Micromat Tech Tool Pro 8 User’s Guide And Reference Manual Techtool En

User Manual: micromat TechTool Pro - 8 - User’s Guide and Reference Manual Free User Guide for Micromat TechTool Pro Software, Manual

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This manual, as well as the software described in it, is furnished under

license and may only be used or copied in accordance with the terms

of such license. The information in this manual is furnished for informa-

tional use only, is subject to change without notice and should not be

construed as a commitment by Micromat Inc. Micromat Inc. assumes no

responsibility or liability for any errors or inaccuracies that may appear in

this book.

Except as permitted by such license, no part of this publication may be

reproduced, stored in a retrieval system, or transmitted, in any form or by

any means, electronic, mechanical, recording, or otherwise, without the

prior written permission of Micromat Inc.

Trademarks

TechTool Pro is a registered trademark of Micromat Inc.

Apple and Macintosh are trademarks of Apple Computer Inc.

User’s Guide and

Reference Manual

www.micromat.com

Contents

User’s Guide and

Reference Manual ..................................................ii

Installation and System Requirements ............ 1.1

Introduction ....................................................................1.2

System Requirements....................................................1.2

Installing TechTool Pro...................................................1.2

What’s Installed ..............................................................1.5

Personalization and Registration ................................1.5

Contacting Technical Support .....................................1.6

About Micromat Inc. ......................................................1.6

Overview of TechTool Pro .................................. 2.1

Summary of Features ....................................................2.2

TechTool Pro Interface ...................................................2.2

TechTool Pro Manual ...................................................... 2.4

Troubleshooting Using TechTool Pro ............... 3.1

Preventive Maintenance ...............................................3.2

Troubleshooting Hints ..................................................3.2

Backup Before Repairing .................................................................3.2

Be Prepared ..........................................................................................3.3

Eliminate Easy Problems First ........................................................ 3.3

Simplify/Isolate ...................................................................................3.3

Keep Your Software Up-to-Date ................................................... 3.3

Make Use of Available Resources .................................................3.3

Document What You Do ..................................................................3.4

Recovering Data from Damaged Drives ....................................3.4

Repairing Drive Problems ............................................................... 3.4

Optimization ...................................................................3.5

Testing Components ...................................................... 3.5

Using TechTool Pro ............................................. 4.1

Launching TechTool Pro ................................................4.2

Sample Diagnostics Section .........................................4.3

Tests ................................................................... 5.1

Automatic Testing ..........................................................5.2

USB ..........................................................................................................5.2

Cache......................................................................................................5.3

Processor ...............................................................................................5.3

Network .................................................................................................5.3

FireWire .................................................................................................5.4

Manual Testing ................................................................5.5

Check Computer .............................................................5.5

Memory Test ........................................................................................ 5.6

SPD Data ...............................................................................................5.9

Surface Scan ......................................................................................5.10

SMART Check ....................................................................................5.11

Volume Structures ...........................................................................5.13

Video Memory ..................................................................................5.15

Fans Test ..............................................................................................5.16

Sensors Test........................................................................................5.17

Battery Test .........................................................................................5.17

File Structures ...................................................................................5.18

Tools .................................................................... 6.1

eDrive ..............................................................................6.2

Volume Rebuild ............................................................. 6.5

File Optimization ..........................................................6.7

TechTool Pro Reports ......................................... 8.1

TechTool Protection ........................................... 9.1

Volume Usage .................................................................9.2

Directory Backup ............................................................ 9.3

Trash History ...................................................................9.4

SMART Check ..................................................................9.5

E-mail Alerts ....................................................................9.6

TechTool Pro Menu Options ............................ 10.1

TechTool Pro ................................................................ 10.2

About TechTool Pro ........................................................................10.2

Check for Update… ........................................................................10.2

Hide TechTool Pro ...........................................................................10.2

Quit TechTool Pro ............................................................................10.2

Mode .............................................................................. 10.2

Help ................................................................................ 10.2

Commonly Asked Questions........................... 11.1

Tips, Short Cuts, and Hidden Features ........... 12.1

The Mac Cats ................................................................ 12.2

TechTool Pro Key Commands .................................... 12.2

Useful Apple Key Combinations ............................... 12.2

Basic Open Firmware Commands (PowerPC Macs) 12.2

Handy Terminal Commands (for Geeks only) ........ 12.3

Macintosh File Systems ................................... 13.1

Volume Header ............................................................ 13.3

B-Trees ........................................................................... 13.4

Catalog File ................................................................... 13.6

Extents File ................................................................... 13.7

Volume Optimization....................................................6.8

Volume Cloning .......................................................... 6.10

Duplicate Cloning ........................................................................... 6.10

File Sync Cloning .............................................................................6.11

Disk Image Cloning .........................................................................6.11

Data Recovery ............................................................. 6.12

Protection ...........................................................................................6.12

Drives ...................................................................................................6.14

Trash .....................................................................................................6.15

Wipe Data .................................................................... 6.17

Overwrite Pattern ............................................................................6.17

Overwrite Level ...............................................................................6.17

Select Item To Wipe… button .....................................................6.17

Wipe Selection… button ..............................................................6.18

Wipe Volume… button ..................................................................6.18

Wipe Free Space… button ...........................................................6.18

Volume Journaling ...................................................... 6.18

Disk Permissions .......................................................... 6.19

Local Network .............................................................. 6.20

Video ............................................................................. 6.21

Video Geometry ...............................................................................6.21

iSight ....................................................................................................6.22

Audio ............................................................................. 6.23

TechTool Protogo ............................................... 7.1

Interface ...........................................................................7.3

Devices Pane .......................................................................................7.4

Proles Pane ........................................................................................ 7.4

Prole Editor ........................................................................................ 7.6

Using a Protogo Device .................................................7.8

Allocation File .............................................................. 13.8

Attributes File .............................................................. 13.8

Startup File ................................................................... 13.9

HFS Wrapper................................................................. 13.9

Journaling ................................................................... 13.10

Glossary ............................................................ 14.1

1.1

Installation and System Requirements

1.2

Introduction

Thank you for purchasing TechTool Pro! We have worked

hard to make TechTool Pro the most powerful and easy-

to-use problem-solving utility available for the Macintosh.

With TechTool Pro you will be able to:

• Protectyourcomputeranddata.

• Createanemergencyrepairpartition.

• Diagnoseandrepairproblemswithyourdrives.

• Optimizeyourdrives.

•Cloneavolume.

• Recoverdatafromdamageddrives.

•Seewhatdevicesandservicesarerunningonyourlocal

network.

• Testcriticalcomputercomponentsandsub-systems.

• Performroutinemaintenanceonyourcomputer.

• DeterminethecauseofproblemsthatcauseyourMacin-

tosh to crash.

• Testnewequipment.

• Makesurethatyourcomputerisrunningasfastasit

should be.

Most importantly, TechTool Pro allows you to test your

computer like a professional without the need of years of

experience or a computer degree. TechTool Pro allows you

to check a variety of components in your Macintosh with

a simple click of your mouse. When TechTool Pro nds a

problem with your computer it will suggest steps you can

take to correct the situation.

Consider TechTool Pro your personal Macintosh techni-

cian—always ready to help and only a mouse click away.

System Requirements

• Intel-basedMacintosh

• OSX10.8orlater

• DVD-ROMdriveforinstallingfromdisk

• 1GBRAMorhigher

These requirements may change with future updates.

Installing TechTool Pro

TechTool Pro uses an automated installer to place the

TechTool Pro application and any ancillary les in their

proper locations.

NOTE If you suspect that your hard drive is damaged

or that there may be other computer problems, do not

install TechTool Pro until it is repaired. We recommend that

you run TechTool Pro before installation to verify that your

desired installation volume does not have any problems.

To do this, you may start up and run TechTool Pro from

another Mac or an eDrive. For instructions on running a

check of the computer see the Sample Diagnostics Section

1.3

under Using TechTool Pro later in this manual.

To install:

• Double-clickontheTechToolProInstallericon.

• Enteryouradministratorpasswordwhenprompted.

• Readtheexplanatorytextontheinstallerscreensandfol-

low the prompts.

TechTool Pro will be installed in the Applications folder on

the startup volume.

NOTE The TechTool Pro Installer contains an Uninstall

option.ToUninstallTechToolPro,clickthe“Customize”but-

ton on the third page of the Main Install screen.

1.4

Then choose “Remove TechTool Pro...

NOTENext,uncheck“InstallTechToolPro,”andcheck

“RemoveTechToolPro”

TechTool Protection

When you launch the installed TechTool Pro application,

the program checks to see if the TechTool Protection is

installed. If it is not, a dialog appears giving you the option

to install TechTool Protection. TechTool Protection includes

program functions that operate automatically in the

background, such as periodic hard drive SMART checks,

Volume Usage, Trash History, etc. These functions are con-

gured via the TechTool Protection pane that is installed in

the System Preferences. You can choose Cancel if you do

not wish to install TechTool Protection at this time.

1.5

What’s Installed

When you install TechTool Pro you install the TechTool Pro

program package. This contains the main program com-

ponents in one convenient location on your hard drive.

