EL 00154 00_A_DEC_STD_154_RX01_Volume_Identification_and_Data_Interchange_May77 00 A DEC STD 154 RX01 Volume Identification And Data Interchange May77

EL-00154-00_A_DEC_STD_154_RX01_Volume_Identification_and_Data_Interchange_May77 EL-00154-00_A_DEC_STD_154_RX01_Volume_Identification_and_Data_Interchange_May77

User Manual: EL-00154-00_A_DEC_STD_154_RX01_Volume_Identification_and_Data_Interchange_May77

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Page Count: 45

Page

I

Standard

for

Floppy

Disk

(RXOl)

Volume

IdentificO!tion

and

Data

Interc'";.nse

:INDEX:

~System

includes

~erminals,

CPU's

or

any

Product

which

uses

the

floppy

in

its'

configuration.

i

DEC

STD

l54

Page

2

r------

PAGE

NO.

A

A

A

A

A

10

A

11

A

" A

.l3

A

"

15

"

17

18

19

,20

121

.n

I"

24

125

I"

,27

I"

"

030

131

!32

:33

SEC.

ReV

Standard

for

Floppy

Disk

(RXOl)

Volume

J:dentification

..

nd

Data

Interchange

19

May

1977

R.

Olson,

Author

Page

3

I

This

standard

defines

the

data

recording

conventions

to

allow

RY.Ol

i~~:~!tt;~

~:Ch

i~~~i~~!~~g

:~~~:~

:~il

D~~

S~!~~~~:

~iCh

w:~il~~t

;~~

I

reading

the

volume

identification.

This

volume

1.0.

will

specify

the

origin

and

format

of

the

data

present

on

the

volume.

This

standard

appl

ies

when

reading

and

writing

diskettes

intended

for

interchange.

All

systems

wlll

oe

capable

of

handling

the

standard

universal

I

interchange

format.

For

interchange

ASCII

is

the

preferred

code

for

,volume

identification,

headers

and

data.

Bowever,

systems

are

l

permitted

to,

but

are

not

required

to,

support

EBCDIC

in

addition

to

ASCII.

EBCDIC

is

defined

in

the

Appendix.

Other

native

formats

may

exist

alld

allow

interchange.

\

l'Ih~

information

is

this

document

is

subject

to

changE!

without

notice

iand

Should

not

be

construed

as

a

commitment

by

Digital

Equipment

ICorporation.

Oigital

Equipment

Corporation

assumes

no

responsibility

Ifor

any

errors

that

may

appear

"in

this

manual.

i

I

copyright

©

1977

by

Digital

Equipment

Corporation

~D~DDmD

~:,':~;''''

"''''''

iDEC

STD

154

I

l.C

,1.1

Motivation

1.1.1

;';hy

Eave

This

Standard

~.1.2

Why Now

:1.2

GOi;lls

1.

3

Scope

11.4

History

,1.

5

Rel(!ted

Standards

~.

6

Future

Standards

Activity

l.7

Known

Incompatibilities

With

Cur:rent

Software

!3.0

u

J.2

3.2.1

J.

2.

2

3.2.3

~.

2.

4

~:

~.

5

p.4

~PPENDICES'

Page

<I

'.0

0:~~~ERSAL

INTERCHANGE"

DISK

LAYOL'T AND

INDEX

TRACK/VOLUME

"UNIVERSAL

INTERCHANGJ:;" DATA

SET

LABELS

DEC

INTERLACES

A:~D

LOGICAL/PHYSICAL

MAPPING

OVt:RALL

PHY3ICAL/LOGICAL

DISKETTE

LAYOUT

REJECTED

ALTERNATIVES

AND

BACKGROUND

INFORMATION

ON

SPECIFIC

8BCDIC

AND

ASCII

CONVERSION

TABLES

iDEe STD

154

I

i1.0

Page

5

?1.1

Why

Have

This

Standard

!This

standard

will

allow

use,s

to

IntE'rchan'le

a

specified

"Data

IFormat"

between

all

DEC

System"

as

"'ell

as

ISM

or

other

vendor

systems

i~~~~~c~~~~~rt

",~i~

i~~~~~ha~~:y,

re~~~~~1en~iS~~~~:~ge

T~~S

d~~~a,:~!.~:~

;systems.

A

dISKette

used

specifically

as

a

"system

device"

10'111

only

be

'lnterchangable

between

equivalent

DEC

systems

supporting

the

same

filii

system

and/o~

specific

data

formats,

either

directly

or

via

a

fllex

f>rogram.

'1.1.:;'

Why

StandardiZe

Now

IE"s

le·.el

standards

m:.1st

b"

establIshed

to

minImIze

retrofit

in

the

iFr"~~nt

nXOl

Hardware/Software

development

e~forts.

Lil{ewise,

futUre

:develo>,m"nt

an.i

support

costs

C<ln

be

minimlzea.

User

education

"nd

:C03t

of

data

interchangE'

can

be

reduced.

i'.2

Coals

of

:Chis

Standard

ITO

define

a

volume

and

data

recorc~ng

f",[mat

for

floppy

interch;;l"ge

On

floppy

disks

between

DEC

iEstdblish

a

basic

10,",

level

standard

WhlCh

is

the

same

a'"ld

only

format

!c:

most

systems.

Thls

baSIC

format

must

blnld

on

the

IBM

hardware

~~;e~~~~~~~e:t~~~:r~~r

e~~~~;."

t~~!n~~~~;a~~o~~e;:~~:~

s

~~~r

da~:~Dl;in~!

itnere

is

a

one

to

one

translation

between

ASCII

and

ESCDIC,

support

of

CBCDIC

15

permltted

in

addition

to

ASCII.

Provide

a

set

of

levels

for

adheren..;:e

by

small

as

well

a'J

latge

syst"ms.

an

effect!ve

procedure

hlr

reliable

volume

ldentiflcation

speclal

operator

mount

lnfo,mation.

recordIng

~nterchange

oOJectives

can

be

brok~n

:~to

steps

or

as

follows:

Every

co"forming

dlSk

wlll

writ""

a

or

terminal

wh

ICr.

IDEC

ST::> 1:>4

,

page

6

reaj

~ng

thf'

st.anddrd

d

15k

iden

ti

t

~cat

Ion.

ThE'

mlnimum

and

"universal

interchange"

format

will

hE' tl1f'

IBr.

IA!-;SI

when

approved)

standard

j'l:erehdnge

format.

1.3

Scope

Whlet:

reads

ana/o.::

""rites

a

read

ilLj/or

wrote

thE'

un,versal

1'hl"

~Lar,dard

applies

to

al~

~onformlng

DEC

products

whiCh

s'.lpport

the

flop?y

d~s.~

as

a

removable

datd

rerordlng

df'Vlce.

1.

~

,"1

story

[C'led!:'.f.· IKI:.\/

~D~eD~O

IDEC

STD

154

Fag

..

7

11.

5

Related

Standards

IIndustryStandardS:

,

The

IBM

Diskette

for

Standard

Data

Interchange-

IBM

Pub.

No.

GA-21-91S2,

date

July

1973.

AIDer

~can

National

Standards

Inst

i

tute

-

No

ex

i

st

ing

:;tanCiard

for

rpcorded

file

and

data

interc_,ange.

Standards

are

belng

proposed

by

IBM

for

physical

meala

specifications

lncluding

physical

data

record

ing

and

addressing.

See

IBM

document

numDer

GA21-919Q-~

(file

no.

GENL-19),

July

1974.

X3.

4-1968

ASCII

a

Proposed

DEC

Stanaard

167,

Volume

Topntif,cation

for

2ernovable

DiSk

Pack

DiSk

Systems"

-

Being

pxpanded

to

address

"Volume

ID

For

Director}

Devices".

The

RXOl

Volume

Identifi.;:ation

does

not

conform

because

of

compatlbllity

with

the

IBM

Intercn;;!.,,:;e

Standard,

except

for

character

code.

DEC

051

Standard

Codpd

Character

So:>t

(ASCII)

'1

6

Future

Standards

Activities

I

Areas

to

be

cOrlsidered

by

thlS

or

rela::ed

standards

(e.g.,

Data

Formats

Record

1/0,

•••

)

are:

a

DEC

interchange

for

til

.. s

on

the

RX01

and

other

rf>mov"ble

direct

access

devices.

o

Industry

standards

for

d ..

ta

interchange

on

dlskettes

ano

other

removable

dlrect

access

devlcE-s.

11.7

Known

Incompatlbilities

With

C"rrent

ScftwarC'

I;~~~~~

t

~~;~t

