette from drive A (leave the
diskette drive door open) and press the Ctrl, Alt,
and Del keys simultaneously (System Reset). If
you have correctly followed the steps above, and a
copy of DOS was stored in the DOS partition,
DOS will start from the fixed disk and you will be
asked to enter the date and time.
Note: Drive A must be empty (no diskette
or the diskette drive door open) in order for
this to work correctly. This is because the
computer will first try to load an operating
system from drive A. If a diskette cannot be
read from drive A, then (and only then), the
computer will try to load an operating system
from the first fixed disk on the computer.

3-11

When you have entered the date and time, you will
notice that the DOS prompt (A» has now
changed. Instead of the letter A> , you will see the
drive letter of your fixed disk. DOS remembers
which drive it was started from, and makes that
drive the default drive.
If you have followed the instructions above, your
fixed disk is now completely initialized.

3-12

Partitioning Your Fixed Disk

In order that more than one operating system can use
the fixed disk, the fixed disk must be divided into
separate areas called partitions. There can be from one
to four partitions on the fixed disk. These partitions can
be different sizes and can be set up in any order . You
can specify which partition the system will get control
of when you start or restart your computer. An
operating system can only access one partition. You
cannot transfer data directly from one partition to
another.
Each operating system that supports the fixed disk
provides a program to allow you to create a partition for
use under that system. If you try to read from, or write
to, the fixed disk using a system that has no partition
assigned to it, you will get an error message.
The DOS Fixed Disk Setup Program can only be used
to create or delete the DOS partition. A partition set up
for another operating system can only be created or
deleted from that operating system.
You can set up one partition for use under DOS at the
location and size you choose. You can also delete the
DOS partition if, for example, you want to create it
again at a different size or location on the fixed disk.
The following functions are supported by the DOS
Fixed Disk Setup Program:
•

Create the DOS partition.

•

Change the active partition (the one that will be
started when the system is restarted).

3-13

•

Delete the DOS partition.

•

Display fixed disk partition data.

•

Select next fixed disk drive.

These functions are described below in separate
sections. In order to get access to them, you need to
start the Fixed Disk Setup Program as follows:
1.

To start, type:
d:FDISK

and then press Enter. Where d: is the drive where
the F;DISK.COM program resides.
2.

If it is on the default drive, just type:
FDiSK

and press Enter . You will then see the following
screen:
IBM Personal Computer
Fixed Disk Setup Program Version 1,00
(C) Copyright IBM Corp. 19S3

FDiSK Options
Current Fixed Disk Drive: 1

Choose one of the following:

1.
2.

Create DOS Partition
Change Active Partition

3.

Delete DOS Partition

4.

Display Partition Data

5.

Select Next Fixed Disk Drive

Enter choice: [1]

3-14

The current fixed disk drive and option number 5
will be shown only if your system has more than
one fixed disk drive. Option 5 selects the next
fixed disk drive. The Fixed Disk Setup Program
will allow you to create an active partition on·a
fixed disk other than the first fixed disk. However,
DOS can only be started from the first fixed disk.
The partition's status is shown as A for active and
N for not active (refer to "Changing the Active
Partition" in this chapter to change the partition
status).
Type the number of the option you want and press
the Enter key. Note that option 1 is the default and
will automatically be selected if you don't type an
option number before pressing Enter. Proceed to
the section below that describes the option you
selected.

Creating the DOS Partition (Option 1)
You can use this option to create the DOS partition. In
order to do so, you need to determine where it should be
located and how large it should be. If there is already a
partition assigned to DOS, you will see an error
message.
A fixed disk is divided into parts called cylinders. The
number of cylinders and their sizes can vary depending
on the fixed disk. AID-megabyte disk contains 305
cylinders and each cylinder contains 34,816 bytes or
characters of information. If you wanted to assign the
whole fixed disk for use under DOS, you would specify
the size as 305 cylinders and the starting cylinder
number as 000.

3-15

The screen you see depends on whether the fixed disk
has any partitions. If it has been initialized, go to step 2.
If not, the following screen appears:
IBM Personal Computer
Fixed Disk Setup Program Version 1.00
(C) Copyright IBM Corp. 1983
Create DOS Partition
Current Fixed Disk Drive:

Do you wish to use the entire fixed
disk for DOS (yIN) ............................. ? [Y]

1.

If DOS is the only operating system that you
intend on using with the fixed disk, then you
should follow the instructions in "Preparing Your
Fixed Disk" in this chapter. Otherwise, type:
n

and then press the Enter key. The following
message appears:
Total fixed disk space is xxxx cylinders.
Maximum available space is xxxx.
cylinders at cylinder xxxx.

These lines show the total number of cylinders on
your fixed disk. Proceed to step 3.

3-16

2.

You will see a screen similar to the following if
your fixed disk has already been set up:
IBM Personal Computer
Fixed Disk Setup Program Version 1.00
(C) CoPvright IBM Corp. 1983
Create DOS Partition
Current Fixed Disk Drive:

Partition
1
2
3

Status
N
A
N

Tvpe
non-DOS
non-DOS
non-DOS

Start End
000 049
050 099
250 304

Size

50
50
55

Total fixed disk space Is 305 evls.
Max avail space Is 150 evls at evl 100.

The "Create DOS Partition" screen shows a
sample fixed disk with 3 partitions. Note that this
is not necessarily a recommended setup. It is
shown only as an example.
The line with the current fixed disk drive will only
appear if you have more than one fixed disk drive.
There will be one line shown for each assigned
partition.
The Partition column shows the relative number of
the partition (in the order it appears on the fixed
disk).
The status column shows which partition's system
gets control when the system unit is started from
the fixed disk. That partition's status is shown as
A (for active), the others are shown as N (for not
active).

3-17

The Type column shows which partition, if any, is
the DOS partition.
The Start and End columns show the starting and
ending cylinder numbers for a partition and the
Size column shows its size in cylinders.
The next line shows you the total amount of space
on the fixed disk, and the line after that shows you
the size of the largest available space that you
could use for a partition and where it is located on
the fixed disk.
3.

The following prompt appears:

J

-------

( Enter partition size ............ : [xxxx)

The partition size entry defaults to the largest
available space on the fixed disk. If you want your
DOS partition to use the largest available space,
simply press the Enter key. Otherwise, type in the
size you want (in cylinders) and press the Enter
key. The next prompt is:
( Enter starting cylinder number.. : [xxxx[

)

-------

4.

The starting cylinder number default depends on
the partition size you specified above. It is the first
cylinder of the largest space on the fixed disk large
enough for the partition. If you want the DOS
partition to be located there, press the Enter key.
Otherwise, type in the starting cylinder number
you prefer and press the Enter key. The cursor is
placed at the bottom of the screen and you see this
message:

( Press Esc to return to FDISK Options [ [

3-18

J

Note that the lines on the screen change to show
the new active partition. The DOS partition has
now been created. With your DOS diskette in
drive A, press the Ctrl, Alt, and Del keys
simultaneously (System Reset).
If you need the partition you just created to be
active (startable), follow the steps in "Changing
Active Partition (Option 2)."
Your DOS partition has been created but you still
need to follow the instructions in "Setting Up the
DOS Partition" in this chapter before you can use
the DOS partition.

Changing the Active Partition (Option 2)
Select this option when you want to start a different
operating system in another partition. You will see a
screen similar to the following:
IBM Personal Computer
Fixed Disk Setup Program Version 1.00
(C) Copyright IBM Corp. 1983
Change Active Partition
Current Fixed Disk Drive:
Press Esc to return to Utility Options
Partition
1
2
3

Status
N
N
A

Type
non-DOS
non-DOS
DOS

Start
000
050
150

End
049
149
304

Size
50
100
155

Total disk space is xxxx cylinders
Enter the number of the partition you
want to make active ............... : [ ]

3-19

1.

Enter the number of the partition whose operating
system you want to get control when the system is
started from the fixed disk. The following message
appears:

C
____

p_re_S_s_E_S_c_t_D_r_ot_u_rn__
to__
FD_I_S_K_D_P_ti_Dn_S__
[]________

~)

Note that the lines on the screen change to show
the new active partition.
2.

Press the Esc key to return to the FDISK options
menu and press it again to return to DOS.
If you want to start the operating system in the
partition you just made active, perform the
following steps:
a.

Open the diskette drive A door.

b.

Press and hold Ctrl and Alt, and then press
Del.

The operating system in the active partition should
then start.

Deleting the DOS Partition (Option 3)
Note: This option could result in loss of the data
in the DOS partition so make sure you have
backed up all of your files before you proceed.
1.

You will need to insert a DOS diskette and restart
the system from diskette drive A if you want to
continue processing under DOS.
If you want to start a system in another fixed disk
partition, you should change the active partition to
that partition number before you delete the DOS
partition.

3-20

You will see a screen similar to the following:
!BM Personal Computer
Fixed Disk Setup Program Version 1.00
(C]Copyright IBM Corp, 1983
De~ete

DOS Partition

Current Fixed Disk Drive:

Pall'titDol1l
2

Status
N
N

~

tNJ

~

At

1

1rtO~aJ~ f~xe!dJ

disk space

Tvpe
non-DOS
non-DOS
[»08
non-DOS
~:s

uxx

Start

End

000
050
Him

049
099
249

250

304

Size
50

50
150

55

cv~hulers

W~rrtling!

[Bata hll the DOS partUion
IDle! you wish to
~o~1tfill1lue .. """""." ...... ",,, ...... ,,.? [N]

cmlid be

2.

~[flst.

If you have backed up all of your files and are
ready to continue, type Y and press Enter. If you
decide to cancel the operation, press either the
Enter key or the Esc key to return to the FDISK
options menu.
If you type Y and press Enter, the partition
information displayed on the screen is updated,
and the following message appears:

(~__p_r_e_SS__Es_c_t_o_r_e_tu_r_n_t_o_f_D_IS_K_O_P_t_iO_n_8_[_]_________)
The DOS partition has now been deleted. You will
need to start another system from the fixed disk or
restart DO S from a diskette to proceed.

3-21

Displaying Partition Data (Option 4)
You can use this option to display fixed disk status
information. Your screen appears similar to the
following:
IBM Personal Computer
Fixed Disk Setup Program Version 1.00
(C) Copyright IBM Corp. 1983
Display Partition Information
Current Fixed Disk Drive: 1

Partition

Status

1

A

2

N

Type
DOS
non-DOS

Start
000
200

End
199
304

Size
200
105

Total fixed disk space is xxxx cylinders

The line with the current fixed disk drive appears only if
you have more than one fixed disk drive.
One line is shown for each assigned partition.
The Partition column shows the relative number of the
partition (in the order it appears on the fixed disk).
The Status column shows which partition's system gets
control when the system unit is started from the fixed
disk. That partition's status is shown as A (for active),
the others are shown as N (non-active).
The Type column shows which partition, if any, is the
DOS partition.

3-22

The Start and End columns show the starting and
ending cylinder numbers for a partition, and the Size
column shows its size in cylinders.
The next line shows you the total amount of space on
the fixed disk.
Press the Esc key when you are ready to return to the
FDISK options menu.

Selecting Next Fixed Disk Drive
(Option 5)
Select this option when you want to use the DOS Fixed
Disk Setup Program with the next fixed disk drive.
After you have entered the option, you see the current
fixed disk drive number change on the FDISK options
menu.
This option is available only if your system has more
than one fixed disk drive.

3-23

3-24

Chapter 4. Configuring Your System

Contents
Introduction ............................

4-3

Configuration Commands ................ 4-3
BREAK Command .................. 4-4
BUFFERS Command ................ 4-5
What Is a Buffer? ............... 4-5
Read/Write Requests ............ 4-5
Random/ Sequential
Applications ................... 4-6
Size of Your Computer ........... 4-7
DEVICE Command ................. 4-8
Loading Standard Device
Drivers ....................... 4-8
Replacing Standard Device
Drivers ....................... 4-8
Installing Your Own Device
Driver ........................ 4-8
FILE S Command ................... 4-9
Accessing a File ................ 4-9
Number of Files Opened ........ 4-10
SHELL Command ................. 4-10

4-1

4-2

Introduction

Each time DOS is started, it searches the root directory
of the drive (from which it was started) for a special
configuration file named CONFIG.SYS. If found, it
reads the file and interprets the text commands within it.

Configuration Commands

The following commands can be included in the
configuration file. If you add or change any of the
configuration file commands, they will become effective
the next time DOS is started.

4-3

BREAK Command

BREAK=ON/OFF
This command should only be used once in the
configuration file. The default value is OFF, and causes
DOS to check for Ctrl-Break being entered at the
standard input device only when DOS is performing an
operation involving:
•

A standard output device

•

A standard input device

•

A standard print device
or

•

An Asynchronous Communication Adapter

With this setting, it may not be possible to cancel an
executing program by using Ctrl-Break unless the
program causes DOS to perform one of those four
operations. Specifying ON causes DOS to check for
Ctrl-Break whenever it performs any function for a
program. This allows you to "break" out of programs
that perform few (or no) standard output device,
standard input device, standard print device, or
auxiliary device operations (such as compilers). The
ON/OFF state set in the configuration file can later
be changed by issuing a BREAK command (see
Chapter 2).

4-4

BUFFERS Command
BUFFERS=xx
Where xx is a number between 1 and 99. This is the
number of disk buffers that DOS should allocate in
memory when it starts up. The default value is 2, and
this value will remain in effect until DOS is restarted
with a different value specified in the configuration file.

What Is a Buffer?
A disk buffer is a block of memory that DOS uses to
hold data being read from, or written to a disk (fixed
disk or diskette), when the amount of data being
transferred is not an exact multiple of the sector size.
For example, if an application reads a 128-byte record
from a file, DOS will read the entire sector into one of
its buffers, locate the correct 128-byte record in the
buffer, and move the record from the buffer into the
application's area of memory. It then marks that buffer
as having been used recently. On the next request to
transfer data, DOS will attempt to use a different buffer.
In this way, all of the buffers will eventually contain the
most recently-used data. The more buffers DOS has,
the more data will be in memory.

Read/Write Requests
Each time DOS is requested to read or write a record
that is not an exact multiple of the sector size, it first
looks to see if the sector containing that record is
already in a buffer. If not, it must read the sector as
described above. But if the data is already in a buffer,
then DOS can simply transfer the record to the
application's area without the need to read the sector
from the disk-this saves time. This savings is realized
on both reading and writing records, since DOS must
first read a sector before it can insert a record your
application is attempting to write.
4-5

Random/Sequential Applications
F or applications that read and write records in a
random fashion (such as many Basic and data base
applications), the likelihood of finding the correct record
already in a buffer increases if DOS has more buffers to
work with. This can greatly speed up the performance of
those applications.
F or applications doing sequential reads and writes,
however (read an entire file, write an entire file), there
is little advantage to having a large number of buffers
allocated.
Because all applications are different, there is no
specific number of buffers that will serve all
applications equally well. If your applications do little
random reading and writing of records, the system
default of 2 buffers (if you do not specify BUFFERS=
in your configuration file) should be sufficient.
However, if you use data-base type applications, or run
programs that perform a lot of random reads and writes
of records, you will want to increase the number of
DOS buffers. The "best" number of buffers for your
particular application can only be determined by using
different values until the best performance is achieved.
F or most data base applications, a value between 10
and 20 buffers will usually provide the best results.
Beyond that point, the system may appear to start
running slower-this is because, with a very large
number of buffers it can take DOS longer to search all
the buffers for the record than it would take to read the
record from disk.

4-6

Size of Your Computer
The final consideration in determining the number of
buffers to allocate is the memory size of your computer.
Since each additional buffer increases the resident size
of DOS by 528 bytes, the amount of memory available
to the application is reduced by that amount. Therefore,
additional buffers may actually cause some applications
to slow down, since there is less memory in which the
application itself can keep data-this could result in
more frequent reads and writes than would otherwise be
necessary.
In summary, the optimum number of buffers must be
determined by you, based on:
1.

The types of applications most often used

2.

The memory size of your computer

3.

Your analysis of system performance when using
your applications with different numbers of buffers
allocated.

4.

For computers with fixed disks, we recommend a
minimum of BUFFERS=3.

4-7

DEVICE Command
DEVICE=[d:] [path].filename[.ext]
This command allows you to specify the name of a file
containing a device driver. During startup, DOS loads
the file into memory as an extension of itself, and gives
it control as described in "Installation of Device
Drivers" in Chapter 3 of DOS Technical Reference.
Please refer to that section for technical information
about install able device drivers.

Loading Standard Device Drivers
The standard device drivers loaded by DOS support the
standard screen, keyboard, printer, auxiliary device,
diskette, and fixed disk devices. A clock driver is also
loaded (see Chapter 3 of the DOS Technical Reference
manual). You don't need to specify any DEVICE=
commands for DOS to support these devices.

Replacing Standard Device Drivers
If you wish to use the "Extended Screen and Keyboard
Control" features described in Chapter 2 of the DOS
Technical Reference manual, you should create the file
CONFIG.SYS on the disk you will be starting DOS
from. The file should contain the command
DEVICE=ANSI.SYS. This command causes DOS to
replace the standard screen and keyboard support with
the extended functions.

Installing Your Own Device Driver
F or systems programmers and application developersif you have written device drivers that you want DOS to
load when it starts, include a DEVICE= command in
the CONFIG.SYS file for each driver to be loaded.
4-8

FILES Command
FILES xx
The maximum value for xx is 99.
Beginning with DOS Version 2.00 and 2.10, there is no
need for an application to construct a special control
block (FeB) in order to access a file. Instead, the
program can simply specify an ASCII string consisting
of drive specifier, complete directory path name and
filename when opening or creating a file. DOS will
locate the correct drive, directory and file, and will
create and return a handle-merely a l6-bit binary
value.

Accessing a File
All file accesses (reads, writes, close) can then be
performed by telling DOS which handle to use. When
an application opens a file in this manner, DOS
constructs a control block in its own memory on behalf
of the application, in an area that was set aside when
DOS started. The size of this area (and consequently,
the maximum number of files that can be concurrently
open), depends on the value specified in the FILES=
command.
The default value is FILES=8; that is, no more than 8
files can be open at the same time. There is no effect on
the number of files that can be concurrently open using
the traditional (OPEN FCB) functions. This default
value is sufficient for the majority of operating
environments. However, if applications are installed
that result in error messages indicating an insufficient
number of handles, the FILES= command should be
used to provide DOS with additional handles.

4-9

Number of Files Opened
The value specified in FILES= becomes the new
maximum number of files that DOS allows to be
concurrently open.
Note that this value is the maximum number of files
allowed for the entire system. The maximum number of
files that a process can have concurrently open is 20
(this number includes the 5 predefined handles for
standard input, output, error, auxiliary, and standard
printer).
If you specify FILES= in your configuration file, the
size of the resident portion of DOS increases by 39
bytes for each additional file above the default value of
8. Consequently, the memory available to the
application is reduced by the same amount. See
function calls hex 3 C through hex 46 in Chapter 5 of
the DOS Technical Reference manual for descriptions
of the new file-handling functions.

SHELL Command
SHELL=[d:] [path]jilename[.ext]
This command allows you to specify the name and
location of a top-level command processor that DOS
initialization will load in place of COMMAND. COM.
System programmers who develop their own top-level
command processor should remember to include
provisions for handling interrupts hex 22, hex 23 and
hex 24, and for reading and executing commands.
Because the internal commands, batch processor, and
EXEC function call (program loader) reside in
COMMAND.COM., these functions will not be
available to the user unless they are duplicated in your
command processor.

4-10

Chapter 5. Using Tree-Structured
Directories

Contents
Introduction

5-3

Directory Types ...........................

5-5

The Current Directory .....................

5-6

Specifying the Path to a File ................

5-7

Directory Commands ......................
Creating a Subdirectory .................
Deleting a Directory ...................
Displaying and Changing the
Current Directory .....................
Displaying the Directory Structure .......

5-10
5-10
5-10
5-11
5-11

Where DOS Looks for Commands
and Batch Files .......................... 5-12

5-1

5-2

v

Introduction

Prior to Version 2.00 and 2.10, DOS used a simple
directory structure that was adequate for managing files
on diskettes. Each diskette contained a single directory
that could hold a maximum of 64 or 112 files,
depending on whether the diskette was single or dual
sided.
With the added support for fixed disks in DOS Version
2.00 and 2.10, however, a single fixed disk can hold
literally thousands of files. Keeping a large number of
files in one directory becomes inefficient for both you
and DOS (the larger a directory is, the longer it can
take DOS to search for a file).
DOS Version 2.10 gives you the ability to better
organize your disk by placing groups of related files in
their own directories-all on the same disk (fixed disk
or diskette).

5-3

For example, let's assume that the XYZ company has
two departments (sales and accounting) that share an
IBM Personal Computer. All of the company's files are
kept on the computer's fixed disk. The logical
organization of the file categories could be viewed like
this:
Disk

Sales

David

~

/I

ReLl

Customer.lst

Joanne

I

Reports

Acctng

""

Don

I

Reports

Karol

f.Jrts

Accounts.rec

With DOS Version 2.10, it is possible to create a
directory structure that matches the file organization.
With this ability, all of DAVID's report files can be
grouped together in a single directory (called
REPORTS), separated from all the other files on the
disk. Likewise, all of the accounts receivable files can
be in a unique directory, and so on.

5-4

Directory Types

As in previous versions of DOS, a single directory is
created on each disk when you FORMAT it. That
directory is called the root directory, or system
directory.
A root directory on diskette can hold either 64 or 112
files- the maximum number of files in a fixed disk root
directory depends on the size of the DOS partition on
the disk.
In addition to containing the names of files, the root
directory can also contain the names of other
directories; and these in tum can contain the names of
other files and directories; and so on.
Unlike the root directory, these other directories called
subdirectories are actually files, and are therefore not
restricted in size-they can contain any number of files
and subdirectories, limited only by the amount of
available space on the disk.
The subdirectory names are in the same format as
filenames-a name of 1-to-8 characters optionally
followed by a period and an extension of 1-to-3
characters. All characters that are valid for a filename
are also valid for a directory name. Each directory can
contain file and directory names that also appear in
other directories. In other words, two or more files or
directories can have the same name, as long as they are
defined in separate directories.

5-5

The Current Directory

Just as DOS remembers a default drive, it can also
remember a default directory for each drive on your
system. This is called the current directory, and is the
directory that DOS will search if you enter a filename
without telling DOS which directory the file is in. You
can change the current directory or find out what your
current directory is for any drive by issuing the CHDIR
command (described in Chapter 2). When DOS is
started, it will automatically use the root directory as
the current directory for each drive until you issue a
CHDIR command.

5-6

Specifying the Path To a File

When you want DOS to create or search for a file,
DOS must know three things-the drive, the name of
the file, and the name of the directory containing the
file.
If the file is in the current directory, you don't need to
specify a directory-DOS automatically looks in the
current directory.
But if the file is not in the current directory, you must
supply DOS with the path of directory names leading to
the desired directory. The path you specify can be
either the path of names starting with the root directory,
or the path from the current directory.
The path consists of a series of directory names
separated by backslashes (\). If a filename is included,
it must also be separated from the last directory name
by a backs lash.
If a path begins with a backslash, DOS starts its search
from the root directory; otherwise, the search begins at
the current directory.

For example, if the current directory is DAVID, and
you Jant to find file ANNUAL.FIG in DAVID's
REPORTS directory, you can specify it in either of
these ways:
\SALES\OAVIO\REPORTS\ANNUAL.FIG

or
REPO RTS\AN NUAL. FI G

5-7

In the first case, the full path from the root directory
(leading backs lash) was specified. In the second case
(no leading backslash), the path from the current
directory was given.
Each subdirectory contains two special entries-you'll
see them listed when you use the DIR command to list
a subdirectory. The first contains a single period
instead of a filename-it identifies this "file" as a
subdirectory. The second entry contains two periods
instead of a filename, and is used by DOS to locate the
higher level directory that defines this directory, the
parent of this directory. For example, in the file
organization illustration shown on the first page of this
chapter, the parent of the directory named JOANNE is
the one named SALES.
This second special entry can be quite useful when you
specify a path to DOS, because entering two periods is
a shorthand way of telling DOS to back up one
directory level. For example, if the current directory is
DAVID, and you want to find file SUMMARY in
JOANNE's REPORTS directory, you can specify it in
either of these ways:
\SALES\JOANNE\REPORTS\SUMMARY

or
..\JOANNE\REPORTS\SUMMARY

The second case causes DOS to back up one level from
the current directory (to the current directory's parent),
and to continue the path from there. The double period
can be used more than once in a path-it simply causes
DOS to back up one level each time it is specified.

5-8

You can specify which drive to use by including a drive
specifier ahead of the path and filename string. For
example:
B:\LEVEL1\MYfILE

Notice that when defining a path, the drive is specified
ahead of the path, rather than the filename.
Nearly all of the DOS commands that accept filenames
also accept path names. For example, if you enter:
DlR \ACCTNG\KAROL\REPORTS

all of the files in KAROL's REPORTS directory are
listed. Similarly, if you enter:
DEL \ACCTNG\KAROL\REPORTS

DOS assumes you want to erase all the files in
KAROL's REPORT directory.
In all cases, to refer to a specific file, simply add the
filename to the end of the path (separated from the path
by a backs lash, of course ).
To refer to the root directory (if the root is not the
current directory), enter one backslash. For example, if
the current directory is DAVID, issuing:
DlR

\

will list all the files in the root directory.
You can create as many subdirectories as you wish.
However, you should ensure that the longest path you
create (from the root to the last directory in a single
path) can be expressed in 63 characters or less.

5-9

\/ Directory Commands

The following commands,. new in DOS Version 2.00
and 2.10, are included to help you create and manage
your directory structure. A brief explanation of each is
presented here-for more detailed information, please
refer to the individual command descriptions in
Chapter 2.
System programmers and application developers should
also refer to the IBM DOS Technical Reference,
particularly Chapter 5 for descriptions of the DOS
function calls.

Creating a Subdirectory
The MKDIR (MD) command is used to create new
directories. Be sure to include the appropriate drive and
path, ending with the name of the new directory you
want created. Also, be sure that the full path from the
root to the new directory name is 63 characters or less.

Deleting a Directory
Directories can be deleted (removed) only with the
RMDIR (RD) command. They cannot be deleted with
the ERASE or DEL commands. A directory can be
removed only if it is empty-that is, it has no files or
subdirectories other than the two special entries shown
as . and .. in the D IR command display. The last
directory name in the specified path is removed-only
one directory at a time can be deleted. The root
directory and the current directory cannot be deleted.

5-10

Displaying and Changing the
Current Directory
The CHDIR (CD) command is used to tell DOS which
directory path it should "remember" as the current
directory. Enter just a backslash for the root, or a full
path for any other directory. The current directory is
where DOS will look to find commands and files whose
names are entered without path specifiers.
Entering CHDIR or CD with no parameters (or only a
drive specification) causes DOS to display the current
directory for the drive.

Displaying the Directory Structure
The TREE command will produce a report describing
the entire directory structure of a disk. Included in the
report are all directory paths and, optionally, the names
of all files in each subdirectory.

5-11

Where DOS Looks for Commands
and Batch Files

When you enter a command, DOS searches the current
directory for it (if the command is not built-in). The
PATH command allows you to specify a series of
additional paths that DOS can search if it does not find
the command in the current directory. The PATH
command is described in Chapter 2.

5-12

Chapter 6. The Line Editor
(EDLIN)

Contents
Introduction

6-3

How to Start the EDLIN Program ..........
Editing an Existing File .................
Editing aNew File .....................

6-5
6-5
6-6

The EDLIN Command Parameters .........

6-7

The EDLIN Commands ...................
Information Common to All
EDLIN Commands ...................

6-9

Append Lines Command

6-9
6-11

Copy Lines Command ..................... 6-12
Delete Lines Command .................... 6-13
Edit Line Command

6-17

End Edit Command

6-20

Insert Lines Command ..................... 6-21
List Lines Command ...................... 6-25
Move Lines Command ..................... 6-30

6-1

Page Command ........................... 6-31
Quit Edit Command ....................... 6-32
Replace Text Command .................... 6-33
Search Text Command ..................... 6-37
Transfer Lines Command .................. 6-41
Write Lines Command ..................... 6-42
Summary of EDLIN Commands ............ 6-43

6-2

lntroduction

In this chapter, you will learn how to use the Line
Editor (EDLIN) program.
You can use the Line Editor (EDLIN) to create,
change, and display source files or text files. Source
files are unassembled programs in source language
format. Text files appear in a legible format.
ED LIN is a line text editor that you can use to:
•

Create new source files and save them

•

Update existing files and save both the updated
and original files

•

Delete, edit, insert, and display lines

•

Search for, delete, or replace text within one or
more lines

The text of files created or edited by EDLIN is divided
into lines of varying length, up to 253 characters per
line.
Line numbers are generated and displayed by ED LIN
during the editing process, but are not actually present
in the saved file.

6-3

When you insert lines, all line numbers following the
inserted text advance automatically by the number of
lines inserted. When you delete lines, all line numbers
following the deleted text decrease automatically by the
number of lines deleted. Consequently, line numbers
always go consecutively from 1 through the last line
number.
Note: EDLIN will erase the original backup
copy (.BAK) of the file when you issue an E (end
edit) command, or if the disk space is required
during the editing session to satisfy a W (write
lines) command.

6-4

How to Start the EDLIN Program

To start EDLIN, enter:
EDLIN [d:][path]filename[.ext][/BI

Editing an Existing File
If the specified file exists on the designated or default
drive, the file is loaded into memory until memory is
75% full. If the entire file is loaded, the following
message and prompt is displayed:
End of input file
*

You can then edit the file.
Note: If you have not used the /B parameter,
EDLIN will stop loading the file when the first
Ctrl-Z is encountered in the file's text. If you wish
to edit a file that is known to contain embedded
Ctrl-Z characters (end-of-file marks), you should
use the /B pararrteter. EDLIN will then process
the entire file regardless of any embedded
'
end-of-file marks.
Notice that the prompt for EDLIN is an asterisk (*).
If the entire file cannot be loaded into memory, ED LIN
loads lines until memory is 75% full, then displays the *
prompt. You can then edit the portion of the file that is
in memory.

6-5

To edit the remainder of the file, you must write some
of the edited lines to disk in order to free memory so
that you can load unedited lines from disk into memory.
Refer to the Write Lines and Append Lines commands
in this chapter for the procedure you will use.

Editing aNew File
If the specified file does not exist on the drive, a new
file is created with the specified name. The following
message and prompt are displayed:
New file

'*
You can now create a new file by entering the desired
lines of text. To begin entering text, you must enter an I
command to insert lines.
When you have completed the editing session, you can
save the original and updated (new) files by using the
End Edit command. The End Edit command is
discussed in this chapter in the section called "The
EDLIN Commands." The original file is renamed to an
extension of .BAK, and the new file has the filename
and extension you specified in the EDLIN command.
N ote: You cannot edit a file with a filename
extension of .BAK with EDLIN because the
system assumes it is a backup file. If you find it
necessary to edit such a file, rename the file to
another extension; then start ED LIN and specify
the new name.

6-6

The EDLIN Command Parameters

Parameter

Definition

line

Denotes when you must specify a line number.
There are three possible entries that you can
make using this parameter:

1.

Enter a decimal integer from 1-65529. If
you specify a number greater than the
number of lines that are in memory, the
line will be added after the last line that
exists.
Line numbers must be separated from each
other by a comma or space.
OR

2.

Enter a pound sign (#) to specify the line
after the last line in memory. Entering a #
has the same effect as specifying a number
greater than the number of lines in
memory.

6-7

Parameter

Definition
OR

line

3.

Enter a period (.) to specify the current
line.
The current line indicates the location of
the last change to the file, but it is not
necessarily the last line displayed. The
current line is marked by an asterisk (*)
between the line number and the first
character of text in the line. For example:
lO:*FIRST CHARACTER OF TEXT

n

Denotes when you must specify a number of
lines.
Enter the number of lines that you want to write
to diskette or load from diskette.
You only use this parameter with the Write
Lines and Append Lines commands. These
commands are meaningful only if the file to be
edited is too large to fit in memory.

string

Denotes when you must enter one or more
characters to represent text to be found,
replaced, deleted, or to replace other text.
You only use this parameter with the Search
Text and Replace Text commands.