By default, the TechTool Pro package is installed in the Ap-

plications folder on your startup volume:

• Applications/TechToolPro

The program’s preferences are stored on a per user basis in:

• ~/Library/Preferences/com.micromat.techtoolpro.plistle

The TechTool Pro Report will be stored in:

~/Library/ApplicationSupport/TechToolPro/

TechTool Pro.reports

If you install TechTool Protection, the following les will

be installed:

• ~/Library/PreferencePanes/TechToolProtection.prefPane

Personalization and Registration

The rst time you launch TechTool Pro, you will be prompt-

ed to enter your serial number. Your serial number is your

proof of ownership of TechTool Pro. Keep it in a safe place

since you may need it when you make future updates or

upgrades. If you lose your serial number, we may be able

to provide it to you if it is registered. In addition, registra-

tion is required to receive free technical support for Tech-

Tool Pro. (This is subject to change without notication.)

You may register your serial number online. Simply direct

your browser to the Micromat web site at www.micromat.

com.

If you do not have internet access, you may call Micromat

Sales at 707-304-5993 and ask them to register for you.

1.6

Contacting Technical Support

Micromat provides technical support to its customers

by telephone or email. For a current listing of telephone

numbers and other contact information, please visit our

website at www.micromat.com. Technical support is avail-

able Monday through Friday (excluding public holidays),

from 9:00 AM to 5:00 PM PT.

If you wish to contact technical support by telephone you

will need to have your TechTool Pro serial number and ver-

sion number ready. Our automated phone attendant will

require you to enter this information before connecting

you to a technician. Please be near your computer when

you phone, since our technicians will need to ask you

questions about your system, and will attempt to guide

you through solving any problems.

Please have the following information ready for the sup-

port technician, and be sure to include it in any email you

send to Micromat.

• Abriefdescriptionofyourproblem.

• VersionnumberofyourTechToolProsoftware.

• TypeofMacintoshandconguration.(Example:InteliMac

3.06GHz,2GBRAM,500GBharddrive.)

About Micromat Inc.

Micromat Computer Systems Inc. has been developing

Macintosh diagnostic utilities since 1989. As the rst com-

pany to oer diagnostic products for Macintosh, Micromat

has pioneered many new technologies for helping Macin-

tosh users bring their computers back to life and to keep

them running their absolute best.

Technical Support

707-566-3860

help@micromat.com

Micromat, Inc

5331 Skylane Blvd.

Santa Rosa, CA 95403

http://www.micromat.com

2.1

Overview of TechTool Pro

2.2

Summary of Features

TechTool Pro is a full-featured computer diagnostic and

repair utility. It includes routines to check your computer’s

hardware, software, and peripherals. If TechTool Pro nds

problems with your computer system, it will let you know

and will provide straightforward advice on how to pro-

ceed. If the problems are of a type that may be repairable

by software, then TechTool Pro will oer you the option to

attempt repairs.

TechTool Pro can perform a number of automatic checks

and routines. These are designed to forewarn you of im-

pending problems and to increase the chances of success-

ful data recovery and repair in the case of disaster. These

automatic features are fully congurable by you.

TechTool Pro also includes a number of features that allow

you to more eectively work with your computer and

data.Theseincludedefragmentationandoptimization

to enhance drive performance, data recovery routines

to rescue data from damaged drives, and Wipe Data to

securely delete sensitive information. You may even set

up an emergency boot partition on your drive (without

reinitializingyourdrive)thatincludesTechToolPro.Then,

if problems arise, you can boot from the emergency parti-

tion and use TechTool Pro to attempt data recovery and/

or repairs.

64 - Bit

TechTool Pro is a 64 - bit application. This allows it to take

full advantage of 64-bit processor Macs, providing greater

memoryallocationsizeforRAMtesting,VolumeRebuild,

andVolumeOptimization.

TechTool Protogo Integration

TechTool Protogo is now integrated into TechTool Pro. With

TechTool Protogo, you can build diagnostic startup disks

that you can use to troubleshoot a variety of Macintosh

computers and portables. More information about using

TechTool Protogo is available in the Protogo section of this

Manual.

2.3

TechTool Pro Interface

Even though TechTool Pro is an extremely powerful pro-

gram, it is designed to be easy to use. When you launch

the program you will see the TechTool Pro application

window.

There are three main categories available within the Tech-

Tool Pro program itself–Tests, Tools, and Reports. When

you launch the program the Tests window appears. Use

the Category Selector bar in the upper left corner of the

window to change categories as desired.

At the bottom of the application window is a bar graph for

each processor core. This graph displays processor use for

each core in real time.

In addition to the three TechTool Pro categories, there is

the TechTool Protection pane in the System Preferences.

This is where you congure the automatic background

routines of TechTool Pro.

The Tests category is where you congure and perform

tests to check the functioning of your computer’s hard-

ware, check for volume corruption, etc. The Tools category

is where you perform various stand-alone functions such

as data recovery, le/volume defragmentation, eDrive

creation, etc. The Reports window displays test results and

other feedback from operations performed in the Tests

and Tools categories. The report information is displayed

in a tabular sortable format.

The Tests and Tools windows are divided into three main

areas. The top half of the window is the Stage. This is

where you view feedback about the currently running

operation. Multiple tests can be queued up and the

queue is displayed in the lower area of the stage. Tests are

performed from left to right. Hovering the cursor above a

queued item pops up a tooltip providing details about the

particular test. Tools cannot be queued since they should

not be interrupted as they perform their specic func-

tion. To the left beneath the stage is the Task Selection list.

Select the Test or Tool that you wish to use from the list.

Congurable options for that function will appear to the

right in the Conguration area. Once conguration is com-

plete, click the appropriate button in the Conguration

2.4

window to add the test to the queue or to begin using the

selected tool. Items in the test queue are automatically

executed in the order they were chosen—left to right. You

can remove a test from the queue by clicking the cancel

button to the lower right of the queued test icon. You can

cancel all queued tests, including the currently executing

test, by clicking the Stop button on the lower

right side of the stage.

As TechTool Pro performs it various tests and other func-

tions, it keeps track of what is done and what is found. This

information can be examined in the TechTool Pro Reports

window.TheReportswindowsummarizestheresultsof

all tests and is covered in detail in the Reference section of

this manual. Select the Reports category from the Cat-

egory Selector bar in the upper left side of the program

window to view the report.

NOTE Because some TechTool Pro operations need

low-level access to the computer, they require system

privileges in order to run. When this is necessary, TechTool

Pro will display a dialog requesting the password for an

administratoraccount.Forsecurityreasons,MacOSXonly

keeps system level privileges active for a certain amount

of time. Consequently, you may need to re-enter the ad-

ministrator password more than once as you use

TechTool Pro.

Online help is available for TechTool Pro through the Apple

Help Center. Simply choose TechTool Pro Help from the

Help menu while running an installed copy of TechTool

Pro. This will bring up the TechTool Pro Help screen with

indexed and searchable online documentation.

Notication Center

TechTool Pro supports Notication Center alerts. You can

congure how these alerts display in the Notications

pane in System Preferences.

TechTool Pro Manual

The TechTool Pro manual is written for the typical Macin-

tosh user. It assumes that you are familiar with the basic

operationofyourMacintoshandMacOSX.Themanual

explains the many features of TechTool Pro and how to use

the program eectively.

The rst ve sections of the manual are introductory.

They include installation instructions, an overview of

the program, and general troubleshooting information.

The following seven sections, from Tests to Menu Op-

tions, are the main reference portion of the manual. They

provide detailed explanations about each of the program’s

features. The next two sections include commonly asked

questions, tips, shortcuts, and hidden features. These are

followed by an overview of the Macintosh le system.

This section is fairly technical and may be of interest if you

want more details about the inner working of the le sys-

tem. An understanding of the le system provides a better

2.5

understanding of the types of problems that may occur

with the volume structures and also the issues that must

be addressed when repairing them. The manual ends with

a glossary, which explains the technical terms used in the

manual, and an index.

As you read through the manual you will encounter two

special icons:

Pay close attention when you see this icon. It

indicates that the information that follows is extremely

important. You should read and understand it before

proceeding. Failure to do so could lead to improper use of

the program and possible loss of data.

This icon indicates that the information to fol-

low provides clarication or supplemental information.

Although the information may not be critical, it is highly

recommended that you read it in order to use the pro-

gram most eectively.

3.1

Troubleshooting Using TechTool Pro

3.2

Preventive Maintenance

One of the most valuable functions of TechTool Pro is its

ability to assist you in nding and repairing problems with

your computer before they get out of hand. For maximum

protection, it is important that TechTool Pro is actually

installed on your system. TechTool Pro includes automatic

features that can regularly check your drive hardware and

backup volume directories. These features are congu-

rable from the TechTool Protection pane in the

System Preferences.

In addition, it is a good idea to run the TechTool Pro tests

on a regular basis (for example, monthly) to more thor-

oughly check your system. This will help ensure that your

computerisrunningatitsfullpotentialandminimize

the chance of crashes and data loss. Using TechTool Pro’s

Check Computer you can quickly and easily run a compre-

hensive set of tests to check your computer for

proper operation.

It is critical to keep backups of valuable data. A hard drive

will always fail at some point. Although TechTool Pro can

often recover your data or bring your drive back to life

when this happens, it cannot do the impossible. If the

drive has failed mechanically or electronically, then no

software can repair it. The insurance and peace of mind

provided by a backup is important. A little time spent

maintaining backups and checking your system regularly

may save you many hours of recovery and repair down

the road.