~~~~~~~o~o

a~~td~~~e

f~rm:~~n~~~d

Isome

software

Will

have

to

be

modified,

others

I""

"""'",'.

I

mD~DDmD'

structure

for

Conseguently

to

support

Page

a

2.0

TERMINOWGY

Floppy:

Locatlon

of

a

sector

on

the

diskette

consistlng

cf

a

track

and

sector

number

(format-nTTOSS",

where

T"'frack

and

S~Sector

Number).

A

computer

character

code

"tandardixed

by

AN5

X3.4

and

DEC

051.

An

equivalent

term

for

the

character

Space.

NOTE:

Blank.

does

not

mean

null

Ibit

pattern

cf

0

in

both

EBCDIC

and

ASCII).

I>.

series

C'f

eight

binary

dlgits

(I>.

byte

used

herein

will

8

bits

unless

otherwise

specified)

.

I>.

complete

ard

related

group

of

records

(payroll;

accounts

receivable,

etc.).

Data

on

index

track

of

diskette

that

ldentlfies

a

Entry)

data

SE't

recorded

on

that

dlSk

by

name

and

location,

and

shows

whether

or

not

the

data

set

has

beer:

v<"rified.

file

A

flexlble

Slngle

surface

cartrldge

disk

enclosed

in

a

jacket.

A

computer

character

code

used

by

IBM

and

for

Digital

in

the

".r>pendlX.

Affectionate

na"!)e

for

a

diSkette.

Preferred

DEC

term

for

Data

Set

Label.

fast

track

on

the

diskette

(track

00);

used

datOl

set

labels,

volume

1 Olbel ,

and

othp(

softwOlre

data.

Process

resulting

in

the

diskette's

orlginal

physical

forr"Olt

(see

IBM

document

GA21-9190-1).

I>.

bit

pattern

of

all

zeroes.

One

or

more

dOlta

fieldS

that

form

ol

UJll.t

of

info:-mation.

(l-12B

bytes

for

universal

interchange

records).

A

section

i,n a

track

on

the

disk

for

a

re~ord

(1024

bitS).

The

portion

of

a

movLng

storage

medium,

suer

olS

a

tape

or

aLskette,

t'1at

is

accesGible

to

G

gl\jen

reading

head

pos~tion

'26

sectors/track

on

'"

diskette).

rEC

STD

154

Pa.ge 9

Volllme:

A

single

diskette

(physica.Lly

is

77

tracks).

I *

Note:

Slzes

speclfied

can

change

with

I

hardware.

1

13

•0

DEFINITION

OF THE STANDARD

~

lthOU9h

this

standard

specifles

the

sOft~are

file/data

recording

and

rocessing

conventlons,

there

are

baSlC

hardware

and

physical

I/O

tandards

referenced

and

required

in

the

lowest

level

of

the

standard.

~

number

of

levelS

have

been

specified

to

accomodate

degreE'S

of

~~~~~~~~~g:;e

s~~l~le~~a\o~~~~!:~~E"

~~

l~~!~

l:~~ll:~~~~a~~~t~~~v~~~

I

baS1S

for

co:>nformance

to

other

levels

-

presencly

or

in

the

future.

Section

3.1

defines

the

dIskette

standard

levels.

Section

3.2

tiescribes

the

recording

components

and

processing

comrentlons

required

to

meet

the

specified

levels.

Sectlon

3.3

indicates

possible

methods

:for

"dherence

to

this

standard

and

a pro!;>Osed

levE'l

of

adherence.

pection

3.4

includes

examples

and

suggestions

for

Implementation

of

fhls

standard.

~haracter

codes

are

specified

for

each

level.

The

charact",r

codes

for

tOlume.

identification.

headers

and

datil

mus.

t

be

same.

ASCII

is

the

referred

character

code

and

all

system"

must

support

ASCII.

In

dditlon,

systems

may

also

support

EBCDIC

Ln

the

Level

I

"universal

~~I~~~ha~J:~ti

fi~:t~~~

i~~r

~:;e~n~e~~h~~g~:c~~~:~t

in

a!~~

s~~~u~~:~ac~~~

tcde.

r

hiS

standard

address.es

itself

to

the

pri.me

knuw"

FlannPd.llses

of

XUl.

Specifically

these

uses

are;

.Data

Interchange,

data

entry

I

.Systems

DeVIce,

system

and

'-!ser

flles

(using

natlve

!

.~;~~w~{:t~T:irib"tlon

media

I

All

vallles

in

this

standard

are

unless

otherwise

stated.

decimal

Quotation

marks

when

used

in

tables.

etc.

wbere

formats

are

being

discussed,

tdentilY

actual

data

content

to

be

recorded.

FEC

STD

154

Page

10

fo~ei:

~~:

~~~:el~;~ll:~~l~sf~~m!~~

~;~k:iie~th!~e1!~~~~~

IfCve:C

(level

iu.ve1

1

is

specifIed

for

wUniversal

Interchange"

Wilich

allows

DEC

to

PEC

and

DEC

to

other

vena

or

Interchange

(I.e.,

primarily

IBM).

ThIS

~evel

is

called

the

"Universal

Interchange"

level.

~

eVel

2

applies

to

DEC

natIve

fil~

tlsage

only.

ThIS

l,-vel,

gillen

Ig~er

level

~ata

fIle

standards

exist,

will

allow

direct

DEC

to

DEC

atlv"

system

fIle/data

interchange.

For

e"ample

wIth

FILES-lIon

pisk

data

structures

RSX-11M

and

lID

will

have

direct

fIle

interchange

via

the

dIskette.

(See

level

2

for

specifIc

details).

See

Figure

1

for

the

aiskette

standard

levels

and

degree

interchange.

P"ge

11

Figure

I

L2

-------------

!

"UwIVEHSAL!

!

BASIC

! INTERCHANGE:" ! !

DEC

FORMAT

Figure

I

LJ::VJ::L/DEGREE

Of

INTERCHANGE

be~ween

systems.

data

itself.

Standard

ASCII

(preferred)

or

Allows

interchange

of

dilt<l

files

and

record

formats

between

systems

(DEC

to

DEC

and

DEC

to

IBM/other).

Volume

ID,

file

headers,

<lnd

data

mllst

be

in

the

same

code

which

may

be

ASCIl

(preferred)

or

EBCDIC.

DEC

systems

wh

ich

formats.