6-8

The EDLIN Commands

This section describes the ED LIN commands and tells
how to use them. The commands are in alphabetical
order; each with its purpose, format and remarks.
Examples are provided where appropriate.

Information Common to All EDLIN
Commands
The following information applies to all ED LIN
commands:
•

With the exception of the Edit Line command, all
commands are a single letter.

•

With the exception of the End Edit and Quit Edit
commands, commands are usually preceded
and/or followed by parameters.

•

Enter commands and string parameters in
uppercase or lowercase, or a combination of both.

•

Separate commands and parameters with
delimiters for readability; however, a delimiter is
only required between two adjacent line numbers.
Remember, delimiters are spaces or commas.

•

Commands become effective only after you press
the Enter key.

•

Stop commands by pressing the Ctrl-Break keys.

•

F or commands producing a large amount of
output, press Ctrl-Num Lock to suspend the
display so that you can read it before it scrolls
away. Press any other character to restart the
display.

6-9

•

Use the control keys and DOS editing keys,
described in the DOS User's Guide, while using
EDLIN. They are very useful for editing within a
line, while the EDLIN commands can be used for
editing operations on entire lines.

•

The prompt from EDLIN is an asterisk (*).

•

It is possible to refer to line numbers relative to the
current line. Use a Minus (-) sign and a number to
indicate a line before the current line. Use a Plus
( +) sign and a number to indicate a line after the
current line. For example:

-10,+10L

This command displays 10 lines before the current
line, the current line, and 10 lines after the current
line.
•

Multiple commands can be entered on one
command line. When you enter the command to
edit a single line using [line], you must use a
semicolon to separate the commands on the line.
In the case of the Search or Replace command the
[string] can be terminated by Ctrl-Z (F6) instead
of the Enter key. Otherwise, one command can
follow another without any special delimiting
characters. For example:
15;-5,+5L
edits line 15 and then displays lines 10 through 20
on the screen.

•

6-10

Control characters can be inserted into the text, or
can be used in the strings for the Search text and
Replace text commands. To enter a control
character, press Ctrl-V, then enter the desired
control character in uppercase. For example, the
sequence Ctrl-V, followed by Z generates the
control character Ctrl-Z.

Append Lines
Command

Purpose:

Adds the specified number of lines from disk to the
file being edited in memory. The lines are added at
the end of the current lines in memory.

Format:

[n]A

Remarks:

This command is only meaningful if the file being
edited is too large to fit in memory. As many lines as
possible are read into memory for editing when you
start EDLIN.
To edit the remainder of the file that will not fit into
memory, you must write edited lines in memory to
disk before you can load unedited lines from disk into
memory by using the Append Lines command. Refer
to the Write Lines command for information on how
to write edited lines to disk.
Notes:
1.

If you do not specify the number of lines,
lines are appended to memory until
available memory is 75% full. No action is
taken if available memory is already 75%
full.

2.

The message End of input file is
displayed when the Append Lines
command has read the last line of the file
into memory.

6-11

Copy Lines
Command

Purpose:

Copies the lines in the specified range to the line
number specified by the third parameter. The new
data is placed ahead of the line that was specified in
the third parameter. This third parameter is not
optional. The operation is repeated the number of
times specified in count.

Format:

[line),[ line),line[,count)C

Remarks:

The parameter count defaults to 1. To repeat text
specify the number of times the operation is to be
performed in count. If the first parameter or the
second parameter is omitted, the default is the
current line. This effectively copies the current line to
the specified line. The file is renumbered accordingly.
The first of the copied lines becomes the current line.
F or example:
1,5,8C

copies lines 1 through 5 to line 8. Line 8 becomes the
current line.
Note: The line numbers must not overlap or
an error is reported. Also, the characters - and
+ are not allowed in the count field.

6-12

Delete Lines
Command

Purpose:

Deletes a specified range of lines.

Format:

[line][,line]D

Remarks:

The line following the deleted range becomes the
current line, even if the deleted range includes the
last line in memory. The current line and any
following lines are renumbered.
Default values are supplied if either one or both of
the parameters are omitted.
If you omit the first parameter, as in:
,lineD

deletion starts with the current line and ends with the
line specified by the second parameter. The
beginning comma is required to indicate the omitted
first parameter.

6-13

Delete Lines
Command

If you omit the second parameter, as in:
lineD

or

only the one specified line is deleted. If you omit both
parameters, as in:

only the current line is deleted, and the line that
follows becomes the current line.

Example:

Assume that you want to edit the following file. The
current line is line 29.
1:

iillh~ ~$ @l ~@JmB!l~[pJ ffBh~

2: rul$erdl fttlll df#m[!)n$~lr~~~

:l:

~hlle ltlhBJ~~tB{jJJ1l1i

4: g(jrilllll

5:

81lWmJaIllWil~r.

~h'lltel m,§IMl~frlH" @J~H'lJfflH'~U~~il1L

o

~5: 5~~ WmlidlU [l]It'JBD~l~tm~

26: tM thffil UiCes
21: ~rad ~hll~ G1l!lJm~mJr$
28: when lines are
29:*deleted.

6-14

Delete Lines
Command

If you want to delete a range of lines, from 5-25,

enter:
5,250

The result is:
1: This is a sample file
2: used to demonstrate
3: line deletion
4: and dynamic
5:*to the lines
6: and line numbers
7: when lines are
8: deleted.

Lines 5-25 are deleted from the file. Lines 26-29 are
renumbered to 5-8. Line 5 becomes the current line.
If you want to delete the current and the following
line, enter:
,60

The result is:
1: This is a sample file
2: used to demonstrate
3: line deletion
4: and dynamic
5:*when lines are
6: deleted.

6-15

Delete Lines
Command

Lines 5-6 are deleted from the file. Lines 7-8 are
renumbered to 5-6. Line 5 is still the current line, but
now it has different text.
If you want to delete a single line, say line 2, enter:
20

The result is:
1: This is a sample file
2:*line deletion
3: and dynamic
4: when lines are
5: deleted.

Line 2 is deleted. Lines 3-6 are renumbered to 2-5.
The new line 2 becomes the current line. If you want
to delete only the current line, enter:
D

The result is:
1: This is a sample file
2:*and dynamic
3: when lines are

The current line, line 2, is deleted. Lines 3-5 are
renumbered to 2-4. The new line 2 becomes the
current line.

6-16

Edit Line
Command

Purpose:

Allows you to edit a line of text. You must enter the
line number of the line to be edited, or enter a period
(.) to indicate the current line.

Format:

[line]

Remarks:

If you just press Enter, you specify that the line after

the current line is to be edited.
The line number and its text are displayed and the
line number is repeated on the line below.
You can use the control keys and the editing keys,
described in the DOS User's Guide, to edit the line,
or you can replace the entire line by typing new text.

When you press the Enter key, the edited line is
placed in the file and becomes the current line.
If you decide not to save the changed line, press
either Esc or Ctrl-Break instead of Enter. The
original line remains unchanged. Pressing the Enter
key with the cursor at the beginning of the line has
the same effect as pressing Esc or Ctrl-Break.
If the cursor is in any position other than the

beginning or the end of a line, pressing Enter erases
the rest of the line.

6-17

Edit Line
Command

Example:

Assume that you want to edit line 6. The following
display would appear on the screen:
6: This
(6:

us ial $mJm~~~ l\.I!lilfStdJOUl~!D~

~i~~rm"

The first line is your request to edit line 6, followed
by the two-line display response.
If you want to move the cursor to the letter u, press
F2 and enter:

The result is:
(6i: 'r~D$ 0$ lID $ca]f{jJjIlJ]~@ [lBUil®(j)l~B:ri~ffil ~Dlj~®"
~: 1f~D$

DS

~ $~m[)ll~(Rl._

If you want to delete the next two characters and
keep the remainder of the line, press Del twice; then
press F3.
The result is:
*6
ij: ini~

C$ SJ $Sl[jrutj]~~
6: Thes 8S a sam~~!Sl

6-18

~m~K1lru'rl~[rl ~~M~It;.

iilldite~ ~!n~,

_. _

Edit Line
Command

N ow you can take one of the following actions:
•

Press Enter to save the changed line.

•

Extend the changed line by typing more text.
You are automatically in insert mode when the
cursor is at the end of a line.

•

Press F5 to do additional editing to the changed
line without changing the original line.

•

Press Esc or Ctrl-Break to cancel the changes
you made to the line. The original contents of
the line will be preserved.

6-19

End Edit
Command

Purpose:

Ends EDLIN and saves the edited file.

Format:

E

Remarks:

The edited file is saved by writing it to the drive and
filename specified when you started EDLIN.
The original file, the one specified when EDLIN was
started, is given a .BAK filename extension. A .BAK
file will not be created if there is no original file; that
is, if you created a new file instead of updating an old
file during the editing session.
EDLIN returns to the DOS command processor,
which displays the command prompt.
Notes:

6-20

1.

Be sure your disk has enough free space to
save the entire file. If your disk does not
have enough free space, only a portion of
the file is saved. The portion in memory
that is not written to disk is lost. In this
case, your original file will not be renamed
to .BAK, and the portion of data that was
written to disk will have a filename
extension of $$$.

2.

EDLIN appends a carriage return, line
feed sequence to the end of the file if they
were not already present, to delimit the last
line of text in the file. Also, a Ctrl-Z
character is added as the last character in
the saved file. This serves as an end-of-file
mark.

Insert Lines
Command

Purpose:

Inserts lines of text immediately before the specified
line. When you create a new file, you must enter the
Insert Lines command before text can be inserted.

Format:

[line]I

Remarks:

If you do not specify line, or if you specify line as a
period (.), the insert is made immediately before the
current line.
If the line number you specify is greater than the
highest existing line number, or if you specify # as
the line number, the insertion is made after the last
line in memory.
EDLIN displays the appropriate line number so that
you can enter more lines, ending each line by
pressing Enter. During the insert mode of operation,
successive line numbers appear automatically each
time Enter is pressed.
You must press Ctrl-Break to discontinue the insert
mode of operation.
The line that follows the inserted lines becomes the
current line, even if the inserted lines are added to the
end of the lines in memory. The current line and any
remaining lines are renumbered.

6-21

Insert Lines
Command

Example:

Assume that you want to edit the following file. Line
3 is the current line:
1: This is a sample file
2: used to demaulIstrattBl
3:*;ggUll iII1!mlethllml

41:

(ffi~!dl

5:

~~me

mlUliUllmirr;
flullmber genei'a~hnil.

If you want to insert text before line 4, the entry and
immediate response look like this:

4:*

Now, if you want to insert two new lines of text,
enter:
~4

~

4:11: Farsi

U!!Ile @f te~U
new IhseJ (1J~ i~ld

fIU~W

5:*S~comll

6:*

and press Ctrl-Break.
The original lines 4 and 5 are now renumbered to
lines 6 and 7.

6-22

Insert Lines
Command

If you display the file with a List Lines command, the
file looks like this:
]:
2:

nn~s ~$ «ll $am!lll~~ ffi~~

Ufl5JlPJrdl ~Iill i!IlemlUnl$~rrafi~

3: UII1f: deletion
~: ~BU'$~

new

~BR1lff1l o~ te~d

5: $ffilrc:rullmnH rI1lew
(ffi:~(IDn[]

71:

~mll1le

~~nlilJ ®~

Re}Klt

dYB1an11lHC

mJmiJer geHmeraU!Dl!l1l.

If the two lines that were inserted had been placed at
the beginning of the file, the screen would look like
this:
"~:

fHli'sil new

~:

Second new line of text

~il1le o~ iex~

3:*11115 is iii sample file .
4: used to demonstrate
5: Une deletion
~: amlllli dynamic
71: iflHll9 IUmmber generatie[1,

If the two lines that were inserted had been placed
immediately before the current line (3 I or . I or I),
the screen would look like this:
~: Ih~s is ill s1l!lmph~ fUIe
2: used to demonstrate
3: ~irst new line of text
4: Second new Une of text
5:*Une deletion
6: and dynamic
7: line number generation.

6-23

Insert Lines
Command

If the two inserted lines had been placed at the end of
the file (6 lor # I), the screen would look like this:
1:
2:
3:
4:
5:
6:
1:

6-24

This is a sample file
used to demonstrate
line deletion
and dynamic
line number generation.
First new line of text
Second new line of text

List Lines
Command

Purpose:

Displays a specified range of lines.
The current line remains unchanged.

Format:

[lineH,line]L

Remarks:

Default values are provided if either one or both of
the parameters are omitted.
If you omit the first parameter, as in:
,lineL

the display starts 11 lines before the current line and
ends with the specified line. The beginning comma is
required to indicate the omitted first parameter.
Note: If the specified line is more than 11
lines before the current line, the display is the
same as if you omitted both parameters. (An
example is provided in this section showing both
parameters omitted.)

6-25

List Lines
Command

If you omit the second parameter, as in:
IineL

or
line,l

a total of 23 lines are displayed, starting with the
specified line.
If you omit both parameters, as in:
L

a total of 23 lines are displayed - the 11 lines before
the current line, the current line, and the 11 lines
after the current line. If there aren't 11 lines before
the current line, then extra lines are displayed after
the current line to make a total of 23 lines.

6-26

List Lines
Command

Example:

Assume that you want to edit the following file. Line
15 is the current line.
TI:

Trtl'ii;:s

[j~;l ii:rl :!,-;;;;iIl!lflj~~~tt;mlJl.j

ct: M:;;?triJfuJ HUh trurbltllloil.lJll'u1JaOcOl'ufri;
~~J: IHtrutlll 1Dl~~~t![jjUtl
i~!, ;: (lil 1m rdJ ttl] ~y ti1l illl nnn 0l)~

l:D': [1~lYil[ffi ITHlllilITul\n@IY ~JJti:Jun~JlI'~a'llD((t)OD"

o

~5:: ~~~U;; \iIlQu]Sitt ~~(ijjU1lLtDfffiU'~~

t2(J]: UUil nthlfrll ~~~hl1el$

"171:

il\H\l~ ~hTIrfJJ mllllllMl~IEHr$

~rBl: ~lUlhJtffit(~ ~Dlfllre$ ;u~

~(fl]: mJti2~®~f2;rl1L

If you want to display a range of lines, from 5-25,
enter:

6-27

List Lines
Command

The screen looks like this:
5: line number generation.

•
•

•
15:*This is the current line (note the asterisk)

•

•
•
25: See what happens

If you want to display the first three lines, enter:
1,3L

The screen looks like this:
1: This is a sample file
2: used to demonstrate
3: line deletion

If you want to display 23 lines of the file, starting
with line 3, enter:
3L

6-28

List Lines
Command

The screen looks like this:
3: line deletion
4: and dynamic
5: line number generation.

•
•
•
15:*This is the current line (note the asterisk)

•

•
•

25: See what happens

If you want to display 23 lines centered around the
current line, enter:
L

The screen looks like this:
4: and dynamic
5: line number generation.

•
•
•
15:*This is the current line (note the asterisk)

•
25: See what happens
26: to the lines

6-29

Move Lines
Command

Purpose:

Moves the range of lines specified by the first two
line parameters ahead of the line specified in the
third line parameter. The third parameter is not
optional.

Format:

[line],[/ine],lineM

Remarks:

Use this command to move a block of data from one
location in the file to another. If the first or second
line parameter is omitted, it will default to the current
line. After the move, the first of the moved lines
becomes the current line. The lines are renumbered
according to the direction of the move. For example:
,+25,100M

moves the data from the current line plus 25 lines to
line 100. If the arguments overlap an entry error is
reported.

6-30

Page
Command

Purpose:

Lists the specified block of lines.

Format:

[line][,line]P

Remarks:

If the first line parameter is omitted, it defaults to the
current line plus one. If the second line parameter is
omitted, 23 lines are listed. The new current line
becomes the last line displayed by the Page
command and is marked with an asterisk. This
command pages through a file displaying 23 lines at a
time. It differs from the List Lines command in that it
changes the current line.

6-31

Quit Edit
Command

Purpose:

Quits the editing session without saving any changes
you may have entered.

Format:

Q

Remarks:

EDLIN prompts you to make sure you really don't
want to save the changes.
Enter Y if you want to quit the editing session. No
editing changes are saved and no .BAK file is
created. Refer to the End Edit command for
information about the .BAK file.
Enter N, or any other character, if you want to
continue the editing session.

Example:

0
Abort edit (Y/N)?_

6-32

Replace Text
Command

Purpose:

Replaces all occurrences of the first string in the
specified range of lines with the second string.
Notes:
1.

If you omit the second string, Replace Text
deletes all occurrences of the first string
within the specified range of lines. If you
omit both strings, EDLIN will reuse the
search string entered with the most recent
(previous) S or R command, and the
Replace Text string entered with the last R
command.

2.

This command uses the F6 key as
normally set up by DOS. If you have
changed the meaning of the F6 key through
"Extended Keyboard Control" (see
Chapter 2 of the DOS Technical Reference
manual), you should press Ctrl-Z where
F 6 is referred to below.

EDLIN displays the changed lines each time they
are changed. The last line changed becomes the
current line.

Format:

[line ][,line ][?]R[string][ string]

6-33

Replace Text
Command

Remarks:

You can specify the optional parameter? to request a
prompt (0. K.?) after each display of a modified line.
Press Y or the Enter key if you want to keep the
modification.
Enter any other character if you don't want the
modification. In either case, the search continues for
further occurrences of the first string within the range
of lines, including multiple occurrences within the
same line.
Defaults occur if either one or both of the line
parameters are missing.
If you omit the first line, the search begins with the
line after the current line. If you omit the second line,
the search ends with the last line in memory. If you
omit both line parameters, the system will search
from the line following the current line to the last line
in memory.
Note: The first string begins with the character
in the position immediately following the R, and
continues until you press F6 or Ctrl-Z (or the
Enter key if the second string is omitted).
The second string begins immediately after you
press F6 or Ctrl-Z and continues until you press
Enter.

6-34

Replace Text
Command

Example:

Assume that you want to edit the following file. Line
7 is the current line.
1:
2:
3:
4:

This is a sample file
used to demonstrate
the Replace ami $earc~
This includes the

5:

1lB~!itl]fI1lidl~ ~~tl'Ci\lIml~ft(flrr

6: and l'eqJui!l"lfUll

iex~ ([;ij~~m«llmlls;o

'1

s~rhll!ID

7:*paramete!l'.

To replace all occurrences of and with or in the lines
in memory, enter:

Then press F6, type or, and press Enter.
The result is:
3: The Rep!ace O~ Search
6: or required string

T~ld Q';mlllmHmllti!lITil~$

Line 6 becomes the current line in the file, because
line 6 was the last line changed. Notice that lines 1,
2, 4, 5, and 7 are not displayed because they were
not changed.

6-35

Replace Text
Command

Greater selectivity can be achieved by requesting a
prompt (by using the ? parameter) after each display
of a modified line. If you request a prompt, the screen
looks like this:
*1,7?

O.K.?
O.K.?
O.K.?

Rand (Press F6, type or, and press Enter)
3: the Replace or Search Text commands
Y
3: the Replace or Search Text commands
N
6: or required string
Y

*
Lines 3 and 6 are displayed like this:
3: the Replace or Search Text commands.
6: or required string

6-36

Search Text
Command

Purpose:

Searches a specified range of lines in order to locate
a specified string.

Format:

[line ][,line ][?]S[string]

Remarks:

The first line to contain the specified string is
displayed and the search ends (unless you use the ?
parameter). The first line found that contains the
specified string becomes the current line.
Note: The Search command always searches
for the exact same character in text. That is, it
searches for UPPERCASE if you enter
UPPERCASE, and lowercase if you enter
lowercase.
You should specify the optional parameter? if you
would like a prompt (O.K.?) after each display of a
line containing the specified string.
If you do not enter a string, the S command will use
the last search string that was entered on a Replace
or Search command. If the specified string is not
found, the search ends and the message Not found is
displayed. The current line remains unchanged. If
you enter Y or press the Enter key, the line that
matches the specified string becomes the current line
and the search ends. Enter any other character to
continue the search until another string is found, or
until all lines within the range are searched. Once all
the lines within the range are searched, the Not
found message is displayed.
6-37

Search Text
Command

The system provides default values if you omit the
first, second, or both line parameters. If you omit the
first line parameter, the system defaults to the line
following the current line. If you omit the second line
parameter, the system defaults to the last line in
memory. If you omit both line parameters, the system
searches from the line following the current line to
the last line in memory.
Notes:

Example:

1.

The string begins with the character in the
position immediately following the Sand
continues until you end the string by
pressing the Enter key.

2.

If you wish to place more than one
command on a line containing a Search
Text command, the Search Text command
should end in a Ctrl-Z (F6), and the next
command should begin in the following
character position.

Assume that you want to edit the following file. Line
7 is the current line.
~: 1Tlhiu~ U~ all $11lJ&111l~~1lJ: tlD~®

:e::

[iJl$~[\] UfIJ oci~BrMmH~~W'all1li:J

~: Um~ $1.el~f~YU I[ZI~tt Gifjrn~iiHIll511iilL

~: lf~e~~ Uliilrt:~l!IJ&:i(fll~ U~W

fBi: fl!~~h:ma~ parameter?
K1i: talmlld! !l'1El1l!]!Ulnrll:Jd stll"hlff1j
7:*[(jj4llHriBlM~~efi',

6-38

Search Text
Command

If you want to search for the first occurrence of and
in the file, enter:
TI

97

S01ll1lail
[{]Jf(

'il9 ~Zl[iO[l~

[,TIlt

TI ~(r,JlmQJ1

The result is:

The and is part of the word command. Notice that
line 3 becomes the current line in the file.
Perhaps this is not the and you were looking for. To
continue the search, simply enter the letter Sand
press Enter. The search will continue with the line
following the current line (the line just found).
The screen looks like this:
.:,

~

9

71

$rmmH~

~: jt[l1l® $®~r(~~ lffilllU lel1JHITIMmltl'>HlIl[hl,

Line 6 now becomes the current line in the file.

6-39

Search Text
Command

You can also search for strings by requesting a
prompt (by means of the? parameter) after each
display of a matching line. In this case, the screen
looks like this:
*1,7 ? Sand
3: the Search Text command.
O.K.? N
6: and required string
O.K.? Y

*

6-40

Transfer Lines
Command

Purpose:

Transfers (merges) the contents of a specified file
into the file currently being edited.

Format:

[line ]T[d:]filename[ .ext]

Remarks:

The filename contents are inserted ahead of the line
in the file being edited. If line is omitted, then the
current line is used.
Note: The file being merged is read from the
current directory of the specified or default
drive. If a path was specified when you issued
the ED LIN command, then that path will be the
current directory for that drive for the duration
of the EDLIN session, and any Transfer Lines
commands for that drive must be satisfied from
the same directory.

6-41

Write Lines
Command

Purpose:

Writes a specified number of lines to diskette from
the lines that are being edited in memory. Lines are
written beginning with the line number 1.

Format:

[n]W

Remarks:

This command is only meaningful if the file you are
editing is too large to fit in memory. When you start
ED LIN, it reads lines into memory until memory is
75% full.
To edit the remainder of your file, you must write
edited lines in memory to diskette before you can
load additional unedited lines from diskette into
memory by using the Append Lines command.
Note: If you do not specify the number of
lines, lines are written until 25 % of available
memory is used. No action is taken if available
memory is already less than 25 % used. All lines
are renumbered so that the first remaining line
becomes number 1.

6-42

Summary of EDLIN Commands

The following chart is provided for quick
reference.
Note: The section called "F onnat
Notation" in Chapter 1 explains the notation
used in the format of the following commands.

Command

Format

Append Lines

[n]A

Copy Lines

[line],[ line],line,[ count]C

Delete Lines

[lineH,line]D

Edit Line

[ line]

End Edit

E

Insert Lines

[line]I

List Lines

[ lineH,line]L

Quit Edit

Q

Move Lines

[line],[ line],lineM

Page

[ lineH,line]P

Replace Text

[lineH,line][?]R[ string] [  string]

Figure 3 (Part 1 of2). EDLIN Commands

6-43

Command

Format

Search Text

[line][,line][?]S[ string]

Transfer Lines

[line] Tfilename[. ext]

Write Lines

[n]W

Figure 3 (Part 2 of2). EDLIN Commands

6-44

Chapter 7. The Linker (LINK)
Program

Contents
Introduction ..............................

7-3

Files .....................................
Input Files ............................
Output Files ..........................
VM.TMP (Temporary File) .............

7-4
7-4
7-5
7-5

Definitions ...............................
Segment ..............................
Group. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .
Class ................................

7-6
7-6
7-7
7-7

Command Prompts ........................

7-8

Detailed Description of the
Command Prompts .......................
Object Modules [.OBJ]: .................
Run File [filename.EXE]: ...............
List File [NUL.MAP]: .................
Libraries [.LIB]: .......................
Linker Parameters .....................
/DSALLOCATION ...............
/HIGH ..........................
/LINE ...........................
/MAP ...........................
/PAUSE .........................
/STACK:size .....................

7-10
7-10
7-11
7-12
7-13
7-14
7-14
7-15
7-16
7-16
7-16
7-17

7-1

How to Start the Linker Program ...........
Before You Begin ......................
Option 1 - Console Reponses ............
Option 2 - Command Line ..............
Option 3 - Automatic Responses .........

7-18
7-18
7-18
7-19
7-21

Example Linker Session ................... 7-23
How to Determine the Absolute
Address of a Segment ................. 7-26
Messages ........ ~ . . . . . . . . . . . . . . . . . . . . . . .. 7-28

7-2

Introduction

The linker (LINK) program is a program that:
•

Combines separately produced object modules

•

Searches library files for definitions of unresolved
external references

•

Resolves external cross-references

•

Produces a printable listing that shows the
resolution of external references and error
messages

•

Produces a relocatable load module

The LINK program resides on your DOS Supplemental
Program Diskette. In this chapter, we show you how to
use LINK. You should read all of this chapter before
you start LINK.

7-3

Files

The linker processes the following input, output, and
temporary files:

Input Files
Type

Default
.ext

Override
.ext

Produced
by

Object

.OBJ

Yes

Compiler l
or MACRO
Assembler

Library

.LIB

Yes

Compiler

Automatic
Response

(None)

N/A*

User

Figure 4. Input files used by the linker

*N/ A - Not applicable.

lOne of the optional compiler packages available for
use with the IBM Personal Computer DOS.

7-4

Output Files
Type

Default
.ext

Override
.ext

Used
by

Listing

.MAP

Yes

User

Run

.EXE

No

Relocatable
loader
(COMMAND.
COM)

Figure 5. Output files used by the Linker

VM.TMP (Temporary File)
LINK uses as much memory as is available to hold the
data that defines the load module being created. If the
module is too large to be processed with the available
amount of memory, the linker may need additional
memory space. If this happens, a temporary file called
VM. TMP is created on the DOS default drive.
When the overflow to the VM. TMP file has begun, the
linker displays the following message:
VM.TMP has been created
Do not change diskette in drive x

If the VM. TMP file has been created on diskette, you

should not remove the diskette until LINK ends. When
LINK ends, it erases the VM. TMP file.
If the DOS default drive already has a file by the name

of VM. TMP, it will be deleted by LINK and a new file
will be allocated; the contents of the previous file are
destroyed. Therefore, you should avoid using VM. TMP
as one of your own filenames.

7-5

Definitions

Segment, group, and class are terms that appear in this
chapter and in some of the messages in Appendix A.
These terms describe the underlying function of LINK.
An understanding of the concepts that define these
terms provides a basic understanding of the way LINK
works.

Segment
A segment is a contiguous area of memory up to 64 K
bytes in length. A segment may be located anywhere in
memory on a paragraph (16-byte) boundary. Each of
the four segment registers defines a segment. The
segments can overlap. Each 16-bit address is an offset
from the beginning of a segment. The contents of a
segment are addressed by a segment register/offset pair.
The contents of various portions of the segment are
determined when machine language is generated.
Neither size nor location is necessarily fixed by the
compiler or assembler because this portion of the
segment may be combined at link time with other
portions forming a single segment.
A program's ultimate location in memory is determined
at load time by the relocation loader facility provided in
COMMAND. COM, based on whether you specify the
/HIGH parameter. The /HIGH parameter is discussed
later in this chapter.

7-6

Group
A group is a collection of segments that fit together
within a 64K-byte segment of memory. The segments
are named to the group by the assembler or compiler. A
program may consist of one or more groups.
The group is used for addressing segments in memory.
The various portions of segments within the group are
addressed by a segment base pointer plus an offset. The
linker checks that the object modules of a group meet
the 64K-byte constraint.

Class
A class is a collection of segments. The naming of
segments to a class affects the order and relative
placement of segments in memory. The class name is
specified by the assembler or compiler. All portions
assigned to the, same class name are loaded into
memory contiguously.
The segments are ordered within a class in the order
that the linker encounters the segments in the object
files. One class precedes another in memory only if a
segment for the first class precedes all segments for the
second class in the input to LINK. Classes are not
restricted in size. The classes are divided into groups for
addressing.

7-7

Command Prompts

After you start the linker session, you receive a series of
four prompts. You can respond to these prompts from
the keyboard, respond to these prompts on the
command line, or you can use a special diskette file
called an automatic response file to respond to the
prompts. An example of an automatic response file is
provided in this chapter.
LINK prompts you for the names of the object, run, list,
and library files. When the session is finished, LINK
returns to DOS and the DOS prompt is displayed. If
linking is unsuccessful, LINK displays a message.
The prompts are described in order of their appearance
on the screen. Defaults are show:t;l in square brackets
([ ]) after the prompt. In the response column of the
table, square brackets indicate optional entries. Object
Modules is the only prompt that requires a response
from you.

7-8

Prompt

Responses

Object Modules [.OBJ]:

[d: ][path lfilename[ .ext]

[+.[ d: ][path lfilename[ .ext]] ...
Run File [filename.EXT]:

[d:] [path] [lilename[ .ext]]

List File [NUL.MAP]:

[d: ][path ][lilename[ .ext]]

Libraries [.LIB]:

[d: ][[path lfilename[ .ext]]

[+.[ d: ][[path lfilename[ .ext]]] ...

Notes:
1.

If you enter a filename without specifying the
drive, the default drive is assumed. If you
enter a filename without specifying the path,
the default path is assumed. The libraries
prompt is an exception-the linker will look
for the libraries on the default drive and if not
found, look on the drive specified by the
compiler.

2.

You can end the linker session prior to its
normal end by pressing Ctrl-Break.

7-9

Detailed Description of the
Command Prompts

The following detailed descriptions contain information
about the responses that you can enter to the prompts.

Object Modules [.OBJ]:
Enter one or more file locations for the object modules
to be linked. Multiple file locations must be separated
by single plus ( +) signs or blanks. If the extension is
omitted from any filename, LINK assumes the filename
extension .OBJ. If an object module has a different
filename extension, the extension must be specified.
Object filenames can not begin with the @ symbol (@
is reserved for using an automatic response file).
LINK loads segments into classes in the order
encountered.
If you specify an object module on a diskette drive, but
LINK cannot locate the file, it displays the following
prompt:
Cannot fill1ld file object module
change diskette 

If you specify an object module on a non-removable
media (like a fixed disk), the linker session will end with
the following message:
Cannot find file object module

7-10

You should insert the diskette containing the requested
module. This permits .0 BJ files from several diskettes
to be included. On a single-drive system, diskette
exchanging can be done safely only if VM. TMP has not
been opened. As explained in the discussion of the
VM. TMP file earlier in this chapter, a message will
indicate if VM. TMP has been opened.
IMPORTANT: If a VM.TMP file has been opened
on a diskette, you should not remove the diskette
containing the VM.TMP file. Remember, once a
VM. TMP file is opened on a diskette, the diskette it
resides on cannot be removed.
After a VM. TMP file has been opened, if you specified
an object module on the same disk that VM. TMP is on
and LINK cannot find it, the linker session ends with
the message:
Cannot find file object module

Run File [filename. EXE] :
The file specification you enter is created to store the
run (executable) file that results from the LINK session.
All run files receive the filename extension .EXE, even
if you specify another extension. If you specify another
extension, your specified extension is ignored.
The default filename for the run file prompt is the first
filename specified on the object module prompt.
You can specify just a drive letter, or a path on the run
file prompt. This changes the place where the run file
filename. EXE is placed.