Troubleshooting Hints

Computers are complex electronic devices. Consequently,

they can be dicult to troubleshoot. Their proper opera-

tion depends on the reliable functioning of both sophisti-

cated hardware and software. TechTool Pro was designed

to simplify the process of diagnostics and repair in the

event of a computer problem. It can also help you nd and

correct small problems before they become big problems.

Be sure to backup your data regularly. Consider keeping

archival backups. This means that instead of having only

one backup you would keep several backups made on

dierent dates. That way if you should discover a le was

damaged, and was backed up damaged, then you might

be able to locate an undamaged version in a prior backup.

It is critical to keep backups since a drive may develop

a problem at any time. If the problem is an electronic

problem, a mechanical problem, or a volume structure

problem that is so serious that it can not be repaired or

the data recovered, then a valid backup would be your

only recourse.

Following are a few tips to help ensure that your computer

is up and running as soon as possible if problems do arise:

Backup Before Repairing

If you are experiencing problems, be sure your backups

are current. If possible, immediately backup any important

data that is not already saved elsewhere. You may need to

3.3

use the data recovery routines in TechTool Pro to do this if

your volume does not mount. Do this before performing

any repairs. It may be impossible to retrieve your data later

if the problems get progressively worse as the computer

is used.

Be Prepared

Set up a preventive maintenance routine so that you can

locate and address problems before they get too seri-

ous. Consider using TechTool Pro to set up an emergency

eDrive on your hard drive before problems arise. That way

you can boot and run the program from the eDrive in the

case of problems on your normal startup volume. Keep

current backups of your work. Know where to nd your

TechTool Pro serial number in case you need to call Micro-

mat Technical Support.

Eliminate Easy Problems First

Use TechTool Pro to repair the startup disk’s permissions.

Log out and then log back in as a dierent user and see if

the problems still occur. There may be a corrupted prefer-

ence in the original user’s account. Start up the computer

in Safe mode (holding down the shift key during startup).

This disables third party routines that may be causing

problems during startup. Run TechTool Pro’s Check Com-

puter while booted to the TechTool Pro eDrive to see if it

reports any problems. It’s possible one of the above items

will help pinpoint or solve the problem.

Simplify/Isolate

Eliminate as many variables as possible. If your problem

appears to be with an internal volume, then power down

your machine and disconnect all external devices. If it is

with an external drive/volume, then connect only that

drive to the computer. Startup and run TechTool Pro from

the TechTool Pro eDrive. This will eliminate the possibil-

ity of system corruption on your normal startup volume

when testing.

Keep Your Software Up-to-Date

Many computer problems are actually software problems.

The producers of most software release regular updates

to address incompatibilities and other issues that they dis-

cover. Do your best to have current versions of software,

drivers, etc. Staying current may keep problems from

developing in the rst place. Updating an older piece of

software may actually solve a nagging problem.

Make Use of Available Resources

There are many sources of assistance available to help

you solve problems. These include local Macintosh Users

Groups,specializednewsgroupsontheInternet,websites,

listservs, and technical support provided by software and

hardware vendors.

3.4

Document What You Do

As you try to solve your computer problems, keep notes

about what you do and the outcomes of these actions.

This can be a valuable reference for you later and can be

extremely helpful if you need to talk to a technical support

representative. Knowing exactly what was done and the

results (including any error messages) can make problem

solving much easier. In addition, if you have problems at

a later time, you may be able to spot a pattern that would

otherwise elude you.

Recovering Data from Damaged Drives

Files are more likely to be recoverable by TechTool Pro’s

data recovery routines if its automatic Protection features

have been enabled for your volumes. Congure these op-

tions within the TechTool Protection pane of the

System Preferences.

Repairing Drive Problems

You probably already understand how critical the proper

operation of your hard drive is for your computer. It con-

tains the data that allows the computer to boot, as well as

the programs you use and the les you’ve created. Tech-

Tool Pro includes powerful diagnostic and repair routines

to keep your drives functioning correctly.

In most cases, this manual will refer to a drive as a “vol-

ume.”Avolumeissimplyaunitofstoragethatappears

tothecomputerasone“logicaldevice.”Theterms“hard

drive”and“volume”arealmostinterchangeable.Although

a hard disk can contain more than one volume (multiple

partitions), a volume cannot contain more than one hard

drive. (This is not entirely true. Some forms of RAID disk

setups can make many drives appear as one volume).

DVDs and CDs may also appear as one or more volumes.

When you view the contents of a volume in the Finder,

you’re not typically seeing everything on the volume.

Every volume contains many invisible les and data les.

This allows the computer to access the data on that par-

ticular volume. Items such as the le catalog or directory,

the extents B-tree, and a host of other objects, dictate

how data is stored on a particular device (see the Glos-

sary section of this manual for denitions of these terms).

Theseitemscomprisethe“volumestructures”ofavolume.

In most cases, when a drive fails and then is repaired by a

utility such as TechTool Pro, it is not the physical drive itself

that is being repaired. It is the software that makes up the

volume structures. If there is a problem with the structure

of a volume, it can prevent the computer from being able

to boot or prevent you from having access to your data.

If there is an actual problem with the physical drive, like

an electrical or mechanical problem, software will not be

able to correct the problem. TechTool Pro is unique in that

it can check the mechanical and electronic aspects of a

drive, as well as repair the volume structures.

To check for disk problems, run the Surface Scan test, the

SMART check (if applicable), and the Volume Structures

test. These tests do a thorough check of the drive hard-

3.5

ware and should locate any problems within a volume’s

directories. If TechTool Pro nds problems, it will let you

know and provide advice on how to proceed. It would

be wise at this point to stop and make a backup of your

important les if necessary. If the problem was a volume

structure problem, you could attempt to repair it using the

Volume Rebuild tool in TechTool Pro. If it appears that a re-

pair is possible, TechTool Pro will provide feedback about

the changes it proposes to make. If you’re satised that

the proposed repairs appear reasonable, then go ahead

and accept them.

After a successful repair the volume will be in good shape.

If the volume structures cannot be repaired, you should

reinitializethevolumeandrestoreyourdata.

Optimization

In order to gain maximum performance from a hard drive

volume,itisagoodideatodefragment/optimizeitocca-

sionally. This can be particularly important when working

with multimedia les where maximum data throughput is

critical. If a multimedia le is fragmented, then it may not

be able to be read fast enough from the drive for smooth

playback. This can lead to dropped video frames or to

gaps in audio playback.

Optimizationrearrangesthedataonthevolumesothat

the data for each le resides sequentially on a contiguous

area of the drive and the free space is consolidated. Opti-

mizationisavailableintheToolssectionofTechToolPro.

Beforeoptimizing,alwayscheckthevolumestructuresof

the volume (and repair if necessary). The volume structure

tests are found in the Tests section of TechTool Pro. Once

the volume passes the volume structure tests it should be

safetooptimizeit.

Testing Components

For your computer to operate correctly its components

must be working properly. TechTool Pro includes a

number of tests that will exercise many of the chips and

other critical components of your system and let you

know if any problems are found. You can easily check your

computer’s memory, cache, processor, video memory, and

much more. Many of these tests are run when TechTool

Pro launches. Others, such as the Memory Test, can be

performed from within the Tests area of the program.

4.1

Using TechTool Pro

4.2

Launching TechTool Pro

TechTool Pro will be installed in the Applications folder on

your startup volume by default. Do not move the TechTool

Pro application out of the Applications folder. To launch

TechTool Pro simply double-click on the TechTool Pro pro-

gram icon in the Applications folder.

The program Installer also adds a TechTool Pro icon to the

dock. An alternative method of launching the program is

to click on the program icon on the dock.

4.3

Sample Diagnostics Section

After launching TechTool Pro you will see the TechTool Pro

Application window.

TechTool Pro does a check of a variety of system compo-

nents automatically on launch. The results of these tests

are displayed in the gauges on the stage.

To do a more thorough check of additional components,

including your computer’s hard drives, as well as any other

hard drive connected to your computer, select Check

Computer from the Tests category and then click the

Check Computer button on the right. This single mouse

click initiates a suite of tests that run automatically, one

after the other. If problems are found, the Report will pro-

vide information on how to proceed. Information about

more in-depth testing and additional features of TechTool

Pro is available in the following sections of this manual.

5.1

Tests

5.2

TechTool Pro includes options to test various hardware

components, drives, and other aspects of your computer

system. These include tests that run automatically at

program launch as well as tests that you select to run

from within the Tests category. These testing options are

covered below.

Automatic Tests

When you launch TechTool Pro, a group of ve hardware

tests run automatically. On completion, the test results are

displayed on the gauges in the stage area at the top of

the screen.

These tests can also be run and the gauges displayed after

completion of manual testing by clicking the

refresh button on the lower right side of the

stage or by pressing the return or enter key. Details of the

ve tests follow.