Volume

10,

PEC STD

154

,.

Page

12

~EVEL

0:

Volume

ID

<lnd

Basic

physical

I/O

compatibility

Level

0 IT,ust

supp"rt:

IBM

diskette

hard"are

corr.patibility,

except

"SCII

rather

EBCDIC

is

the

preferred

charac':;er

code.

'I'he

software

will

read

anil

write

every

bit

(1.U24)

,

in

every

sector

(26)

On

all

tracks

(77)

Re"d

and

",'rite

sectors

on

a 1

to

1

interlace

(i.e.,

contiguously)

system

VOlume

ID

in

bytes

1-4

at

section

3.2.2

",,,thor

ized

coiles)

Read"

process

~"e

stanciard

000(7).

The

processing

of

Tn"

minirr.1.l."!l

requirement

is

via

a

utility.

t<o

i:':terpretatl.On

is

applit>d

to

che

data.

~'un

iv<=r

sal

Interchange"

Supports

all

attributes

of

Level

0

plus:

system.

reguest

Re<ld

and/or

writ"

<ldditional

Volume

ID

Inforrr.<ltion

(80

bytes

at

<lddress

00007."

pas

..

1-4

"'VOI,l"' -

Sp"cifies

Universal

Interchange

5-10

users

External

Volume

Label

("ame)

11

access

code

77-78

sector

sequence

80

::;tandard

label

versi·:m

(A

full

u<2scription

of

these

fields

H'

in

APPENDIX A

dnd

section

3.2.2)

..

All

,:,ositions

not

speclfipd

arp

rpserved

for

future

systems

use

l1\,;st

be

written

blank

and

i<JEOred

,n

read.

iDE.:

Pa"e

13

I

I

Software

support

of

the

ERMAP

(sector

05,

track

00)

!

tracks.

(SeC!

APPBNDIX

I\.

and

SectlOn

3.2.5).)

Must

support

the

file

header

information

bela",.

(S<?e

APPENDIX

E

for

deta~l)

1-4

"HDRl"

Data

Set

Header

Ind

i~ator

23-27

Block/Record

Slze

pas.

29-33

Beginnlng

of

extent

(BOI:::)

-

Starting

track/slec;tor

addLess

for

the

datE<

filE'

pas.

35-39

End

of

Extent

(EOE) -

Last

addrt>ss

J;esefved

for

this

data

flle

pas.

43

The

value

~P"

means

read

only.

Blank

allows

read

and

wrlte

pos.

44

Must

be

blank

A

blank

indicates

lntended

interchange

pOS.

45

Indicates

stngle

or

blank

indicates

sinqle

volume.

and

"L"

spe<':lfics

the

lazt

volume

1n

a

46-47

Multi

volume

seguence

identlfiers

pas.

75-79

End

of

Data

(EOD).

Indtcates

the

address

the

next

unused

sectOf.

5.

slock/R",cord

length

is

flXed

(can

be

between

1-128

bytes)

Support

DEC

and

ANSI

ASCII

code

fOf

headers

and

data.

In

a<l.ditlon

it

is

an

~mplementor

optlOn

to

provide

EBCDIC

"upport

for

headers

and

data.

Padding

of

the

rest

o[

the

record

is

done

uSlllg

the

Null

character

(0

in

both

ASClr

and

EBCDIC).

The

complE'te

layou~

of

VallJme,

Error

map,

and

Data

Set

Label

formats

is

gIven

l.n

APPEt>ODIX

A

dnd

B.

Track

00

is

the

~D~DDmD

-,

~Jn9~?'·r"tr,~fk"

which

contatnS

thlS

basic

iCEe

'TO

154

Page

14

10

and

directory

data.

IDEe

Volume

10

3.nd

Nat.ive

Formats

:

Support

all

attributes

of

Level

0

plus

=

1.

DEC

standard

11;7,

Volume

Identification

for

Removable

Disk

Pack

Disk

Syst.ems

(See

Section

1.5

of

this

standard).

2.

Accomodate

a

sector

interlace

of

2:1

(i.e.,

Read

or

Write

every

other

sector

in

a

single

block

10

transfer).

The

track

to

track

offset.

(skew)

is

Six

(6)

sectors.

Virtual

Block

7

(in

appendix

C)

is

mapped

with

the

2:1

interlace

and

b

sector

track

to

track

offset..

{See

APPENDIX C

for

the

specific

mappJ.ngJ.

3.

Virtual

block$

a::e

512

bytes

in

length

(4

physical

sectors)

Support

s<:-~lldard

DEC

ASCII

characters

in

volume

10,

file

header,

alOd

data.

EBCDIC

is

not

permitted

in

level

2.

5.

Documentation

defining

approved

-Native

DEC~

file

formats

for

use

on

the

Floppy

Disk

is

identified

in

appendix

-En

of

this

standard.

Any

"Native

nEC"

file

format

to

be

supported

on

the

floppy

dlSk

mu.st

be

registered

with

the

Standards

Committee

so

that

it

can

be

ECO'd

into

appendix

"E-.

Registration

is

initiated

by

presenting

the

proposed

native

file

format

to

the

Standuds

Administrator

and

re{,juesting

it

be

put

on

the

Standards

Committee's

agenda

for

approval

to

be

made

a

part

of

appendix

"E".

Attendance

at

the

Standards

meeting

which

will

ad'lress

this

agenda

item

may

be

required.

It

is

strongly

recommended

that

prior

to

defining

a

new

native

format,

the

ones

identL::ied

in

appendix

-E"

be

evaluated

for

use

rather

than

creating

a

new

one.

This

evaluation

should

take

place

early

in

the

product

development

phase

so

that

the

product

won't

be

impacted

in

later

stages

by

file

format

issues.

The

StandardS

Committee

is

not

likely

to

approve

a

new

native

format

until

all

existing

ones

hllve

been

evaluated

for

possible

use.

r,

2

Recording

And

Processing

Specifications

is

section

gives

a

precise

statement

of

what

happens

during

the

rl_DmD!fD::~~~"9Rn'T.,,r;lli-pg

initial

i2atlOn,

Volume

ID,

data

PEC STD

154

,

Page

15

~irectO[Y

operations,

data

"cc~ss,

error

ban~ling

a~(!

devi.ce

handling.

he

actual

recording

speciflcations

at:"

tdentifled

throughout

this

Sect10n

and

the

Append1ces.

Tbe

processIng

of

"levels"

will

be

properly

differentiated

..

nere

'lecessary.

?2.1

Physical/LogIcal

Layout

~he

physIcal

organization

is

the

standard

IBM

Interchange

Diskette

format.

APPENDIX D

shows

the

complete

layout.

~he

10gLcal

layout

varies

dspe"ding

on

pr1mary

uSe

{i.e.,

Interchange

1's

native

Systems

Device)

.

!JNlVERSAL

INTSRCRANGE:

;r'he

overall

laY0:.Jt

,",PPJ::NDIX

A.

SYSTEM/NATIVE:

:r'he

RXOI

flIe

svstem

fO,.OC"i>

I

"univer

sal

interchange"

1S

described

il'l

natn'e

files

device

"'ill

be

functionally

the

wbich

it

res1des.

A

Dt.C

"UniveLsal"

file

standard.