7-11

List File [NUL.MAP]:
The linker list file is sometimes called the linker map.
The list file is not created unless you specifically
request it. You can request it by overriding the default
with a drive letter, path, orfilename[.ext]. If you do not
include a filename extension, the default extension
.MAP is used. If you do not enter anything, the DOS
reserved filename NULL specifies that no list file will
be created.
The list file contains an entry for each segment in the
input (object) modules. Each entry also shows the offset
(addressing) in the run file.
You can specify just a drive letter or a path on the list
file prompt. This changes the place where the list file is
placed.
Note: If the list file is allocated to a file on
diskette, that diskette must not be removed until
the LINK has ended.
If you specify an object module on the same diskette
drive as the diskette drive to which the list file is
allocated, and LINK cannot find the object module, the
linker session ends with the message:
Cannot find file object module

To avoid generating the list file on a diskette, you can
specify the display or printer as the list file device. For
example:
List File [NUL.MAP1: CON

If you direct the output to your display, you can also
print a copy of the output by pressing Ctrl-PrtSc.

7-12

Libraries [. LIB]:
You may either list the file locations for your libraries,
or just press the Enter key. If you press the Enter key,
LINK defaults to the library provided as part of the
Compiler package.
The LINK program will look for the Compiler package
library on the default drive. If it cannot find the library
there, then it will look for the library on the drive
specified by the Compiler package. For linking objects
from just the MACRO Assembler, there is no
automatic default library search.
If you answer the library prompt, you specify a list of
drive letters and [path lfilename. ext separated by plus
signs ( +) or spaces. You can enter from one to eight
library file locations. Specifying a drive letter tells linker
to look on that drive instead of the Compiler package
supplied drive for all subsequent libraries on the library
prompt. The automatically searched library file
specifications are conceptually placed at the end of the
response to the library prompt.
LINK searches the library files in the order in which
they are listed to resolve external references. When
LINK finds the module that defines the external
symbol, the module is processed as another object
module.
If two or more libraries have the same filename,
regardless of the location, only the first library in the list
is searched.

When LINK cannot find a library file, it displays a
message like this:
Cannot find library A:library file
Enter new drive letter:

The drive that the indicated library is located on must
be entered.
7-13

The following library prompt responses may be used:
Libraries [.LlB]: B:

Look for compiler .LIB on drive B.
Libraries [.LlB]: B:USERLIB

Look for USERLIB.LIB on drive Band
compiler. LIB on drive A.
libraries [.LlB]: A:LlBl +UB2+B:LlB3+A:

Look for LIB1.LIB and LIB2.LIB on drive A,
LIB3.LIB on drive B, and compiler. LIB on drive A.

Linker Parameters
At the end of any of the four linker prompts, you may
specify one or more parameters that instruct the linker
to do something differently. Only the / and first letter of
any parameter are required.

/DSALLOCATION
The /DSALLOCATION (/D) parameter directs LINK
to load all data defined to be in DGROUP at the high
end of the group. If the /HIGH parameter is specified,
(module loaded high), this allows any available storage
below the specifically allocated area within DGROUP
to be allocated dynamically by your application and still
be addressable by the same data space pointer.
Note: The maximum amount of storage which
can be dynamically allocated by the application is
64K (or the amount actually available) minus the
allocated portion of DGROUP.

7-14

If the IDSALLOCATION parameter is not specified,
LINK loads all data defined to be in the group whose
group name is DGROUP at the low end of the group,
beginning at an offset of O. The only storage thus
referenced by the data space pointer should be that
specifically defined as residing in the group.

All other segments of any type in any GROUP other
than DGROUP are loaded at the low end of their
respective groups, as if the /DSALLOCATION
parameter were not specified.
For certain compiler packages, IDSALLOCATION is
automatically used.

/HIGH
The IHIGH (/H) parameter causes the loader to place
the run image as high as possible in storage. If you
specify the /HI G H parameter, you tell the linker to
cause the loader to place the run file as high as possible
without overlaying the transient portion of
COMMAND. COM, which occupies the highest area of
storage when loaded. If you do not specify the /HIGH
parameter, the linker directs the loader to place the run
file as low in memory as possible.
The IHIGH parameter is used with the
IDSALLOCATION parameter.

7-15

/LINE
F or certain IBM Personal Computer language
processors, the /LINE (lL) parameter directs LINK to
include the line numbers and addresses of the source
statements in the input modules in the list file.

/MAP
The /MAP (1M) parameter directs LINK to list all
public (global) symbols defined in the input modules.
F or each symbol, LINK lists its value and
segment-offset location in the run file. The symbols are
listed at the end of the list file.

/PAUSE
The /PAUSE (lP) parameter tells LINK to display a
message to you as follows:
About to generate. EXE file
Change disks 

This message allows you to insert the diskette that is to
contain the run file.

7-16

/STACK:size
The size entry is any positive decimal value up to
65536 bytes. This value is used to override the size of
the stack that the MACRO Assembler or compiler has
provided for the load module being created. If you
specify a value greater than 0 but less than 512, the
value 5 12 is used.
If you do not specify /STACK (IS), the original stack
size provided by the MACRO Assembler or compiler is
used.
If the size of the stack is too small, the results of
executing the resulting load module are unpredictable.
At least one input (object) module must contain a stack
allocation statement, unless you plan to use the
EXE2BIN program. This is automatically provided by
compilers. For the MACRO Assembler, the source
must contain a SEGMENT command that has the
combine type of STACK. If a stack allocation
statement was not provided, LINK returns a
Warning: No Stack statement message.

7-17

How to Start the Linker Program

Before You Begin
•

Make sure the files you will be using for linking are
on the appropriate disks.

•

Make sure you have enough free space on your
disks to contain your files and any generated data.

You can start the linker program by using one of three
options:

Option 1 - Console Responses
From your keyboard, enter:
LINK

The linker is loaded into memory and displays a series
of four prompts, one at a time, to which you must enter
the requested responses. (Detailed descriptions of the
responses that you can make to the prompts are
discussed in this chapter.)
If you enter a wrong response, such as an incorrectly
spelled filename, you must press Ctrl-Break to exit
LINK, then restart LINK. If the response in error has
been typed but you haven't pressed Enter yet, you may
delete the wrong characters (on that line only).

An example of a linker session using the console
response option is provided in this chapter in the section
called "Example Linker Session."

7-18

As soon as you have entered the last filename, the
linker begins to run. If the linker finds any errors, it
displays the errors on the screen as well as in the listing
file.
Note: After any of these responses, before
pressing Enter, you may continue the response
with a comma and the answer to what would be
the next prompt, without having to wait for that
prompt. If you end any with the semicolon (;), the
remaining responses are all assumed to be the
default. Processing begins immediately with no
further prompting.

Option 2 - Command Line
From your keyboard, enter:
LINK objlist,runfile,mapfile,liblist [parm) ... ;

objlist

is a list of object modules separated by spaces
or plus signs ( +).

runfile

is the name you want to give the run file.

mapfile

is the name you want to give the linker map.

lib list

is a list of the libraries to be used, separated
by plus signs ( +) or spaces.

parm

is an optional linker parameter. Each
parameter must begin with a slash (/).

The linker is loaded and immediately performs the tasks
indicated by the command line.
When you use this command line, the prompts
described in Option 1 are not displayed if you specified
an entry for all four files or if the command line ends
with a semicolon.
7-19

If an incomplete list is given and no semicolon is used,
the linker prompts for the remaining unspecified files.
Each prompt displays its default, which may be
accepted by pressing the Enter key, or overridden with
an explicit filename or device name. However, if an
incomplete list is given and the command line is
terminated with a final semicolon, the unspecified files
default without further prompting. The parms are never
prompted for, but may be added to the end of the
command line or to any file specification given in
response to a prompt.
Certain variations of this command line are permitted.
Examples:
LINK module
The object module is MODULE.OBJ. A
prompt is given, showing the default of
MODULE.EXE. After the response is
entered, a prompt is given showing the default
of NUL. MAP. After the response is given, a
prompt is displayed showing the default
extension of .LIB.
LINK module;
If the semicolon is added, no further prompts
are displayed. The object module of
MODULE.OBJ is linked, the run file is put
into MODULE.EXE, and no list file is
produced.
LINK module,,;
This is similar to the preceding example,
except the list file is produced in
MODULE.MAP.

7-20

LINK module"
U sing the same example, but without the
semicolon, MODULE.OBJ is linked, and the
run file is produced in MODULE.EXE, but
a prompt is given with the default of
MODULE. MAP.
LINK module"NUL;
No list file is produced. The run file is in
MODULE.EXE. No further prompts are
displayed.

Option 3 - Automatic Responses
It is often convenient to save responses to the linker for
use at a later time. This is especially useful when long
lists of object modules need to be specified.

Before using this option, you must create the automatic
response file. It contains several lines of text, each of
which is the response to a linker prompt. These
responses must be in the same order as the linker
prompts that were discussed earlier in this chapter. If
desired, a long response to the object module or
libraries prompt may be contained on several lines by
using a plus sign ( +) to continue the same response
onto the next line.
To specify an automatic response file, you enter a file
specification preceded by an @ symbol in place of a
prompt response or part of a prompt response. The
prompt is answered by the contents of the diskette file.
The file specification may not be a reserved DOS
filename.

7-21

From your keyboard, enter:
LINK @[d:][path]filename1[ext]

Use of the filename extension is optional and may be
any name. There is no default extension.
Use of this option permits the command that starts
LINK to be entered from the keyboard or within a
batch file without requiring any response from you.
Example

Automatic Response File - RESP1
MODA+MODB+MODC+
MODB+MODE+MODF

Automatic Response File - RESP2
runfile/p
printout

Command line
LINK @RESPl +mymod,@RESP2;

Notes:

7-22

1.

The plus sign at the end of the first line in
RESPI causes the modules listed in the first
two lines to be considered as the input object
modules. Mter reading RESPl, the linker
returns to the command line and sees
+mymod, so it includes MYMOD.OBJ in
the first list of object modules as well.

2.

Each of the above lines ends when you press
the Enter key.

Example Linker Session
This example shows you the type of information that is
displayed during a linker session.
Once we enter:
b:link

in response to the DOS prompt, the system responds
with the following messages and prompts, which we
answer as shown:
IBM Personal Computer linker
Version 2.10 (C) Copyright IBM Corp. 1981, 1982, 1983
Object Modules [.OBJ]: example
Run File [EXAMPLE.EXE]: /map
List File [NUL.MAP]: prn/line
Libraries [.LlB]:

Notes:
1.

By specifying /map, we get both an
alphabetic listing and a chronological listing
of public symbols.

2.

By responding prn to the list file prompt, we
send our output to the printer.

3.

By specifying the /LINE parameter, LINK
gives us a listing of all line numbers for all
modules. (The /LINE parameter can
generate a large amount of output. )

4.

By just pressing Enter in response to the
libraries prompt, an automatic library search
is performed.

7-23

Once LINK locates all libraries, the linker map displays
a list of segments in the relative order of their
appearance within the load module. The list looks like
this:

Start

Stop

Length

Name

Class

OOOOOH
0OO30H
00100H
00100H
038D4H

0OO28H
OOOF6H
00100H
038D3H
04921H

0029H
OOC7H
OOOOH
37D4H
104EH

MAINOO
ENTXOO
INIXOO
FILVOO _CODE
FILUOO _CODE

CODE
CODE
CODE
CODE
CODE

074AOH
074AOH
0759FH
07925H
082A9H

OOOOH
OOOOH
0100H
0386H
097AH

HEAP
MEMORY
STACK
DATA
CONST

MEMORY
MEMORY
STACK
DATA
CONST

•
•

•

074AOH
074AOH
074AOH
075AOH
07930H

The information in the Start and Stop columns shows a
20-bit hex address of each segment relative to location
zero. Location zero is the beginning of the load module.
The addresses displayed are not the absolute addresses
of where these segments are loaded. To find the
absolute address of where a segment is actually loaded,
you must determine where the segment listed as being at
relative zero is actually loaded; then add the absolute
address to the relative address shown in the linker map.
The procedure you use to determine where relative zero
is actually located is discussed in this chapter, in the
section called "How to Determine the Absolute
Address of a Segment."

7-24

Now, because we specified the /MAP parameter, the
public symbols are displayed by name and by value.
For example:

Address

Publics by Name

0492:0003H
06CD:029FH
0492:00A3H
06CD:0087H
0602:000FH

ABSNQQ
ABSRQQ
ADDNQQ
ADDRQQ
ALLHQQ

•

•
•
WT4VQQ

0010:1 BCEH
0010:lD7EH
0010:1887H
0010:19E2H
0010:11 B2H

WTlVOO
WTNVQQ
WTRVQQ

Address

Publics by Value

0000:0001 H
0000:0010H
0000:0010H
0003:0000H
0003:0095H

WTFVQQ

MAIN

ENTGQO
MAINOQ

BEGXQO
ENDXOO

•
•

•

F82B:F31 CH
F82B:F31 EH
F82B:F322H
F82B:F5B8H
F82B:F5EOH

CRCXQO
CRDXQO
CESXQO
FNSUQQ
OUTUQQ

7-25

The addresses of the public symbols are in the
segment:offset format, showing the location relative to
zero as the beginning of the load module. In some cases,
an entry may look like this:
F8CC:EBE2H

This entry appears to be the address of a load module
that is almost one megabyte in size. Actually, the area
being referenced is relative to a segment base that is
pointing to a segment below the relative zero beginning
of the load module. This condition produces a pointer
that has effectively gone negative. The memory map
which follows illustrates this point.
When LINK has completed, the following message is
displayed:
Program entry point at 0003:0000

How to Determine the Absolute Address
ofa Segment
The linker map displays a list of segments in the relative
order of their appearance within the load module. The
information displayed shows a 20-bit hex address of
each segment relative to location zero. The addresses
that are displayed are not the absolute addresses of
where these segments are actually located. To
determine where relative zero is actually located, we
must use DEBUG. DEBUG is described in detail in
Chapter 8.

7-26

Using DEBUG,
1.

Load the application. Note the segment value in
CS and the offset within that segment to the entry
point as shown in IP. The last line of the linker
map also describes this entry point, but uses
relative values, not the absolute values shown by
CS and IP.

2.

Subtract the relative entry as shown at the end of
the map listing from the CS:IP value. For
example, let's say CS is at 05DC and IP is at
zero.
The linker map shows the entry point at
0100:0000. (0100 is a segment ID or paragraph
number; 0000 is the offset into that segment.)
In this example, relative zero is located at
04DC:0000, which is 04DCO absolute.

If a program is loaded low, the relative zero location is
located at the end of the Program Segment Prefix, in the
location DS plus 100H.

7-27

Messages

All messages, except for the warning messages, cause
the LINK session to end. Therefore, after you locate
and correct a problem, you must rerun LINK.
Messages appear both in the list file and on the display
unless you direct the list file to CON, in which case the
display messages are suppressed.
All of the linker messages are included in Appendix A.

7-28

Chapter 8. The DEBUG Program

Contents
Introduction ..............................

8-3

How to Start the DEBUG Program

8-4

The DEBUG Command Parameters

8-7

The DEBUG Commands .................. 8-13
Information Common to All
DEBUG Commands .................. 8-13
Assemble Command

8-15

Compare Command

8-19

Dump Command .......................... 8-21
Enter Command .......................... 8-23
Fill Command ............................ 8-27
Go Command ............................. 8-28
Hexarithmetic Command ................... 8-31
Input Command .......................... 8-32
Load Command ........................... 8-33

8-1

Move Command

8-36

N arne Command

8-37

Output Command ......................... 8-39
Quit Command ........................... 8-40
Register Command ........................ 8-41
Search Command ......................... 8-47
TraceCommand .......................... 8-49
Unassemble Command .................... 8-51
Write Command .......................... 8-55
Summary of DEBUG Commands ........... 8-60

8-2

I

Introduction

This chapter explains how to use the DEBUG program.
The DEBUG program can be used to:
•

Provide a controlled testing environment so you
can monitor and control the execution of a
program to be de bugged. You can fix problems in
your program directly, and then execute the
program immediately to determine if the problems
have been resolved. You do not need to reassemble
a program to find out if your changes worked.

•

Load, alter, or display any file.

•

Execute objectfiles. Object files are executable
programs in machine language format.

8-3

How to Start the DEBUG Program

To start DEBUG, enter:
DEBUG [d:][path][filename[.ext]] [parm 1] [parm2]

If you enter filename, the DEBUG program loads the
specified file into memory . You may now enter
commands to alter, display, or execute the contents of
the specified file.
If you do not enter a filename, you must either work
with the present memory contents, or load the required
file into memory by using the Name and Load
commands. Then you can enter commands to alter,
display, or execute the memory contents.

The optional parameters, parmI and parm2, represent
the optional parameters for the namedfilespec. For
example,
DEBUG DlSKCOMP.COM A: B:

In this command, the A: and B: are the parameters that
DEBUG prepares for the DISKCOMP program.

8-4

When the DEBUG program starts, the registers and
flags are set to the following values for the program
being debugged:
•

The segment registers (eS, DS, ES, and SS) are
set to the bottom of free memory; that is, the first
segment after the end of the DEBUG program.

•

The Instruction Pointer (lP) is set to
hex 0100.

•

The Stack Pointer (SP) is set to the end of the
segment, or the bottom of the transient portion of
the program loader, whichever is lower. The
segment size at offset 6 is reduced by hex 100 to
allow for a stack of that size.

•

The remaining registers (AX, BX, ex, DX, BP,
SI, and DI) are set to zero. However, if you start
the DEBUG program with a filespec, the ex
register contains the length of the file in bytes. If
the file is greater than 64 K, the length is contained
in registers BX and ex (the high portion in BX).

•

The flags are set to their cleared values. (Refer to
the Register command.)

•

The default disk transfer address is set to hex 80 in
the code segment.

8-5

All of available memory is allocated; therefore, any
attempt by the loaded program to allocate memory will
fail.
Notes:
1.

If a file loaded by DEBUG has an extension
of .EXE, DEBUG does the necessary
relocation and sets the segment registers,
stack pointer, and Instruction Pointer to the
values defined in the file. The DS and ES
registers, however, point to the Program
Segment Prefix at the lowest available
segment. The BX and CX registers contain
the size of the program (smaller than the file
size).
The program is loaded at the high end of
memory if the appropriate parameter was
specified when the linker created the file.
Refer to ".EXE File Structure and Loading"
in Chapter 9 of the DOS Technical Reference
manual for more information about loading
.EXE files.

2.

8-6

If a file loaded by DEBUG has an extension
of .HEX, the file is assumed to be in Intel
hex format and is converted to executable
form while being loaded.

The DEBUG Command Parameters

Parameter

Definition

address

Enter a one- or two-part designation in one of
the following formats:

•

An alphabetic segment register
designation, plus an offset value, such as:
CS:OHUJ

•

A segment address, plus an offset value,
such as:
4BA:OHJO

•

An offset value only, such as:
~oo

(In this case, each command uses a default
segment.)
Notes:
1.

In the first two formats, the colon is
required to separate the values.

2.

All numeric values are hexadecimal and
may be entered as 1-4 characters.

3.

The memory locations specified in address
must be valid; that is, they must actually
exist. Unpredictable results will occur if an
attempt is made to access a nonexistent
memory location.

8-7

Parameter

Definition

byte

Enter a one or two character hexadecimal
value.

drive

Enter a single digit (for example, 0 for drive A
or 1 for drive B) to indicate which drive data is
to be loaded from or written to.
(Refer to the Load and Write commands.)

filespec

Enter a one- to three-part file specification
consisting of a drive designation, filename, and
filename extension. All three fields are optional.
However, for the Name command to be
meaningful, you should at least specify a drive
designator or a filename.
(Refer to the Name command.)

list

Enter one or more byte and/or string values.
For example,
E CS:l00 F3 'XYZ' 8D 4 "abed"

has five items in the list (that is, three byte
entries and two string entries having a total of
10 bytes).
portaddress

Enter a 1-4 character hexadecimal value to
specify an 8- or 16-bit port address.
(Refer to the Input and Output commands.)

8-8

Parameter

Definition

range

Enter either of the following formats to specify
the lower and upper addresses of a range:

•

address address
F or example:
CS:100 110

Note: Only an offset value is
allowed in the second address. The
addresses must be separated by a
space or comma.

•

address L value
where value is the number of bytes in
hexadecimal to be processed by the
command. For example:
CS:100 L 11

Notes:

registername

1.

The limit for range is hex
10000. To specify that value
within four hexadecimal
characters, enter 0000 (or 0).

2.

The memory locations specified
in range must be valid; that is,
they must actually exist.
Unpredictable results will occur
if an attempt is made to access a
non-existent memory location.

Refer to the Register command.

8-9

Parameter

Definition

sector sector

Enter 1-3 character hexadecimal values to
specify:
1.

The starting relative sector number

2.

The number of sector numbers to be
loaded or written

In DEBUG, relative sectors are obtained by
counting the sectors on the disk surface. The
sector at track 0, sector 1, head 0 (the first
sector on the disk) is relative sector O. The
numbering continues for each sector on that
track and head, then continues with the first
sector on the next head of the same track. When
all sectors on all heads of the track have been
counted, numbering continues with the first
sector on head 0 of the next track.
Note: This is a change from the sector
mapping used by DOS Version 1.10.
The maximum number of sectors that can be
loaded or written with a single command is hex
80. A sector contains 512 bytes.
(Refer to the Load and Write commands.)

string

Enter characters enclosed in quotation marks.
The quotation marks can be either single (') or
double (").
The ASCII values of the characters in the string
are used as a list of byte values.

8-10

Parameter

Definition

string
(cont.)

Within a string, the opposite set of quotation
marks can be used freely as characters.
However, if the same set of quotation marks (as
the delimiters) must be used within the string,
then the quotation marks must be doubled. The
doubling does not appear in memory. For
example:

1.

'This "literal" is correct'

2.

'This' 'literal' ' is correct'

3.

'This 'literal' is not correct'

4.

'This ""literal"" is not correct'

5.

"This 'literal' is correct"

6.

"This ''''literal'''' is correct"

7.

"This "literal" is not correct"

8.

"This' 'literal' , is not correct"

In the second and sixth cases above, the word
literal is enclosed in one set of quotation marks
in memory. In the fourth and eighth cases
above, the word literal is not correct unless you
really want it enclosed in two sets of quotation
marks in memory.

8-11

Parameter

Definition

value

Enter a 1-4 character hexadecimal value to
specify:

8-12

•

The numbers to be added and subtracted
(refer to the Hexarithmetic command), or

•

The number of instructions to be executed
by the Trace command, or

•

The number of bytes a command should
operate on. (Refer to the Dump, Fill,
Move, Search, and Unassemble
commands.)

The DEBUG Commands

This section presents a detailed description of how to
use the commands to the DEBUG program. The
commands appear in alphabetical order; each with its
format and purpose. Examples are provided where
appropriate.

Information Common to All DEBUG
Commands
The following information applies to the DEBUG
commands:
•

A command is a single letter, usually followed by
one or more parameters.

•

Commands and parameters can be entered in
uppercase or lowercase, or a combination of both.

•

Commands and parameters may be separated by
delimiters. Delimiters are only required, however,
between two consecutive hexadecimal values.
Thus, these commands are equivalent:
dcs:l00 110
d cs:l00 110
d,cs: 100, 110

•

Press Ctrl-Break to end commands.

•

Commands become effective only after you press
the Enter key.

8-13

•

F or commands producing a large amount of
output, you can press Ctrl-Num Lock to suspend
the display to read it before it scrolls away. Press
any other character to restart the display.

•

You can use the control keys and the DOS editing
keys, described in Chapter 2 of DOS User's Guide
while using the DEBUG program.

•

If a syntax error is encountered, the line is
displayed with the error pointed out as follows:
III cs: U)O CS: 1 HJ
®1l'l1'tllH'f

In this case, the Dump command is expecting the
second address to contain only a hexadecimal
offset value. It finds the S, which is not a valid
hexadecimal character.

8-14

•

The prompt from the DEBUG program is a
hyphen (-).

•

The DEBUG program resides on your DOS
Supplemental Program diskette.

Assemble
Command

Purpose:

To assemble IBM Personal Computer Macro
Assembler language statements directly into memory.

Format:

A[address]

Remarks:

All numeric input to the Assemble command is in
hexadecimal. The assembly statements you enter are
assembled into memory at successive locations,
starting with the address specified in address. If no
address is specified, the statements are assembled
into the area at CS:OI00, if no previous Assemble
command was used, or into the location following the
last instruction assembled by a previous Assemble
command. When all desired statements have been
entered, press Enter when you are prompted for the
next statement, to return to the DEBUG prompt.
DEBUG responds to invalid statements by
displaying:

and redisplaying the current assemble address.
DEBUG supports standard 8086/8088 assembly
language syntax (and the 8087 instruction set), with
the following rules:
•

All numeric values entered are hexadecimal and
can be entered as 1-4 characters.

8-15

Assemble
Command

•

Prefix mnemonics must be entered in front of
the opcode to which they refer. They can also
be entered on a separate line.

•

The segment override mnemonics are CS:, DS:,
ES:, and SS:.

•

String manipulation mnemonics must explicitly
state the string size. For example, MOVSW
must be used to move word strings and MOVSB
must be used to move byte strings.

•

The mnemonic for the far return is RETF.

•

The assembler will automatically assemble
short, near, or far jumps and calls depending on
byte displacement to the destination address.
These can be overridden with the NEAR OR
FAR prefix. For example:
0100:0500 JMP 502
; a 2 byte short jump
0100:0502 JMP NEAR 505; a 3 byte near jump
0100:0505 JMP FAR 50A ; a 5 byte far jump

The NEAR prefix can be abbreviated to NE,
but the FAR prefix cannot be abbreviated.

8-16

Assemble
Command

•

DEBUG cannot tell whether some operands
refer to a word memory location or a byte
memory location. In this case, the data type
must be explicitly stated with the prefix
"WORD PTR" or "BYTE PTR". DEBUG
will also accept the abbreviations "WO" and
"BY". For example:
NEG BYTE PTR [128]
DEC WO [SI]

•

DEBUG also cannot tell whether an operand
refers to a memory location or to an immediate
operand. DEBUG uses the common convention
that operands enclosed in square brackets refer
to memory. For example:
MOV AX,21
MOV AX,[21]

•

;Load AX with 21 H
;Load AX with the
contents of memory
location 21 H

Two popular pseudo-instructions have also been
included. The DB opcode will assemble byte
values directly into memory. The DW opcode
will assemble word values directly into memory.
F or example:
DB
DB
DB

1,2,3,4,"THIS IS AN EXAMPLE"
"THIS IS A QUOTE: " ,
"THIS IS A QUOTE: ' "

OW

1000,2000,3000", BACH"

8-17

Assemble
Command

•

All forms of the register indirect commands are
supported. For example:
ADD
POP

BX,34[BP+2].[SI-l]
[IBP+m]

PUSH [SI]

•

•

All opcode synonyms are supported. For
example:
lOOPl
LOOPE

1011]
100

JA
JNBE

200
200

For 8087 opcodes the WAIT or FW AIT prefix
must be explicitly specified. For example:

fLD TRITE PTR [BX]
Example:

C>debug
-a200
0884:0200 xor aX,3x
0684:0202 miiV [bx],alx

0894:0204
0884:0205

8-18

iit

;This line will
assemble a
FWAIT prefix
;This line will not

Compare
Command

Purpose:

Compares the contents of two blocks of memory.

Format:

C range address

Remarks:

The contents of the two blocks of memory are
compared; the length of the comparison is determined
from the range. If unequal bytes are found, their
addresses and contents are displayed, in the form:
addr 1 byte 1 byte2

addr2

where, the first half ( addr 1 byte 1) refers to the
location and contents of the mismatching locations in
range, and the second half (byte2 addr2) refers to
the byte found in address.
If you enter only an offset for the beginning address

of range, the C command assumes the segment
contained in the DS register. To specify an ending
address for range, enter it with only an offset value.

Example:

C 100120 200

The 32 bytes of memory beginning at DS: 100 are
compared with the 32 bytes beginning at DS:200.

8-19

Dump
Command

Purpose:

Displays the contents of a portion of memory.

Format:

D [address]
or

D [range]
Remarks:

The dump is displayed in two parts:
1.

A hexadecimal portion. Each byte is displayed
in hexadecimal.

2.

An ASCII portion. The bytes are displayed as
ASCII characters. Unprintable characters are
indicated by a period (.).

With a 40-column system display format, each line
begins on an 8-byte boundary and shows 8 bytes.
With an 80-column system display format, each line
begins on a 16-byte boundary and shows 16 bytes.
There is a hyphen between the 8th and 9th bytes.
Note: The first line may have fewer than 8 or
16 bytes if the starting address of the dump is
not on a boundary. In this case, the second line
of the dump begins on a boundary.

8-20

Dump
Command

The Dump command has two format options:
Option 1
Use this option to display the contents of hex 40
bytes (40-column mode) or hex 80 bytes (80-column
mode). For example:

D address
or
D

The contents are dumped starting with the specified
address.
If you do not specify an address, the D command
assumes the starting address is the location following
the last location displayed by a previous D
command. Thus, it is possible to dump consecutive
40-byte or 80-byte areas by entering consecutive D
commands without parameters.
If no previous D command was entered, the location
is offset hex 100 into the segment originally
initialized in the segment registers by DEBUG.
Note: If you enter only an offset for the
starting address, the D command assumes the
segment contained in the DS register.

8-21

Dump
Command

Option 2
Use this option to display the contents of the
specified address range. For example:
D range

Note: If you enter only an offset for the
starting address, the D command assumes the
segment contained in the DS register. If you
specify an ending address, enter it with only an
offset value.
For example:

A 40-column display format might look like this:
04BA:OUJl[]

42 45 52: 5d/l 4 TI 2!Ul @4 [llf!]
!alf!Rli~ 1f,

04BA:0108

2~

42 41F 52 41
BOCIDIRHBl

8-22

Enter
Command

Purpose:

The Enter command has two modes of operation:
Replaces the contents of one or more bytes,
starting at the specified address, with the values
contained in the list. (See Option 1.)
Displays and allows modification of bytes in a
sequential manner. (See Option 2.)

Format:

E address [list]

Remarks:

If you enter only an offset for the address, the E
command assumes the segment contained in the DS
register.
The Enter command has two format options:
Option 1
Use this option to place the list in memory beginning
at the specified address.
E address list

F or example:
IE iDs: 100 F3 "xyz" 8D

Memory locations ds: 100 through ds: 104 are filled
with the five bytes specified in the list.

8-23

Enter
Command

Option 2
Use this option to display the address and the byte of
a location, then the system waits for your input.
For example:
E address

Now you can take one of the following actions:
1.

Enter a one or two character hexadecimal value
to replace the contents of the byte; then take any
of the next three actions:

2.

Press the space bar to advance to the next
address. Its contents are displayed. If you want
to change the contents take action 1, above.
To advance to the next byte without changing
the current byte, press the space bar again.

3.

Enter a hyphen (-) to back up to the preceding
address. A new line is displayed with the
preceding address and its contents. If you want
to change the contents take action 1, above.
To back up one more byte without changing the
current byte, enter another hyphen.

8-24

Enter
Command

4.

Press the Enter key to end the Enter command.
Note: Display lines can have 4 or 8 bytes of
data, depending on whether the system display
format is 40- or 80-column. Spacing beyond an
8-byte boundary causes a new display line, with
the beginning address, to be started.
F or example:
E cs:l00

might cause this display:
04BA:Ol00 EB._

To change the contents of04BA:0100 from hex
EB to hex 41, enter 41.
04BA:Ol00 EB.41_

To see the contents of the next three locations,
press the space bar three times. The screen
might look like this:
04BA:Ol00

EB.41

10.

00.

BC.

8-25

Enter
Command

To change the contents of the current location
(04BA:OI03) from hex Be to hex 42, enter 42.

Now, suppose you want to back up and change
the hex 10 to hex 6F. This is what the screen
would look like after entering two hyphens and
the replacement byte:
IDJ4!8l~:(!))UlJ[JJ

[E~,&j} ~

1Dl41B1DlldH02

DO,rn

(!)J4!BlI:OHH

H16f _

Hl),

[][Jl,

tBC.42w

Press the Enter key to end the Enter command.
You will see the hyphen (-) prompt.

8-26

Fill
Command

Purpose:

Fills the memory locations in the range with the
values in the list.

Format:

F range list

Remarks:

If the list contains fewer bytes than the address
range, the list is used repeatedly until all the
designated memory locations are filled.