USB

USB stands for Universal Serial Bus. It is a medium speed

protocol for connecting devices to a computer. USB can oper-

ate at 1.5 Mbps or 12 Mbps. The USB 2.0 standard has a raw

data rate at 480 Mbps, and the latest USB 3.0 standard a rate

of 5 Gbps. USB is present on all recent Macintosh models. In

addition, USB ports may be added via PCI cards or as USB

hubs attached to existing ports. Typical USB devices include

keyboards, mice, joysticks, game pads, and other low-band-

width, low-cost devices. Unlike FireWire, USB controls periph-

eral devices in a master/slave relationship. USB oers several

benets such as low cost, expandability, auto-conguration,

hot-plugging and outstanding performance. It also provides

power to the bus, enabling many peripherals to operate

without the added need for an AC power adapter.

TechTool Pro checks the built-in USB bus in your computer

to ensure that it is functioning. If the test passes, the speed

of the USB interface is displayed in the USB gauge. If the test

failsorifnoUSBinterfaceisrecognized,thiswillbeindicated

on the gauge. TechTool Pro cannot test the functioning of the

USB ports since this would require additional hardware.

5.3

Cache

Cache is fast RAM (random-access memory) that is used to

store data for CPU operations. Cache speeds up process-

ing by storing frequently used instructions. Since the

cache is built into the CPU itself, it can be accessed at a

faster speed than memory attached to the standard sys-

tem bus. A good analogy to the cache would be a bulletin

board that holds frequently used phone numbers on Post-

It™ notes. The numbers would be available on the board

for quick reference. That way you would not need to take

the time to look them up in the telephone book (analo-

gous to main memory) every time they were needed.

TechTool Pro checks for the presence of cache and, if

found, tests it and displays its speed on the Cache gauge.

If the cache tests fail or if no cache is detected, this will be

indicated on the gauge.

Processor

Every computer contains one or more CPUs (Central

ProcessingUnits).Thesearethe“brains”ofyourcomputer.

If more than one processor is present, they may reside on

individual chips (such as in a dual processor G5), may exist

as multiple cores on one chip (such as in an Intel Core 2

Duo iMac), or both (such as in a Dual Quad Core Mac Pro).

The CPU is the main component that dictates a machine’s

overall speed of operation. A slower CPU with an ecient

instruction set may actually provide better performance

than a faster CPU with a less ecient design.

Although the CPU is the master component in a computer,

its function is easily understood. It takes data supplied by

other components, moves it, does simple logical opera-

tions or math operations, and outputs the results. The

magic lies in the vast amount of data processing it can do

in a very short amount of time. Your CPU processes mil-

lions of instructions per second. Although each individual

instruction is very simple, the fact that so many calcula-

tions are done so quickly allows your computer to perform

extremely complex tasks within a reasonable amount

of time.

TechTool Pro veries the operation of your CPU chip(s)

with both machine-level native instruction tests and more

complex system-level data operations. When the Proces-

sor tests complete, the processor speed is displayed on

the Processor gauge.

Network

AllMacOSXcapablecomputersincludeEthernetnet-

working capability. The ability to print, communicate with

other computers in your local network, and connect to

internet services is dependent on proper conguration

and operation of the networking components.

Ethernet is the most widely installed local area network

(LAN) technology. Ethernet was originally developed by

XeroxandisspeciedintheIEEE802.3standard.AnEth-

ernet LAN may be hardwired using a variety of cable types

or it may be wireless. The most common Ethernet systems

5.4

use 10Base-T cabling and provide transmissions speeds

of up to 10 Mbps. Fast Ethernet or 100Base-T provides

speeds of up to 100 Mbps, Gigabit Ethernet supports up to

1000 Mbps, and 10-Gigabit Ethernet goes all the way to 10

billion bits per second.

AirPort is Apple’s name for the IEEE 802.11 wireless net-

working standard. The original AirPort implementation re-

leased in 1999 is based on the IEEE specication 802.11b.

It transmits data at a maximum speed of 11 Mbps and

has a typical range of 100 feet. The newer AirPort Extreme

released in 2003 is based on the 802.11g specication. It

has a maximum speed of 54 Mbps and range of 50 feet at

full speed. The newest AirPort devices are based on the

802.11n protocol which increases performance even fur-

ther to a maximum of 600 Mbps. Both AirPort and AirPort

Extreme transmit on one of 11 channels in the

2.4GHzband.

The Network test performs the following functions on the

built-in network interface:

• NetworkCheck1—Thistestcheckstheavailabilityofthe

network services for the system.

• NetworkCheck2—Thistestcheckswhetheranetworkhost

name is reachable using the current network conguration.

NOTE It is necessary to have at least one other net-

work device attached (printer, router, or another comput-

er) to use these tests since it is necessary to query another

device to determine communication abilities.

When the tests complete, the speed of the network

interface is displayed on the Network gauge. For multiple

network interfaces, the fastest one is displayed. If the test

fails or if no network interface is detected, this will be

displayed as well.

Note that TechTool Pro cannot test the networking hard-

wareitself.Thisrequiresspecializedtestequipment.Ifthe

problem appears to be faulty hardware you will probably

need to contact a qualied technician.

FireWire

FireWire is a cross-platform implementation of the high-

speed serial data bus dened by IEEE Standard 1394.

FireWire was conceived by Apple and then developed

within the IEEE 1394 Working Group. It can move large

amounts of data between computers and peripheral

devices. It features simplied cabling, hot swapping, and

transfer speeds of up to 400 Mbps. The newer IEEE 1394b

specication, termed FireWire 800 by Apple, handles data

rates of 800 Mbps.

FireWire is integrated into most recent Macintosh models.

Most of these machines include FireWire ports that oper-

ate at up to 800 Mbps, although earlier models may use

the 400 Mbps interface. FireWire ports may also be added

via PCI cards or FireWire hubs attached to existing ports.

The high data transfer speed of FireWire makes it great

for use with multimedia peripherals such as digital video

cameras and other high-speed devices such as hard disk

5.5

drives and scanners.

TechTool Pro checks the built-in FireWire bus in your

computer to ensure that it is functioning. Note that the

program itself cannot check the FireWire ports to verify

that data is being sent and received properly. This would

require special loopback hardware not normally available.

If the tests pass, the speed of the FireWire interface is

displayed in the FireWire gauge. If the test fails or if no

FireWire interface is detected, this will be indicated on

the gauge.

Manual Testing

To run any of TechTool Pro’s manual tests, click the Tests

tab if necessary to display the Test Selection window.

Select a test from the Test Selection list and congure it as

desired in the Test Conguration window to the right.

Then click the Run button in the Conguration window to

add the test to the test queue. An individual test can be

stopped as it is running by pressing the Stop button

on the lower right of the test icon in the queue or

by pressing Command-period. All queued tests can be

stopped by pressing the large Stop button on the lower

right side of the stage or by pressing Command-Option-

period. As a test runs, progress information is displayed on

the stage. Upon completion of a test or group of tests, the

results are displayed in the Job Results From Last Run

window on the left side of the stage. Selecting a test from

this list displays detailed test results on the right side of

the stage. All test results are also stored in the TechTool

Pro Report. The report can be viewed by selecting the

Reports category. Details about the individual tests follow.

Check Computer

In addition to the hardware checks that are done auto-

matically at program launch, you can use Check Computer

to easily run a more intensive group of tests to check

other components of your computer, including drive and

volume tests. You might consider using Check Computer

once or twice a month as part of a program of preventive

maintenance for your computer. Even though problems

with your computer may not be apparent, they could

be developing in the background. It is best to nd and

correct them at the rst opportunity, before they become

so severe that you lose data and/or they may no longer

be correctable. All that is required to do a comprehensive

suite of tests with TechTool Pro is one click of the mouse.

Choose Check Computer from the Tests category to bring

up the Check Computer Conguration screen.

5.6

The Conguration screen displays an image of your com-

puter with the computer model and date of manufacturer

listed below (this information may not be available if the

computer’s logic board has been replaced). An icon for

each hard drive attached to the computer appears to the

right of the computer graphic. Hover the cursor over a

drive icon to reveal a tooltip displaying the drive identier,

connection type, and volumes on the drive.

Click the Check Computer button to queue up and run all

tests on the computer and all available volumes/drives.

Feedback about the tests is displayed on the stage as the

tests are run. Progress and result information are

listed there.

At the conclusion of the tests, all results are saved to the

Report. Any test failures are listed there, along with advice

on how to proceed.

The following tests are run by Check Computer.

• MemoryTest—checksthecomputer’savailableRAM.

• SurfaceScan—checksattachedavailableharddrivesfor

physical bad blocks.

• SMARTCheck—checksthebuilt-inharddrive

SMART parameters.

• VolumeStructures—checksallattachedavailableMacin-

tosh formatted volumes for directory corruption. Note

that this test cannot be performed on the current startup

volume, since it requires unmounting the volume. Boot the

computer and run the test from another location (such as

an eDrive) to test the normal startup volume.

• VideoMemory—checksthevideoRAM.

• FileStructures—checksforspecicletypecorruption.

For further details about a test, refer to the specic test’s

description later in this manual.

Memory Test

Random Access Memory (RAM) is one of the most impor-

tant components in your computer. Because almost every

operation done on a computer passes through RAM, its

5.7

accuracy is critical to the proper operation of your com-

puter. It is also one of the components most susceptible

to damage and failure. This is because RAM upgrades

are common and hence RAM is handled more than most

other components. RAM is extremely susceptible to dam-

age from static electricity and handling it can expose it

tothishazard.Also,likeanychip,RAMissusceptibleto

overheating and thermal uctuations.