F.2.2

volume

InItialization

<lnd

10

~~~~:~

'~~;~~~

IZ~

~i~~e

a~~an~~~~

~if~~~~~~~

iZ~~~~~e~

orm~:~ni~r!f

~;:~iO~~

t~~~i~~~a~l~~o~nl=~~

~o~f~

a~~~:d;t;~~~t:~o~~:;t~~t

a~~~~~

i~6e

;~co~~7~~

~t

aauu,,,::cs

. .onrl

SO

on.

~vel

0 -

BaslC

Evet:y

system

must

write

a sys'I;Cem

ID

in

sector

07

of

track

00.

This

g~~~~~

ID

is

a

four

(4)

byte

coca

in

positions

1-4

of

dIskette

address

L

he

code

fat:

the

"Universal

Interchange"

1S

"VOLl".

In

ASCII

tpreferredl,

the

ii-bIt

octal

equivalents

are

12(,

117,

114,

61.

In

EBCDIC,

the

Ii

bit

octal

equivalents

are

345,

326, 323,

361.

If

the

EBCDIC

is

printed

as

ASCII

aftel

stripping

off

the

left

most

(high

~rcier)

bit,

the

result

is

"eVSq".

The

actu;:.l

character

codes

to

be

written

ace

8

hit

in

all

cases.

On

readlng

a

diskette

the

software

¢an

determine

whether

the

dlS',ette

15

us~ng

ASCII

or

EBCDIC

by

100k1ng

F:

n;~e

p;:;~n~~6

~s~i~'

i;6~o

c~:r:~;~~e~~des.

If

these

char

acter

codes

The

Gode

to

be

recorded

for

any

other

formatted

floppy

other

than

.Universal

Interchange"

must

be

r"gistered

with

th1S

standard.

In

~D~DDmD"

PEC

STD

154

I

Page

16

~u<;h

cases

ASCII

only

is

permitted.

Authoriz.,d

additional

formats

and

~Olllme

TO

codes

are:

(always

representeo/ln

ASCII)

DrAG

C300

-RT-ii

File

Structure

-FILES-II

File

Structure

-as

8

File

Structure

-Scratch

software

such

as

diagnostics

must

wr

i

te

this

code.

-Diagnostic

Software

-(:05300

SystemS

These

formats

are

official

only

after

they

have

been

authorized

~~an~~;d.

Stanclards

Comml-ttee

ancl

inclUded

in

Appendix

E

of

this

All

Volume

ID

cc>des

must

be

"PRINTABLE

ft

ASCII

cod.:.s

{i.e.,

they

must

use

characters

in

the

41-135

ectal

value

range

after

stripping

bit

8,

the

left

most

(bigh

order)

bit).

Every

system

m:lst

be

able

to

read

"nd

process

the

hasic

four

byte

Volume

ID.

The

minimum

req:lirement

is

to

print

out

lhis

rD.

It

is

required

for

systems

with

mO'lnt

or

similar

commands

to

also

indicate

their

ability

to

process

the

volume

and

.;;ontinue

automati<;:ally

if

the

t~~~me

v!~:.~~cel~:~~~fic~~~;~t

:~:~1

t~~e

t~la~~e

w~~~~~~or

~~y

~~~~~~~;

information

or

assistance.

The

Volume

ID

function

should

be

performed

l'Iutomalically

as

a

part

of

the

rnour.t

function.

figure

2

depicts

the

speciflC

values

and

level

of

support

for

Universal

Interchange.

The

purpose

ar,d

steps

for

initialization

are

fls

follows:

PiSk

Initialization

hll

diSKS

are

initialized

before

they

are

shipped

to

a

customer.

F-einitializing

should

bf'

avoided

if

possible;

it

is

required

only

if:

A

sector

sequence

other

than

the

sequence

existing

on

the

disk

LS

desired.

See

figure

2

~n

th,S

section

for

~nformation

on

how

to

specify

the

desired

sector

sequence.

~D~DDmD··

IDse

STD

154

Page

17

r----------------------------------------------

;The

purpose

of

initializ"Ition

~s,

to

reinitial

ize

when

be>

re-used

fot

new

1.

To

write

a

,,,"cord

in

c:'!ch

sector

of

each

active

tr"ck.

All

records

are

filled

with

the

blank

character

(EBCDIC)

except

in

track

00.

In

the

future,

if

DEC

provides

hardware

to

perform

HlitLlliz"tion,

Nulls

rather

than

spaces

will

be

written.

This

is

because

most

of

O'.lr

character

oriented

harcll"are

and

softwa.re

strip

out

nulls.

To

write

SO-character

Volume

ana

file

ne,Hler

records

in

track

00.

After

the

index

track

is

written,

sectors

1

blar.ks

each.

Sector

S

positions

1-5

followed

by

7S

blank

characters.

If

on"

or

~,>pccified,

the

numbECr

of

the

first

b~d

t.rack

:and

8

of

sector

S

with

a

zero

in

position

9,

th'"

,"Old

track

will

be

in

positions

11

Clnd

12

of

position

l:l*.

L

_____________

_

"

Llmited

lor

no

suppC'rt.

Support

on

read

anI:,.

(See

Figure

2

below).

Pag-"

L8

Sector

7

contains

i'1

pORit~ons

1

through

4,

thE'

vcllL"'"

ID

in

positions

5

tht"ough

10,

ttle

sector

sequence

code

is

in

positions

71

and

78,

a

"101"

in

position

80,

and

bl~nks

in

all

remaining

positions

of

the

first

80.

Sector

8

contains

the

following

do.ta

set

label:

"HDRl"

is

positions

1-4

"DATA~

in

positions

6-9

"80"

in

positions

25-27

"01001"

in

positions

2'<-13

"73026"

in

positions

35-39

~OlOOl"

in

positio"s

75-79

bl,mks

in

all

other

positions

Sectors

9

through

26

contain

deleted

File

header

recores

{See

Sec~ion

3.2.5

for

"xplanat;,~n}

with

the

following

content,

"DDRl"

in

positions

1-4

~cctcr

number

in

positions

10-11

~80"

in

positions

25-27

"74lJOl"

in

positions

29-33

"73026"

in

positions

35-39

"740[))"

in

positions

75-79

Blanks

in

all

other

positions

As

<>

final

step.

disk

i.nitializatior.

c~,ec"s

ttl"

d~sk

to

see

that

it

is

Iwr

i

tten

correctly.

PEC STD

154

I

Figure

2

(60

blanks)

, . )

, )

( )

positions

1-5

'"

ERMAI'

positions

7

and

8

'"

First

bad

track

positwns

II

and

12

'"

Second

bad

track

positions

9

and

13

contain

zeroes

(Remaining

positions

ilre

blank)

All

positions

except

1-5

will

be

blank

if

there

are

no

bad

trackS.

Reserved

(80

blanLs)

Volume

Label:

positions

1-4

'"

VOLl

in

EBCDIC

Or

ASC-=I

(for

Universal

Interchange).

or

other

authorized

4

byte

codes

(ASCl'

only)

which

uniquely

identify

the

format

of

this

diskette

(e.g.

"RTll"

for

RTll

system

disk

format)

positions

5-10

specifies

the

ID

of

this

specific

volume.

Comes

from

IBM

when

new

as

'IBMIRD".

If

reinitial-

ized

it

wi:<1

either

be

blanked

or

will

contain

a

user

specified

10.

position

11

'"

·'Accessibility".

Blank

indicates

ava;lable

for

processing.

Any

non-blank

character

means

disk

is

not

accessible.

positions

36-51

'"

owner

10.

positions

77-7~

=

"Sector

Seque"lce

"::ode" .

01

- A

one

to

on

..

interlace

(i.e.

sectors

are

processed

1.