If the list contains more bytes than the address range,
the extra list items are ignored.
Note: If you enter only an offset for the
starting address of the range, the Fill command
assumes the segment contained in the DS
register.

Memory locations 04 BA: 100 through 04 BA: 104 are
filled with the 5 bytes specified. Remember that the
ASCII values of the list characters are stored. Thus,
locations 100-104 will contain F3 58 59 5A 8D.

8-27

Go
Command

Purpose:

Executes the program you are debugging.
Stops the execution when the instruction at a
specified address is reached (breakpoint), and
displays the registers, flags, and the next instruction
to be executed.

Format:

G [=address] [address [address ... ]]

Remarks:

Program execution begins with the current
instruction, whose address is determined by the
contents of the CS and IP registers, unless overridden
by the =address parameter (the = must be entered).
If =address is specified, program execution begins
with CS:=address.
The Go command has two format options:
Option 1
Use this option to execute the program you are
debugging without breakpoints. For example:
G [=address]

This option is useful when testing program execution
with different parameters each time. (Refer to the
Name command.) Be certain the CS:IP values are set
properly before issuing the G command, if not using
= address.

8-28

Go
Command

Option 2
This option performs the same function as Option 1
but, in addition, allows breakpoints to be set at the
specified addresses. For example:
G [=address] address
[address ... ]

This method causes execution to stop at a specified
location so the system/program environment can be
examined.
You can specify up to ten breakpoints in any order.
You may wish to take advantage of this if your
program has many paths, and you want to stop the
execution no matter which path the program takes.
The DEBUG program replaces the instruction codes
at the breakpoint addresses with an interrupt code
(hex CC). If anyone breakpoint is reached during
execution, the execution is stopped, the registers and
flags are displayed, and all the breakpoint addresses
are restored to their original instruction codes. If no
breakpoint is reached, the instructions are not
restored.
Notes:
1.

Once a program has reached completion
(DEBUG has displayed the "Program
terminated normally" message), it will be
necessary to reload the program before it
can be executed again.
8-29

Go
Command

2.

Make sure that the address parameters
refer to locations that contain valid 8088
instruction codes. If you specify an address
that does not contain the first byte valid
instruction, unpredictable results will
occur.

3.

The stack pointer must be valid and have 6
bytes available for the Go command;
otherwise, unpredictable results will occur.

4.

If only an offset is entered for a breakpoint,
the G command assumes the segment
contained in the CS register.

F or example:

Execution begins with the current instruction,
whose address is the current values of CS:IP.
The =address parameter was not used.
Three breakpoints are specified; assume that the
second is reached. Execution stops before the
instruction at location CS: 1EF is executed, the
original instruction codes are restored, all three
breakpoints are removed, the display occurs,
and the Go command ends.
Refer to the Register command for a description
of the display.

8-30

Hexarithmetic
Command

Purpose:

Adds the two hexadecimal values, then subtracts the
second from the first.
Displays the sum and difference on one line.

Format:

H value value

Example:

il~
~1

tiM;: fr~
[J]g

The hexadecimal sum of OOOF and 0008 is 001 7,
and their difference is 0007.

8-31

Inp~t

Command

Purpose:

Inputs and displays (in hexadecimal) one byte from
the specified port.

Format:

I portaddress

Example:

I 2F8

68

The single hexadecimal byte read from port 02F8 is
displayed (6B).

8-32

Load
Command

Purpose:

Loads a file or absolute diskette sectors into memory.

Format:

L [address [ drive sector sector]]

Remarks:

The maximum number of sectors that can be loaded
with a single Load command is hex 80.
Note: DEBUG displays a message if a diskette
read error occurs. You can retry the read
operation by pressing F 3 to redisplay the Load
command. Then, press the Enter key.
The Load command has two format options:
Option 1
Use this option to load data from the diskette
specified by drive, and place the data in memory
beginning at the specified address. For example:
L address drive sector sector

The data is read from the specified starting relative
sector (first sector) and continues until the requested
number of sectors is read (second sector).
Note: If you only enter an offset for the
beginning address, the L command assumes the
segment contained in the C S register.

8-33

Load
Command

F or example, to load data, you might enter:
i 41BlA:l00 1 OF 60

The data is loaded from the diskette in drive Band
placed in memory beginning at 4BA:I00. Hex 6D
(109) consecutive sectors of data are transferred,
starting with relative sector hex OF (15) (the 16th
sector on the diskette).
Option 2
When issued without parameters, or with only the
address parameter, use this option to load the file
whose filespec is properly formatted in the file
control block at CS:5C. For example:

or

This condition is met by specifying the filespec when
starting the DEBUG program, or by using the Name
command.
Note: If DEBUG is started with a filespec
and subsequent Name commands are used, you
may need to enter a new N arne command for the
proper filespec before issuing the Load command.

8-34

Load
Command

The file is loaded into memory beginning at CS: 100
(or the location specified by address), and is read
from the drive specified in the filespec (or from the
default drive, if none was specified). Note that files
with extensions of .COM or .EXE are always loaded
at CS:IOO - if you specify an address, it will be
ignored.
The BX and CX registers are set to the number of
bytes read; however, if the file being loaded has an
extension of .EXE; BX and CX are set to the actual
program size, and the file may be loaded at the high
end of memory. Refer to the notes in "How to Start
the DEBUG Program" at the beginning of this
chapter for the conditions that are in effect when
.EXE or .HEX files are loaded.
F or example:
DiEfHJrij

-WJ

!m'll!lJrfl!llml

-II.

The file named myprog is loaded from the default
diskette and placed in memory beginning at location
CS:OIOO.

8-35

Move
Command

Purpose:

Moves the contents of the memory locations
specified by range to the locations beginning at the
address specified.

Format:

M range address

Remarks:

Overlapping moves are always performed without
loss of data during the transfer. (The source and
destination areas share some of the same memory
locations. )
The data in the source area remains unchanged
unless overwritten by the move.
Notes:
1. If you enter only an offset for the beginning
address of the range, the M command
assumes the segment contained in the DS
register. If you specify an ending address for
the range, enter it with only an offset value.
2. If you enter only an offset for the address of
the destination area, the M command assumes
the segment contained in the DS register.

Example:

M CS: 100 110 500

The 17 bytes of data from CS:I00 through CS:II0
are moved to the area of memory beginning at
DS:500.
8-36

Name
Command

Purpose:

The Name command has two functions:
- Formats file control blocks for the first two
filespecs, at CS:5C and CS:6C. (Starting
DEBUG with a filespec also formats a file control
block at CS:5C.)
The file control blocks are set up for the use of the
Load and Write commands, and to supply
required filenames for the program being
debugged.
-

All specified filespecs and other parameters are
placed exactly as entered, including delimiters, in
a parameter save area at CS:81, with CS:80
containing the number of characters entered.
Register AX is set to indicate the validity of the
drive specifiers entered with the first two filespecs.

Format:

N [d:] [pathJfilename[. ext]

Remarks:

If you start the DEBUG program without a filespec,
you must use the Name command before a file can
be loaded with the L command.

8-37

Name
Command

Example:

DEBUG
·N myprog

·l

To define filespecs or other parameters required by
the program being debugged, enter:
DEBUG myprog
m&\l

fUel file2

In this example, DEBUG loads the file myprog at
CS: 100, and leaves the file control block at CS:5C
formatted with the same filespec. Then, the Name
command formats file control blocks forjilel and
jile2 at CS:5C and CS:6C, respectively. The file
control block for myprog is overwritten. The
parameter area at CS:81 contains all characters
entered after the N, including all delimiters, and
CS:80 contains the count of those characters
(hex OC).

8·38

Output
Command

Purpose:

Sends the byte to the specified output port.

Format:

0 portaddress byte

Example:

To send the byte value 4F to output port 2F8, enter:
(ll

2F8 4F

8-39

Quit
Command

Purpose:

Ends the DEBUG program.

Format:

Q

Remarks:

The file that you are working on in memory is not
saved by the Quit command. You must use the Write
command to save the file.
DEBUG returns to the command processor which
then issues the normal command prompt.

Example:

8-40

-0
A>

Register
Command

Purpose:

The Register command has three functions:
It displays the hexadecimal contents of a single

register, with the option of changing those
contents.
It displays the hexadecimal contents of all the

registers, plus the alphabetic flag settings, and
the next instruction to be executed.
It displays the eight 2-letter alphabetic flag

settings, with the option of changing any or all
of them.

Format:

R [registername]

Remarks:

When the DEBUG program starts, the registers and
flags are set to certain values for the program being
debugged. (Refer to "How to Start the DEBUG
Program" at the beginning of this chapter.)
Display a Single Register
The valid registernames are:
AX
BX
CX
DX
SP

BP
SI
DI
DS
ES

SS
CS
IP
PC
F

Both IP and PC refer to the instruction pointer.
8-41

Register
Command

F or example, to display the contents of a single
register, you might enter:

R AX
The system might respond with:

Now you may take one of two actions:
Press Enter to leave the contents unchanged.
or
Change the contents of the AX register by
entering a 1-4 character hexadecimal value,
such as hex FFF.

Now pressing Enter changes the contents of the AX
register to hex OFFF.

8-42

Register
Command

Display All Registers and Flags
To display the contents of all registers and flags (and
the next instruction to be executed), enter:

The system might respond with:
ffi!I)[=[JJtE[ll~

BX=O@ff

~~=uU](lJJ1 trn)i;(=(O)IJ ~;IT;

Sf=039[ll BP=llOOO

$~=ifllfrn[5C

rmS=mJ4H8i~ 1E$=~4IBlA

$$=ij49ttl1
tMG ~l I~

~P=fI]~

1A NlV LHP

[!l~~A:!UJ1 ~A

m

C[DlJ~~

m=@@[lllDl
tr;$=[Jl'i!~Li!\

~[£ rM[~

~L~m

~"TI

The first four lines display the hexadecimal contents
of the registers and the eight alphabetic flag settings.
The last line indicates the location of the next
instruction to be executed, and its hexadecimal and
unassembled formats. This is the instruction pointed
to by CS:IP.

8-43

Register
Command

Note: A system with an 80-column display
shows:
1st .line - 8 registers
2nd line - 5 registers and 8 flag settings
3rd line - next instruction information
A system with a 40-column display shows:
1st line - 4 registers
2nd line - 4 registers
3rd line - 4 registers
4th line - 1 register and 8 flag settings
5th line - next instruction information
Display All Flags
There are eight flags, each with 2-letter codes to
indicate either a set condition or a clear condition.

8-44

Register
Command

The flags appear in displays in the same order as
presented in the following table:

Flag Name

Set

Clear

Overflow (yes/no)

OV

NV

Direction (decrement/increment)

DN

UP

Interrupt (enable/disable)

EI

DI

Sign (negative/positive)

NG

PL

Zero (yes/no)

ZR

NZ

Auxiliary carry (yes/no)

AC

NA

Parity (even/odd)

PE

PO

Carry (yes/no)

CY

NC

Figure 6. Alphabetic Flag Settings

To display all flags, enter:
R F

If all the flags are in a set condition, the response is:
OV ON EI NO ZR AC PE CV - _

8-45

Register
Command

Now you can take one of two actions:
1.

Press Enter to leave the settings unchanged.

2.

Change any or all of the settings.

To change a flag, just enter its opposite code. The
opposite codes can be entered in any order-with or
without intervening spaces. For example, to change
the first, third, fifth, and seventh flags, enter:

They are entered in reverse order in this example.
Press Enter and the flags are modified as specified,
the prompt appears, and you can enter the next
command.
If you want to see if the new codes are in effect,
enter:

The response will be:

The first, third, fifth, and seventh flags are changed
as requested. The second, fourth, sixth, and eighth
flags are unchanged.
Note: A single flag can be changed only once
per R F command.
8-46

Search
Command

Purpose:

Searches the range for the character( s) in the list.

Format:

S range list

Remarks:

All matches are indicated by displaying the addresses
where matches are found.
A display of the prompt (- ) without an address means
that no match was found.
Note: If you enter only an offset for the
starting address of the range, the S command
assumes the segment contained in the DS
register.

Example:

If you want to search the range of addresses from
CS:100 through CS:110 for hex 41, enter:

8-47

Search
Command

If two matches are found the response might be:
048A:0104
048A:0100

If you want to search the same range of addresses
as in the previous example for a match with the
4-byte-Iong list, enter:
S CS:l00 L 11 41 "AB" E

The starting addresses of all matches are listed. If no
match is found, no address is displayed.

8-48

Trace
Command

Purpose:

Executes one or more instructions starting with the
instruction at CS:IP, or at =address if it is specified.
The = must be entered. One instruction is assumed,
but you can specify more than one with value.
Displays the contents' of all registers and flags after
each instruction executes. For a description of the
display format, refer to the Register command.

Format:

T [=address] [value]

Remarks:

The display caused by the Trace command continues
until value instructions are executed. Therefore,
when tracing multiple instructions, remember you can
suspend the scrolling at any time by pressing
Ctrl-Num Lock. Resume scrolling by entering any
other character.

Example:

T

If the IP register contains 011 A, and that location
contains B40E (MOV AH,OEH), this might be
displayed:
AX=OEOO BX=OOFF CX=0007 OX=Ol FF
SP=0390 BP=OOOO SI=005C 01=0000
OS=04BA ES=04BA SS=04BA CS=04BA
IP=Oll C NV UP 01 NG NZ AC PE NC
04BA:011 C C021
INT 21

8-49

Trace
Command

This displays the results after the instruction at 011 A
is executed, and indicates the next instruction to be
executed is the INT 21 at location 04BA:OIIC.

Sixteen instructions are executed (starting at CS:IP).
The contents of all registers and flags are displayed
after each instruction. The display stops after the
16th instruction has been executed. Displays may
scroll off the screen unless you suspend the display
by pressing the Ctrl-Num Lock keys.

8-50

Unassemble
Command

Purpose:

Unassembles instructions (translates the contents of
memory into assembler-like statements) and displays
their addresses and hexadecimal values, together with
assembler-like statements. For example, a display
might look like this:
04BA:Ol00 206412 lUUiJ ~S~+12],A~
04BA:OUJl3 Fe
rr:Ull
04BA:OHJ4 1665
JBIE OUll1Bl

Format:

U [address]

or
U [range]

Remarks:

The number of bytes unassembled depends on your
system display format (whether 40 or 80 columns),
and which option you use with the Unassemble
command.
Notes:
1.

In all cases, the number of bytes
unassembled and displayed may be slightly
more than either the amount requested or
the default amount. This happens because
the instructions are of variable lengths;
therefore, to unassemble the last
instruction may include more bytes than
expected.

8-51

Unassemble
Command

2.

Make sure that the address parameters
refer to locations containing valid 8088
instruction codes. If you specify an address
that does not contain the first byte of a
valid instruction, the display will be
erroneous.

3.

If you enter only an offset for the starting
address, the U command assumes the
segment contained in the CS register.

The Unassemble command has two format options:
Option 1
Use this option to either unassemble instructions
without specifying an address, or to unassemble
instructions beginning with a specified address. For
example:

u
or
U address

Sixteen bytes are unassembled with a 40-column
display. "Thirty-two" or "display"; 32 bytes are
unassembled with an 80-column display.
Instructions are unassembled beginning with the
specified address.

8-52

Unassemble
Command

If you do not specify an address, the U command
assumes the starting address is the location following
the last instruction unassembled by a previous
U command. Thus, it is possible to unassemble
consecutive locations, producing continuous
unassembled displays, by entering consecutive
U commands without parameters.
If no previous U command is entered, the location is
offset hex 0100 into the segment originally initialized
in the segment registers by DEBUG.
Option 2
Use this option to unassemble instructions in a
specified address range. For example:
U range

All instructions in the specified address range are
unassembled, regardless of the system display
format.
Note: If you specify an ending address, enter
it with only an offset value.

8-53

Unassemble
Command

F or example:
U 04ba:Ol00 108

The display response might be:
04BA:Ol00 206412 AND [S3+72]jlH

aJl48A:OHD3 Fe
CUJ
04BA:0104 1665
JBE 0168
04BA:Ol06 201370 AND [BP+m+1'O],DH

The same display appears if you enter:
as 04BA:l00 L 1

or

or
ill 04BA:l00 L 9

8-54

Write
Command

Purpose:

Writes the data being debugged to diskette.

Format:

W [address [drive sector sector]]

Remarks:

The maximum number of sectors that can be written
with a single Write command is hex 80.
DEBUG displays a message if a diskette write error
occurs. You can retry the write operation by pressing
F3 to redisplay the Write command, then press the
Enter key.
The Write command has two format options:
Option 1
Use this option to write data to diskette beginning at
a specified address. For example:
W address drive sector sector

8-55

Write
Command

The data beginning at the specified address is written
to the diskette in the indicated drive. The data is
written starting at the specified starting relative sector
(first sector) and continues until the requested
number of sectors are filled (second sector).
Notes:
1.

Be extremely careful when you write data
to absolute sectors because an erroneous
sector specification will destroy whatever
was on the diskette at that location.

2.

If only an offset is entered for the
beginning address, the W command
assumes the segment contained in the C S
register.

3.

Remember, the starting sector and the
sector count are both specified in
hexadecimal.

F or example:
W 1FD 1 100 A

The data beginning at CS:OIFD is written to the
diskette in drive B, starting at relative sector hex 100
(256) and continuing for hex OA (10) sectors.

8-56

Write

Command

Option 2
This option allows you to use the Write command
without specifying parameters or only specifying the
address parameter. For example:

w
or
Waddress

When issued without parameters (or when issued
with only the address parameter), the Write
command writes the file (whose filespec is properly
formatted in the file control block at CS:5C) to
diskette.
This condition is met by specifying the filespec when
starting the DEBUG program, or by using the Name
command.
Note: If DEBUG was started with a filespec
and subsequent Name commands were used,
you may need to enter a new Name command
for the proper filespec before issuing the Write
command.

8-57

Write
Command

In addition, the BX and CX registers must be set to
the number of bytes to be written. They may have
been set properly by the DEBUG or Load
commands, but might have been changed by a Go or
Trace command. You must be certain the BX and
ex registers contain the correct values.
The file beginning at CS:I00, or at the location
specified by address, is written to the diskette in the
drive specified in filespec or the default drive if none
was specified.
The debugged file is written over the original file that
was loaded into memory, or into a new file if the
filename in the FCB didn't previously exist.
Note: An error message is issued if you try to
write a file with an extension of .EXE or .HEX.
These files must be written in a specific format
that DEBUG cannot support.

8-58

Write
Command

If you find it necessary to modify a file with an
extension of .EXE or .HEX, and the exact
locations to be modified are known, use the
following procedure:

1.

RENAME the file to an extension other
than .EXE or .HEX.

2.

Load the file into memory using the
DEBUG or Load command.

3.

Modify the file as needed in memory, but
do not try to execute it with the Go or
Trace commands. Unpredictable results
would occur.

4.

Write the file back using the Write
command.

5.

RENAME the file back to its correct
name.

8-59

Summary of DEBUG Commands

The following chart is provided for quick reference.
The section called "Format Notation" in Chapter 1
explains the notation used in the format of the following
commands.

Command

Purpose

Format

Assemble

Assembles statements

A [address]

Compare

Compares memory

C range address

Dump

Displays memory

D [address]
or
D [range]

Enter

Changes memory

E address [list]

Fill

Changes memory blocks

F range list

Go

Executes with optional
breakpoints

G [=address]
[address
[address ... ]]

Hex arithmetic Hexadecimal add-subtract H value value
Input

Reads/displays input
byte

I portaddress

Load

Loads file or absolute
diskette sectors

L [address [drive
sector sector]]

Move

Moves memory block

M range address

Figure 7 (Part 1 of 2). DEBUG Commands
8-60

Command

Purpose

Format

Name

Defines files and
parameters

[d:]
[path lfilename[.ext]

Output

Sends output byte

o portaddress byte

Quit

Ends DEBUG program

Q

Register

Displays registers/flags

R [registername]

Search

Searches for characters

S range list

Trace

Executes and displays

T [=address]
[value]

Unassemble

Unassembles instructions

U [address]
or
U [range]

Write

Writes file or absolute
diskette sectors

W [address[drive
sector sector]]

Figure 7 (Part 2 of 2). DEBUG Commands

8-61

8-62

Appendixes

Contents
Appendix A. Messages

A-I

Introduction ..............................

A-I

Responses ................................

A-2

Device Error Messages ....................

A-3

Other Messages ...........................

A-9

Appendix B. Running Compilers and
Assembler ...............................
U sing Compilers and Assemblers With
Fixed Disk ..........................
Exceptions ...........................
Appendix C. Running the Pascal
Compiler ................................
Using Pascal Hex Patch With
Fixed Disk ..........................

B-1
B-2
B-2
C-l
C-l

Appendix D. Considerations for Using
Applications ............................

D-l

Accounting Packages by BPI
Systems, Inc. ............................

D-2

Accounting Packages Version 1.00 by
Peachtree Software, Inc. ..................

D-2

A-i

Accounting Packages Version 1.10 by
Peachtree Software, Inc. ..................

D-2

Arithmetic Games 1 and 2 .................

D-3

Asynchronous Communications Support
Version 1.00 .............................
The Procedure ........................

D-3
D-4

Asynchronous Communications Support
Version 2.00 .............................
The Procedure ........................

D-6
D-7

EasyWriter Version 1.10 ...................

D-9

Fact Track ............................... D-ll

A-ii

Multiplan

D-12

pfs:FILE ................................
Using pfs:FILE with the IBM
Fixed Disk ..........................
Storing PFS Data Files on the
Fixed Disk ......................
Copying pfs:FILE to the
Fixed Disk ......................
Error Conditions ......................
Running the pfs:FILE Program from a
Fixed Disk ..........................
Changing Settings When Using the
Fixed Disk ..........................

D-13
D-13
D-13
D-14
D-15
D-16
D-16

pfs:REPORT .............................
Using pfs:REPORT with the IBM
Fixed Disk ..........................
Storing PFS Data Files on the
Fixed Disk ......................
Copying pfs:REPORT to the
Fixed Disk ......................
Error Conditions ......................
Running the pfs:REPORT Program from a
Fixed Disk ..........................
Changing Settings When Using the
Fixed Disk ..........................

D-17
D-17
D-18
D-18
D-20
D-21
D-21

The Dow Jones Reporter Version 1.00 ....... D-21
SNA 3270 Emulation and RJE Support
Version 1.00 ............................. D-22
The Procedure ........................ D-22
Typing Tutor ............................. D-23
VisiCalc by VisiCorp. ..................... D-24
Putting DOS 2.10 on Your Program
Diskette ............................ D-24
3101 Emulator Version 1.00 ............... D-25
The Procedure ........................ D-26
Appendix E. DOS Version 2.00 and 2.10
Enhancements ........................... E-l
For All Users ......................... E-l
New Commands ...................... E-5
Enhanced Commands .................. E-9
For Programmers ...................... E-12
Appendix F. Some Keys You Use
with DOS ................................ F-l

A-iii

A-iv

Appendix A. Messages

Introduction

This chapter contains device errors (the message that
DOS uses to indicate errors while reading or writing to
devices on your system), and Other messages (the
remainder of the DOS messages) in alphabetical order.
Messages are listed in bold type and the explanation
and action follow the message.
The first word of the description of each message is the
name of the program or command that generated the
message.
In some cases, the message could be generated by
several different programs or commands. In that case,
the first word is commands. Where the message is
generated by an internal DOS function, the first word is
DOS.

A-I

Responses

When any of the device error messages are displayed,
the system waits for you to respond. If you know what
caused the problem, you can take corrective action
before you actually choose a response. The system
waits until you make one of these responses. To recover
from an error condition, the responses should be made
in the following order:

A-2

R

Retry the operation because the error may not
occur again. The system tries the disk read or write
operation again. We strongly recommend that you
use Retry first.

A

Abort the program. The system ends the program
that requested the disk read or write.

I

Ignore the error condition and continue the
program. (Be careful when choosing this response
because data may be lost.) The system pretends
the error did not occur and continues the program.

Device Error Messages

When an error is detected during reading or writing to
any of the devices (disk drives, printer, etc.) on your
system, DOS displays a message in the following
format:
 error reading 
Abort, Retry, Ignore?

or
 error writing 
Abort, Retry, Ignore?

In these messages,  is the name of the device
in error, such as PRN, or B:, and  is one of the
types listed on the following pages:
Bad call format
Explanation: A device driver was passed an
incorrect length request header.
Action: Refer to "Responses" at the beginning of
this group of device messages.
•

Use DEBUG.

•

Review your programming specifications.
Patch and reassemble.

•

If you are using a purchased program, contact
the dealer you purchased the device driver
from.

A-3

Bad command
Explanation: A device driver has issued an
invalid command to .
Action: Refer to "Responses" at the beginning of (
this group of device messages.
•

Review your device interface specification
and DOS driver implementation to make sure
everything you are trying to do is supported.

•

Check your program to see if you have a
coding problem that needs debugging.

Bad unit
Explanation: A device driver has been passed
an invalid subunit number.
Action: Refer to "Responses" at the beginning of
this group of device messages. If you are using a
purchased program, contact the dealer you
purchased the device driver from.
Data
Explanation: DOS was unable to read or write
the data correctly. This message usually means a
disk has developed a defective spot.
Action: Refer to "Responses" at the beginning of
this group of device messages.

A-4

Disk error reading
Explanation: An error of a type not described
elsewhere in this list has occurred.
Action: Refer to "Responses" at the beginning of
this group of device messages. Choose Retry first.
Then choose Abort if this problem requires further
investigation by a programmer.
If you are using a purchased program, contact the
dealer you purchased it from.

Disk error writing
Explanation: An error of a type not described
elsewhere in this list has occurred.
Action: Refer to "Responses" at the beginning of
this group of device messages. Choose Retry first.
Then choose Abort if this problem requires further
investigation by a programmer.
If you are using a purchased program, contact the
dealer you purchased it from.
No paper
Explanation: The indicated printer is either out
of paper or not turned on.
Action: Turn the printer ON, press the
ONLINE switch, or add paper and retry.
Refer to "Responses" at the beginning of this
group of device messages.

A-5

Non-DOS disk
Explanation: The file allocation table contains
invalid information. The disk needs to be
reformatted.
Action: Refer to "Responses" at the beginning of
this group of device messages.
Try running CHKDSK to see if any corrective
action is possible. Reformatting will correct the
disk, but the files are lost forever.
Not ready
Explanation: The named device is not ready to
accept or transmit data.
Action: Check that the disk drive door is closed
and choose Retry for your response if this is the
problem.
Refer to "Responses" at the beginning of this
group of device messages.
Read fault
Explanation: DOS was unable to read the data
from the device.
Action: Refer to "Responses" at the beginning of
this group of device messages.

A-6

•

Make sure the diskette is properly inserted in
the drive.

•

If you get the same message, choose Abort
and rerun the command with a different disk.

Sector not found
Explanation: The sector containing the data
could not be located on the disk.
Action: Refer to "Responses" at the beginning of
this group of device messages.
If you get the same message, choose Abort and
rerun the command with a different disk.

Seek
Explanation: The fixed disk or diskette drive
was unable to locate the proper track on the disk.
Action:
•

Make sure the diskette is properly inserted in
the drive.

•

Try a different drive

•

RunCHKDSK

Refer to "Responses" at the beginning of this
group of device messages.

A-7

Write fault
Explanation:
to the device.

DOS was unable to write the data

Action:
•

Make sure the diskette is properly inserted in
the drive.

•

If the diskette is not the problem, choose
Retry.

•

If you get the same message, choose Abort
and rerun the command with a different disk.

Refer to "Responses" at the beginning of this
group of device messages.
Write protect
Explanation: An attempt was made to write on a
write protected diskette.
Action: Investigate carefully before you decide
to write on a write protected diskette.
Note: One of the preceding messages will
appear if you attempt to use a dual-sided
diskette in a single-sided drive, or if you
attempt to use a 9-sector-per-track diskette on
a pre-version 2.00 or 2.10 level of DOS.
Warning: If any of the preceding messages
appear for a diskette drive, DO NOT change
diskettes before responding with Abort,
Retry, or Ignore.

A-8

Other Messages

The following messages are in alphabetical order.

A
About to generate .EXE file
Change disks 
Explanation: LINK. Informational message.
This message is displayed when you specify the
IPAUSE parameter.
Action: Insert your Runfile diskette into the
appropriate drive and press Enter.
Access denied
Explanation: DEBUG. An attempt was made to
write to a file that is marked read only. The
.
filename you are using is protected.
Action:

Use a different filename.

All files canceled by operator
Explanation: PRINTIT. Informational message.
You used the PRINT command with the IT
parameter to cancel the printing of all queued files.
Action: No action required. This message
appears on the printer.

A-9

All specified file(s) are contiguous
Explanation: CHKDSK. Informational
message. The file or files you named are all written
sequentially on the disk.
Action:

No action required.

Allocation error for file, size adjusted
Explanation: CHKDSK or CHKDSK/F. A
filename precedes this message. An invalid cluster
number was found in the file allocation table.
Action:
•

If you specified the IF parameter, the file is
truncated at the end of the last valid cluster.

•

If you did not enter the IF parameter, the
message is for your information and no action
is needed. Enter:
CHKDSKIF

to correct the file size.
Amount read less than size in header
Explanation: EXE2BIN. The program portion
of the file was smaller than indicated in the file's
header.
Action: Recompile or reassemble the program,
and then reLINK it.

A-IO

An internal failure has occurred
Explanation: LINK. An error occurred in the
linker program.
Action: Write down the conditions under which
the message appeared. Report this to your
Authorized IBM Personal Computer Dealer.
Attempt to access data outside
of segment bounds
Explanation:

LINK. An object file is invalid.

Action:
•

Review the .ASM file or assembled listing for
segmentation violations.

•

Look for a bad reference or invalid
instruction.

Attempted write protect violation
Explanation: FORMAT. The diskette being
formatted is write protected and cannot be written
on.
Action: In response to the displayed prompt,
insert a new diskette and press any key to restart
formatting.

A-II

B
Backup file sequence error
Explanation: RESTORE. A file to be restored
was backed up on more than one diskette. You did
not insert the diskette with the first part of the file.
Action: Rerun RESTORE and start with the
correct diskette.
Bad command or filename
Explanation: DOS. The command you just
entered is not a valid DOS command.
Action: Check the spelling of the command and
re-enter it.
If the command name is spelled correctly, check to
see that the default or specified drive contains the
external command or batch file you are trying to
execute.
Bad numeric parameter
Explanation: LINK. The value you specified
with the /STACK parameter is not a valid
numeric constant.
Action: Use a valid numeric constant and try
LINK again.

A-12

Bad or missing Command Interpreter
Explanation: DOS. The disk that DOS is being
started from does not contain a copy of
COMMAND.COM, or an error occurred while
the disk was being loaded.
This message also appears ifCOMMAND.COM
has been removed from the directory it was in
originally when DOS was started; or if the
COMSPEC= parameter in the environment
points to a directory not containing
COMMAND.COM and DOS is trying to reload
the command processor.
Action: Do a System Reset. If System Reset
fails to solve the problem, start DOS with your
backup DOS diskette. Then copy
COMMAND.COM from the backup diskette to
the root directory of the disk that failed.
Bad or missing 
Explanation: DOS. This message appears only
at startup and indicates one of the following:
a.

The name of a device driver named in a
DEVICE=  parameter in the
CONFIG.SYS file was not found.

b.

A break address was out of bounds for the
machine size.

c.

An error occurred while the driver was being
loaded. That driver is not installed by DOS.

A-13

Action:
a.

F or an incorrect device driver name, use
the correct spelling for the device drive
name, or use the diskette with the named
device driver.

b.

For items Band C, correct the coding in the
device driver.

c.

If you still cannot correct the problem, see
your IBM Personal Computer dealer.

Batch file missing
Explanation: DOS. DOS could not locate the
batch file it was processing. The file may have
been erased or renamed by one of the steps within
it. Batch processing stops and the DOS prompt
appears.
Action:

A-14

1.

If the filename was changed or if the file was
deleted, correct the command that changed
the name( s).

2.

If the file was erased, use your backup copy.
If you used ED LIN to create the file or make
changes, rename the .BAK file to .BAT.
Correct the command that deleted the file.