Most other failures on your computer are more obvious

than a RAM failure. For example, if your hard drive begins

to malfunction, you will probably start to see read and

write errors appear via dialogs displaying messages like,

“Couldnotwritelebecauseofadiskerror.”However,

RAM errors are much less obvious since software uses

dierent areas of RAM at dierent times. RAM problems

usually manifest as unexplained and inconsistent crashes.

There is no clear error message indicating a RAM failure.

RAM is very susceptible to damage. Static, heat and even

normal air moisture can damage the RAM used to store

your Mac’s workspace. It is possible that damaged RAM

will prevent your Mac from booting. However, the most

common symptom of bad RAM is much more subtle. Usu-

ally,thesymptomwillbeaninexplicablesystemfreeze

that is dicult to reproduce consistently. Conventional

troubleshooting techniques won’t isolate the problem. In

fact, standard techniques will prove to be more frustrat-

ing since the problem appears only intermittently, leading

you to believe you’ve solved it only to discover later that

the problem still exists and manifests somewhere else.

Unlike physically damaged storage areas on your hard

drive that can be remapped by software so that they are

no longer used, faulty RAM bits cannot be mapped out

of use. While a technician with adequate equipment and

replacement components can repair a RAM module, the

cost to do this would greatly outweigh the cost to replace

the entire module.

TechTool Pro oers one of the most comprehensive Mac

OSXsoftware-basedmemorytestersavailableforMacin-

tosh. A wide variety of RAM tests allow you to check the

available memory in your Macintosh computer. TechTool

Pro uses special read/write test patterns designed to exer-

cise the RAM in such a way as to pinpoint specic types of

RAM failures. TechTool Pro performs the following tests:

• StuckAddress—Ontherstpass,thistestwritestheaddress

of each memory cell to that cell itself. On the second pass,

the address is read and veried to ensure address

space uniqueness.

• Checkerboard—Thistestmakesfourpasses.Therstwrites

a pattern (dierent for each run). The second pass read/

veries the pattern and writes the inverse of the original

pattern. The third round travels downward back through

memory as it reads/veries the inverse and then writes the

original pattern. Finally, the fourth round veries the

original pattern. This checks for adjacent bit sensitivity - that

addresses other than the one being modied are aected.

• ExtendedMarchC—Thistestusesacomplexalgorithm

consisting of six passes through memory. It moves upwards

through memory during the rst three passes, writing and

reading/verifyingeitherzeroesorones.Thenexttwopasses

5.8

movedownward,reading/writingonesandzerosagain

(alternatively). The nal pass may travel either direction,

verifying that the last write was successful. This test detects

address faults, coupling faults, stuck-at faults, stuck-open

faults, and transition faults.

• RandomValues—Thistestrstwritesaseriesofrandom

numbers into memory. Then, on the second pass, the initial

pattern is veried. Testing with randcom values can help lo-

cate intermittent problems. This test is also helpful in check-

ing for neighborhood pattern sensitivity. Over multiple runs,

it can help identify temperature sensitivity.

• SolidBits—Thistestwritesasolidbitpatternintomemory,

for example all 1’s. The initial pattern is checked and then

complemented - switched to all 0’s - and checked again. This

checks that all addresses are both readable and writeable.

Choose Memory Test in the Tests category to display the

Memory Test Conguration screen.

Click the Run Memory Test to add the test to the test

queue.

As the tests run, a graphic of the memory conguration

for your computer is displayed on the stage, including

howtheslotsarepopulatedandthetypeandsizeofany

memory installed. In particular, the following information

is shown:

• Slotidentierandwhetherornotamoduleisinstalled.

• Modulesizeatthatlocation(ifpresent).

• Typeofmoduleatthatlocation(ifpresent).

• Modulemodelatthatlocation(ifpresent).

The individual memory test that is running, amount of

memory being tested, and the progress of testing is

shown in the upper left area of the stage.

If you wish to stop the test, click the cancel button on the

memory test icon in the queue.

NOTE The Memory Test tests available RAM. For

best results be sure to quit currently running processes,

and ideally, run the test just after startup and/or from an

eDriveinordertomaximizetheamountofRAMtested

5.9

When the tests complete, the results will be displayed in

the Memory Results area on the right side of the stage

(along with a graphical representation of the results) and

in the Job Results From Last Run pane on the left.

Upon completion of testing, the test results are saved to

the Report.

SPD Data

The Memory Test includes the ability to display ancillary

information about the memory (RAM) installed in your

Mac. Clicking the SPD Data... button will display a table

with information gathered directly from the hardware it-

self. SPD, better known as Serial Presence Detect, is a stan-

dard used by memory manufacturers to store information

about a memory module. TechTool Pro can read this data,

when available, and display it in table form.

Viewing the SPD information can be useful in identify-

ing mis-matched RAM, as well as verifying that the RAM

installed in your computer matches the specications for

your particular Mac. Viewing SPD data may also help iden-

tify the problematic DIMM if the test discovers memory

errors.

NOTE Macs with soldered memory chips don’t have a

dedicated SPD chip. As a result, the information displayed

will be more limited.

5.10

Surface Scan

TechTool Pro can do a Surface Scan test of your hard drives

to check them for bad blocks. Bad blocks are areas of

media that cannot store data reliably. All hard disks have

a few bad blocks when they are manufactured. These are

“mapped-out”bythemanufactureratthefactoryorwhen

adriveisreinitializedusingthe“zeroalldata”option.Map-

ping out bad blocks stores their location in a “bad block

table.”Onceabadblockismappedout,dataisnolonger

written to that defective area of the disk. Occasionally a

good block will go bad. If this occurs in a block storing a

le, the le may be corrupted.

The Surface Scan test in TechTool Pro scans your physi-

cal drives for bad blocks and reports if any are found. In

addition, if a le resides in the area of a bad block, the

program will let you know the le name. The Surface Scan

test reads data from every block on the drive to check the

integrity of the drive surface.

Choose Surface Scan from the Tests category to display

the Surface Scan Conguration screen.

Allrecognizedharddrivesaredisplayedontheleftside

of the conguration screen. Mouse over a drive icon for

volume information. Select the hard drive or volume (par-

ticular partition on the hard drive) you wish to test from

the list and click the Run Surface Scan button to add the

test to the queue. As the test runs, the program scrolls live

data being read from the drive across the disk drive image

displayed on the center of the stage.

NOTE The Surface Scan test may take several hours

to complete on large hard drives since it must read and

check data from every block on the drive.

5.11

The pane on the left side of the stage displays information

about the drive and test progress. This includes:

• Devicedescription

• Deviceserialnumber(ifavailable)

• Numberofblocksonthedevice

• Numberofblocksprocessed

• Elapsedtime

• Estimatedtimetocompletion

If bad blocks are found, the pane on the right side of the

stage displays the block number and, if a le resides in

that area, the le name. This information will also be avail-

able in the Report once the test completes.

ATA and SATA are the most common types of hard drive.

These are typically pre-installed in new Macintosh com-

puters and are generally used in USB and FireWire en-

closures. TechTool Pro should not normally report bad

blocks for these types of drives. The drive controller in

them automatically tries to map out bad blocks as they

are encountered. It will do this unless either the bad block

is in a critical area that cannot be mapped out at the mo-

ment or the bad block table is full. If this occurs, TechTool

Pro will report a bad block and you will ultimately need to

doalowlevelreinitializationofthedrive.Whenthedrive

isreinitialized,theentireplatterisaccessiblesothatbad

blocks can be mapped out if possible no matter where

they occur.

WARNINGReinitializingadriveerasesalldataonthe

drive. If possible, be sure to backup your data

beforereinitializing.

YoucanuseApple’sDiskUtilitytoreinitializeyourdrive.

BesuretochoosetheSecurityOptionto“zerooutdata.”

Choosing this option will map out bad blocks, if possible,

duringthereinitialization.Thismaytakeseveralhours

(dependingonthesizeofyourdrive).Ifthereinitializa-

tion is successful, the drive should be ne at that point.

We suggest, however, that you do a Surface Scan a few

times in the next month or two just to be sure no new bad

blocks are developing. If they are, then the drive is prob-

ably failing and you should consider replacing it. If a low

levelreinitializationfails,thisindicatesthedriveisfaulty

and needs to be replaced.

SMART Check

SMART stands for Self-Monitoring Analysis and Reporting

Technology. This technology was developed through the

eorts of the SMART Working Group (SWG), a consortium

of major hard disk manufacturers, to increase the reliabil-

ity of hard drives. SMART routines are now incorporated

into most new hard disk drives. Although the SMART

5.12

specication was developed by the SWG, each drive

manufacturer uses their own proprietary routines in their

drives. The routines monitor important drive parameters

as a drive operates and stores the results in the drive’s

SMART registry. An examination and analysis of these

parameters can aid in the prediction of drive failure. This

could provide the warning you need to backup your data

and repair or replace a drive before it fails. It is estimated

that SMART monitoring can predict 70% of drive hardware

failures before they occur.

SMART technology monitors a drive as it is used and

looks for unusual behavior. The routines keep track of disk

performance, bad sectors, calibration, CRC (data) errors,

disk spin-up time, distance between the head and the

disk, temperature, features of the media, heads, motor and

servomechanism. For example, motor or bearing failure

can be predicted by an increase in the drive spin-up time

and the number of retries required to spin-up the drive.