2.

3

•.

25.26)

02

- A

two

to

one

interlace

(i.e.

Fectors

are

processed

1.

3.

5

..•

23.

25.

2,

4

.•.

14.26)

77

-

DEC

11

Interlace.

A

two

to

one

interlace

with

a 6

sector

track

to

track

offset.

Actual

layout

alld

specification

is

in

Appendix

C.

oor:;ition

60

-

"W"

The

"W"

stanos

for

.

standard

label

processing.

This

fielo

must

be

own

fcyr

Interchange

,,11

other

positior:s

in

the

Volume

Label

are

blank

Page

19

DEC

STD

154

po;ition

1-4

-

"HDRl~

or

"DDRln.

Sector

8

lS

initialize'']

to

"HDRlw

and

9-26

to

"DDRl",

"DDRI"

indicates

a

nOn-

existent

or

del".ted

data

set,

tecause

of

the

"D"

1n

2osition

1

of

the

SE'ctor.

~vel

2 -

DIgital

Native

biskettes

InitIalized

tor

"native"

system

flle

us",

n",ed

not

all

the

initializati'Jn

specifications

of

level

1.

~~~~ir~:~~;r

i~h~~

~~:tE~g;I~e~~!r~c;~;u~~d;~

specifIcation

Directory

OperatIons/Data

Set

"aoels

Page

20

bata

Set

Labels

(DSL)

must

be

processed

according

to

the the

recording

~~~~~~t~:t5~~~

s~!

L:~~~S.

level

and

APPENDIX

B.

Level

0

does

not

~vel

1 - DNIVERSAL

INTEHCHANGE

Section

3.1

(levels)

Indicates

what

DSL

functlons

are

supp<)rted.

f

ertain

features

such

as

creatlon

and

expiratIon

dates

are

not

u?ported.

The

uSer

must

b"

capa0le

of

creating,

modIfying

and

m;n::~:~:c:O:e~":;;:;,;~;o~:"~:::";e<

(;~:~"

~~:r~;;;iL

op~::~~

lelds

1n

a

Data

Set

Label

(e.g.

End

of

Data

De

updated

during

data

access

processing.

Othf'rs

are

,,[eatlon

of

a

flle

(e.g.

BOE,

and

EOE,

data

set

naJ>le,

and

so

and

block

level

Slze

have

been

trhe

intent

of

level

2

is

to

iden'cify

a

minimum

(one

15

1deal)

set

oi

DIGITAL

native

ftle

formats

for

structured

nati.ve

£lIe

system

usage

of

the

Diskette

wtth

the

broadest

degree

of

DEC

to

DEC

in':erchange.

~.2.~

Data

Recording/Access

I

l

:ve~y

system

Shall

read

and

wrlt.e

evcr}

bit

in

every

sect:!r

~

,e:::

:"h"O

,"codoco

0"'/0'

'"CO

""oo,",e

oe,omed.

:eadjWrite

support

of

fIXed

l"'ngth

records

from

1-128

bytes

wlil

be

'ro~DdmDDmDl,~,l.mum

support

113

sequential

access.

The

dat~

:ec'nds

arE'

!DEC

STD

154

Rfiy

A

Page

21

IlunblOCked

with

no

centrol

information

(exc:e>pt

possibly

format

effectors

alld

for

error

processing.

See

next

Section

-

3.2.5).

Irecording

mode

for

IBM

interchange,

VOL

10

=

"VOLl-

is

EBCDIC.

Inormal

file

access

functions

apply.

,Level

2

I

'Data

Access

is

specifled

under

each

level

in

the

DEC

native

recording

specifications

(see

Appendix

EJ

,

:3.2.5

Error

Mapping

and

Processing

[Levell

IThe

ERMAP

processing

as

defined

in

the

"Universal

Interchange"

format

limplies

both

software

and/or

hardware

support.

If

hardware

can

i1nit1al1:/:e

addresses

it

shOUld

completely

skip

a

given

bad

track

and

!reassign

addresses

to

the

next

tICack

in

sequence

toward

the

center

of

the

disk.

'.rhe

hardware

should

fill

the

track

with

bad

track

codes.

j(Present

RXOI

hardware

does

not

support

the

above).

i

The

sottware

must

set

the

addresses}

of

either

one

or

two

bad

tracks

,in

the

proper

positions

of

sector

5,

track

0

if

hardware

support

exists

for

readdressing.

!If

more

than

two

bad

tracks

exist,

the

diskette

(after

recovering

:existing

good

data)

should

be

discarded.

;All

conforming

DEC

systems

supporting

Level

1

or

a':love

of

this

standard

must

at

least

recognize

the

ERHAP

information

on

READ

OInd

indl.cate

support

or

non-support.

If

there

arE'

bad

tracks

marked

and

the

system

does

not

handle

them,

this

:TIust

be

so

indicated.

WRITE

support

need

not

be

provided

(write

support

requires

hardware

support).

!l'hc NDEI.ETED

DATA-

(DO)

mark

is

used

in

level

1

as

buth

a

deleted

iPhysical

data

indicator

and

as

logical

data

delete.

If

the

deleted

kiata

mark

is

set

then

the

first

byte

of

the

128

byte

sector

is

linterpreted

as

follows

1

Value

(ASCII

or

EBCDIC)

Meaning

the

record

has

been

log

ically

deleted.

As

an

example,

t'le

1ata

set

labels

in

sectors

9-12

of

sector

0

contain

a

~D-

in

position

1

when

the

floppy

is

initialized

and

files

do

not

yet

exist.

indicates

a

surface

defect

and

the

record

IDEC

STD

154

I

I

1

3.3

REy

Page

r

",hich

",as

to

have

been

wr

itten

here

",as

dia~

~!~~~~.

to

the

nE'xt

sequential

All

systems

must

supper

t

Level

o.

~s

a

minimum

all

conforming

systems

whwh

",ill

use

the

floppy

for

i,nterchange

must

support

this

standard

at

level:.

Level

0

applies,

~~~n

eX:~le

~

~~t~~:n~~~!o~;s~;:g~~!t~~

~~!t;~~~p~

m~~~

s~~=~~~sle::~c~

Irf1~he

f~~:~~:rd

t~it~:r

~!~~C~~J

t~~

~~~p;y

f!;~t

t~:n~;~~~t~~~r~th

t~!~

fStandard.

Specific

support

levels

and

dates

for

support

are

a

subject

for

another

document.

It

is

recom'!lended

that

all

conforming

systems

.support

levell,

at

least

wlth

ASCII

",ith

duect

I/O.

Exceptions

can

~e

made,

but

must

be

approved

by

tne

Software

Standarols

committee

to

~llow

conformaEce

via

such

mechanlsms

as

a

"file

conversion"

or

to

rllOw

deviation

from

the

standard

as

such.

,

I

!3.4

EXAMPLES,

SUGGESTIONS

~vice

handlers

should

themselves

~e

designed

to

accomodate

varying

sector

sequences.

Once

thlS

is

accomplIshed,

the

direct

support

of

'the

floppy

1n

either

"UnIversal

Interchange"

or

nNative"

formats

can

~e

handled

VIa

a

higher

level

file

support

function.

C~~l

at~~ch~~e

aPi:~d

!~:~

1

~~~a~~~~~e~~e~he

l~j41

S~~~d~~~~

g

~~~u~~~i~~le~~

E>>:amples

of

usage,

functional

descrIptions,

and

so

On

of

the

diskette.