BF
Explanation: DEBUG. Bad flag. An invalid flag
code setting was specified.
Action: Try the Register (R F) command again
with the correct code.
BP

Explanation: DEBUG. Breakpoints. More than
ten breakpoints were specified for the GO
command.
Action: Re-enter the GO (G) command again
with ten or fewer breakpoints.
BR
Explanation: DEBUG. Bad register. An invalid
register name was specified.
Action: Re-enter the Register (R) command
using a correct register name.
BREAK is On IOff
Explanation: BREAK. This message indicates
the status of BREAK, either on or off.
Action: Enter the command you want. For
example, if Break is off is displayed and Break is
on is desired, enter the command:
BREAK ON

A-1S

c
Cannot do binary reads from a device
Explanation: COPY. You used the /B
parameter with a device name while trying to copy
from the device. The copy cannot be performed in
binary mode because COpy must be able to detect
end-of-file from the device.
Action: Re-enter COpy and omit the /B
parameter or use the / A parameter after the device
name.
Cannot edit .BAK file-rename file
Explanation: EDLIN. Files with the extension
.BAK are considered to be backup files, with more
up-to-date versions of the files assumed to exist.
Therefore, .BAK files shouldn't ordinarily be
edited.
Action: If it is necessary to edit the .BAK file,
rename the file giving it an extension other than
.BAK. Or else, copy the file and give the copy a
different filename extension.

A-16

Cannot find file object file
Chan~ili~ette

Explanation: LINK. The linker could not locate
the specified object module on the drive.
Action: Insert the correct diskette with the object
file on it and press Enter.
Warning: If it is necessary to change the diskette
that contains the open VM.TMP file, you need to
exit LINK by pressing Ctrl-Break instead of
changing diskettes, and then restart LINK with a
different drive specified to locate the object file.
Otherwise there may be a loss of data on the
diskette inserted. This usually occurs when using
default drive values for the object file.
Cannot find library library file
Enter new drive letter:
Explanation: LINK. The specified library could
not be found on the drive.
Action: Enter the correct letter for the drive the
library is on.
Warning: If it is necessary to change the diskette
that contains the open VM. TMP file, you need to
exit LINK by pressing Ctrl-Break instead of
different diskettes, and then restart LINK with a
changing drive specified to locate the object file.
Otherwise there may be a loss of data on the
diskette inserted. This usually occurs when using
default drive values for the object file.

A-I7

Cannot format an ASSIGNed drive
Explanation: FORMAT. The ASSIGN x y
was executed prior to the attempted execution of
FORMAT.
Action: Execute ASSIGN to restore the original
drive letter assignment. Then proceed to execute
FORMAT.
Cannot load COMMAND, system halted
Explanation: DOS. DOS attempted to reload
the command processor, but the area in which
DOS keeps track of available memory was
destroyed; or the command processor was not
found in the path specified by the COMSPEC
parameter.
Action: Restart DOS. Don't forget to put the
DOS diskette in the drive.
Cannot nest response file
Explanation: LINK. You used @filespec within
an automatic response file. Automatic response
files cannot be nested.
Action:

A-18

1.

Change the initial auto response file to
eliminate nested auto response file.

2.

Or, if you did not intend this to be an auto
response file, fix the syntax error.

Cannot open list file
Explanation:
full.

LINK. The directory or disk is

Action: Insert another disk, or delete some files
from the disk that is full.
Cannot open overlay
Explanation:
full.

LINK. The directory or disk is

Action: Insert another disk, or delete some files
from the disk that is full.
Cannot open response file
Explanation: LINK. The automatic response
file could not be found.
Action: Include drive specifier and/or path for
the response file. Place file on proper disk.
Cannot open temporary file
Explanation:
full.

LINK. The directory or disk is

Action: Insert another disk, or delete some files
from the disk that is full.

A-19

Cannot start COMMAND, exiting
Explanation: DOS. While DOS was attempting
to load another copy of the command processor,
either the FILE S= parameter in the configuration
file was found to contain too small a value, or
there is not enough available memory to contain
the new copy of COMMAND. COM.
Action:
•

Restart DOS.

•

If necessary, increase the parameter value of
FILES= parameter in CONFIG.SYS.

COMn: bbbb,p,d,s,t initialized
Explanation: MODE. Informational message.
The Asynchronous Communications Adapter is
initialized. The values represent:
n

adapter (COMl or COM2)

bbbb baud rate
p

s

A-20

parity
e

even

o

odd

n

none

stop bits (lor 2)

t

type of serial device
p

serial printer (serial time outs will be
retried)
other serial device (serial time outs will
not be retried)

Action: No action required. The feedback
message from MODE shows its interpretation of
the MODE command and the parameters you
entered.
Compare error at offset XXXXXXXX
Explanation: CaMP. Informational message.
The files being compared contain different values
at the displayed offset (in hexadecimal) into the
file. The differing values are also displayed in
hexadecimal.
Action: No action required. This message is for
your information to give you the location that
contains mismatching information in two files.
Compare error(s) on
Track xx, side xx
Explanation: DISKCOMP. One or more
locations on the indicated track and side contain
different information when the diskettes are
compared.
Action: This message is to inform you that there
is a difference between diskettes. If you want an
exact copy of a diskette, use DISKCOPY.

A-21

Compare more diskettes (YIN)?
Explanation: DISKCOMP.
•

This message indicates completion of
DISKCOMP.

•

You may compare more than one set of
diskettes without re-entering the
DISKCOMP command.

Action: If you wish to compare another pair of
diskettes, enter Y, and DISKCOMP will ask you
to insert the required diskettes. If you do not want
to compare any more diskettes, enter N.
Compare more files (YIN)?
Explanation: COMPo COMP has finished
comparing files. You may compare more files
without re-entering the COMP command.
Action:

A-22

•

If you wish to compare the contents of two
more files, enter Y, and COMP will prompt
you for the names of the files to compare.

•

If you do not wish to compare more files,
enter N.

Comparing x sectors per track, n side(s)
Explanation: DISKCOMP. The n will be either
1 or 2, indicating the number of sides that
DISKCOMP will compare on the two diskettes.
This number is determined by the number of sides
DISKCOMP was able to successfully read from
the first track of the first diskette. The x indicates
the number of sectors per track found on the first
diskette (8 or 9). If you use 18, then the number 8
will appear.
Action: If x or n is not what you expected let
DISKCOMP finish comparing diskettes. Re-enter
the DISKCOMP command with or without
additional parameters.
Contains invalid cluster, file truncated
Explanation: CHKDSK. The file name
preceding this message means that the file contains
an invalid pointer to the data area.
Action: Use the IF parameter to truncate the file
at the last valid data block. No corrective action
occurs if CHKDSK is executed without the IF
parameter.

A-23

Contains xxx non-contiguous blocks
Explanation: CHKDSK. Informational
message. The file name preceding this message
means that the file is not written sequentially on
the disk-it is written in xxx pieces on different
areas of the disk.
This message is for your information and does not
indicate a problem with the disk.
Action: Since fragmented files take longer to
read, you should consider copying badly
fragmented files to another disk with the COpy
command. This will record the file sequentially,
resulting in better system performance when the
file is read.
Convert directory to file (YIN)?
Explanation: CHKDSK. The directory name
preceding this message means the directory
contains too much invalid information to be usable
as a directory.
Action:

A-24

•

If you reply Y, CHKDSK will convert the
directory to a file so that you may examine it
with DEBUG.

•

If you reply N, the entry is not changed.

xxx lost clusters found in yyy chains.
Convert lost chains to files (YIN)?
Explanation: CHKDSK located xxx blocks of
the data area which were marked as allocated, but
were not associated with a file. These clusters are
assumed to contain "lost" data, and CHKDSK
will ask whether you wish to free them, or to
recover each chain into a separate file.
Action:
•

If you reply Y and you have used the IF
parameter, CHKDSK will recover each chain
into a separate file.

•

If you reply N, CHKD SK frees the blocks up
so they can be allocated to new files.

•

If CHKDSK was specified (no IF), then
messages displayed afterwards are
informational (no corrective action was
taken).

Copy another (YIN)?
Explanation: DISKCOPY. This message allows
you to make exact images of additional diskettes
without re-entering the DISKCOPY command.
Action:
•

If you wish to copy another entire diskette,
enter Y. DISKCOPY will ask you to insert
the required diskettes.

•

If you do not wish to make any more copies,
enter N.

A-25

Copy complete
Explanation:
message.

DISKCOPY. Informational

Action: No action required. The source diskette
contents have been successfully copied to the
target diskette.
Copying x sectors per track, n side(s)
Explanation: DISKCOPY. The n will be either
1 or 2, indicating the number of sides that
DISKCOPY has successfully read from the first
track of the source diskette. The x will be 8 or 9,
indicating the number of sectors per track found on
the source diskette. If the diskette has been
formatted double sided and subsequently formatted
single sided, DISKCOPY will say it is copying 2
siders}. In this situation, use DISKCOPY /1.
If the diskette has ever been formatted with 9
sectors per track, then subsequently formatted for
8-sector-per-track use, DISKCOPY will say it is
copying 9 sectors per track. However, DOS will
only use the first 8 sectors per track to contain
data.
Action:

A-26

No action required.

D
DF
Explanation: DEBUG. Double flag. Conflicting
codes were specified for a single flag.
Action: DEBUG is infonning you that a flag can
be changed only once per Register (R F)
command.
Disk boot failure
Explanation: DOS. An error occurred when you
tried to load DOS into memory.
Action: Restart the system. If subsequent
attempts to start the system also fail, place a
backup DOS diskette in drive A and restart your
system.
Disk error writing FAT X
Explanation: CHKDSK. A disk error was
encountered while CHKDSK was attempting to
update the file allocation table (FAT) on the
specified drive. X will be 1 or 2, depending on
which of the 2 copies of the file allocation table
could not be written.
Action: If this message appears twice, for FAT's
1 and 2, format the disk to make it usable again. If
FORMAT fails, discard the disk since it is
probably unusable.

A-27

Disk full-write not completed
Explanation: EDLIN. An End Edit command
ended abnormally because the disk is full (not
enough free space to save the entire file). Any
editing done to the file is lost.
Action: Obtain a fresh diskette, copy the file on
to the fresh diskette, and start editing again.
Disk not compatible
Explanation: FORMAT. You cannot use the
DOS FORMAT command to format a diskette
using the drive you specified. This message
informs you that the drive you specified is not
supported by the IBM device interfaces that
FORMAT requires.
Action:

Obtain a compatible disk drive.

Disk unsuitable for system disk
Explanation: FORMAT. A defective track was
detected where the DOS files were to reside. The
diskette can be used only for data.
Action: Use another disk if you wish to copy
DOS files.
Diskettes compare OK
Explanation: DISKCOMP. Informational
message. The two diskettes just compared contain
identical information.
Action:

A-28

No action required.

Diskette is not a backup diskette
Explanation: BACKUP and RESTORE. The
diskette was not created by BACKUP. The first
file on a backup diskette must be
BACKUPID.@@@.
Action: Retry the command with the correct
diskette.
Divide overflow
Explanation: DOS. A program tried to divide a
number by zero, or a logic error caused an internal
malfunction. The program ends and you return to
DOS.
Action: Correct the programming error and
continue. If this is a purchased program, take it
back to your dealer.
Do you see the leftmost 91 (YIN)
Explanation:

MODE. ,R,T was specified.

Action: Respond Y or N. This prompt is
repeated until you respond Y.
Do you see the rightmost 91 (YIN)
Explanation:

MODE. ,L,T was specified.

Action: Respond Y or N. This prompt is
repeated until you respond Y.

A-29

Do you wish to use the entire fixed
disk for DOS (yiN) ................? [ ]
Explanation: FDISK. When the "Create DOS
Partition" option is used on the current fixed disk
and the fixed disk has never been set up, this
question is asked.
Action:
•

If you enter Y, the entire current fixed disk is
used for DOS and it will be made active.

•

If you enter N, you are asked to enter the
limits of the DOS partition you want to
create.

DOS partition created
Explanation: FDISK. Informational message. A
DOS partition has been created on the fixed disk.
Action: You will need to run the FORMAT
command on the DOS partition before you can
store files on the fixed disk.
DOS partition deleted
Explanation: FDISK. Informational message.
The DOS partition no longer exists on the fixed
disk.
Action:

A-30

No action required.

Dup record too complex
Explanation: LINK. The problem is caused by
too many structures or D UP statements in the
object module created from an assembler source
program.
Action: Reduce the number of structures or
D UP statements in the assembler source program,
create a new object module, and retry LINK.
Duplicate filename or file not found
Explanation: RENAME. You tried to rename a
file to a filename that already exists on the disk, or
the file to be renamed could not be found on the
specified (or default) drive.
RENAME is warning you that you are using the
same name for two files, or else it can't find the file
you are trying to rename.
Action: Did you type the filename correctly?
Take a second look at the filename you want to
change, and re-enter the RENAME command.

E
Enter the number of the partition you
want to make active ............... : [ ]
Explanation: FDISK. The "Change Active
Partition" option is requesting you to enter the
number of the partition you want to make active.
Action: Type the number of the partition that
you want to make active on the current fixed disk.
Then press the Enter key.
Note: The partitions are displayed above
the prompt.
A-31

Enter partition size ............ : [dddd]
Explanation: FDISK. The "Create DOS
Partition" option is requesting that you enter the
size of the partition you wish to create.
Action: The number shown in the brackets is the
default size. If you only press Enter, that size will
be used as the partition size. Otherwise, enter the
desired size, then press Enter.
Enter primary file name
Explanation: COMPo DOS asks you for
primary filename.
Action: Enter the filespec of the first of two files
to be compared.
Enter 2nd file name or drive id
Explanation: COMPo DOS asks you for filespec
of second of the two files you want compared.
Action: Enter the filespec of the second of two
files to be compared, or just enter the drive letter
and/or path if the filename is the same as the
primary filename.
Enter starting cylinder number.. : [dddd]
Explanation: FDISK. The "Create DOS
Partition" option is requesting that you enter the
starting cylinder number for the DOS partition you
are creating. The value in the brackets is the
default value. It is the starting cylinder of the
largest piece of free space on the current fixed
disk.
Action: Type the starting cylinder number and
press Enter, or just press Enter to use the default
value.
A-32

Entry Error
Explanation:
syntax error.

EDLIN. EDLIN has detected a

Action: Correct the syntax error on the last
command.
Entry has a bad attribute
(or size or link)
Explanation: CHKDSK. This message may
begin with one or two periods, indicating which
entry in the subdirectory was in error. One period
indicates the current directory is in error. Two
periods mean the parent directory is in error. If
you did not enter the IF parameter, no corrective
action is taken.
Action:

Enter: CHKDSK IF

CHKDSK will then try to correct the error. If you
don't enter the IF parameter, CHKDSK does not
write any corrections on the disk.
EOF mark not found
Explanation: CaMP. CaMP could not find the
end of valid data in the last block of the files being
compared. This message usually occurs when
comparing nontext files; it should not occur when
comparing text files.
Action: For more details, see the CaMP
command in Chapter 2.

A-33

Error found, F parameter not specified
Corrections will not be written to disk
Explanation: CHKDSK. Informational
message. An error was found and you have not
used the IF parameter.
CHKDSK will perform its analysis as though it
were going to correct any errors detected, so that
you can see the results of its analysis, but it will
not actually write the corrections on the disk.
Action:

No action required.

Error in EXE file
Explanation: DOS. An error was detected in the
relocation information placed in the file by the
LINK program. This may be due to a modification
to the file.
Action:
•

If you are using a purchased program, rerun
the program using your backup copy.

•

If you still have trouble see your authorized
dealer.

•

If you are using a program you wrote
yourself, go through the LINK procedure
again.

Error in EXE/HEX file
Explanation: DEBUG. The file contained
invalid records or characters.
Action: Get another copy of the program, and
run DEBUG again.

A-34

Error loading operating system
Explanation: Startup. A disk error occurred
while attempting to load your operating system
from fixed disk.
Action: Restart the system. If the error persists
after several tries, restart the system, (you should
start DOS from your DOS diskette) and use the
SYS command to transfer a new copy of DOS to
your fixed disk.
Error reading fixed disk.
Explanation: FDISK. The FDISK program was
unable to read the startup record of the current
fixed disk after five tries.
Action: Try the FDISK program again. If after
several tries you still get the same error, consult
the IBM Guide to Operations book, "Problem
Determination" section. If you still can't solve the
problem, see your IBM Personal Computer
Dealer.
Error writing fixed disk.
Explanation: FDISK. The FDISK program was
unable to write the startup record of the current
fixed disk after five tries.
Action: Try the FDISK program again. If after
several tries you still get the same error, consult
the IBM Guide to Operations book, "Problem
Determination" section. If you still can't solve the
problem, see your IBM Personal Computer
Dealer.

A-35

Error writing to device
Explanation: Commands. Informational
message. DOS encountered an I/O error when
writing output to a device. The device is unable to
handle the number of bytes requested.
Action: Change amount of data in the file and
retry the command.
Errors on list device indicate that
it may be off-line. Please check.
Explanation: PRINT. The device being used for
background printing is off line. This message only
appears when the device is off line and you enter a
new PRINT command.
Action: Make sure the printing device is
connected and switched on.
EXE and HEX files cannot be written
Explanation: DEBUG. This error normally
occurs when you load a .HEX or .EXE file,
modify it, and then attempt to write the file back
out to a diskette.
You should understand that .EXE and .HEX files
contain loading information that is used to load the
file. When DEBUG is executed, it loads the .EXE
file while at the same time discarding the
information. During direct execution of an .EXE
file, the same thing happens. When you use
DEBUG to write an .EXE file, the information is
gone; therefore, a correct .EXE file cannot be
generated. That is why you get this error message.

A-36

The error might also be caused by the fact that the
data consists of a .COM file loaded in with
DEBUG and you are now trying to write it to an
.EXE or .HEX file. This is not possible. The data
would require a backwards conversion that
DEBUG doesn't support.
Action: If you need to look at the file's control
information you can rename the file using a
different extension, then execute DEBUG.
DEBUG then reads the file in instead of loading
it, and you can examine the control portion of the
file.
EXEC failure
Explanation: Commands. DOS encountered an
error while reading a command from disk, or the
FILE S= command in the configuration file
(CONFIG.SYS) does not specify a large enough
value.
Action: Increase the FILES= value. Restart
DOS. If restarting DOS does not work, then there
may be a problem with the disk itself.

F
File allocation table bad, drive x
Abort, Retry, Ignore?
Explanation:

DOS.

Action: See the message Disk error reading
drive x under "Device Error Messages" at the
beginning of this appendix. If this error persists,
the disk is unusable and should be formatted again.

A-37

File AND File
Explanation: COMPo Informational message.
This message indicates the full path and filenames
of the two files being compared.
Action:

No action required.

File canceled by operator
Explanation: PRINT. Informational message.
This message appears on the printer after you
cancel the printing of a file to serve as a reminder
that the printout is incomplete.
Action:

No action required.

File cannot be copied onto itself
Explanation: COPY. You tried to COpy a file
and place the copy (with the same name as the
original) in the same directory and on the same
disk as the original file.
Action: Change the name given to the copy, or
put it in a different directory, or put it on another
disk.
File creation error
Explanation: DOS and commands. An
unsuccessful attempt was made to add a new
filename to the directory or to replace a file that
was already there.
Action: If the file was already there, check
whether the file is marked read only and cannot be
replaced . Otherwise, run CHKDSK to determine
if the directory is full, or if some other condition
caused the error.

A-38

File is cross-linked:
on cluster xx
Explanation: CHKDSK. This message appears
twice for each cross-linked cluster number, naming
the two files in error. The same data block is
allocated to both files.
Action: No corrective action is taken
automatically. You must correct the problem by
doing the following:
1.

Make copies of both files (use COpy
command).

2.

Delete the original files (use ERASE
command).

3.

Review the files for validity and edit as
necessary.

File is currently being printed
File is in queue
Explanation: PRINT. Informational message.
These messages appear together when you issue a
PRINT command with no parameters. They occur
individually when you queue the first or a
subsequent file for printing.
Action:

No action required.

File not found
Explanation: DOS and commands. A file
named in a command or command parameter does
not exist in the directory of the specified (or
default) drive.
Action: Retry the command using the correct
filename.
A-39

Files are different sizes
Explanation: COMP. Informational message.
The sizes of the files to be compared do not match.
This means that a comparison cannot be done
because one of the files contains data which does
not match the data in the other file.
Action:

No action required.

Files compare OK
Explanation: COMPo Informational message.
The two files just compared contain identical
information.
Action:

No action required.

First cluster number is invalid,
entry truncated
Explanation: CHKDSK. Informational
message. The file whose name precedes this
message contains an invalid pointer to the data
area. If you specify IF parameter the file is
truncated to a zero length file.
Action:

No action required.

Fixed disk already has a DOS partition.
Explanation: FDISK. You chose the "Create
DOS Partition" option for a fixed disk that already
has a DOS partition.
Action: Return to the Main Menu and choose
option 4, Display Partition Data. Read Chapter 3
before continuing.

A-40

Fixup offset exceeds field width
Explanation: LINK. An assembler instruction
refers to an address with a NEAR attribute instead
of aFAR attribute.
Action: Edit assembler source program and
process again.
Fixups needed - base segment (hex):
Explanation: EXE2BIN. The source (.EXE)
file contains information indicating that a load
segment is required for the file.
Action: Specify the absolute segment address at
which the finished module is to be loaded.
Note: We do not recommend using such a
program as a .COM file because the program
is dependent upon being loaded at a specific
memory location.
FOR cannot be nested
Explanation: Batch. More than one FOR
subcommand was found on one command line in
the batch file.
Action: Use only one FOR subcommand per
command line. Then retry command.
Format failure
Explanation: FORMA T. A disk error was
encountered while creating the target disk.
Action: Try format again-if the error persists,
then the disk is unusable.

A-41

Formatting while copying
Explanation: DISKCOPY. Informational
message. The target diskette contains unformatted
tracks. DISKCOPY will format the remainder of
the target diskette as it copies data.
Action:

No action required.

Note: If this message is followed by the
message Incompatible drive types, you tried
to copy a dual-sided diskette to a drive that
does not have dual-sided capability. This
cannot be done. Processing ends and the
target diskette contains no useful data.

I
Illegal Device Name
Explanation:
must be:
•

LPT1:

•

LPT2:

MODE. The specified printer

or,
•

LPT3:

The specified Asynchronous Communications
Adapter must exist and be:
•

COM1:
or,

•

A-42

COM2:

There must be no more than one blank between
MODE and its parameters.
Action: Use the correct device name and retry
the command.
Incompatible diskette or drive types
Explanation: DISKCOMP. The first diskette
was successfully read on both sides, but the second
diskette could only be read on the first side.
Either the second drive or diskette is single sided
or the first diskette contains 9-sectors per track
and the second diskette contains only 8-sectors per
track.
Action: The diskette or drive types must be
compatible. Make sure you put the correct diskette
in the drive. Retry command.
Incompatible drive types
Explanation: DISKCOPY. The source diskette
and drive are dual-sided, but the target drive has
only single-sided capability. The target diskette
contains no useful data.
Action: Use compatible drive types and retry
command.
Incompatible system size
Explanation: SYS. The target diskette contained
a copy of DO S that is smaller than the one being
copied. The system transfer does not take place.
Action: Format a blank diskette (use the
FORMAT IS command) and then copy any files
to the new diskette.

A-43

Incorrect DOS version
Explanation: Commands. The command you
just entered requires a different version of DOS
than the one you are using.
Action: Obtain correct version of DOS and retry
command.
Insert backup diskette xx
in drive x:
Strike any key when ready
Explanation:

RESTORE.

Action: Insert the backup diskette( s) in sequence
in accordance with the prompt. Press any key and
RESTORE will continue.
Insert backup diskette xx
in drive x:
Warning! Diskette files will be erased
Strike any key when ready
Explanation:

BACKUP.

Action: Insert the next diskette to be used for the
backup. Use DOS formatted diskettes only. Press
any key and BACKUP continues.
Note: Any files on the backup diskette are
erased.
Insert COMMAND.COM disk in drive x:
and strike any key when ready
Explanation: DOS. DOS is attempting to reload
the command processor, but COMMAND.COM
is not on the drive that DOS was started from.

A-44

Action: Insert the DOS diskette in the indicated
drive and press any key.
Press any key to begin recovery
of the file (s) on drive X:
Explanation:

RECOVER.

Action: Insert the diskette to be recovered in the
indicated drive and press any character key.
Insert disk with batch file
and strike any key when ready
Explanation: DOS. The diskette that contained
the batch file being processed was removed. The
batch processor is trying to find the next command
in the file.
Action: Insert the diskette in the appropriate
drive and press any key. Processing will then
continue.
Insert DO S disk in X:
and strike any key when ready
Explanation: SYS and FORMAT. FORMAT
or SYS is trying to load the DOS files, but the
indicated drive X: does not contain the DOS
diskette.
Action: Follow the prompt and insert the DOS
diskette. Press any key and processing continues.

A-45

Insert DOS diskette in drive A:
Press any key when ready ...
Explanation: FDISK. You have successfully
created the DOS partition on the current fixed
disk.
Action: Insert the DOS diskette into drive A and
press any key. This restarts your IBM Personal
Computer.
The current fixed disk is now assigned a fixed disk
letter and you can now FORMAT the fixed disk.
Insert first diskette in drive x
Insert second diskette in drive x
Explanation:

DISKCOMP.

Action: Insert the first (or second) of the two
diskettes to be compared into the indicated drive.
One or both of these messages is followed by the
message Strike any key when ready. Press a key
and the comparison starts.
Insert source diskette in drive x
Insert target diskette in drive x
Explanation:

DISKCOPY.

Action: Insert the appropriate diskette into the
indicated drive, and press any key when asked.
The copying process starts.

A-46

Insufficient disk space
Explanation: DOS and commands. The disk
does not contain enough free space to contain the
file being written.
Action: If you suspect this condition is invalid,
run CHKDSK to determine the status of the disk.
Otherwise, use another disk and retry the
command.
Insufficient memory
Exp lanation: Commands. The amount of
available memory is too small to allow these
commands to function.
Action: Change the BUFFERS= parameter in
the CONFIG.SYS file to a smaller value (if you
have specified BUFFERS=), restart the system,
and try the command again. If the message still
appears, your system does not have enough
memory to execute the command.

A-47

Insufficient room in root directory
Erase files from root and repeat CHKDSK.
Explanation: CHKDSK. You instructed
CHKDSK to create files from the "lost" data
blocks it has found, but the root directory is full,
and all of the lost chains could not be recovered
into files.
Action:
1.

Copy some of the recovered files to another
disk for further examination.

2.

Delete the recovered files from the disk you
are checking.

3.

Run CHKDSK again to recover the
remainder of the lost data.

Insufficient space on disk
Explanation: DEBUG. A write command was
issued to a disk that doesn't have enough free
space to hold the data being written.
Action: If you are writing to a diskette, you can
insert a diskette that has enough free space, then
reissue the write command. Otherwise, you should
erase files from the disk and run DEBUG again.

A-48

Intermediate file error during pipe
Explanation: DOS. DOS is unable to create one
or both of its intermediate files because the default
drive's root directory is full, or DOS is unable to
locate the piping files, or the disk does not have
enough space to hold the data being piped.
Action: Erase some files from the default drive's
root directory, and reissue the command that
failed. If you get the same message, one of the
programs in the command line has erased one or
both of the piping files. Correct the program and
reissue the command line.
Invalid baud rate specified
Explanation:

MODE.

Action: Specify the baud rate as 110, 150, 300,
600, 1200, 2400, 4800, or 9600 (you need specify
only the first two characters of the number).
Invalid characters in volume label
Explanation: FORMAT. One or more of the
characters you entered in the volume label is not a
valid filename character, or the name contained a
period (volume labels contain 1 to 11 valid
characters without a period).
Action:

Retry using valid characters.

A-49

Invalid COMMAND.COM in drive n
Explanation: DOS. When DOS tried to reload
the command processor, the copy of
COMMAND.COM on the disk was found to be
an incorrect version.
Action: Insert the correct DOS diskette and
press any key to continue.
Invalid date
Explanation: DATE. You entered an invalid
date or delimiter. The only valid delimiters in a
date entry are hyphens (-) and slashes (/).
Action:

Re-enter valid date.

Invalid device
Explanation: CTTY. The device name you
specified is an invalid name to DOS.
Action:
name.

Retry command using valid device

Invalid directory
Explanation: DOS and commands. One of the
directories in the specified path does not exist.
Action:

A-50

Retry command using valid directory.

Invalid drive in search path
Explanation: DOS. An invalid drive specifier
was found in one of the paths specified in the
PATH command.
This message appears when DOS attempts to
locate a command or batch file, not at the time you
issued the erroneous PATH command.
Action:
1.

Enter PATH. This displays the PATH's you
previously defined.

2.

Find the invalid specifier.

3.

Re-enter the PATH command with the valid
drive specifier and the paths you desire.

Invalid drive specification
Explanation: DOS and commands. An invalid
drive specification was just entered in a command
or in one of its parameters.
Action: Re-enter the command using a valid
drive specifier.
Invalid format file
Explanation:

LINK. A library is in error.

Action: Restore library file from your backup
disk and try again.

A-51

Invalid number of parameters
Explanation: Commands. You have specified
too few or too many parameters for the command
you issued.
Action: Review this command in the
"Commands" section of this book.
Invalid numeric parameter
Explanation:
digits.

LINK. The numeric value is not in

Action: Run LINK again and name the numeric
parameter with values of 0 through 9 for each
digit.
Invalid object module
Explanation: LINK. Object module(s) were
incorrectly formed or unobserved errors occurred
during compilation. The disk may be bad.
Action: Recompile the module to either the same
or a different disk.
Invalid parameter
Explanation: DOS and commands. One or more
of the parameters entered for these commands is
not valid.
Action: If the program expects a drive specifier,
enter a colon following the drive letter. In other
cases, make sure the character following the
slash (/) is valid for the program being run.

A-52

Invalid parameters
Explanation:

MODE.

•

No parameters were entered

•

The first parameter character was other than
L,orC

•

The first parameter was other than 40, 80,
BW40, BW80, C040, C080, MONO, L, R

•

The display adapter the parameter refers to is
not present in the machine.

Action: Check the preceding list and correct
accordingly.
Invalid partition table
Explanation: Startup. While attempting to start
DOS from your fixed disk, the start-up procedures
detected invalid information in the disk's partition
information.
Action:
1.

Start DOS from the diskette.

2.

Use the FDISK command to examine and
correct the fixed disk partition information.

Invalid path
Explanation: TREE. Tree was unable to use a
directory whose name was found in another
directory.
Action: Run CHKDSK to find out what is
wrong with the directory structure.

A-53

Invalid path, not directory
or directory not empty
Explanation:
•

RMDIR.

The specified directory was not removed
because one of the names you specified in the
path was not a valid directory name
or,

•

The directory you specified still contains
entries for files or other subdirectories (with
the exception of the . and .. entries)

•

You cannot remove a current directory

Action:

Try one of the following:

•

Correct the invalid directory name in the path

•

Delete any files or remove any subdirectories
in the directory

Invalid path or file name
Explanation: COPY. You specified a directory
or file name that does not exist.
Action: Use correct name. Check for the
following, then retry command:

A-54

•

Correct spelling of names

•

Valid directory names

•

Existence of file in the subdirectory specified

Invalid subdirectory
Explanation: CHKDSK. Invalid information
was detected in the subdirectory whose name
precedes this message.
Action: CHKDSK will attempt to correct the
error if you have used the IF parameter. For more
specific information about the nature of the error,
run CHKDSK with the IV parameter.
Invalid switch
Explanation: LINK. The character indicated on
the preceding line is not a valid linker parameter
(switch).
Action: Review Chapter 7, "The Linker (Link)
Program" to determine which characters are valid
link parameters (switches).
Invalid time
Explanation: TIME. An invalid time or
delimiter was entered.
Action: Re-enter the correct time. The only valid
delimiters are:
•

A colon (:) between the hours and minutes

•

A colon (:) between the minutes and seconds

•

A period (.) between the seconds and
hundredths of a second.