Excessive use of error correction routines could indicate a

broken drive head or contamination on the head. Spotting

these types of errors early may prevent future catastrophe.

The SMART specication also includes drive self-test

routines that can be executed to verify that a drive is able

to accurately read and write data. The TechTool Pro SMART

routines execute a self-test on a drive as well as check on

the results stored its SMART registry. Problems found in

either of these areas indicate possible impending drive

failure. This advance notice might give you enough time

to back up your data before it becomes inaccessible.

Choose SMART Check from the Tests category to display

the SMART Check Conguration screen.

Select the drive you wish to test from the drive list on the

left. Click the Run SMART Check button to add the test to

the queue. As the test runs, a pane on the left side of the

stage displays the name of the device being tested, as well

as any volumes residing on the device. A pane on the right

displays a bar graph showing the results for each

SMART parameter.

The graph lists each parameter identier (if available from

the specic drive manufacturer) followed by the param-

eter number (in parentheses). A green bar indicates that

the parameter is well above the failure threshold. As it

approaches the threshold, it turns yellow. When the pa-

5.13

rameter falls below the failure threshold, it will be shown

in red. Upon completion of the test, the results are saved

to the Report.

If a drive fails the SMART test and you continue to use it,

be sure to keep good backups of the data on the drive. It is

possible the drive will fail within the near future. If the fail-

ure happens within the drive’s warranty period, you might

want to consider contacting the drive manufacturer. They

will typically replace the drive if it fails SMART.

NOTE SMART is only available for ATA or SATA drives.

SCSI drives do not support SMART. FireWire and USB drive

interfaces do not pass the SMART calls necessary to per-

form the SMART test routines even though the drive in the

housing may be an ATA drive.

Volume Structures

There are a number of invisible les, settings, and parame-

ters that the Macintosh le system uses to locate les, free

disk space, and for other maintenance and management

routines on Macintosh volumes. These are known col-

lectivelyasthe“volumestructures.”TheCatalogandDisk

Directory are part of the volume structures. Among other

things, the volume structures keep track of the folders

and folder hierarchy on a volume, what les are stored on

a volume, and where all the individual pieces that make

up those les are located. Individual les may actually be

stored in many pieces scattered about across the surface

of a disk. Damage to a volume’s critical data structures can

result in lost or damaged les and may even necessitate a

completereinitializationofthevolume(whichwill

erase it).

Volume structure damage may manifest in a number of

ways. It can appear as missing les or folders. It can show

up as le corruption, so that you receive an error when

trying to open a le or launch a program. It can lead to

problems when trying to copy a le from one location to

another or when trying to empty the trash. In the worst

caseitmaymakeavolumeunrecognizablebythesystem.

Generally, volume structure problems get worse over time.

It is best to catch them early when chances of recovery

and repair will be greatest. For this reason it is a good idea

to check the volume structures regularly (perhaps month-

ly) as part of a program of regular

preventive maintenance.

5.14

TechTool Pro can scan your volumes for problems related

to the numerous structures that are necessary for the

volumestofunctionproperly.TechToolProwillanalyze

and can often repair problems in the following attributes

of a volume:

• BootBlocks—Thebootblocksarecreatedwhenavolumeis

blessed. If they are corrupted, you may not be able to boot

the computer from the volume.

• MasterDirectoryBlock—Thisblockofdataiscreatedwhen

the volume is created and contains important data about

the rest of the volume. It is present on all HFS volumes and

is similar to the HFS+ Volume Header. Because most HFS+

volumes contain an HFS wrapper, they will contain a Master

Directory Block.

• VolumeHeader—Thisblockofdataiscreatedwhenan

HFS+ volume is created and contains important data about

the rest of the volume such as its name, number of les and

folders, and the amount of free space available on

the volume.

• AllocationFile(Bitmap)—Thisleactsasthemaindirectory.

It keeps track of the blocks that are allocated for use and the

blocks that are free.

• ExtentsFile(B-Tree)—Thislecontainstheextentdatafor

the entire volume. Extents are the separate pieces that make

up a discontiguous le.

• CatalogFile(B-Tree)—Thislekeepstrackofallthelesand

folders on the volume.

• AttributesFile—Thisletracksalloftheattributesofeachle

and folder on a volume. Some attributes include whether the

le is locked and the last time the volume was backed up.

• HFSWrapper—Theparameterswithinthislecontainthe

information used by the computer ROM to determine what

program will boot the computer. In almost every case, this

will be congured to point to the System.

NOTE For a detailed explanation of the volume struc-

tures see the Macintosh File Systems section later in the

manual.

Select Volume Structures in the Tests category to display

the Volume Structures Conguration screen.

Select the volume you wish to test and click the Run Vol-

ume Structures button to add the test to the queue.

NOTE In order to test the volume structures of a

volume, it must be unmounted. This means that you can-

not do a volume structure check of the current startup

volume. To do this, you must reboot the computer and run

TechTool Pro from another volume, such as from an eDrive.

5.15

NOTETechToolPromaybeabletorecognizeandtest

volumes that are damaged and do not mount normally on

the desktop.

As the test runs, feedback is provided on the stage.

The progress of testing and elapsed time is displayed in

the Volume Structures pane on the left side of the stage.

The particular area of the volume structures being exam-

ined is shown on the right side of the stage in the Valida-

tion Progress pane. When an individual test completes, the

indicator to the right of the test will turn green if it passed

or red if it failed. As the tests run, live data being read from

the volume is scrolled across the drive displayed in the

center of the stage.

If problems are found on a volume during testing, a failure

message appears on the stage at the completion of test-

ing and is also saved in the Reports. In the case of failure,

be sure you have important data from that volume backed

up (if possible). Then, proceed by using TechTool Pro’s

Volume Rebuild tool to attempt to repair the problem. If a

volume structure problem cannot be repaired successfully,

thenextstepwouldbetoreinitializethevolume(using

Apple’s Disk Utility) and restore the data.

Video Memory

VRAM (Video RAM) is memory that holds the image that is

displayed on your computer’s screen. Like the other criti-

cal components of your computer video circuitry, VRAM

must always be fully functional for graphics to be correctly

displayed. Damaged VRAM can cause missing bits, screen

noise,systemlockups,orfreezes.

The Video Memory tests employ the same tests that are

used in the Memory tests. For test details please refer to

the Memory Test section earlier in the manual.

Choose Video Memory in the Tests category to display the

Video Memory Conguration screen.

5.16

Click the Run Memory Test button to add the test to the

test queue. As the test runs, the computer’s screen will dis-

play strange patterns and/or colors. This is normal. When

the test completes, the results will appear on the stage

in the Job Results From Last Run and the Video Memory

Results panes.

The Video Memory test results are also saved to

the Reports.

NOTE TechTool Pro tests the video memory for the

main display. To check a second display you will need to

designate it as the main monitor before testing. This is

done via the Displays pane in the System Preferences.

Fans Test

All Macintosh models have a selection of fans that are

used to regulate the temperature of various components.

Components that typically have fan cooling include

processors and hard drives. Dierent Mac models use

assorted fan layouts, ranging from just one fan to as many

as ve.

TechTool Pro’s fan test modulates the speed of any avail-

able fans from their current speed upward and then back

tothebasespeedtoverifythatyourMaccanutilizeits

fans to increase cooling if needed.

5.17

To start the Fans Test, select the Fans Test from the Tests

Category screen and click the Run Fans Test button. A

graphic will appear in the stage for each fan and an anima-

tion will accompany a display of the current rotational

speed along with the minimum and maximum for the

appropriate fan. The test will conclude with a table listing

the results for each fan.

Sensors Test

Macs are equipped with a number of sensors that are

used to monitor temperatures, voltages, and currents of

various components on and attached to the motherboard.

The Sensors test gathers the current values reported by

the various sensors and compares them to a database of

known minimum and maximum values. If any of the sen-

sors falls outside of the current range, a failure is reported.

In the event of a failure, it is recommended to take your

MactoanauthorizedApplerepaircenter.

To start the Sensors Test, select the Sensors Test from

the Tests Category screen and click the Run Sensors Test

button. An animation will display on the Stage, and at the

conclusion of the test, a list of results will be displayed.

To get more information about a sensor category, click

the disclosure arrow next to that category. In the event

of a failure in a given category, it will automatically be

expanded to show you the individual pass and fail reports

for each sensor in that category.

Battery Test

Laptop batteries are used to provide power to laptops

when they are not plugged in. The condition of the bat-

tery determines battery’s total capacity and how long that

charge will last. The Battery test will report the condition

of the battery along with other important statistics.

When the Battery test selection is clicked, some basic bat-

tery infomation is displayed, including the current charge,

5.18

condition and capacity.

Clicking Run Battery Check displays additional battery sta-

tistics, including Capacity Life Remaining and Cycle Count

among others. If the Condition of the battery reads ‘Needs

Service’ or ‘Failing,’ the battery will need to be replaced. If a

laptop does not have a user-replaceable battery, it should

betakentoanAppleauthorizedrepaircenter.