1'\.150

useful

background

information

are

the

DIGITAL

speCIilcations

(Engineer1ng

spec.

for

th.,

RXOl,

1'11357

RX8E

OMnibus

interface,

and

r78"

'Xl!

'oibo"

iO,",Coool.

i

I

p3Qe

n

EBCDIC

and

ASCII

Conversion

Tables

Page

"

ASCII

EBCDIC

CHARACTER

CODE CODE

"L

000 000

,00

00>

001

STX

002

0:)2

'TX

0"'

COl

om

00'

067

ONO

005

055

AC'

006

056

''"

007

m

"

010 026

'T

Oll

COS

"

012

04'>

VT

013

OIl

"

01.

Ol<

CR

015

01,>

50

016 016

"

on

OL'

'"

020

DCl

021

021

DC2

022

022

DCl

023

C23

DC.

02.

07<1

NA'

025

075

026

062

046

~1[)

010

eM

03.

OJI

'00

032

077

ESC

""

047

C5

03<

m

05

035

015

R,

OJ6

016

0'

017

SPACE

0.0

100

,

0<1

In

0<2

177

DO

1'3

044

m

0<5

IS.

0.6

120

040

'",

llS

051

135

OS>

10.

051

116

OS.

153

~D~DD~

,/:i.;i.~.

,

,1.~O

PagE' 25

056

113

05'

141

060

360

061

361

062

"2

063

363

06.

'"

060,

365

066

366

061

W

070

no

on

371

072

In

073

136

07.

114

075

176

076

156

077

157

100

17.

101

301

",

302

103

303

".

'"

105

305

106

306

107

307

110

310

lU

3U

112

321

113

m

11.

023

115

m

H6

325

117

326

120

327

W

DO

122

331

123

3"

124

343

'"

344

126

345

'"

346

130

W

131

350

132

351

133 112

134

340

J

135

132

~IDmDDmlH

.

.,~

l,"

fCC

l-

i

STD

154

Page

"

140

17l

Hl

201

'"

'"

143

203

'"

'"

H5

205

He

2"

141

207

150

210

151

211

152

221

153

m

15'

m

155

'"

15£

225

157

'"

160

'"

161

23G

102

231

163

'"

16.

W

165

'"

166

"5

246

no

'"

171

250

m

251

m

300

m

152

175

320

176

W

177

007

Conversions

from

EBCDIC

to

ASCII

which

are

not

defined

should

result

in

the

ASCII

Substitute

(S[JB~032).

1.1':.,

Control

Z.

See

ANSI

x3.4

and

DEC

051

standards.

Systems

",hi<;h

use

Control

z

to

mf'an

End

of

File,

should

use

Reverse

Slant

(134)

inoltead

of

SUB.

The

above

conversions.

\Jere

obtained

From

ANSI

X3.26-1970,

Hollerith

Plmched

Card

Code.

(Tahi.=

dl

in

Appendix

B).

FEC

STD

154

UNIVERSAL

INTERCHANGE

DISK

LAYOUT AND

INDEX

TRACK/

IBM

PUBLICATION

No.

GIl.21-9182,

dated-

July

197.1

Page

27

!DEC

STD

154

Page

28

Flsk

Layout

and

Addressing

iPerhaps

the

easies~

way

to

descrl~e

the

layout

of

the

d,-skette

disk

15

!lea

camp"re

It

with

Items

famllar

to

you

-

phonogr"ph

records

and

record

players.

'First,

assume

shaped

like

a

that

you

have

placed

a

magnetic-coated

disk

that

is

r

ecerd

onto

your

record

pI

ayor.

Then,

assumE'

record

player:

Instead

of

the

tone

arm

(the

arm

holding

the

needle)

moving

freely

as

the

disk:

turns,

the

arm

remains

motionless

at

any

spot

to

which

it

has

been

moved.

You

have

dev

iEed

a

way

to

mve

the

arm

to

anyone

of

77

possible

locations

along

the

radltl5

of

thf>

disk

(that

is,

along

a

line

extending

from

the

outer

edge

of

the

disk

to

t!l~

center

of

the

dlSk)

and

have

ntlmb

..

rea

these

locations

consecutlvely

from

0,

starting

at

the

outer

edge

of

the

disk.

YOlJ

have

replaced

tne

needle

usually

held

by

the

tone

arm

wlth

a

read/Vlrite

head

Similar

to

the

One

llsed

on

tape

recorders.

The

deV1C'"

you

would

have

bUilt

would

be

slmile~

1n

principle

to

tne

device

used

to

read

and

write

data

O;lto

the

disk

in

a

dlskette.

Conslder

what

wOlJld

happen

as

the

disk

on

your

record

player

turned.

At

each

locatlon,

a

band

the

width

of

the

read/write

hc.ad

would

pass

under

the

head,

forming

a

circular

band

(track)

when

the

disk

had

made

pne

cOffi>llete

revolution.

These

tracks

would

be

concentric,

and

c,?lJld

be

identlfied

by

the

same

numbers

assigned

to

each

arm

locatlon.

trherefore,

moving

the

arm

to

location

0

would

always

place

the

lead/write

head

over

track

00,

moving

the

arm

to

posltlon

5

would

filways

III

ace

the

head

over

track

05,

and

so

On.

The

disk

wOu-Id

have

been

divlded

effectively

lnto

77

S2parate

tracks

that

"'2

could

~dentify

by

number

ar;d

to

whlch

we

could

mOV2

the

head

W:lenever

we

(:leslred.

Data

could

be

recorded

onto

or

read

from

the

track

as

it

passed

under

the

head.

iDEe

STD

154

Page

29

~---------------------------------------------

I

The

disk

slJrface

is

divided

into

26

equal

equal-size

wedges.

The

wedges

are

each

assigned

a

dIfferent

nllmDer,

from

01

t;~roLlg~

26,

and

are

called

sectors.

nLmbering

always

starts

with

"ector

nurnber

01.

r"rom I

to

128

characters

can

he

stored

in

each

sector.

Data

stored

in

f'

Sf>ctor

is

called

a

record.

To

locate

information,

the

machine

locates

the

record

address,

"-hat

is,

the

tt"ack

and

sector

number.

1I.lthotlgh

the

disk

has

71

tracks,

the

IBM

3741.

3742. 3747,

and

cannot

uSe

more

than

74

tracks

at

a

time.

Two

of

the

tracks

jY

~1I!I1~Dt.~.e",~,~~k",,~~~,.be,ing

reinlti"J.ued

by

the

3741

or

J,'age

30

110"

T~<'01"Ld.'>d'Md."f"'d

~~:c~·;.::;;,:O:~::·t~::::::C:,:~·CL

fu,

,u'''''''''"

."0'

'h.""'~~

POlge 31

178

Sv,e,

D

...

f,,'d J

\

TO

,

••

dor

w<".

'nf,,,m~',,,,,.

, ....

<I<"eloc.o'

..

:.~,~;,~e.<t:;~lkO~~.:lC;"..tr;~~:::-:r::t

t,.ld"'oc

...

d.m.d".efO.d,12S~t

..

of

do"trom

the da<.

fi.'d

ru';n~.

'

••

do".'",,,,,,

",_"

..

ll8~1

••

c'd."~"I'1~'_'"

"P"tot>on.

IA~""

(·fdoto"

ulUoI'v

M!"ol

'o.,mlli.""

...

d'1lJt.o',~'.'<~"oc'"

b".~.".""".

com

.... , .te l

Th~.dd,

..