A-55

L
Label not found
Explanation: Batch. Informational message. A
GOTO command named a label that does not
exist in the batch file. This caused the system to
read to the end of the batch file, ending batch
processing.
Action: If you do not want the GOTO to exit the
batch file, edit the batch file and put the label in
the desired location.
Line too long
Explanation: EDLIN. Upon replacing a string,
the replacement caused the line to expand beyond
the 253-character limit. The REPLACE text
command is ended abnormally.
Action: Split the long line into shorter lines; then
issue the REPLACE text command again.
List output is not assigned to a device
Explanation: PRINT. The device you named as
the PRINT list device is not recognized as a valid
device.
Action: Reissue the PRINT command and reply
with a valid list device name when asked.

LPT#: not redirected.
Explanation: MODE. Informational message.
The parallel printer will now receive its own
output, even if this printer's output had previously
been redirected to a serial device.
This message is provided for your information and
indicates cancellation of any previous redirection
which may have been in effect, because you have
set the printer width or vertical spacing.
Action: No action required.
LPT#: redirected to COMn:
Explanation:

MODE. Informational message.

This message is provided for your information and
indicates that any request that would normally
have gone to the parallel printer LPT# (#= 1, 2,
or 3) is sent instead to the serial device COMn
(n=l or 2).
Action: No action required.
LPT#: set for 80
Explanation: MODE. Informational message.
You tried to set the printer line length to 80
characters by requesting standard type format.
If the attempt is unsuccessful, an error message
follows this message on the screen.
Action: No action required.

A-57

LPT#: set for 132
Explanation: MODE. Informational message.
You tried to set the printer line length to 132
characters by requesting compressed type format.
If the attempt is unsuccessful, an error message
will follow this message on the screen.

Action:

No action required.

M
Maximum available space is xxxx
cylinders at cylinder xxxx.
Explanation: FDISK. Informational message.
The "Create DOS Partition" option displays the
largest available piece of space on the current fixed
disk. These numbers are also used as the defaults
for the two prompts that will follow.
Action:

No action required.

Memory allocation error
Cannot load COMMAND, system halted
Explanation: DOS. A program destroyed the
area in which DOS keeps track of available
memory.
Action:

A-58

Restart DOS.

Missing operating system
Explanation: Startup. When you tried to start
DOS from fixed disk, the startup procedures
determined that the DOS partition was marked
"bootable" (startable), but that it doesn't contain a
copy of DOS.
Action: Start DOS from diskette and use
FORMAT with the /S parameter to place a copy
of DOS on the fixed disk. You might want to back
up your files before doing the FORMAT.
Must specify destination line number
Explanation: EDLIN. A Move or Copy
command was entered without a destination line
number.
Action: Re-enter the command with a valid
destination line number.

N
N arne of list device [PRN]:
Explanation: PRINT. This message appears the
first time you start print after DOS has been
restarted.
Action: Reply with the reserved device name
which is to receive the printed output, or simply
press Enter if the first parallel printer [PRN] is to
be used.

A-59

No DOS partition to delete.
Explanation: FDISK. You chose the "Delete
DOS Partition" option but there was no DOS
partition on the current fixed disk.
Action:
1.

Return to the Main Menu.

2.

Select the Display Partition Data to review.

3.

Proceed with your next choice.

No free file handles
Cannot start COMMAND, exiting
Explanation: DOS. An attempt to load a second
copy of the command processor failed because
there are too many files open.
Action: Increase the number in the FILES=
command in the configuration file
(CONFIG.SYS), and restart DOS.
No fixed disks present
Explanation: FDISK. The FDISK program was
run on an IBM Personal Computer that:
•

does not have a fixed disk, or

•

has a fixed disk in the expansion unit and the
expansion unit is not powered on, or

•

has a fixed disk that is not properly installed

Action: From the above list find out what caused
the problem and take appropriate action. Check to
make sure the expansion unit is powered ON first.

A-60

No object modules specified
Explanation: LINK. You did not name any
object modules in the command line or in response
to the prompt.
Action: Name the object modules, since the
linker needs some files to link.
No partitions to make active.
Explanation: FDISK. You chose the "Change
Active Partition" option but there were no
partitions on the current fixed disk to be made
active.
Action: Use the "Create DOS Partition" option
to create a partition, then the "Change Active
Partition" option to make it the active partition.
No path
Explanation: PATH. Informational message.
There is currently no alternate path for DOS to
search to find commands and batch files if it does
not find them in the specified (or current
directory) .
Action: Informational message unless you want
to define a set of paths. If so, enter PATH and the
set of paths you want. Then press Enter.
No room for system on destination disk
Explanation: SYS. The destination diskette does
not contain the required reserved space for DOS;
therefore, the system cannot be transferred.
Action: Format a blank diskette (use the
FORMAT /S command), then copy any other
files to the new diskette.
A-61

No room in directory for file
Explanation: EDLIN. The directory on the
specified disk is full. Your editing changes are lost.
Action: Make sure that your disk has available
directory entries and run ED LIN again.
No space for a xxxx cylinder partition.
Explanation: FDISK. You entered a "Partition
Cylinder Size" that is larger than the largest piece
of free space on the disk.
Action:

Enter a smaller number.

No space for a xxxx cylinder partition
at cylinder xxxx.
Explanation: FDISK. You requested a partition
to be created at a place on the current fixed disk
and there is no space at that place to create a DOS
partition.
Action: Look for typographical errors.
Reinvestigate your partitioning requirements.
No space to create a DOS partition.
Explanation: FDISK. You chose the "Create
DOS Partition" option on the current fixed disk
which has no space to create a DOS partition.
Action: Remove or reduce the size of the
existing partition. Then run FDISK again to create
the DOS partition(s).

A-62

No subdirectories exist
Explanation: TREE. Informational message.
The specified drive contains only a root directory.
Therefore, there is no directory path to display.
Action:

No action required.

Non-System disk or disk error
Replace and strike any key when ready
Explanation: Startup. No entry exists for
IBMBIO.COM or IBMDOS.COM in the
directory; or a disk read error occurred when you
started up the system.
Action: Insert a DOS diskette in drive A and
then restart your system.
Not enough room to merge the entire file
Explanation: EDLIN. Informational message.
A Transfer command was unable to merge the
entire contents of the specified file because of
insufficient memory. Only part of the file was
merged.
Action: Use the Write lines command to write
some of the lines out to disk and retry the Transfer
command. If this does not work either reduce the
size of one of the files being merged, or install
more memory.
Not found
Explanation: EDLIN. Informational message.
ED LIN count not find the string specified by the
REPLACE text or SEARCH text commands
within the specified range of lines. Or, if a search
is resumed by replying N to the OK? prompt, no
further occurrences of the string were found.
Action: Check to be sure you properly used
upper and lower case for the string to be searched.
A-63

o
Out of environment space
Explanation: DOS. Informational message.
DOS was unable to accept the SET command you
just issued because it was unable to expand the
area in which the environment information is kept.
This normally occurs when you try to add to the
environment after loading a program which makes
itself resident (PRINT, MODE, or GRAPHICS
for example).
Action:

No action required.

Out of space on list file
Explanation: LINK. There is not enough disk
space for the List file.
Action: Use a disk with enough free space to
hold the file.
Out of space on run file
Explanation: LINK. There is not enough disk
space for the Run file (.EXE).
Action: Use a disk with enough free space to
hold the file.
Out of space on VM.TMP
Explanation: LINK. No more disk space
remained to expand the VM. TMP file.
Action: Use a disk with enough free space to
hold this file.

A-64

p
Parameters not compatible
Explanation: FORMAT. You attempted to use
two parameters that are not compatible with each
other (/B and /V for example).
Action: Review the FORMAT command.
Correct parameter and re-enter the command.
Parameter not compatible with fixed disk
Explanation: FORMA T. You wrongly specified
the /1 or /8 parameter while formatting a fixed
disk. Neither of these parameters is valid for a
fixed disk.
Action: Review the FORMAT command.
Correct parameter and re-enter the command.
Partition 1 is already active
Explanation: FDISK. Informational message.
Partition 1 is the only partition defined and it is
already marked as active.
Action:

No action required.

Partition xx made active
Explanation: FDISK. Informational message.
Partition xx is now marked as bootable.
Action:

No action required.

A-65

Press any key to begin formatting x:
Explanation: FORMAT. The fixed disk
(drive x) is about to be formatted. Formatting will
lose track of all previously existing data on the
disk.
Action: If you do not want the disk formatted,
press Ctrl-Break. If you do want the disk
formatted, press a character key.
Print queue is empty
Explanation: PRINT. Informational message.
There are currently no files being processed by
PRINT.
Action:

No action required.

Print queue is full
Explanation: PRINT. You tried to add more
than the limit of ten files to the print queue.
Action: Wait until a file is printed before you
add another file to the print queue.
Printer error
Explanation: MODE. The MODE command
(option 1) was unable to set the printer mode
because:

A-66

•

There is an I/O error

•

The printer is out of paper (or POWER
OFF)

•

There is a printer time out (not ready)
condition

•

The printer is omine

Action: Determine which of above conditions
caused the error message and take corrective
action.
Printer lines per inch set
Explanation: MODE. Informational message.
You tried to set the printer vertical spacing to the
specified 6 or 8 lines per inch.
Action: If the attempt was unsuccessful, an error
message will follow this message on the screen.
Probable non-DOS disk
Continue (YIN)?
Explanation: CHKDSK. The file allocation
table identification byte contains invalid
information. Either the disk was not formatted by
DOS or has it become badly damaged.
Action: If you did not use the IF parameter, and
you reply Y, CHKDSK will indicate its possible
corrective actions without actually changing the
disk. We recommend doing this first, before you
consider using the IF switch and replying Y.
Processing cannot continue
Explanation: CHKDSK. Informational
message. This message is followed by another
message which explains why CHKDSK cannot
continue.
This message is normally issued when there is not
enough memory.
Action:

No action required.

A-67

Program size exceeds capacity of LINK
Explanation: LINK. Load module is too large
for processing.
Action:

Reduce the size of your program.

Program too big to fit in memory
Explanation: DOS. The file containing the
external command cannot be loaded because it is
larger than the available free memory.
Action: Reduce the number in the BUFFERS=
parameter in your CONFIG.SYS file (if you have
specified BUFFERS=), restart your system, and
reissue the command.
If the message reappears, your system does not
have enough memory to execute the command.

R
Reinsert new diskette for drive X
Explanation: FORMAT. This message, which
usually occurs after you enter FORMAT IS,
means:

A-68

•

DOS filled the memory with system files, but
could not read all of the files into memory
because of insufficient memory size.

•

After asking for the new diskette, FORMAT
started formatting it and wrote all of the files
in memory on the new diskette.

•

FORMAT then asked that the DOS diskette
be inserted so it could finish loading the rest
of the DOS files into memory.

Action: FORMAT is now asking you to insert
the new diskette again so it can finish the task of
writing the DOS files onto the new diskette.
Requested stack size exceeds 64K
Explanation:

LINK.

Action: Specify a stack size of less than or equal
to 64K bytes when the STACK SIZE: prompt
appears.
Resident part of PRINT installed
Explanation: PRINT. Informational message.
The message appears the first time you use the
PRINT command.
This message indicates that a program has been
loaded into memory to handle subsequent PRINT
commands. Available memory for your
applications has been reduced by approximately
3200 bytes.
Action:

No action required.

Resident portion of MOD E loaded
Explanation:

MODE. Informational message.

This message indicates that when MODE is
invoked for a non-screen-setting function it is
sometimes necessary to load a portion of code to
be made permanently resident.
Action:

No action required.

A-69

s
Sector size too large in file 
Explanation: Startup. The device driver named
in  specifies a device sector size larger
than the devices previously defined to DOS.
Action: Reduce sector size to conform with the
sector size of DO S.
If this is a purchased program, return it to your
dealer.
Segment size exceeds 64 K
Explanation: LINK. This message indicates that
you attempted to combine identically named
segments which resulted in a segment requirement
of greater than 64K bytes. You cannot address
more than 64K bytes.
Action: Change segment names in object
modules and try link again.
Specified command search directory bad
Explanation:
specified.

Commands. Invalid path name

Action: Enter a correct SET COMSPEC=
command, or correct the problem that caused the
command processor's directory path to become
invalid.
Stack size exceeds 65535 bytes
Explanation: LINK. Informational message.
The size specified for the stack must be less than
or equal to 65535.
Action:
A-70

No action required.

Symbol defined more than once
Explanation: LINK. The Linker found two or
more modules that define a single symbol name
Action:

Check for the following:

•

Are you sure you're not linking the same files
twice?

•

Does one of the modules being linked have a
symbol incorrectly identified as public
instead of external?

Symbol table capacity exceeded
Explanation: LINK. Many, very long names
were entered. The names exceeded approximately
SDK bytes.
Action:

Use shorter and/or fewer names.

Syntax error
Explanation: DOS. The command you entered
is improperly formatted.
Action: Check to make sure you have used the
correct format for this command.
System will now reboot
Insert DO S diskette in drive A:
Press any key when ready
Explanation: FDISK. Informational message.
FDISK requires the system to restart in order to
recognize the fixed disk (so you can format it.)
Action: Place DOS diskette in Drive A: and
press any key.

A-71

T
Target diskette may be unusable
Explanation: DISKCOPY. This message
follows an unrecoverable read, write, or verify
error message. The copy on the target diskette may
be incomplete because of the unrecoverable I/O
error.
Action:
•

If error is on the target diskette, get a fresh
diskette for your target, and retry the
DISKCOPY command.

•

If the error is on the source diskette, copy all
files from the source diskette to another
diskette. Then try to reformat the source
diskette.

Target diskette write protected
Correct, then strike any key
Explanation: DISKCOPY. You are trying to
produce a copy on a diskette that is write
protected.
Action: Either remove the write protect tab, or
use another diskette that is not write protected.
Terminate batch job (YIN)?
Explanation: DOS. This message appears when
you press Ctrl-Break while DOS is processing a
batch file.
Action: Press Y to stop processing the batch file.
Pressing N only ends the command that was
executing when Ctrl-Break was pressed; processing
resumes with the next command in the batch file.
A-72

The current active partition is x.
Explanation: FDISK. Informational message.
The "Change Active Partition" option displays the
active partition on the current fixed disk.
Action:

No action required.

The last file was not restored
Explanation: RESTORE. You stopped
RESTORE before it completely restored the last
file listed, or there was not enough room on the
fixed disk and RESTORE deleted the partially
restored file.
Action: If RESTORE has ended, you can
re-enter the RESTORE command with the
filename of the file( s) not restored to continue from
the point where RESTORE stopped.
If the problem occurred because you ran out of
room on the fixed disk, you must evaluate which
files to keep and which ones to delete. Then
continue the execution of RESTORE.
There was/were number errors detected
Explanation: LINK. This message is displayed
for your information at the end of the link session.
Action:

No action required.

Too many external symbols in one module
Explanation: LINK. The limit is 256 external
symbols per module. This message indicates that
the limit was exceeded.
Action:

Break up some modules.

A-73

Too many groups
Explanation:
DGROUP.

LINK. The limit is 10 including

This message indicates that the limit was
exceeded.
Action:

Reduce the number of groups.

Too many libraries specified
Explanation:

LINK. The limit is 8 libraries.

This message indicates that the limit was
exceeded.
Action:

Reduce the number of libraries.

Too many overlays
Explanation:

LINK. The limit is 64 overlays.

This message indicates that the limit was
exceeded.
Action:

Reduce the number of overlays.

Too many public symbols
Exp lanation:
symbols.

LINK. The limit is 1024 public

This message indicates that the limit was
exceeded.
Action:

A-74

Reduce the number of public symbols.

Too many segments or classes
Explanation: LINK. The limit is 247 segments
or classes taken together.
This message indicates that the limit was
exceeded.
Action:
classes.

Reduce the number of segments or

Total disk space is xxxx cylinders.
Explanation: FDISK. Informational message.
This message shows the total space on the current
fixed disk.
Action:

No action required.

Track 0 bad-disk unusable
Explanation: FORMAT. Track 0 is where the
boot record, file allocation table, and directory
must reside. The disk is unusable.
Action: Obtain another disk and retry the
FORMAT command.
Tree past this point not
processed
Explanation: CHKDSK. Informational
message. CHKDSK is unable to continue
processing past the directory path currently being
examined. The cause of the error is displayed in
the previous message.
Action:

No action required.

A-75

u
Unable to create directory
Explanation: MKDIR. The directory you want
to create already exists, or one of the directory
path names you specified could not be found, or
you attempted to add a directory to the root
directory and it is full. Make sure a file by that
name does not already exist in that directory.
Action:

Do the following:

•

Check to see if a directory by that name
exists in the parent directory (or current
directory)

•

Recheck all your directory names to make
sure they are valid

•

Use CHKDSK to see if your directory is full

Unable to write BOOT
Explanation: FORMAT. The first track of the
diskette or DOS partition is bad. The BOOT
record could not be written on it. The diskette or
DOS partition is not usable.
Action: Obtain another diskette and retry the
FORMAT command.
Unexpected end-of-file on library
Explanation: LINK. Informational message.
This is caused by an error in the library file.
This usually means that the object file contains
bytes that are of the same value as end-of-file. If
this occurs, LINK continues processing to the
physical end-of-file as given in the directory.
Action:
A-76

No action required.

Unexpected end of tile on VM.TMP
Explanation: LINK. Informational message.
The diskette containing VM. TMP was removed.
Action:

No action required.

Unrecognized command in CONFIG.SYS
Explanation: Startup. An invalid command was
detected in the configuration file CONFIG.SYS.
Action: Edit the file, correct the invalid
command, and restart DOS.
Unrecognized switch
Explanation: LINK. The character(s) specified
by z do not uniquely identify a linker parameter
(switch).
Action:

See the message, "Invalid Switch."

Unrecoverable format error on target
Target diskette unusable
Explanation: DISKCOPY. An unrecoverable
error was encountered while formatting the target
diskette. The diskette contains no usable data.
Action: Obtain another diskette and retry the
DISKCOPY command.

A-77

Unrecoverable read error on drive x
Track xx, side x
Explanation: DISKCOMP. Four attempts were
made to read the data from the diskette in the
specified drive. The data could not be read from
the indicated track and side.
Action: If the error occurred on the target
diskette Gust created by DISKCOPY) get a fresh
diskette and retry the DISKCOPY and
DISKCOMP commands. Otherwise, use:
COpy *.*

to copy all files from the damaged diskette to
another diskette. Then reformat the bad diskette or
else discard it.
Unrecoverable read error on source

Trackxx, side x
Explanation: DISKCOPY. Four attempts were
made to read the data from the source diskette.
DISKCOPY continues copying, but the copy may
contain incomplete data.
Action:

Use:

COpy *.*

to copy all files from the damaged diskette to
another diskette. Reformat the bad diskette, or else
discard it.

A-78

Unrecoverable verify error on target
Track xx, side x
Explanation: DISKCOPY. Four attempts were
made to verify the write operation to the target
diskette. DISKCOPY continues copying, but the
copy may contain incomplete data.
Action: Repeat the DISKCOPY command, or
else use a different diskette.
Unrecoverable write error on target
Track xx, side x
Explanation: DISKCOPY. Four attempts were
made to write the data to the target diskette.
DISKCOPY continues copying, but the copy may
contain incomplete data.
Action: Obtain a fresh diskette and re-enter the
DISKCOPY command. Use FORMAT on the
bad diskette to see if it can be reused. If it is a bad
diskette, discard it.
Unresolved externals: list
Explanation: LINK. The external symbols
listed were not defined in the modules or library
files that you specified.
Action: Do not attempt to run the executable file
created by the linker.
Make sure you specified all appropriate object
modules and libraries. Check the source code for
the program that caused the message and make
corrections to that program.

A-79

v
VERIFY is OFF/ON
Explanation:

VERIFY. Informational message.

Action: If VERIFY is ON is displayed, and
VERIFY is OFF is what you want, enter:
VERIFY OFF

VM. TMP is an illegal file name and has been ignored
Explanation: LINK.VM. TMP cannot be used
for an object filename. Informational message that
is meant as a warning.
Action:

No action required.

Volume label (11 characters, ENTER for none) ?
Explanation: FORMAT. You are requested to
enter a 1 to 11 character volume label which will
be written on the disk being formatted.
Action: If you do not want a volume label on the
disk, press only the ENTER key.

A-SO

w
Warning! Data in the DOS partition
could be lost. Do you wish to
continue .................... ? [ ]
Explanation: FDISK. The "Delete DOS
Partition" option is warning you that if you
continue, all data in the DOS partition on the
current fixed disk could be destroyed.
Action: If you press Enter, the DOS partition
will NOT be destroyed. If you do wish to delete
the DOS partition, type Y and press Enter.
Warning-directory full
Explanation: RECOVER. There is insufficient
directory space to recover more files.
Action: Copy some of the files to another disk,
erase them from this disk, and run RECOVER
again.
Warning! Diskette is out of sequence
Replace the diskette or continue
Strike any key when ready
Explanation: RESTORE. The backup diskette
is not the next one in sequence.
Action: Replace the diskette unless you are sure
no files on the diskette( s) you skipped would be
restored. RESTORE will continue when you press
a key. This message will be repeated if you try to
skip a diskette which contains part of a file being
restored.

A-81

Warning! File xx
is a read-only file
Replace the file (YIN)?
Explanation:
read only.

RESTORE. The indicated file is

Action: Enter Y if you want to replace it or N if
you do not. RE STO RE will continue after you
press ENTER. You will see this message only if
you specified the IP option.
Warning! File xx
was changed after it was backed up
Replace the file (YIN)?
Explanation: RESTORE. The indicated file on
the fixed disk has a later date and time than the
corresponding file on the backup diskette.
Action: Enter Y if you want to replace it with
the backed up version or N if you do not.
RESTORE will continue after you press ENTER.
You will see this message only if you specified the
IP option.
Warning! No files were found to back up
Explanation: BACKUP. No fixed disk files
were found that matched the backup file
specification.
Action: Make sure the criteria you specified for
BACKUP is what you want. If so, this is an
informational message.

A-82

Warning! No files were found to restore
Explanation: RESTORE. No backup diskette
files were found that matched the restore file
specification.
Action: Make sure the criteria you specified for
BACKUP is what you want. Otherwise, this is an
informational message.
Warning: no stack segment
Explanation: LINK. Informational message.
None of the object modules specified contain a
statement allocating stack space.
Action:

No action required.

WARNING-Read error on EXE file
Explanation: EXE2BIN. An error occurred
while reading the input file. EXE2BIN will
attempt to continue, but the resulting file may be
unusable.
Action:
1.

Use the COPY *.* command to copy the
diskette to a new diskette.

2.

Copy your backup version of the .EXE file to
this diskette.

3.

Format the diskette that had the error to mark
any bad tracks.

4.

Discard the bad diskette, if necessary.

A-83

x
x is not a choice. Enter a choice.
Explanation: FDISK. You entered x which is
not a choice for this question.
Action: Enter a valid choice.
x is not choice. Enter Y or N.
Explanation: FDISK. You entered x which is
not a choice for this question.
Action:

Enter Y or N.

XXXXXXXXXX bytes disk space freed
Explanation: CHKDSK. Informational
message. Disk space marked as allocated was not
associated with a file. If you used the IF
parameter, the space was freed and made
available.
Action:

No action required.

xxxx error on file yyyy
Explanation: PRINT. This message appears on
the printer. While attempting to read data from file
yyyy for printing, a disk error of type xxxx was
encountered. Printing of that file is stopped.
Action:

A-84

Check that disk drive is ready.

xxx lost clusters found in yyy chains.
Convert lost chains to files (YIN)?
Explanation: CHKDSK. CHKDSK located
xxx blocks of the data area which were marked as
allocated, but were not associated with a file.
These clusters are assumed to contain "lost" data,
and CHKDSK will ask whether you wish to free
them, or to recover each chain into a separate file.
Action: If you reply Y and you have used the IF
parameter, CHKDSK will recover each chain into
a separate file, otherwise, if you reply N,
CHKDSK frees the blocks up so they can be
allocated to new files. If CHKDSK was specified
(no IF), then messages displayed afterwards are
informational (no corrective action was taken).

*** Backing up files to diskette xx ***
Explanation: BACKUP. Informational
message. This message is followed by a list of files
that were backed up on the indicated diskette.
Action:

No action required.

*** Files were backed up xx/xx/xxxx ***
Explanation: RESTORE. Informational
message. The files on the backup diskette were
backed up on the indicated date.
Action:

No action required.

*** Restoring files from diskette xx ***
Explanation: RESTORE. Informational
message. This message is followed by a list of files
that were restored from the indicated diskette.
Action:

No action required.
A-85

--More-Explanation: MORE. The screen is full and
there is more data waiting to be displayed.
Action:
screen.

Press any character to see the next full

Numbers
10 Mismatches - ending compare
Explanation: CaMP. Informational message.
Ten mismatched locations were detected in the
files being compared. CaMP assumes that the
files are so different that further comparisons
would serve no purpose.
Action:

A-86

No action required.

Appendix B. Running Compilers
and Assemblers

Using Compilers and Assemblers With
Fixed Disk
The following is a summary of how to run the IBM
Personal Computer compilers and the IBM Personal
Computer Macro Assembler with the Disk Operating
System (DOS) Version 2.10. For the purposes of this
appendix, the word compile will also refer to assemble.
1.

Make sure to back up your original language
diskettes using the techniques described within this
book and/or the respective language books.

2.

Make sure all source code you will compile is in
the current directory of your disk.

3.

Most of the language processors may be located in
any directory at compile time (see exception list at
the end of this appendix).

4.

When Compiling you should use the command
lines as described in your language book. You can
modify the drive specifier in the command line to
indicate the location of the particular language
processor.

5.

When Linking, use the IBM Personal Computer
Linker, Version 2.10, provided with DOS Version
2.10. The instructions within this book and your
language book will provide the necessary
information for linking.

B-1

6.

When running a program (.BAT, .COM, or a
.EXE file) it is not always necessary for that
program to be in the current directory (see the
PATH command in Chapter 2 of this book).
However, if the program requires another file at
runtime; such as a data file or a Common Runtime
Module, then those files must be in the current
directory at runtime.

7.

It is possible for COMMAND. COM to be

overwritten in memory. Therefore, it is usually
helpful to have a copy of COMMAND. COM in
the root directory of the drive from which DOS
was started.

Exceptions
•

All IBM Personal Computer Language Products:
All files accessed by your program must be in
the current directory at runtime.
Any Common Runtime Module used by your
program must be in the current directory at
runtime.

•

IBM Personal Computer BASIC Compiler:
BASRUN.EXE, if used at runtime, must be
in the current directory.

B-2

•

IBM Personal Computer COBOL Compiler:
COBOL. COM and its overlays must be in
the current directory at compile time.
To compile, you must use the command line
and indicate the drive location of the overlays
with the IC parameter.
COBRUN .EXE must be in the current
directory at runtime.

•

IBM Personal Computer Pascal Compiler:
Pascal requires a hex update (see "Pascal
Hex Patch" in Appendix C) in order to run
this compiler from a drive other than drive A.
P ASKEY must be in the current directory at
compile time.

B-3

B-4

Appendix C. Running the Pascal
Compiler

Using Pascal Hex Patch With Fixed Disk
The IBM Personal Computer Pascal Version 1.00
Compiler requires that a special file called PASKEY be
in the current directory on diskette drive A. The
following hex update can be used so that the Pascal
compiler will look on the default drive for this
PASKEY file.
The following describes how to update your PAS 1
diskette. Follow the instructions carefully. If you make
a mistake don't panic. Just start again.
To update your PASI diskette, you need a blank
formatted diskette. Put your DOS diskette in diskette
drive A and the blank formatted diskette in diskette
drive B. You must use the DOS DISKCOPY command
to make an exact copy of your PAS 1 diskette.

C-l

After the DISKCOPY program is started and you see
the message Strike any key when ready, insert the
ORIGINAL copy of the Pascal PASl diskette in
diskette drive A. It must be the diskette from your IBM
Personal Computer Pascal Compiler package or an
exact copy of it. Anything else will not work. After you
insert the diskettes, press the Spacebar to start the disk
copy:

Place your DOS diskette back in diskette drive B. You
now have an exact copy of your Pascal PAS 1 diskette
in diskette drive B. You can now apply the update to the
PAS! diskette with the DOS DEBUG program on the
DOS diskette.
The DEBUG program prompt is "-." All the things that
you type are after the "-."
When you are responding to the "-" prompt, you must
press the Enter key. Note that the xxxx in the data
displayed line will be filled with the appropriate
memory addresses:
A>WJl!E~Iu.m

mU]S: HDO 1 A5 1
-DDS: 171 Ul
xrum:[Jl117 4li 3A 5041 5349455920
m

xxxx:OHJO 20

C-2

A:PASKEV

If you do not see the above line of data after the
"DDS:177 LA" command then you did something
wrong and you should start again. You can start again
by typing Q followed by Enter. This returns you to
DOS:
mIEDS: 177 'PASKEY'
-WDS: 100 1 A5 1

-0
(Remember to enter the two blanks after PASKEY.)
You are now back in DOS; you should now recreate
your working PAS 1 diskette from the updated diskette
and mark both diskettes so you know which are the
updated ones. The PASl.EXE file on the updated
PAS 1 diskette will now look for the PASKEY file in
the current directory on the default drive.

C-3

C-4

Appendix D. Considerations for
U sing Applications

If you have any of the following applications, please
refer to the appropriate section in this appendix for
additional information about using these applications
with DOS 2.10.

Note: This information is for users of the IBM
Personal Computer and the IBM Personal
Computer XT. For any other model IBM Personal
Computer, see your dealer about using these
application programs with DOS 2.10.
•

Accounting Packages by BPI Systems, Inc.

•

Accounting Packages Version 1.00 by Peachtree
Software, Inc.

•

Accounting Packages Version 1.10 by Peachtree
Software, Inc.

•

Arithmetic Games 1 and 2

•

Asynchronous Communications Support Version
1.00

•

Asynchronous Communications Support Version
2.00

•

EasyWriter Version 1.10

•

Fact Track

•

Multiplan

D-l

•

pfs:FILE

•

pfs:REPORT

•

SNA 3270 Emulation and RJE Support Version
1.00

•

The Dow Jones Reporter Version 1.00

•

Typing Tutor

•

VisiCalc

•

3101 Emulator Version 1.00

Accounting Packages by
BPI Systems, Inc.
These packages are designed for, and should be used
only with DOS 1.00 or DOS 1.10. You should not use
these applications with DOS 2.10.

Accounting Packages Version 1.00 by
Peachtree Software, Inc.
These packages are designed for, and should be used
only with DOS 1.00 or DOS 1.10. You should not use
these applications with DOS 2.10.

Accounting Packages Version 1.10 by
Peachtree Software, Inc.
These packages are designed to be used with either
DOS 1.10 or DOS 2.10. If you use these packages with
DOS 2.10 on a diskette-only system, you must have
128K bytes memory and 320K byte diskette drives in
order to accommodate the larger size of DOS 2.10 and
BASIC 2.00.
D-2

The Accounting Packages Version 1.10 by Peachtree
Software, Inc. include functions allowing both programs
and data files to reside on the IBM Personal Computer
fixed disk. When using the fixed disk, these packages
require DOS 2.10 and 128K bytes of memory.
Data files created using Accounting Packages Version
1.00 by Peachtree Software, Inc. may be used with the
Version 1.10 packages.

Arithmetic Games 1 and 2
When using the arithmetic games with DOS 2.10, you
must have a minimum of 96K bytes of memory. In
addition, if you have a single-drive IBM Personal
Computer, you should use the single-drive setup
procedure.

Asynchronous Communications Support
Version 1.00
To use this application with DOS 2.10 you must
have a minimum of 96K bytes of memory.
To install this application in a subdirectory on a
fixed disk, use the following procedure. This
procedure assumes the following:
•

The name of the subdirectory is ASYNC.

•

The fixed disk is the default drive.

•

The fixed disk drive is drive C.

•

The root directory of the fixed drive contains
DOS 2.10.

D-3

The Procedure
1.

Insert the Asynchronous Communications
Support diskette in drive A.

2.

Enter the following commands in order to
create the subdirectory ASYN C and to copy
the files from drive A to drive C:
MD \ASYNC
Create the subdirectory
CD \ASYNC
Operate from it
COpy A:*.* C:\ASYNC
Copy all files on the application diskette
COPY C:\BASIC.COM C:\ASYNC
Copy BASIC. COM to the subdirectory
ERASE UPDATE.BAT
Not needed
ERASE MESSAGE
Not needed

D-4

3.