File Structures

The File Structures test in TechTool Pro checks a variety of

le types for corruption. The test checks each individual

le to ensure it conforms to the specications for that

le type. If there is anything unusual, TechTool Pro lets

you know which les may be corrupted. There is no way

for TechTool Pro to repair a corrupt le, since there is no

way to know what the correct data in the le should have

been. If corrupt les are found, you should delete them

and then restore them from a known good source.

NOTE If a le is agged during testing, this does not

necessarily mean the le is bad. It simply means that there is

something atypical about the le based on its le type. If you are

having problems with the computer or with an application that

might be eected by that le, consider temporarily removing it

or replacing it with a new copy if possible.

TechTool Pro checks the le type specications to ensure they

are valid. It cannot check actual data held within the le itself. For

example, TechTool Pro can check to be sure that a GIF graphics

le meets all specications for that le type. However, it is not

possible to tell is some of the pixels within the graphic image are

incorrect, which could cause the image to display incorrectly.

5.19

NOTE A le’s type is determined by its extension. This

is a three or four character code appended after a period

totheendofthelename.MacOSXdoesnotnormally

display the extension in the Finder (although you can

change the Finder preferences to display this information).

If a le has the wrong extension, the File Structures test

will ag it since the le type will be mis-identied.

Choose File Structures in the Tests category to display the

File Structures Conguration screen.

The File Structures Conguration screen lists each rec-

ognizedMacintoshformattedvolumeattachedtothe

computer. Select the volume you wish to test. To the right

of the volume selection area are three check boxes. Check

the boxes to indicate the type of les you wish to check.

The choices are:

•CheckDatabases(e.g.plistandxmlles)

•CheckImageFiles(e.g.bmp,gif,jpg,pngandtiles)

•CheckTime-basemedia(e.g.MPEG,MP3,PDFles)

Once you have selected the le type(s) you wish to test,

click the Run File Structures button to add the test to the

queue. As the test runs, feedback is provided on the stage.

On the left side of the stage the File Structures pane dis-

plays information and test progress, including:

• Volume

• CurrentState

• Numberoflesprocessed

• Numberofproblemsdetected

TechTool Pro tests the following le types:

• PLIST,XML

• BMP,GIF,PNG,JPEG,TIFF

• MPEG,MP3

Additional le types may be added in the future.

The full le path name of the le currently being checked

is displayed below the drive graphic. The right side of the

stage displays any problems detected and the names of

the corresponding les. Hover the cursor over a lename

5.20

to display the full path to the le. A complete list of prob-

lem les is saved to the Report after the test completes.

Upon completion of testing, the stage displays the results

in the File Structures pane on the right.

The volume name, number of les validated, and number

of problems detected are listed in the File Structures pane.

Select a lename from the File Problems Detected list on

the right and press the Show File button bring up a Finder

window with the selected le selected.

6.1

Tools

6.2

TechTool Pro includes a number of tools that you can

select from the Tools category. These include:

• eDrive—create,remove,mount,orrestarttheeDriveparti-

tion

• VolumeRebuild—rebuildandrepairavolume’sdirectory

• FileOptimization—defragmentlesonavolume

• VolumeOptimization—consolidatefreespaceonavolume

•VolumeCloning—createacloneordiskimageofavolume

• DataRecovery—damagedvolumeorTrashdatarecovery

• WipeData—securelydeletedatafromavolume

• VolumeJournaling—enableordisablele

system journaling

• DiskPermissions—verifyorrepairdiskpermissions

•LocalNetwork—seewhatBonjourenableddevicesand

services are running on your local network.

• Video—monitorcalibrationandiSightverication

• Audio—manipulateandmonitortheaudiosignal

Select a tool from the list to display its conguration

screen on the right.

Tools cannot be queued on the dock like Tests, since they

cannot be interrupted while they perform their individual

functions. The various tools are described in detail below.

eDrive

Use TechTool Pro’s eDrive tool to create an emergency

startup partition containing TechTool Pro on one of your

hard drives. This new partition is created WITHOUT the

need to reformat the drive on which it is created. The

eDrivecontainsabasicMacOSXsystemforyourcom-

puter as well as a copy of TechTool Pro. If you ever have

trouble with your normal startup volume, you can simply

restart your computer from the eDrive. This will give you

immediate access to the tools you need for recovery and

repair. It eliminates the need for a bootable DVD or ancil-

lary hard drive for system volume repair or maintenance.

This may be particularly attractive for use on a portable

computer. With an eDrive installed, you will not need to

carry a repair DVD with you on the road.

WARNING Always remember to backup important

data prior to performing major operations such as eDrive

creationorremoval,optimizations,andvolumerebuilds.

6.3

Choose eDrive from the Tools category to display the

eDrive Conguration screen.

Use the eDrive Destination Volume pop-down menu to

select the volume on which you wish to create the eDrive.

You may choose the active system volume or an external

volume.Thevolumesizeandamountoffreespaceonthe

volume is displayed beneath the pop-down menu.

NOTE The eDrive partition takes up 15 GB on the

eDrive Destination Volume, and requires at least 20 GB

free to create the partition (this may change with future

updates). In addition, there should be at least 10% to

15% free space remaining on the eDrive volume after the

eDrive creation for optimal performance.

NOTE An eDrive cannot be created on a RAID volume

since the partitioning of a RAID is controlled by the par-

ticular RAID software.

UsetheMacOSXSourceVolumepop-downmenuto

selectthevolumecontainingtheMacOSXsystemcom-

ponentsyouwishtocopytotheeDrive.TheMacOSXver-

sion and build will be listed beneath the pop-down menu.

NOTEFileVaultmustbedisabledontheMacOSX

Source Volume prior to creating an eDrive. It can be re-

enabled once the eDrive has been created.

eDrive status information is displayed in the eld below

the two pop-down elds. If an eDrive currently exists, this

is indicated in the status information eld and the two

pop-down menus will be inactive. Only one eDrive is al-

lowed at a time.

To create an eDrive, select the eDrive Destination Volume

andtheMacOSXSourceVolumefromtheappropriate

pop-down menus. Then click the Create eDrive button.

The eDrive creation process occurs in ve steps.

• Partitioning—thedriveischeckedandtheeDrive

partition created

• Applications—includedapplicationsarecopiedtothe

eDrivefromtheMacOSXSourceVolume

• Users—theUsersfolderiscopiedtotheeDrivefromthe

MacOSXSourceVolume

• MacOSXFiles—thenecessarySystemandLibrarylesare

copiedtotheeDrivefromtheMacOSXSourceVolume

6.4

Progress is displayed on the stage as the eDrive partition is

created and les copied to it.

As les are copied to the eDrive partition, their names will

ash by below the animated stage graphics.

It typically takes between a half hour and an hour to create

an eDrive. However, if there is not enough contiguous free

space on the eDrive Destination Volume to hold the eDrive

partition, it may take longer since les will need to be moved

out of the way during the Partitioning. You can press the Stop

button on the lower right side of the stage to stop the eDrive

creation. This will result in incomplete eDrive which you can

remove using the Remove eDrive option discussed below.

Use the Remove eDrive button to remove an existing

eDrive and return the space used by the eDrive partition

back to the original volume.

Click the Restart eDrive button to restart the computer

from the eDrive. You can also restart from the eDrive

usingthestandardMacOSXmethodofchoosingthe

eDrive as the startup volume after restarting while hold-

ingdownthe“option”key.Whenthecomputerboots

from the eDrive, TechTool Pro will automatically launch.

When you quit TechTool Pro while started from the eDrive,

the Startup Disk pane appears so that you can select the

volume from which to restart.

TechTool Pro automatically unmounts the eDrive from

your desktop when your computer boots from a startup

volume containing a valid installation of TechTool Pro. This

is to protect the eDrive from possible corruption during

regular computer use. We strongly suggest that you do

not alter the contents of the eDrive for this reason. Doing

so may make it unavailable during an emergency. When

the eDrive is unmounted, it will not appear as a startup

choice in the Startup Disk pane of the System Preferences.

You can click the Mount eDrive button if you wish to

mount the eDrive volume on the desktop.

WARNING Do not use your computer for regular op-

erations while booted from the eDrive. Use it for emergen-

cy recovery and repair only. The eDrive contains a minimal

MacOSXsystem.ProgramsotherthanTechToolPromay

not function as expected and this could cause problems

and possible data loss when using other applications.

6.5

Volume Rebuild

The volume structures of a volume keep track of where ev-

ery le and folder reside on a hard drive. This information

is stored in a number of data structures, several of which

arearrangedas“trees”.Asdataiswrittentoandreadfrom

a drive, the layout of the data in these tree structures may

become lopsided. This complicates the data structures

and causes a slowdown in accessing data as the lopsided

tree branches are traversed. For further information about

the volumes structures, refer to the Volume Structures test

earlier in this manual or the Macintosh File Systems sec-

tion later in this manual.

Volume Rebuild attempts to build new volume structures

fromscratch,fullyoptimizingthedirectorydatastructures

as it does so. In addition, if the volume structures are cor-

rupted (as determined by the Volume Structures test), a

volume rebuild may be able to correctly reconstruct them,

resolving the problem.

Select Volume Rebuild in the Tools category to open the

Volume Rebuild Conguration window.

Select the volume you wish to rebuild from the volume

list.