,,,,,,'k.,,bct~,.)en!,Iy!h"Ollo

...

,g

f,e'd

:mot

,'_

,n.

t>-;t.,

bo'_en

AM2

",

A~3

."d

Ihe "

..

'.d<\"";n

....

'j

"'<!oU".'d

AM2

'~~';',~~.~::;::::.f:~~d.

"t~:'~·~:'n~.~~

::::m,

IDEC

STO

154

f

IINDEX

TRACK (TRACK

(0)

LABEL

INFORMATION

lAND

INITIAL

CONTENT

i

Page

32

lese

th~5

chart

~n

conj":lllction

with

the

reference

manual

foe

the

device

lor

devlces

lJSlng

t_h"_"_'_'""_U_"_"

__________

==::--,

~~~g~:~~~~~~~~~:::~~~::,:~,:

~''''

..

,"

;~~~2:~:.:·:~~~~~~~"~·:~:":::=·,

..

__

"""0"'

....

",,,",_ .....

_ot,

......

<

....

,"_

..

'oe"",,,'3 _0,' 'W"""

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__

, ",,0""".

"t",,-

0,"",,0"

,3,0''''"''

~""

•

•

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.....

n_"

.. ....

•

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....

r,,''' ......

'''"''

......

<"~

....

_,,.''''

.....

oo,ob

"J~o

... n.'9'"

::::',::;~~

•

.:,:::'t~::,':.:vO,::.~"

...

,,'."".r

....

J_

"".,:1,'

"'''.<0

..

""."

,,,.

.",,"

..

,,0".'

....

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••••

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.

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,·o""_.VOlIL"Ol',_tof.

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......

,

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..,.".-.,~."'''.]."'''.'',.'

....

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MV

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

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,

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.....

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__

....

m

..

".",""

....

' •

.",,11

3'

.......

'

..

·•

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....

,"""'"

....... ' ,or,.'.

Th"

,

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"

"",'''''''''''.,,''''''''''

.,'''''0.,5216

.......

'

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'0

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I--+-----=:;;~~j~:~~~~i.:~;~~~;;~~;~;;~:~~,~~:~~::":"

I"."

~""

..

_''''

....

"".'0

""'0

,".

""

..

'

,_"

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..........

"

,.~

".1.,",

'"''''''''~'

s..

.,.,.$0,

L-'

. .:.- ""

....

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1.Soo1lo1.S.':"O

.....

U.""'."dl",'

..

,C~M.""

~II~IIII~II

DHA"8.'

Page

33

"UNIVERSAL

INTERCHANGE"

IBM

PUblication

No.

Gil.21-9182,

dated-

July

1973

._",0".""",,"

R",,,,,,,,·on.'

D".

Dn,'.

,_.'m

.....

A"."

...

S"",",o,,,.,,",,,08,..

"",,,',.'d<,,",.,",,e.,,.,,,,,,",obo,

..

do"'.

::":,~;,"~

..

,,

...

b

".

'".,"w,.,,,"

co.,".'',

IINITIALIZATION

OF

ID

FIE:LDS

ON

NEW

DISKETTES

Page

34

•

..

,

...

","

..

"N_D,

......

C

..

,

.....

,~~"'.,.

~tSkettes

IB~l

with

the

identification

spctors

Sectors

are

numbered

in

:sequence

sector

01

thrOllgh

track

76,

IDEC

STD

154

(SAMPLE VIRTUAL aLOCK TO

PHYSICAL

SECTOR MAPPING)

VIRTUAL

TRACK

AND

SECTOR

NUMBER

(TTOSS)

•

I

BLOCK

f

01001

01009 01011

01017 01019

01025

01002

01008

01010

01016

01018

01024

01026

02011

02013

02019

02021

02001 02003

02010

02012

02018 02020

02026 02002

1'1' = Two

digit

track

*

(00-76)

55

= Two

digit

sector

t

(01-26)

01007

01013

01015

01021 01023

01004 01006

01012 01014

01020 01022

02007 02009

02015 02017

02023

02025

02005 02008

02014 02016

02022

02024

02004 02006

BLOCK"

512

(10)

bytes

SECTOR"

128

(10)

bytes

Page

35

IDEC

STD

154

Page

36

TRACK

OFFSET

(used

by

OS/B)

(SAMPLE

VIRTUAL

BLOCK

TO

PHYSICAL

SECTOR

MAPPING)

TRACK

AND

S£CTOK

NUMBER

(TTOSS)

*

01001

01003 01005

01009

01011 01013

01017 01019

01021

01025 01002 01004

01008 01012

,

01016

01018

01020

7

01024

01026 02001

e

02005

02007

02009

,

02013 02015

CZ017

"

02021 02023

02025

02004

02006

02008

02012

0201

~

02016

02020

02022

02024

T'!: = TwO

digit

track

*

(00-76)

BLOCK

=

5L'.

(10)

bytes

55

=

Two

digit

sector

'if

(01-20)

SECTOR"

123(10)

bytes

:DEC

STD

154

_____

---'":.:'-.-"-

________

--""'""'g,'--'-',,_

VIRTUAL

BLOCK t

DEC

3:1

INTER[J>.CE (COS

310)

(SAMPLE VIRTUAL BLOCK TO

PHY3lCAL

SECTOR MAPPING)

01001

01010

01019

010('2

01011

01020

01003

01012

01021

02004

01004

01013

01022

01005

01014

01023

01006

01015

01024

02007

01007

01016

01025

01008

,n017

vl026

01009

01018

02001

02010

COS

310

3:1

interlace

without

any

offset

appears

above.

Three

(3)

form

one

block.

The

mapP;·TIg

of

PDP-iI,

12

bit

words

to

the

8

bit

sector

bytes

is

as

follows:

A

block

is

256,

12

bit

wo~'c".

The

fust

4

bits

(left

or

L1Fpermost)

arf'

stripped

[rom

each

of

the

256

words

(lnd

packed

in

128,

Z

bit

bytes

(i.e.,

the

first

sector

out

of

three

which

will

contain

a

block).

3.

The

remaining

lower

B

bits

of

each

word

are

written

next

two

sectors

USing

the

J,l

interlace.

From

the

above

exan.ple,

block

1

is

mapped

as

follows:

Upper

4

bits

of

2~6

words

are

in

sector

01001.

bits

"n.'

packed

(IS

follows:

,

:

<-----byte

1

of

sector

(OlOOl)

from

word

1

P"ge

36

The

lower

6

bits

of

the

first

12B

words

arE>

in

sector

(01004)

.

3.

The

lower

B

bits

of

the

last

128

words

(:;>'..It

of

256)

are

in

sector

(01007).

5.

There

is

no

trac~

offset.

A

b1oc~

will

always

begin

at

sector

01

of

each

track.

~D~DDmD

~:.,

,

..

,

IGEe

STD_'_"

__________________________________

p_'9_"_3_'

__

!

*BON

-

ftBeginning

of

Native"

Digital

file

system

space

on

a

Diskette

will

norI:lally

contain

the

primary

(initial

boot

when

used

,,,,

a

"systems

device".

PDP

8/11

Systems

boot

from

sector

1,

track

1.

Page

40

'*Each

developer

must

insure

inclusion

of.

their

on-disk

structure

'form<lts

~n

this

<lppendix.

!

DEC

STD

154

Page

41

This

appendix

lists

the

approved

~DEC

NATIVE H

file

form"ts

used

on

the

Flop.,y

Disk

System.

The

major

software

system

supporting

the

native

file

format.

the

docllJIlentation

defining

the

format

and

the

necessary

ordering

information

for

the

documentation

are

defined

for

each

fOflilat.

RT-ll

Native

File

format

For

Floppy

Disks

softwar~

systen;(s)

supportjng

this

for.mat:

and

order

number

of

doo:::umentation

defining

the

native

format

RT-ll

Software

Support

Manual

(DE(:-ll--QRPGA-B-D-ONI)

OS/8

software

systems(s)

supporting

this

format,

L

OS/8

RTS/B

and

order

number

of

documentation

defining

the

native

format

1.

OS/8

Software

Support

Manual

(DEC-58-oRTMA-B-D)

RTSj8

Oser'

s

Manual

(DEC-OS--QRTMA-B-D)

fEC

STU 154.

Page

~2

~.3

FILES-ll

rajar

software

system(s)

supporting

this

format'

1.

Name

and

order

number

of

docume:ltation

defining

the

native

format

FILES-Il

On-Disk

Structure

SpecifiCOItion

(~13a-9S8-032-01)

*lnternal

DEC

DOClJment

Retrieval

Number

1.

4 COS

310

Major

software

syst",m(s)

supporL_ng

this

focmat:

Ham.:.

and

order

nUIT!ber

of

documentation

de£in1"g

the

native

focmat

cos

300/310

System

Reference

Manual

(DEC-08-oCOSA-F-D)

~.

5 XXDP

DIAGNOSTIC

SOFTWARE

Major

software

system(s)

supporting

thiE'

format:

XXDP

Diagnostics

bocumentation

defining

the

native

format

Maintenance

Documentation

(*,;u·rOCAT-l1-QzQXA-A-D)

*Diagnostic

Engineering

ID

number

F

,m

154

- !

iLEVELS

I

Other

Alternatives

and

Bac~g!ound

Information

on

Specific

L,sues

attempts

to

summarize

and

highlight

general

iss

lies

decisions

and

rejected

alternatives

in

this

standard.

covered

in

outl

ine

order

of

section

3

of

this

document.

Since

this

standard

appl

ies

to

a;

1

conforming

systems

supporting

the

!floppy,

it

was

determined

that

SOme

degree

of

levels

...-as

necessary.

!Very

small

or

speci<:l

systems

as

well

as

large

sy.stems

had

to

be