You must now patch TERMIN AL.BAS by doing
the following:

BASIC

Run BASIC

LOAD "TERMINAL.BAS

Load the program to
be patched

1 DEFINT I-M:DIM
M(12):1=0:J=0:K=0:DATA
&H5 5 ,&H8B,&HEC,&H8B,
&H7E,&H06,&H8C,&HD8,
&H05 ,&HOO,&Hl 0,&H89,
&H05,&H5D,&HCA,&H02,
&HOO:I=O:J=O:K=O:
IDSEG=o

Patch 1

2 J=VARPTR(M(I)):FOR
1=1 TO 17:READ K:POKE
1+J -1 ,K:NEXT:ON
ERROR GOTO 3:
J=VARPTR(M(I)):CALL
J(IDSEG):ON ERROR
GOTO O:GOTO 4

Patch 2

3 RESUME 4

Patch 3

4 ON ERROR GOTO
O:ERASE M:CLS:LOCATE
10,5 :PRINT "Initializing":
I=O:J=O:K=O:DEF S
EG=IDSEG

Patch 4

210 DEF SEG =IDSEG

Patch 5

115

Delete this line

205 (DEFINT I-M)

Delete this line

117 D$( 1)="C";
DS$(2)="A"

Patch for Asynch
1.00 with PC-XT
fixed disk

SAVE "TERMINAL.BAS"

Save the patched
program

SYSTEM

Leave BASIC and
return to DOS 2.10
D-5

4.

You may now run the Asynchronous
Communications Support program by doing the
following:

CD \ASYNC

Operate from the
subdirectory

AUTOEXEC

Run the program

CD \

Return to the root
directory

Notes:
1.

The use of the subdirectory name of ASYNC
is an example only. You may use any name
you wish.

2.

All file transfers will be to and from the files
in the subdirectory unless the printer is the
destination.

3.

This program tests the length of a filespec,
and does not accept subdirectory names as
part of a filespec.

4.

You may rename AUTOEXEC.BAT if you
choose.

Asynchronous Communications Support
Version 2.00
To use this application with DOS 2.10 you must have a
minimum of96K bytes of memory.

D-6

To install this application in a subdirectory on a fixed
disk, use the following procedure. This procedure
assumes the following:
•

The name of the subdirectory is ASYNC.

•

The fixed disk is the default drive.

•

The fixed disk drive is drive C.

•

The root directory of the fixed drive contains DOS
2.10.

The Procedure
1.

Insert the Asynchronous Communications Support
diskette into drive A.

2.

Enter the following commands in order to create
the subdirectory ASYNC and to copy the files
from drive A to drive C:
MD \ASYNC
Create the subdirectory
CD \ASYNC
Operate from it
COpy A:*.* C:\ASYNC
Copy all files on the application diskette
COpy C:\BASIC.COM C:\ASYNC
Copy BASIC. COM to the subdirectory
ERASE UPDATE. BAT
Not needed
ERASE MESSAGE
Not needed

D-7

3.

You may now run the Asynchronous
Communications Support program by doing the
following:
CD \ASYNC
Operate from the subdirectory
AUTOEXEC
Run the program
CD \
Return to the root directory

4.

You may run the file conversion program,
FILECONV, by doing the following:
CD \ASYNC
Operate from the subdirectory
FILECONV
Run the FILECONV program
CD

\
Return to the root directory

Notes:

D-8

1.

The use of the subdirectory name of ASYNC
is an example only. You may use any name
you wish.

2.

All file transfers will be to and from the files
in the subdirectory unless the printer is the
destination.

3.

This program tests the length of a filespec,
and does not accept subdirectory names as
part of a filespec.

4.

You may rename AUTOEXEC.BAT if you
choose.

v

EasyWriter Version 1.10
To use EasyWriter Version 1.10 with DOS 2.10 it is
recommended your IBM Personal Computer have a
minimum of 128K bytes of memory.
To copy DOS 2.10 to your EasyWriter program
diskette, use the following procedure:
1.

Follow the instructions in the" Startup" section of
your EasyWriter manual for copying DOS to your
EasyWriter program diskette. While copying DOS
2.10 to the program diskette, you may see the
message:
INSUFFICIENT DISK SPACE

(or)

SECTOR NOT FOUND ERROR WRITING DRIVE B
ABORT, RETRY, IGNORE?

If you see the second message above, enter I (for

ignore).
Note: F or a system with a fixed disk, follow
the instructions for copying DOS 2.10 to
your EasyWriter program diskette for a
one-drive system.
Due to insufficient diskette space, the DOS 2.10
FORMAT.COM utility was not transferred to your
EasyWriter diskette. To use the FORMAT.COM
utility, insert the DOS 2.10 diskette in drive A and a
blank diskette in drive B. Then type: FORMAT B: and
press the enter key. This will format the diskette in
drive B.

D-9

2.

EasyWriter 1.10 recognizes drive A and drive B
as the drives to read or write from for EasyWriter
files. Because the fixed drive is initially defined as
drive C, you must reassign its name to be drive B.
Enter:
ASSIGN B=C

3.

You can have your fixed disk automatically
assigned to be drive B everytime you load your
EasyWriter program. Use the following procedure
to do this:
a.

Copy DOS 2.10 onto your EasyWriter
program diskette following the instructions
given above.

b.

Start DOS 2.10 from the fixed disk. The
DOS prompt C> should appear.

c.

Put your EasyWriter program diskette into
drive A.

d.

Enter COPY ASSIGN.COM A:

e.

Enter COPY CON A:AUTOEXEC.BAT

f.

Enter DATE

g.

Enter TIME

h.

Enter ASSIGN B=C

i.

Enter EW

J.

Press the F6 key. Now press the Enter key.

The fixed disk can now be used to store and read
your EasyWriter data files. Every time you load
your EasyWriter program the fixed disk will
automatically be assigned as drive B.

D-I0

Fact Track
To use Fact Track with DOS 2.10 you need 96K bytes
of memory.
If you have DOS 1.10, you should use it to follow one
of the setup procedures documented in the Fact Track
user manual. The setup procedure copies the necessary
DOS programs onto the Fact Track program diskette.
From then on, start the Fact Track program diskette in
drive A.

If you have only DOS 2.10, and if you have an IBM
Personal Computer with one or two disk drives, you
should start up DOS in drive A. Enter the date and time
as requested. When the system responds:

A>
you enter:
BASICA

When the system responds:
OK

remove the DOS diskette from drive A and insert the
Fact Track diskette into drive A and close the door.
Enter:
RUN "COLOR

Do this every time you want to run the Fact Track
program.

D-11

If you have DOS 2.10, but do not have DOS 1.10, and
an IBM Personal Computer with a fixed disk that
contains DOS or BASICA, you should start up DOS
from the fixed disk. Enter the date and time as
requested. When the system responds:

C>
put the Fact Track program diskette in drive A and
close the door.
You enter:

A:
When the system responds:

A>
you enter:
C:BASICA COLOR

Do this every time you want to run the Fact Track
program.

Multiplan
Please take note of this warning if you are planning to
use DOS 2.00 or DOS 2.10 on the Multiplan Program
Diskette. Due to space limitations on the Multiplan
Program diskette and the increase in size of DOS 2.00
and 2.10, only DOS 1.1 or earlier versions may be
placed on the program diskette. Do NOT attempt to
copy any DOS other than DOS 1.1 or earlier versions
to your Multiplan Program diskette.
Warning: Do not attempt to use DOS 2.00 or
DOS 2.10 with Multiplan or you may permanently
damage your"Multiplan Program diskette.

D-12

If you have any further questions please see your
nearest IBM Personal Computer dealer for additional
information.

pfs:FILE
To use pfs:FILE with DOS 2.10 you need a minimum
of 128K bytes of memory.
Follow the instructions in Part 1 of the Introduction
"Getting Ready to Use FILE." Use your DOS 2.10
diskette whenever the instructions ask for the DOS
diskette.

Using pfs:FILE with the IBM Fixed Disk
You can use pfs:FILE with the IBM fixed disk in two
different ways. First, you can store your data files on
the fixed disk, thus allowing larger files to be stored,
and faster access to forms in the stored files. Second,
you can copy the pfs:FILE program to the fixed disk
and then load it from there. This allows you to load the
program faster, without using the program diskette.

Storing PFS Data Files on the Fixed Disk
You can store a data file on the fixed disk provided you
include the drive identifier for the fixed disk as part of
the file name. If you specify the fixed disk drive as the
default drive, then it is not necessary to include the
drive identifier as part of the file name. Note that your
data file must be in the same directory as your pfs:FILE
program.

D-13

Copying pfs:FILE to the Fixed Disk
Follow these steps to copy the pfs:FILE program to the
fixed disk:
1.

Insert the DOS 2.10 diskette into drive A and turn
on your IBM Personal Computer. Enter the date
and time when the computer asks you to do so.

2.

When the DOS prompt appears, remove the DOS
2.10 diskette and replace it with the pfs:FILE
program diskette.

3.

Follow the instructions in Appendix D of the
pfs:FILE manual called "Setting Up a Serial
Printer and the Work Drive" to run the setup
program. Change the work drive name to the drive
name of your fixed disk. For example, if your fixed
drive is drive C, then the work drive item on the
setup menu should be drive C.

4.

If you have a serial printer, enter the correct values
for the other items on the setup menu.

5.

Press the F 10 key to complete the setup program.
Then enter FTRANS in response to the DOS
prompt.

The in use lights will come on alternately as the
program is copied from the diskette to the fixed disk.
The copy is placed in the current directory. The DOS
prompt reappears when the copy is complete.
If you have more than one fixed disk, the copy will be
made to the drive whose name is last in the alphabet.
For example, if two drives are named C and D, the
copy will automatically be made to drive D.

D-14

Error Conditions
The following error conditions might occur during the
copy procedure.
Message

Explanation

Corrective Action

CAN'T COpy
PROGRAM FILE

Your program
diskette has been
damaged.

Try the copy
procedure with the
backup copy of the
program diskette.

Your fixed disk is
improperly
formatted. (also
applies to the
CREATE message)

Copy to diskette
any files on the
fixed disk. Then
reformat the fixed
disk, and try the
copy procedure
again.

CAN'T CREATE
PROGRAM FILE

Your current
directory is full.

If you have

NAME ERROR

Possible DOS error.

Reload DOS 2.10
and start the copy
procedure again.

WRONG
VERSION

Cannot find the
fixed disk.

Make sure that your
fixed disk is
properly connected,
and that you are
using DOS 2.10.

unnecessary files in
the root level
directory, delete
them and start the
copy procedure
again.

D-15

Running the pfs:FILE Program from a
Fixed Disk
To run the pfs:FILE program from a fixed disk, make
sure that you have followed the instructions under
"Copying pfs:FILE to the Fixed Disk." Then in
response to the DOS prompt, type and enter the drive
identifier for the fixed disk followed by the name of the
program. For example, to run the pfs:FILE program
from drive C, enter C:FILE. If the default drive is C,
you need only enter FILE in response to the DOS
prompt.

Changing Settings When Using the Fixed Disk
To change the work drive or the information stored for
your serial printer after copying the pfs:FILE program
to the fixed disk, you need to insert the pfs:FILE
program diskette into drive A and run the setup program
from that diskette. Use the COpy command to copy the
file named IBMSETUP.PFS from the diskette in
drive A to the fixed disk.

D-16

pfs:REPORT
To use pfs:REPORT with DOS 2.10 you must have a
minimum of 128K bytes of memory, and you should do
the following:
1.

Copy the sample file called STAFF, which is on
the pfs:REPORT program diskette, to a blank
formatted diskette or to a fixed disk. See
"Formatting Diskettes" and "Copying a File" in
Appendix C of the pfs:REPORT manual.

2.

Erase the STAFF file from the pfs:REPORT
program diskette using the ERASE command of
DOS 2.10.

3.

N ow follow the instructions in Part 1 of the
Introduction in the pfs:REPORT manual "Getting
Ready to Use REPORT." Use your DOS 2.10
diskette when the instructions ask for the DOS
diskette.

Using pfs:REPORT with the IBM Fixed Disk
You can use pfs:REPORT with the IBM fixed disk in
two different ways. First, you can store your files on the
fixed disk, thus allowing larger files to be stored, and
faster access to forms in the stored files. Second, you
can copy the pfs:REPORT program to the fixed disk
and then load it from there. This allows you to load the
program faster, without using the program diskette.

D-17

Storing PFS Data Files on the Fixed Disk
You can store a data file on the fixed disk provided you
include the drive identifier for the fixed disk as part of
the file name. If you specify the fixed disk drive as the
default drive, then it is not necessary to include the
drive identifier as part of the file name. Note that your
data file must be in the same directory as your pfs:FILE
program.

Copying pfs:REPORT to the Fixed Disk
Follow these steps to copy the pfs:REPORT program to
the fixed disk:

D-18

1.

Insert the DOS 2.10 diskette into drive A and tum
on your IBM Personal Computer. Enter the date
and time when the computer asks you to do so.

2.

When the DOS prompt appears, remove the DOS
2.10 diskette and replace it with the pfs:REPORT
program diskette.

3.

Follow the instructions in Appendix D of the
pfs:REPORT manual called "Setting Up a Serial
Printer and the Work Drive" to run the setup
program. Change the work drive name to the drive
name of your fixed disk. For example, if your fixed
drive is drive C, then the work drive item on the
setup menu should be drive C.

4.

If you have a serial printer, enter the correct values
for the other items on the setup menu.

5.

Press the FlO key to complete the setup program.
Then enter RTRANS in response to the DOS
prompt.
The "in use" lights will come on alternately as the
program is copied from the diskette to the fixed
disk. The copy is placed in the current directory.
The DOS prompt reappears when the copy is
complete.
If you have more than one fixed disk, the copy will
be made to drive whose name is last in the
alphabet. For example, if two drives are named C
and D, the copy will automatically be made to
drive D.

D-19

Error Conditions
The following error conditions might occur during the
copy procedure.
Message

Explanation

Corrective Action

CAN'T COpy
PROGRAM FILE

Your program
diskette has been
damaged.

Try the copy
procedure with the
backup copy of the
program diskette.

Your fixed disk is
improperly
formatted. (also
applies to the
CREATE message)

Copy to diskette
any files on the
fixed disk. Then
reformat the fixed
disk, and try the
copy procedure
again.

CAN'T CREATE
PROG RAM FILE

Your current
directory is full.

If you have
unneeded files in
the current
directory, delete
them and start the
copy procedure
again.

NAME ERROR

Possible DOS error.

Reload DOS 2.10
and start the copy
procedure again.

WRONG
VERSION

Cannot find the
fixed disk.

Make sure that your
fixed disk is
properly connected,
and that you are
using DOS 2.10.

D-20

Running the pfs:REPORT Program from a
Fixed Disk
To run the pfs:REPORT program from a fixed disk,
make sure that you have followed the instructions under
"Copying pfs:REPORT to the Fixed Disk" (make sure
the current directory contains pfs:REPORT). Then in
response to the DOS prompt, enter the drive identifier
for the fixed disk followed by the name of the program.
For example, to run the pfs:REPORT program from
drive C, enter: C:REPORT. If the default drive is C,
you need only type and enter REPORT in response to
the DOS prompt.

Changing Settings When Using the Fixed Disk
To change the work drive or the information stored for
your serial printer after copying the pfs:REPORT
program to the fixed disk, you need to insert the
pfs:REPORT program diskette into drive A and run the
setup program from that diskette. Use the COpy
command to copy the file named IBMSETUP.PFS
from the diskette in drive A to the fixed disk.

The Dow Jones Reporter Version 1.00
The Dow Jones Reporter Version 1.00 directs data to
be saved only on diskette drive A. In addition, the
program diskette is copy protected, and you cannot
install the program on a fixed disk.
Dow Jones is a registered trademark of the Dow Jones
Company, Inc.

D-21

SNA 3270 Emulation and RJE Support
Version 1.00
To use SNA 3270 Emulation and RJE Support Version
1.00 with DOS 2.10 you need a minimum of 128K
bytes memory.
To install this application in a subdirectory, SNA, on a
fixed disk, use the procedure described below, which
assumes the following:
•

The fixed disk is drive C.

•

The fixed disk drive is the default drive.

•

The root directory in the fixed disk contains DOS
2.10.

The Procedure
1.

Insert the SNA program diskette into diskette
drive A.

2.

Edit the files 3270COPY.BAT and
SRJECOPY.BAT to change all drive B references
to drive C.

3.

Enter the following commands to create the
subdirectory, SNA, and to copy the needed files
from drive A to drive C.
MD \SNA
Create the subdirectory
CD \SNA
Operate from it
A:3270COPY
Copy required files

D-22

A:SRJECOPY
Copy required files
COPY C:\BASIC.COM C:\SNA
Copy a needed file
4.

You may now run the SNA program by entering
the following commands:
C:

Change the default drive

CD \SNA
Operate from the SNA subdirectory
programname
Enter the correct program name as specified
in the SNA manual in response to the DOS
prompt
CD \
Return to the root directory
Notes:
1.

The use of the subdirectory name SNA
is as an example only. You may use any
name you wish.

2.

All file transfers for SRJE are to and
from files in the SN A subdirectory.

3.

The SNA program does not accept
subdirectory names as part of a filespec.

Typing Tutor
To use Typing Tutor with DOS 2.10 it is recommended
that your IBM Personal Computer have a minimum of
64 K bytes memory. If you have a single diskette drive
system, you should use the single drive setup procedure.

D-23

VisiCalc by VisiCorp.
To use VisiCalc with DOS 2.10 it is recommended that
your IBM Personal Computer have a minimum of
128K bytes of memory. The following are procedures to
put DOS 2.10 on your VisiCa1c program diskette, and
to make your program diskette self starting for fixed
disk. These procedures assume the following:
•

You have at least one diskette drive and one fixed
disk.

•

You are familiar with loading DOS 2.10 from your
fixed disk.

•

You are aware that VisiCa1c supports a maximum
of two secondary storage devices. Only one of
these two devices may be accessible during
operations.

Putting DOS 2.10 on Your Program Diskette
Follow these steps to put DOS 2.10 on your VisiCalc
program diskette and to make that diskette self starting:
1.

Start DOS 2.10. You should see the DOS prompt

C>.

D-24

2.

Remove the write protect tab from the VisiCalc
program diskette.

3.

Place the program diskette into drive A.

4.

Enter COpy COMMAND. COM A:

5.

Enter SYS A:

6.

Enter COPY ASSIGN.COM A:

7.

Enter COPY CON A:AUTOEXEC.BAT

8.

Enter DATE

9.

Enter TIME

10. Enter ASSIGN B=C (or any other drive
designator)
11. Type VC80
12. Enter ASSIGN (space) (press F6) (then press
Enter)
13. Remove the program diskette and replace the write
protect tab on your program diskette.
The fixed disk can now be used to store and retrieve
your VisiCalc data files. Every time you load your
VisiCalc program the fixed disk will be assigned as
drive B.

3101 Emulator Version 1.00
To use the 3101 Emulator Version 1.00 with DOS 2.10
requires a minimum of 96K bytes memory.
Use the procedure described below to install the 3101
Emulator in a subdirectory, EM31 0 1, on the fixed disk.
The procedure assumes the following:
•

The fixed disk is drive C.

•

The fixed disk is the default drive.

D-25

The Procedure
1.

Insert the 3101 Emulator program diskette into
drive A.

2.

Enter the following commands to create the
subdirectory, EM31 0 1, and to copy the needed
files from drive A to drive C:
MD \EM3101
Create the subdirectory
CD \EM3101
Operate from it
COpy A:*.* C:\EM3101
Copy all files on the 3101 Emulator program
diskette
ERASE COPYFILS.BAT
Not needed
ERASE AUTOEXEC.BAT
Not needed
CD \
Return to root directory

3.

You may now run the 3101 Emulator by entering
the following commands:
CD \EM3101
Operate from the EM31 0 1 subdirectory
IBM3101
Run the 3101 Emulator program
CD \
Return to the root directory

D-26

4.

You may run the file conversion program,
FILECONV, by entering the following commands:
CD \EM3101
Operate from the EM31 01 subdirectory
FILECONV
Run the file conversion program
CD

\
Return to the root directory

Notes:
1.

The use of the subdirectory name EM31 0 1 is
as an example only. You may use any name
you wish.

2.

All file transfers will be to and from files in
the EM3101 subdirectory.

3.

The 3101 Emulator does not accept
subdirectory names as part of a filespec.

D-27

D-28

Appendix E. DOS Version 2.00
and 2.10 Enhancements

The information in this appendix is divided into two
categories-those topics that apply to all users, and
those topics that apply to system programmers or
application developers. In each case, a brief description
of the feature or change is offered, and you are referred
to another section of the book for further details.

F or All Users
DOS Versions 2.00 and 2.10 incorporate the following
new and changed features:

•

Special characters. The characters <, >,:, and \
now have special meanings to DOS, and can no
longer be used in filenames. If you have files
whose names contain any of these characters, they
should be renamed (using your old version of
DOS) before attempting to use them with DOS
Version 2.00 or 2.10.

•

Configuration file. You can create a file of special
commands that DOS will read each time it starts
up. The commands allow you to specify the
number of disk buffers DOS should use, the names
of device drivers, and additional information
concerning DOS operation. Please refer to
"Configuring Your System" in Chapter 4 for
additional information.

E-l

B-2

•

Support for one or more fixed disk devices. The
disk can be divided into multiple partitions, each
usable by a different operating system. You can
start (boot) your operating system from the fixed
disk, and utility programs included to perform disk
initialization, backup, and restore functions. If you
have a fixed disk, please read the "Preparing Your
Fixed Disk" information in Chapter 3 for setup
instructions and the BACKUP and RESTORE
commands in Chapter 2 for their respective
functions.

•

Support for increased diskette capacity.
Beginning with DOS Versions 2.00 and 2.10,
DOS formats diskettes at 9 sectors per track,
which increases capacity from 163840 to 184320
characters of information for single-sided diskettes,
and from 327680 to 368640 characters for
dual-sided diskettes. The smaller capacity
diskettes created by DOS Version 1.00 or DOS
Version 1.10 (8 sectors per track) are also usable
with DOS Versions 2.00 and 2.10. You do not
need to reformat them. Please see the FORMAT
and DISKCOPY commands in Chapter 2 for more
information.

•

Multiple disk buffers. A disk buffer is an area of
user memory that DOS reserves at startup and is
used for performing disk and diskette operations.
DOS normally allocates two disk buffers at
start-up time. Some users, however, will find that
certain applications, such as data base
applications, may run faster if DO S has more
buffers available to it. DOS Versions 2.00 and
2.10 allow you to specify the number of buffers
that DOS should reserve at start-up time. Please
refer to "Configuring Your System" in Chapter 4
for instructions on specifying additional buffers.

•

Tree-Structured Directories. This new feature
allows you to place related groups of files in their
own directories-all on the same disk. The
individual directories are isolated from each other,
giving the appearance of separate disks. Therefore,
a search for a file in a given directory will not
"see" files in other directories on the same disk.
Each directory, beginning with the normal system
directory (called the root directory) may contain
special entries naming other directories on the
same disk. These other directories, in tum, may
contain entries for even more directories, and so
on. When viewed in a logical order beginning with
the root directory, the directory structure appears
much like a diagram of a family tree-thus the
term tree-structured directories.
You may add or remove directories, copy files
from one directory to another, instruct DOS to
look in a specific directory to locate a file, etc. For
complete details, please refer to Chapter 5 "Using
Tree-Structured Directories".

•

Disk Volume Labels. This feature allows you to
specify a unique volume label (up to 11
characters) at the time you format a disk. The
volume label is placed in the root directory, and is
included in the displays produced by the DIR,
CHKDSK, and TREE commands. Please refer to
the FORMAT command for further information.

E-3

v

•

Extended DOS screen and keyboard
control. This feature allows you to issue special
character sequences from within your program that
DOS will use for screen cursor positioning and
color, and further allows you to assign the meaning
of any key on the keyboard. For example, you
may assign the character string "DIR A:" to FlO
so that simply pressing FlO has the same result as
entering the D IR A: command. Please refer to
"Configuring Your System" in Chapter 4 for more
detailed information.

•

Redirection of Standard Input and Output. This
feature applies to all DOS programs that read from
the keyboard or write to the screen (the standard
input and output devices). By using the special
characters < (for input) and > (for output), you
can cause a program to receive its input from a
source other than the keyboard, or to direct its
output to a destination other than the screen. For
example, the command:
DlR A:>DlRLlST

causes the directory listing from drive A to be
placed in a file named DIRLIST on the default
drive. Device names can also be used. For
example, the command:
DlR A:>PRN

causes the directory listing to appear on the printer
instead of the screen. Please refer to "Redirection
of Standard Input and Output" in Chapter I for
further information.

E-4

•

Piping of standard input and output. This feature
allows the standard output of one program to be
used as the standard input to another. DOS acts as
a "pipeline" to direct the output of the first
program to the input of the second-thus, the term
"piping." For further information and an example
of its use, please refer to "Piping of Standard Input
and Output" in Chapter 1.

New Commands
The following new commands have been added to DOS
Versions 2.00 and 2.10. Please consult the command
descriptions in Chapter 2 for further details and
examples of their use.

ASSIGN
Allows you to reassign drive letters so that a request for
a given drive can be routed to a different drive.

BACKUP
Backs up one or more files from a fixed disk to
diskettes.

E-5

BREAK
Allows you to specify when DOS should check for a
Ctrl-Break being entered at the keyboard. Normally,
DOS only performs this check during screen, keyboard,
printer, or auxiliary device operation. With this
command, you can instruct DOS to check for
Ctrl-Break whenever a program requests DOS to
perform any function (such as disk operations). In this
way, it is possible to "break out" of a program that
performs few or no screen or keyboard operations (such
as a compiler).

CLS
Clears the screen when used from a batch file or the
keyboard.

CITY
Allows you to define a different primary console, so
that a remote terminal device can be used in place of
the standard screen and keyboard. This command also
reverses this assignment, to restore the keyboard and
screen as the standard input and output devices.

ECHO, IF, FOR, SHIFT, GOTO
New subcommands provided to extend the flexibility of
batch processing.

E-6

FDISK
Initializes and configures a fixed disk.

Note: This command must be used before you
use your fixed disk for the first time. Please refer
to Chapter 3 "Preparing Your Fixed Disk".

GRAPHICS
Allows the Shift-PrtSc keys (display screen contents on
printer) to print the image of a graphics display screen.

MKDIR, RMDIR and CHDIR
Create, remove, and inform DOS to use a directory
other than the system directory.

PATH
Allows you to specify one or more paths of directory
names that DOS will search if the command you have
issued was not found in the current directory. They
allow conditional execution of commands within a batch
file by causing DOS to check for specified conditions.

PRINT
Prints a queue (list) of files on the system printer while
you are using the system for other work.

B-7

PROMPT
Allows you to change the system prompt to a desired
string.

RECOVER
Recovers a specific file that cannot be copied or
otherwise used because of a defective spot on the disk
that prevents the file from being read. This command
also recovers multiple files when the directory has been
damaged.

RESTORE
Restores one or more files from a diskette to a fixed
disk.

SET
Allows you to enter keywords and parameters into a
DOS "environment" that is accessible by commands
and applications.

TREE
Displays the entire directory structure of the specified
disk.

VER
Displays the DOS version number on the screen.

E-8

VERIFY
Instructs DOS to perform a verify operation (or to stop
performing the verify) each time data is written to disk,
until a new verify command is issued to turn the verify
feature off. The verify operation increases assurance
that the data was properly recorded on disk (that is, it
can be read without error).

VOL
Displays the volume label of the disk in the specified
drive.

Enhanced Commands
The following commands, that existed in DOS Version
1.10, have been enhanced for DOS Versions 2.00 and
2.10. For more detailed information, please consult the
individual command descriptions in Chapter 2.

CHKDSK
Supports the fixed disk, the new and old diskette
formats, and analyzes all directories on the volume. It
also enables you to create files containing all sectors
that were found to be allocated but were not associated
with a file, so that you can recover "lost" data. An
important feature is that, unlike Version 1.10
CHKDSK, it will take no corrective action on the disk
being analyzed unless instructed to do so.

E-9

COMP
The file compare utility now allows multiple files to be
compared. For example, you can compare all of the
files on one disk with their counterparts on another disk.
Also, COMP no longer prompts you to insert diskettes
before comparing.

DEBUG
Now contains a command allowing you to enter
assembly language statements that are assembled
directly into memory.

DIR
Now displays the volume identification of the specified
disk and clearly identifies entries that contain the names
of other directories. It also displays the amount of
available space left on the disk.

DISKCOPY and DISKCOMP
Supports the new 9-sector-per-track diskette format.

EDLIN
The line editor contains several new subcommands for
more flexible management of source data. They include
commands to copy and move lines, and to merge the
contents of another file. The Replace and Search
commands have been changed to begin their search at
the current line plus one.

E-IO

ERASE
Now requires you to press the Enter key after entering
the YIN response to the
Are you sure (YIN)?

message that appears when you instruct DOS to erase
all of the files on a volume. This is intended to prevent
accidental erasure of all files from the larger capacity
devices supported by DOS Versions 2.00 and 2.10.

FORMAT
Now formats diskettes at 9 sectors per track (in DOS
1.00 and 1.10 diskettes were formatted at 8 sectors per
track), allowing each new diskette to hold more data. It
also allows you to specify a volume identification that is
recorded in the disk's directory. Support for initializing
a fixed disk is also included.

LPT2:, LPT3:, and COM2:
Now recognized as valid device names by DOS, and
can be used in place of filenames.

E-11

For Programmers
Programmers may find the IBM DOS Technical
Reference helpful.
•

DOS Versions 2.00 and 2.10 include the ability to
install your own device drivers for character or
block-oriented devices.

•

Three changes were made to internal functions that
cause different results from those obtained on
DOS Version 1.10:
1.

The function call (hex IB) that previously
returned a pointer to the file allocation table
now returns a pointer to only the table's
identification byte, for purposes of determing
the disk type. All applications that use call
hex 1B to obtain the file allocation table
should be changed to use interrupt hex 25 to
read the file allocation table directly from the
disk. The file allocation table always begins
at logical sector 1, and its size can be
determined from the information returned by
call hex 36. We recommend that you avoid
using calls hex IB and hex Ie.

2.

The mapping of logical sectors on dual sided
diskettes has been rearranged to facilitate
program loading and to improve system
performance.
This change allows DEBUG to load an entire
file with a single L command.
Applications that use interrupts hex 25 and
hex 26 on multi-sided disks or diskettes may
require modification to operate properly on
DOS Versions 2.00 and 2.10.

E-12

3.

•

Additional bits have been defined in the file
attribute byte of the DOS disk directory.
Programs that depended upon the file
attribute byte being equal to zero if a file was
not a hidden or system file may not work
correctly.

A new set of function calls has been made
available to provide a wide variety of services. We
suggest that systems programmers and application
developers review all of Chapter 5 of the IBM
DOS Technical Reference for details on these new
functions.

E-13

E-14

Appendix F. Some Keys
You Use with DOS

In addition to the keys you'd find on a typewriter, your
keyboard has some special keys you'll use with DOS.
Before you use the special keys, please be sure to read
the keyboard section of the IBM Guide to Operations.

F-l

DOS Editing Keys

Use the DOS editing keys to make corrections to
commands and input lines as they are being entered.
Note that the meaning of these keys can change if you
alter their assignments through extended keyboard
control.
The DOS editing keys are used to edit within a line.
The Line Editor (EDLIN) program operates on
complete lines within a file or document. When you are
working with EDLIN and want to edit within a line,
however, use the DOS editing keys. For more
information about ED LIN, refer to Chapter 6.
Note: Some word processing programs define
special editing rules; therefore, the DOS editing
keys may not work as described in this chapter.
You can also define special editing rules when
using the BASIC Program Editor while
programming in BASIC.
Any line you enter from the keyboard is retained in an
input buffer when you press Enter. The line is then
made available to your program for processing.
Since the line remains in the input buffer, you can use
that line as a template for editing purposes. The DOS
editing keys operate on that copy of the line. You can
repeat or change the line by using the DOS editing
keys, or you can enter an entirely new line.
Here is a summary of the DOS editing keys, their
functions, and their locations on the keyboard:

F-2

DO S Editing Key

Function

Del

Skips over one character in the template.
The cursor does not move.

Esc

Cancels the line currently being
displayed. The template remains
unchanged.

F 1 or - .

Copies one character from the template
and displays it.

F2

Copies all characters up to a specified
character.

F3

Copies all remaining characters from the
template to the screen.

F4

Skips over all characters up to a specified
character. (F 4 is the opposite of F 2. )

F5

Accepts an edited line for continued
editing - the currently displayed line
becomes the template, but it is not sent to
the requesting program.

Ins

Allows you to insert characters within a
line.

F-3

Examples of Ways to Use DOS
Editing Keys
The following examples show how you use the DOS
editing keys with the Line Editor (EDLIN) program.
If you want to try these examples, you must use the
EDLIN program. The EDLIN program is on your
DOS diskette and is discussed in Chapter 6. You do not
need to review the EDLIN chapter to complete these
examples - just follow the steps provided.
Notes:
1.

Because the DOS diskette shipped with your IBM
Personal Computer is write protected, you cannot
create the file used in the following examples on
that diskette. You must use a copy of your DOS
diskette to complete these examples.

2.

In the following examples, to enter something
means that you should type the information and
then press the Enter key.

3.

If you finish one or more of the following examples
and you do not want to try the rest of the
examples, go to "To Stop the Editing Session" at
the end of this chapter.

To Start EDLIN
1.

Insert your DOS diskette into drive A.

2.

Create a file named EXAMPLES.
If you want the EXAMPLES file to reside on the
diskette in your default drive, enter:
EDLIN EXAMPLES

or

F-4

If you want the EXAMPLES file to reside on the
diskette in another drive, you must specify the
drive, as in:
EDLIN B:EXAMPLES

This command tells DOS to load the EDLIN
program and create a file called EXAMPLES.
The following message and prompt will be
displayed:
New file
*

Notice that the prompt for ED LIN is an asterisk
(*).
3.

Now, enter the letter I.
This tells EDLIN that you want to begin inserting
lines in the file named EXAMPLES.
The screen looks like this:
New file
*1

1:*_

4.

Type This is a mailorder file. on line 1 and press
Enter.

5.

Type Editing is easy. on line 2 and press Enter.
You now have two lines of text in your
EXAMPLES file.

6.

Press the Ctrl-Break keys.
Pressing Ctrl-Break will end the insert mode of
operation and return you to the ED LIN prompt.

F-5

7.

Enter the number 1.
This tells EDLIN that you want to display line 1
on the screen.
The screen should look like this:
1:*This is a mailorder file.
1:*_

You are now ready to begin the examples.
Note: If you encounter any problems while
trying these examples, press the Ctrl-Break keys.
The ED LIN prompt will be displayed and you can
start over.

Example 1
Let's delete the first two characters in the word This
and then copy the remainder of the line.
1.

Press the Del key twice to delete the first two
characters.

2.

Press F 3 to copy the remainder of the line to the
screen. The screen looks like this:
1:*This is a mailorder file.
1:*is is a mailorder file._

If you want to continue with the next example:

F-6

1.

Press Ctrl-Break to return to the ED LIN prompt.
(The changes you made to line 1 will not be
saved.)

2.

Enter the number 1.

Example 2
Now we'll change line 1; then, using Esc, we will cancel
the change. A backslash (\) will be displayed to
indicate that the displayed line has been cancelled.
Note: If the insert mode is on, the system
automatically turns it off when you use Esc.
The screen looks like this:
1:*This is a mailorder file.
1:*_

To change line 1 to Sample file:
1.

Type Sample file, but do not press Enter.
1:*This is a mailorder file.
1:*Sample file_

2.

To cancel the line we just entered, press the Esc
key.
1:*This is a mailorder file.
1:*Sample file \

Now we can continue to edit the original line This
is a mailorder file.
3.

Press F 3 to copy the original line to the screen.
The screen looks like this:
1:*This is a mailorder file.
1:*Sample file \
This is a mailorder file._

If you want to continue with the next example:

1.

Press Ctrl-Break to return to the ED LIN prompt.

2.

Enter the number 2.

F-7

Example 3
Now let's copy one character by using Fl or -+. (Fl
or -+ is the opposite of Del. Del skips over one
character in the template.)
The screen looks like this:
2:*Editing is easy.
2:*_

1.

Press F 1 or -+ key three times.
The screen looks like this:
2:*Editing is easy.
2:*EdL

Each time you press Fl or --+ key, one more
character appears.
If you want to continue with the next example:
1.

Press Ctrl-Break to return to

2.

Enter the number 2.

th~

EDLIN prompt.

Example 4
Now let's use F2. Remember, F2 copies all characters
from the template to the screen up to, but not including,
the first occurrence of a specified character.
You must always specify a character when using this
key. If the specified character is not present in the
template, nothing is copied.

F-8

The screen looks like this:
2:*Editing is easy.
2:*_

1.

Press F2 and enter the letter g.
The screen looks like this:
2:*Editing is easy.
2:*Editi"-

Now we'll copy all the remaining characters in the
template to the screen by using F 3.
(If you pressed Enter now, only Editin would be
saved in the EXAMPLES file as line 2.)
2.

Press F3.
The screen looks like this:
2:*Editing is easy.
2:*Editing is easy,-

If you want to continue with the next example:
1.

Press Ctrl-Break to return to the ED LIN prompt.

2.

Enter the number 1.

Example 5
Now let's scan and locate specific characters within the
template by using F 4. This is a way to skip over
characters. The cursor does not move when you use this
key, and no characters are displayed.
You must always specify a character after you press F 4.
If the specified character is not present in the template,
no characters in the template will be skipped.

F-9

We will also use F 3 to copy the remaining characters in
the template to the screen.
The screen looks like this:
1:*This is a mailorder file.
1:*_

1.

Press F4 and enter the letter o. (No characters are
displayed. )

2.

Press F3 to copy the remainder of the line.
The screen looks like this:
1:*This is a mailorder file.
1:*order file ___

If you want to continue with the next example:
1.

Press Ctrl-Break to return to the EDLIN prompt.

2.

Enter the number 1.

Example 6
Now we'll move the currently displayed line into the
template by using F 5. Pressing F 5 is the same as
pressing Enter, except that the line is not sent to your
program. An @ character is displayed to indicate that
the new line is now the template.
Note: If the insert mode is on, the system
automatically turns it off when you use F5.
Once you press F5, you can continue to make changes
to a line. When you are finished, press Enter to send the
line to your program.

F-10

The screen looks like this:
1:*This is a mailorder file.
1:*_

1.

Type This is not a sample file.
The screen looks like this:
1:*This is a mailorder file.
1:*This is not a sample file._

2.

Press F5.
The result is:
1:*This is a mailorder file.
1:*This is not a sample file.@

The replacement line This is not a sample file. is
now in the template. The replacement line is
acceptable, but let's continue to edit it.
3.

To remove the word not from the replacement
line, press F 1 eight times:
1:*This is a mailorder file.
1:*This is not a sample file.@

4.

Press Del four times to remove one blank space
and the word not.

5.

Press F 3 to copy the remaining characters to the
screen.
The screen looks like this:
1:*This is a mailorder file.
1:*This is not a sample file.@
This is a sample file.

F-l1

6.

Press Enter to make the replacement line This is a
sample file. the template in place of the original
line and to send the line to your program.
(If you want to do more editing without sending
the line to your program, press F5 again to put the
displayed line into the template.)
Note: Pressing Enter immediately after
pressing F5 empties the template.

If you want to continue with the next example:
1.

Press Ctrl-Break to return to the EDLIN prompt.

2.

Enter the number 1.

Example 7
Let's look at an example using the Ins key. The Ins key
serves as an on/off switch for entering and leaving insert
mode. You can press the Ins key to enter insert mode,
and press the Ins key again to leave the insert mode.
While in the insert mode of operation, any characters
that you enter are inserted in the line being displayed.
The characters do not replace characters in the
template.
When you are not in the insert mode of operation, any
characters that you enter replace characters in the
template. If you are entering characters at the end of a
line, the characters will be added to the line.
The screen looks like this:
1:*This is a sample file.
1:*

F-12

Let's change the word sample to salary.
1.

Press F2 and enter the letter m.
The screen looks like this:
1:*This is a sample file.
1:*This is a sa_

2.

Press the Ins key and enter the characters lary.
The screen looks like this:
1:*This is a sample file.
1:*This is a salary_

Notice that the characters lary were inserted, but
no characters from the template were replaced.
3.

Now, press Ins again to leave the insert mode.

4.

Enter one blank space and the three characters
tax.
1:*This is a sample file.
1:*This is a salary tax_

5.

Press F 3 to copy the remaining characters in the
template to the screen.
1:*This is a sample file.
1:*This is a salary tax file._

Notice that we inserted lary and we replaced mple
with a blank space and tax.
6.

Now press Enter to make the replacement line the
template in place of the original line and send the
line to the requesting program.

F-13

To Stop the Editing Session

You have now completed the examples.
To return to the A> prompt:
1.

Press Ctrl-Break.

2.

Enter the letter Q.

Q tells EDLIN that you don't want to save the
EXAMPLES file and that you want to quit the
editing session. ED LIN will prompt you with this
message:
Abort edit (YIN)?

to make sure you don't want to save the file.
3.

F-14

Enter the letter Y.

Index

Special Characters
secondary command
processor 1-11
. - period 6-8, 6-17
.COM file format 2-83, 2-85
+ (plus sign)
in automatic response
file 7-21
in response to linker
prompt 7-10
$$$ - filename extension 6-5
* - EDLIN prompt 6-5 6-10
* - global filename
'
character 1-1 7
- (DEBUG prompt) 8-13
DEBUG 8-13
IC parameter 2-87"
IP parameter 2-66
IS parameter 2-93
IV parameter 2-49,2-87,2-92
IW parameter 2-66
11 parameter 2-73
DISKCOMP 2-74
18 parameter,
DISKCOMP 2-74,2-76
% (percent sign) 2-22
? - global filename
character 1-20
# - pound sign 6-7
= equal sign 1-15

A
A> prompt 1-12
abort readlwrite
operation A-2
absolute sector 8-56
absolute segment address
how to determine 7-26
AC flag set condition 8-45
accessing a file 4-9
adding hexadecimal
values 8-31
address - DEBUG
parameter 8-7
address, disk transfer 8-5
analyze
diskettes 2-80
status report 2-38
the directory 2-38
the File Allocation
Table 2-38
Append Lines
Command 6-11,2-49
applications,
randoml sequential 4-6
ASCII characters 8-20
ASCII representation 8-7
ASCII values 8-12
Assemble Command 8-15
assembler 7-7
ASSIGN (Drive)
Command 2-6
ASSIGN command 2-146

X-I

ASSIGN drive command 2-7
Asynchronous
Communications
Adapter 2-33, 2-100, 2-104
AUTOEXEC.BAT file 2-15
automatic response file
linker 7-21
AUX - reserved device
name 1-19
auxiliary carry flag 8-45
AX register 8-5

B
BACKUP (Fixed Disk)
Command 2-9
BACKUP command 2-9,
2-146
backup diskette 2-75
back up 2-75
backup file, edit 6-4
BAK filename extension 6-4,
6-20,6-32
.BAK 6-4, 6-20, 6-32
BAT filename extension 2-13
Batch Commands 2-13
batch file 2-13,2-25,2-26,
2-134,2-145
.BAT 2-13
change 2-25
enter 2-134
batch processing 2-13
boundary, paragraph 7-6
boundary, 16-byte 8-20
boundary, 8-byte 8-20
BP register 8-4
brackets, square 1-15
BREAK (Control Break)
Command 2-34
Break command 2-33, 2-146
X-2

breakpoint 8-27
buffer, what is a 4-5
BUFFERS command 4-5
BX register 8-5, 8-35
byte - DEBUG parameter 8-8
byte contents
display 8-23
fill 8-27
replace 8-23

c
carry flag 8-45
change console,
CTTY 2-61
change date 2-63
change diskettes 2-32
change filenames 2-122
change time 2-134
changing active
partition 3-19
changing the current
directory 5-11
CHDIR (Change Directory)
Command 2-35
CHDIR command 2-35,
2-146
check for control break 2-34
CHKDSK (Check Disk)
Command 2-38
CHKDSK command 2-38,
2-146
class 7-7
clear condition 8-44
clear screen 2-42
CLS (Clear Screen)
Command 2-42
CLS command 2-146
codes, 8088 instruction 8-30
colon 1-15

Color/Graphics Monitor
Adapter 2-102
COM filename extension 1-14
comma 1-15
command line
linker 7-19
command parameters
DEBUG 8-7
DOS 1-13
EDLIN 6-6
command prompt,
DEBUG 8-14
command prompts, linker 7-8
COMMAND.COM 8-4
commands
DEBUG 8-13
DOS 2-6
EDLIN 6-9
commands for directories 5-10
commands, end 1-24
commands, summary of
DEBUG 8-60
DOS 2-145
Communications
Adapter 2-100
COMP (Compare Files)
Command 2-44
COMP command 2-44,2-73,
2-146
Compare Command 8-19
comparing diskettes 2-76
comparing 2-76
comparing files 2-44
comparing memory 8-19
compilers, using fixed
disk B-1
computer, size of your 4-7
COMI - reserved device
name 1-19, 2-61
COM2 2-61
CON - reserved name for
console/keyboard 1-19

concatenation 2-48
console/keyboard 1-19
control keys 1-21,6-8,8-14
entering DOS
commands 1-23
using DEBUG 8-14
copy and combine files 2-60
COpy command 2-13, 2-49,
2-77,2-79,2-147
Copy Lines Command 6-12
copy with different
filename 2-59
copy with same filename 2-51
copying diskettes 2-77
copying 2-77
copying files 2-49
create DOS partition 3-13,
3-14
creating a .BAT file 2-1 7
creating a batch file 2-13
creating a new file 6-18
creating a subdirectory 5-10
CS register 8-5, 8-28, 8-30,
8-33,8-47,8-52
Ctrl-Break 7-9
Ctrl-Break keys 1-24, 2-12,
2-28,6-9,6-17,6-19,8-13
Ctrl-NumLock keys 1-25, 6-8,
8-14
Ctrl-PrtSc keys 2-139
Ctrl-Z character 2-49
Ctrl-Z keys 2-46
CTTY command 2-61,2-147
CTTY Command (Change
Console) 2-61
CTTY command 2-61
current directory, changing
or displaying 2-35, 5-11
current directory, what is 5-5
CX register 8-5, 8-35, 8-58
CY flag set condition 8-45

X-3

D
d:
default 1-16
parameter 1-16
DATE Command 2-63 ,
2-147
change 2-63
enter 2-63
DEBUG commands
Assemble 8-15
Compare 8-19
Dump 8-20
Enter 8-23
Fill 8-27
Go 8-28
Hexarithmetic 8-31
Input 8-32
Load 8~33
Move 8-36
Name 8-37
Output 8-39
Quit 8-40
Register 8-41
Search 8-41
Trace 8-49
Unassemble 8-51
Write 8-55
DEBUG program
command parameters 8-7
commands 8-13
common information 8-13
ending 8-40
how to start 8-4
prompt 8-14
summary of
commands 8-60
what it does 8-3
default disk transfer
address 8-5

X-4

default drive
linker 7-9
parameter 1-16
default segment 8-6
defective tracks 2-89
DEL Command 2-65
delete DOS partition 3-14
Delete Lines Command 6-13
deleting a directory 5-10
deleting a file 2-65
deleting DOS partition 3-20
deleting files 2-81
delimiters 1-24,6-8,8-13
destination area 8-36
device error messages A-3
device names, reserved 1-19 ,
2-59
device redirection 1-5
DGROUP 7-14
DI flag clear condition 8-45
DI register 8-5
D IR (Directory)
Command 2-66
DIR command 1-22,2-66,
2-92, 2-147
direction flag 8-45
director, analyze 2-38
directory entries,
listing 2-67
directory path format 1-1 7
filenames 1-1 7
directory search,
PATH 2-104
directory structure,
displaying 5-11
directory types, how they
work 5-5
directory, display 2-138
directory, make 2-98
directory, remove 2-127

disk transfer address 8-5
DISKCOMP (Compare
Diskette) Command 2-73
DISKCOMP command 2-73,
2-62, 2-147
DISKCOPY (Copy Diskette)
Command 2-77
DISKCOPY command 2-77,
2-147
display
byte contents 8-24
flags 8-43
lines 6-23
registers 8-41
remarks 2-29
display contents of
directory 2-138
Display DOS version
number 2-108
display instructions 8-49
display partition data 3-22
displaying directory
structure 5-11
displaying memory 8-20
displaying the current
directory 5-11
DN flag set condition 8-43
DOS commands
ASSIGN 2-6
BACKUP 2-9
Batch processing 2-13
BREAK 2-33
CHDIR 2-35
CHKDSK 2-38
CLS 2-42
common information 1-23
COMP 2-43
COPY 2-48
CTTY command 2-61
DATE 2-63
DEL 2-65

DIR 2-66
DISKCOMP 2-73
DISKCOPY 2-77
ERASE 2-81
EXE2BIN command 2-83
external 1-13
FIND Filter
command 2-87
FORMAT 2-89
GRAPHICS 2-96
internal 1-13
MKDIR command 2-98
MODE 2-100
MORE Filter 2-107
PATH 2-108
PAUSE 2-28
PRINT Command 2-110
PROMPT 2-116
RECOVER Command 2-119
REM 2-29
RENAME (or REN) 2-122
RMDIR 2-127
SET command 2-128
SORT Filter 2-131
summary of 2-145
SYS 2-133
TIME 2-135
TREE 2-136
TYPE 2-139
types of 1-13
VER Command 2-141
VERIFY Command 2-143
VOL Command 2-144
DOS diskette, about your iii
DOS filters 1-10
DOS partition
changing active 3-19
creating 3-15
deleting 3-20
display data 3-22

X-5

DOS version number,
display 2-141
DOS, setting up the
partition 3-9
DOS, when it starts 3-5
drive 1-16
directory path 1-1 7
drive - DEBUG
parameter 8-8
drive letters, fixed
disk 3-5
drive, assign new 2-6
DS register 8-6, 8-22,
8-27, 8-36
/DSALLOCATION linker
parameter 7-14
dummy device 1-19
dummy parameters 2-18, 2-19
ECHO 2-20
Dump Command 8-20, 8-60
DX register 8-5

E
ECHO Subcommand 2-20,
2-145
edit
backup file 6-4
existing file 6-5
partial file 6-11
Edit Line Command 6-1 7
editing a new file 6-6
editing keys F-l, 6-10, 8-13
EDLIN
prompt 6-5
Append Lines 6-11
command parameters 6-7
commands 6-9
common information 6-9
Copy Lines 6-12
X-6

creating a batch file 2-9
Delete Lines 6-13
Edit Line 6-1 7
End Edit 6-20
how to start 6-5
Insert Lines 6-21
List Lines 6-25
Move Lines 6-30
Page command 6-31
program 6-3
Quit Edit 6-32
Replace Text 2-30
Search Text 2-35
Transfer Lines 2-37
EI flag set condition 8-43
ellipsis 1-15
End Edit command 6-6, 6-20
end-of-file 2-56
ending commands 1-24
Enter Command 8-23,8-60
enter date 2-63
Enter key 1-19, 6-9
enter time 2-134
environment, set 2-131
equal sign (=) 1-15
ERASE Command 2-81,
2-148
erasing files 2-81
erasing 2-81
error message, device A-3
error messages A-I
error, recover from A-2
error, syntax 8-15
ES register 8-5, 8-6
Esc key 6-17
EXE filename extension 1-14,
7-11, 8-6, 8-35, 8-59
.EXE 8-6, 8-35
.EXE filename
extension 7-11
execute instructions 8-43

execute program 8-28
. executing a .BA T file 2-18
EXE2BIN Command 2-83,
2-148
existing file, edit 6-5
ext 1-18
extensions 1-18
characters, valid 1-18
external commands 1-14
.COM 1-14
.EXE 1-14

F
FCB (see File Control Block)
FDISK command 3-6, 3-14
File Control Block
(FCB) 8-37
file, editing a new 6-6
filename characters,
global 1-17
filenames
characters, valid 1-1 7
length of 1-17
renaming 2-122
files, list all 2-67
files, list selected 2-68
files, number opened 4-10
filespec 1-18
filespec - DEBUG
parameter 8-8
Fill Command 8-27, 8-60
Filter commands
filtering data 1-10

FIND Filter Command 2-87
FIND command 2-87
FIND Filter
command 2-87
First Asynchronous
Communications Adapter
port 1-19
fixed disk drive letters 3-5
fixed disk partitioning 3-13
Fixed Disk Setup
Program 3-13
fixed disk, backup 2-9
fixed disk, preparing
your 3-3, 3-6
fixed disk, restore 2-125
fixed disk, select next
drive 3-23
fixed disk, start 3-12
fixed disk, using compilers
and macro assembler B-1
fixups, segment 2-83
flag values 8-45
flags 8-5
flags, display 8-43
FOR Subcommand 2-22,
2-145
FOR 2-22
FORMAT Command 2-89,
2-148
format notation 1-15
FORMAT status
report 2-92
fragmented diskettes 2-79
fragmented files 2-59
fragmented 2-59
F3 key 8-33
F5 key 6-19
F6 key 1-19, 2-16

X-7

G
generating line numbers 6-3
global filename characters
* 1-20
? 1-20
examples using 1-22
in command name 1-24
in COpy 2-50
in DIR 2-67
in ERASE 2-81
in RENAME 2-122
Go Command 8-28, 8-58,
8-60
GO TO Subcommand 2-23,
2-145
GO TO 2-23
GRAPHICS (Screen Print)
Command 2-96
GRAPHICS command 2-96,
2-148
group 7-7

H
HEX filename extension 8-6,
8-35, 8-59
.EXE 8-59
.HEX 8-6,8-35,8-59
Hex arithmetic
Command 8-38,8-60
hidden files 2-39, 2-92
HIGH 7-14
HI G H linker parameter 7-6
high memory 7-14, 8-6
how directories work 5-3
how to use tree-structured
directories 5-3, 5-4

X-8

I
IBMBIO.COM 2-66, 2-82,
2-92
IBMDOS.COM 2-66, 2-82,
2-92
IF Subcommand 2-24, 2-145
IF 2-24
initialize
analyze 2-89
diskettes 2-89
initialize 2-89
initializing the asynchronous
adapter 2-100
Input Command 8-32,8-60
input files
linker 7-4
Insert Lines Command 6-21
insert mode 6-21
inserting lines 6-3
instruction codes, 8088 8-30
Instruction Pointer (lP) 8-5
instructions
display 8-49
execute 8-50
unassemble 8-51
variable length 8-51
internal commands 1-13
interrupt codes 8-29
interrupt flag 8-45
invoking one batch file from
another 2-15
IP (Instruction Pointer) 8-5
IP register 8-28, 8-41

K
keyboard 1-19
keys, control 1-21,6-9,8-13
keys, DOS editing 1-25, 6-8
ED LIN prompt 6-10
using EDLIN 6-9
keywords 1-15

L
LINE 7-16
line - ED LIN parameter 6-7
Line Editor Program 6-3
line numbers 6-3
lines, renumber 6-13, 6-21
LINK
See linker (LINK) program
linker (LINK) program
command line 7-19
command prompts 7-8
example session 7-23
messages 7-28
starting 7-18
linker files
automatic response 7-4,
7-21
input 7-4
library 7-4, 7-13
listing 7-5, 7-12
object 7-4, 7-10
output 7-5
run 7-5, 7-11
linker parameters 7-14
/DSALLOCATION 7-14
/HIGH 7-15
/LINE 7-16
/MAP 7-16
/PAUSE 7-16
/STACK 7-17

linker prompts 7-10
list - DEBUG parameter 8-7
list all files 2-67
List Lines Command 6-21
list selected files 2-68
listing data lines 6-25
listing directory entries 1-20,
2-67
Load Command 8-33, 8-58,
8-60
load module 7-17,7-24
loading programs 2-83
loading standard device
drivers 4-8
LPT 1 - reserved name for
printer 1-19

M
macro assembler, using fixed
disk B-1
make directory, MKDIR 2-77
/MAP linker parameter 7-16
MAP extension 7-12
.MAP 7-12
memory
high 7-15,8-5
low 7-15
memory status report 2-38
memory, loading files into 6-5
EDLIN 6-4
EDLIN prompt 6-5
messages A-I
messages, linker 7-28
MKDIR (Make Directory)
Command 2-98
MKDIR command 2-98
MKDIR command 2-98,
2-148

X-9

MODE Command 2-100,
2-149
MORE Filter
Command 2-107
MORE command 2-107
MORE Filter
command 2-107
Move Command 8-36,8-60
Move Lines Command 6-30

N
n - ED LIN parameter 6-8
NA flag clear condition 8-44
Name command 8-34,8-37,
8-60
NC flag set condition 8-45
NG flag set condition 8-45
notation, format 1-15
NUL: - reserved device
name 1-19
numbers, line 6-3,6-13
NV flag clear condition 8-45
NZ flag clear condition 8-45

o
OBJ extension 7-9
.OBJ 7-9
object files 8-3
object modules 7-9
object program files 2-139
object program 2-139
text 2-139
operating systems, more than
one 3-13
operation, suspend
system 2-23

X-tO

optional remarks, PAUSE
command 2-23
Output Command 8-39,8-61
output files
linker 7-5
OV flag set condition 8-45
overflow flag 8-45

p
Page Command 6-31
paragraph boundary 7-6
parallel printer to
Asynchronous
Communications
,Adapter 2-100
parameters
command parameters 1-16
DEBUG 8-7
DOS 1-16
dummy 2-18
EDLIN 6-7
testing with different 8-28
parameters, Linker 7-14
parity flag 8-45
partial file, edit 6-11
partition setup 3-9
partition, display data 3-22
partitioning your fixed
disk 3-13
Pascal hex patch C-l
PASKEY, see Pascal hex
patch C-l
PAS 1, update your
diskette C-l
PATH (Set Search Directory)
Command 2-108
PATH command 2-108
PAUSE 7-16

PAUSE command 2-28
PAUSE subcommand 2-145
PC register 8-41
PE flag set condition 8-45
percent sign (%) 2-18
period (.) 6-8, 6-17
Piping standard I/O 1-8, E-5
piping, what is 1-8
PL flag clear condition 8-45
plus sign
in automatic response
file 7-21
in response to linker
prompt 7-10
PO flag clear condition 8-45
portaddress - DEBUG
parameters 8-7
pound sign (#) 6-7
prepare diskettes 2-89
preparing 2-89
preparing fixed disk 3-6
preparing your fixed disk 3-2
PRINT Command 2-110,
2-149
printer 1-19, 2-96
printing graphics 2-96
PRN - reserved name for
printer 1-19
program execution, stop 8-28
Program Segment Prefix 8-6
PROMPT (Set System
Prompt) Command 2-116
PROMPT Command 2-116,
2-130
public symbols 7-25
punctuation 1-15

Q
question marks 1-15
Quit Command 8-40, 8-61
Quit Edit Command 6-27
quotation marks 8-10

R
random/sequential
applications 4-6
range - DEBUG parameter 8-9
read/write requests 4-5
recording format,
diskette 2-89
defective tracks 2-89
RECOVERCommand 2-119,
2-150
recover from error A -2
redirection of I/O devices 1-5,
E-4
Register Command 8-41, 8-61
registername - DEBUG
parameter 8-9
registernames, valid 8-41
registers, display 8-43
relative sector number 8-10
relative zero 7-24
relocatable loader 7-6
REM command 2-29, 2-146
remarks, display 2-29
remarks, PAUSE
command 2-28
remove directory,
RMDIR 2-127
REN command 2-122
RENAME (or REN)
Command 2-122
RENAME command 2-122,
2-150, 8-53

X-II

renumber lines 6-13, 6-21
replace byte contents 8-23
replace standard device 4-8
reserved device names 1-19,
2-52
responses to the system A-2
RESTORE (Fixed Disk)
Command 2-124
RESTORE command 2-124,
2-150
retry read/write
operation A -2
RMDIR (Remove Directory)
Command 2-127
RMDIR command 2-127,
2-150
root directory, what is 5-5
run file 7-11

s
saving diskette space 2-83
screen 1-19
screen print, graphics 2-96
screen, clear CLS 2-42
Search Command 8-45,8-55
search directory , PATH 2-108
sector - DEBUG
parameter 8-10
sector number, relative 8-10
sector, absolute 8-56
sectors 2-79, 8-10
segment 7-6, 7-10
SEGMENT command 7-17
segment fixups 2-84
segment registers 8-5

X-12

segment, default 8-7
segments, class 7-7
selecting fixed disk drive,
next 3-23
semicolon delimiter 1-24
SET (Set Environment)
Command 2-128
SET Command 2-128,2-150
set condition 8-42
set system prompt
command 2-133
setting up the DOS
partition 3-8
SHIFT Subcommand 2-30,
2-145
SHIFT 2-30
SI register 8-5
sign flag 8-45
single-drive system 2-79,
2-79
fragmented 2-79
slashes 1-15
SORT Filter Command 2-131
source area 8-36
source drive 1-25
source files 6-3
source 6-3
SP (Stack Pointer) 8-5
space delimiter 1-24
special characters 1-20, E-l
global filename
character 1-20
specifying a drive 1-16
specifying the path to a
file 5-7
square brackets 1-15
SS register 8-5
stack allocation
statement 7-14,7-15
Stack Pointer (SP) 8-5

standard I/O device
redirection 1-5
standard I/O, piping 1-8
starting DEBUG 8-4
starting EDLIN 6-5
starting the linker 7-18
status report 2-38
stop program execution 8-27
string - DEBUG
parameter 8-10
string - ED LIN
parameter 6-7, 6-8
subdirectory, creating a 5-10
subdirectory, what is 5-5
suinming files 2-59
symbols, global and
public 7-16
syntax error 8-15
SYS (System)
Command 2-133
SYS command 2-133,2-150
system configuration
commands 4-3
system devices 1-19
system files, transfer 2-133
system prompt 1-23
system prompt command,
set 2-130
system prompt, command is
complete 1-23

T
target drive 1-25
temporary file, VM.TMP 7-5
text files 2-139, 6-3
text 6-3
TIME Command 2-134,
2-151
time, change 2-134
Trace Command 8-49,8-58,
8-61

tracks, defective 2-89
recording format 2-89
transfer system files 2-133
TREE (Display Directory)
Command 2-136
TREE command 2-136,
2-151
tree-structured directories,
how to use 5-3, 5-4
TYPE Command 2-139,
2-151
displaying contents
of 2-139
types of DOS commands 1-13

u
Unassemble Command 8-51,
8-55
unassemble instructions 8-51
unprintable characters 8-20
UP flag clear condition 8-45
using fixed disk 3-13

v
value 8-12
variable length
instructions 8-51
VER (Version)
Command 2-144
VER Command 2-141,2-151
VERIFY Command 2-142,
2-151
VM.TMP temporary file 7-5
VOL (Volume)
Command 2-144
VOL command 2-144
VOLUME Command 2-144

X-13

w
where DOS looks for
commands and batch
files 5-11
Write Command 8-55,8-61

z
zero flag 8-45
ZR flag set condition 8-45

X-14

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Comments:

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The Personal Computer
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DOS

1502343

Your comments assist us in improving the usefulness of
our publication; they are an important part of the input
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IBM may use and distribute any of the information you
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continue to use the information you supply.
Please do not use this form for technical questions
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the IBM Personal Computer, or for requests for
additional publications; this only delays the response.
Instead, direct your inquiries or request to your
authorized IBM Personal Computer dealer.
Comments:

111111

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=IRST CLASS

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The Personal Computer
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DOS

1502343

Your comments assist us in improving the usefulness of
our publication; they are an important part of the input
used for revisions.
IBM may use and distribute any of the information you
supply in any way it believes appropriate without
incurring any obligation whatever. You may, of course,
continue to use the information you supply.
Please do not use this form for technical questions
regarding the IBM Personal Computer or programs for
the IBM Personal Computer, or for requests for
additional publications; this only delays the response.
Instead, direct your inquiries or request to your
authorized IBM Personal Computer dealer.
Comments:

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NECESSARY
IF MAILED
IN THE
UNITED STATES

BUSINESS REPLY MAIL
:IRST CLASS

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BOCA RATON, FLORIDA 33432

POSTAGE WILL BE PAID BY ADDRESSEE

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