~~~~~:~d.

Ot;~~

~~:~~~;t~~~:k~~~s~!e~~~e:n~

3

~e~:~~!~

:~f:~r$

to

I)e

the

I

Combining

level

0

ana

1.

This

would

preclude

the

application

of

the

standard

to

support

areas

such

as

stand

<II

one

diagnostic

software,

software

distribution,

and

so

on.

Breaking

le...-el

1

and

2

into

two

(2)

levels.

This

would

allow

a

basic

or

minimum

support

as

well

as

full

or

more

comprehensive

support

at

these

levels.

It

was

detecmined

that

this

was

not

necessacy

and

also

difficult

to

segment.

k;IJLUI~E

10

l'ith

the

required

goal

of

a

reliable,

universal

&

singulOic

volume

10

~apability

-

with

no

operata!:

supplied

info

(i.e.,

self

identifying),

~~ec

~~~ca~l~~~d

~~~;

~~:~I;

af~ow~e

e;::~

s~~~~~o~~n~;:at

a~ec

i~~

7

I~~

track

0

as

the

single

position

to

read

and

record

volume

10.

Any

other

alternative

would

be

open

to

risk

and

compromise.

~s

a

corollary

ta

the

above,

the

committ~e

decided

not

to

use

any

!

Ortions

of

track

zero

(even

reserved

<l.reas)

for

things

other

than

pecified

in

the

IBM

interc~ange

document.

This

decision

covers

all

se

of

the

diskette

-

Including

the

"Native"

uses.

Consequently,

~

hings

like

boots

begin

in

track

1,

sector

I

and

not

track

0,

sector

.

Although

a

floppy

being

llse,j

as

a

native

systems

device

cOllld

llse

ther

portions

of

track

00

except

s-,ctO(

5

and

7,

it

seemed

!:isky

and

ith

unce,-,-ain

ramifications

to

all

future

syste,ns

adhering

tQ

this

I

~D~DDmD'

,W

'dUm

fEe

STD

154

Page

44

f;tandar-d.

The

decision

to

place

the

process~'r

boot

in

sector-

1

tr-ack

~

is

ar-bitrar-y,

yet

this

appr-oach

is

clean.

(Some

decision

had

to

be

ade.

It

could

';!ctually

vary

acress

systems

and

need

not

necessarily

e

requir-ed

portIon

of

thIS

standard).

,,"a

iS5'.1,--'

other

than

a

question

~oncerning

subsetting.

I

fHARACTER

CODE

FOR

INTERCHANGE (LEVEL

1)

i'<t

first

it

was

thought

that

EBCDIC

should

be

only

code

for

volume

~~:~;!;~c~~t~n~as

h~:~:~~ed

a~~ca~;!a ma~~r

o~n~~~c~~~f~m!~~m~~v!

l~~el

n;!,j

~~Sf!~~~r~~a~~~y

;;~~it~~~~

EB~~IC~ou~~CO~~l~~i~~

t~~~l~nd

h~~~se;~~:r:

problems

supporting

an

eventual

ANSI

floppy

standard

which

specifies

only

ASCII

if

we

had

only

EBCDIC.

Finally,

Digital

is

firmly

committed

to

the

support

of

ASCII

both

for

interchange

and

internal

processIng.

~e

issue

of

having

one,

slngle

floppy

format

is

impractical.

If

in

~act

we

wish

to

allow

multiple

uses

.of

alsKette

(e.g.,

i

r:terCh.ang-e,

sy.stems

devioe,

release.

meala),

must

accomodate

lfferent

formats.

For

Interchange

there

is

only

one

-

IBM

as

pecif~ec

in

thlS

standard.

For

System

use,

there

can

be

as

many

ormats

as

there

are

file

systems.

This

issue

is

to

ei':her

control

or

l:iisallow

use

of

the

floppy

on

certain

systems,

or

reduce

the

number

of

:systems,

or

require

that

certain

sy"tems

support

a

system

format

<.-ther

t.han

their

aim

(i.e.,

RSX

support

RT-ll).

Because

of

its

size

and

a

reasonable

base

for

a

minimum

file

sytem,

RT-ll

was

chosen

as

the

~:::e

t:ative

for:::~ats

and

use

of

the

floppy

in

many

native

modes,

rhey

/:i~~i:~e~om:~~hb;~~~

~~:~~~r~t

t~h~\~~;~~e1~ve~\I"1

0

I

FRROR

PROCESSING/MAPPING

~ince

Di~ital

nardware

does

not

presently

,,110w

physically

~

eaddreSSln9

of

the

f~oppy,

we

cannot

use

the

aWlsw

alternate

ERMAP

cherne

proposed

by

lEM

wlth

our

present

systems.

It

has

also

been

oted,

that

once

a

floppy

has

a

number

or

errOrS

per

track,

the

whole

~~~~~t

w!~;h

s~~:

~io

t~~s

h~~~t~~e

a

i~a~~e

b~~~~!~;y

7~y

i~~~:fore

do

not

):t

is

also

true

that

any

newly

I'bad

tracks".

This

issue

is

py

inslsting

on

recognition

of

?itect

support

on

initializatiun.

r

~D~DDmD

:,;''''