NOTE In order to rebuild the volume structures of a

volume, it must be unmounted. This means that you can-

not do a volume structure rebuild of the current startup

volume. To do this, you must reboot the computer and run

TechTool Pro from another volume, such as from an eDrive.

WARNING Before attempting to rebuild a volume, be

sure any important data is backed up rst if possible. Use

the routines in TechTool Pro’s Data Recovery tool if you

cannot backup les normally. Although TechTool Pro will

do its best to repair a corrupted volume, this is not always

possible depending on the extent and seriousness of the

corruption. There is always the chance that an attempt at

repair may make problems worse and recovery afterwards

more problematic.

6.6

Click the Run button to start the volume rebuild. Progress

is displayed on the stage as the rebuild progresses.

If you want to stop the volume rebuild, click the Stop but-

ton on the right side of the stage. This will safely terminate

the rebuild and leave the original volume

structures untouched.

NOTE Volume Rebuild does not ocially support

non-Apple RAID volumes. Your results may vary.

If TechTool Pro can rebuild the volume structures, it will

display a Technical Comparison Data screen for

the volume.

The Technical Comparison screen provides important

technical information about both the original directories

and the newly created directories. This includes details

such as the total number of folders, les, etc. This data can

help you decide whether or not to commit to the rebuild.

6.7

Dierences between the new and old directories are high-

lighted in color. Green indicates a normal change and red

indicates an unusual and possibly problematic change.

Click the Replace button to replace the original directories

with the newly rebuilt ones. Click the Cancel button to

keep the original directories.

WARNING If there are RED changes in the Technical

Comparison, it would be prudent to press the Cancel

button and verify that important data is backed up before

proceeding with the rebuild. An incorrect rebuild usually

requiresreinitializingthevolumeandrestoringthedata.

File Optimization

FileOptimizationshouldbeusedaspartofageneraldisk

maintenance routine for your Macintosh. Although a frag-

mented drive will not cause your Macintosh to malfunc-

tion, it may keep it from performing to its full potential.

As les are written to and read from a volume, the le sys-

tem instructs the drive mechanism where to store the le

data. It can place this information anywhere there is avail-

able free space on the volume. If there is not a contiguous

free area large enough to store a le, then the le system

will fragment the le. It will save pieces onto dierent

areas of the drive. This is transparent to you. Although a

le appears as one complete logical item, in most cases

it is actually physically scattered around the disk in many

pieces. Fragmentation complicates the volume structures

and makes the drive work harder to read the les, possibly

slowingdownperformance.Fileoptimizationdefrag-

ments the individual les on a volume.

ClickFileOptimizationfromtheToolscategorytodisplay

theFileOptimizationCongurationscreen.

Selectthevolumeyouwishtoinspectoroptimizefrom

thevolumelistontheleft.ClickthePreviewOptimization

button to display the amount of le fragmentation for the

selectedvolume.Uponcompletion,thesizeandnamesof

all fragmented les are listed on the right side of the stage,

as well as the total number of fragmented les. Click on a

le name from the list to show the full path to the le or

click the Show button to open a Finder window with the

le selected in it.

6.8

ClicktheRunFileOptimizationbuttontodefragment

any fragmented les on the selected volume. Progress is

displayed on the stage during defragmentation.

NOTERunningFileOptimizationfromyourstartup

volume can only defragment inactive les.

WARNINGBeforeoptimizing,youshouldperforma

Volume Structure test to be sure there is no corruption

inthedisk’sdirectories.Optimizingacorruptedvolume

would most likely spread the corruption as le fragments

are moved around on the hard disk.

FileOptimizationisfairlytimeconsuming.Itmaytake

several hours to complete (you might want to start it at

the end of the day and let it run overnight). You can stop

the process if you wish by clicking the Stop button on the

lower right side of the stage. When you click this button,

TechTool Pro will nish defragmenting any les it is work-

ing on and gracefully stop the process.

WARNING Do not force quit TechTool Pro when it is

intheprocessofoptimizing.Anunexpectedquitduring

optimizationcouldcauselecorruption.

Tofullyoptimizeavolumebydefragmentingallindividual

les and consolidating the free space, run Volume Optimi-

zation.

Volume Optimization

VolumeOptimizationshouldbeusedaspartofageneral

disk maintenance routine for your Macintosh. Although

a fragmented drive will not cause your Macintosh to mal-

function, it may keep it from performing to its

full potential.

As les are written to a volume, they may be scattered

around on the hard drive. This fragments the free space

on the hard drive. The Macintosh le system sometimes

needs to allocate large contiguous blocks of free space for

6.9

certain operations, such as for swap space. If it cannot do

this,systemperformancemaysuer.VolumeOptimization

displays a graphical representation of the free and used

spaceandalsooptimizesthevolumebyconsolidatingthe

free space on it.

SelectVolumeOptimizationintheToolscategorytodis-

playtheVolumeOptimizationCongurationscreen.

Selectthevolumeyouwishtoinspectoroptimizefrom

thevolumelistontheleft.ClickthePreviewOptimization

button to display information about the volume and a

graph of the volume space usage on the stage.

ClicktheRunVolumeOptimizationbuttontoperforma

volumeoptimizationoftheselectedvolume.Progressis

displayed on the stage as the free space is defragmented.

The stage displays a dynamic bar graph showing the dis-

tribution of data and free space on the drive. The higher

the bar, the more data is stored in that area of the drive. As

theoptimizationprogresses,theareaofthevolumecur-

rentlybeingoptimizedwillbedisplayedinashingyellow

inthebargraph.Thegoalofvolumeoptimizationisto

move all data to the beginning of the drive and all the free

space to the end.

NOTETooptimizeavolume,itmustbeunmounted.

Thismeansthatyoucannotoptimizethecurrentstartup

volume.Tooptimizethenormalstartupvolumeyoumust

boot the computer and run the program from another

location, such as an eDrive.

WARNINGBeforeoptimizing,youshouldperforma

Volume Structure test to be sure there is no corruption

inthedisk’sdirectories.Optimizingacorruptedvolume

would most likely spread the corruption as le fragments

are moved around on the hard disk.

6.10

VolumeOptimizationisfairlytimeconsuming.Itmaytake

several hours to complete (you might want to start it at

the end of the day and let it run overnight). You can stop

the process if you wish by clicking the Stop button on the

lower right side of the stage. When you click this button,

TechTool Pro will nish relocating any les it is working on

and gracefully stop the process.

WARNING Do not force quit TechTool Pro when it is

intheprocessofoptimizing.Anunexpectedquitduring

optimizationcouldcauseseriousdirectorycorruption.

WARNING Be sure to backup prior to performing

anyVolumeOptimization.Thisisespeciallytruewhen

performinganoptimizationonnon-AppleRAIDcongura-

tions. Many non standard RAID congurations (5, 50, etc.)

have not been tested, and your results may vary.

NOTEInsomecases,theVolumeOptimizationtool

may report that the Volume Header has become frag-

mented. In this case, you can use the Volume Cloning tool

tooptimizethevolume,describedbelow.

Volume Cloning

TechTool Pro oers the ability to create either a duplicate

clone of an entire disk, or a le sync clone that copies

every le on a disk to a backup drive, and then syncs

changed les for subsequent clones. If the disk selected

for cloning is a startup volume, the clone can also be

bootable. A duplicate clone oers the possibility (but not

a guarantee) that les lost on the original volume may be

recoverable from the clone.

Disk Image cloning saves the clone to a le. This is advan-

tageous if another drive is not available. If a disk image of

a bootable volume is created, the image may be restored

to a disk using Apple’s Disk Utility (located in /Applica-

tions/Utilities). The resulting drive can also be bootable.

NOTE Volume Cloning is only available on systems

runningMacOSX10.5orlater.

Duplicate Cloning

To create a Duplicate clone, select Duplicate Cloning from

the drop-down menu. Only disks or partitions larger than

the source partition will be available as a destination for

the clone.

6.11

Checking ‘Verify destination copy’ performs a verica-

tion on the destination volume after the copy to ensure a

proper duplication from the source volume.

Checking ‘Restore destination name’ restores the destina-

tion volume to its original name. Otherwise, the name of

the source volume will be used.

WARNING Be sure to verify that the volume you are

using as the destination for a volume clone does not con-

tain any les before you erase it. All les on the destina-

tion volume will be lost.

File Sync Cloning

File Sync Cloning is another option. By choosing File

Sync Cloning, the destination volume does not need to

be erased. Subsequent clones will only copy les that are

new or have changed since the last sync.

Choosing ‘Skip newer destination les’ ignores newer

les on the destination volume. Files on the destination

volume that have changed since last sync will not be

replaced.Ifonlythelesizediers,thedestinationlewill

be replaced.

Choosing ‘Enable destination ownership’ copies owner

and group permission settings from the source volume

to the destination volume. This allows the volume to be

bootable after sync. Otherwise, the owner and group set-

tings of the current user and group will be used.

Optimizing with Cloning Tool

IftheVolumeOptimizationtoolreportsthatthedirec-

toryofavolumeistoofragmentedtooptimize,youcan

achieve the same eect using the Volume Cloning tool

and an empty partition on an available drive that is large

enough to contain all of the data on the volume to be

optimized.

Beginbycreatinganemptypartitionthatisthesamesize

or slightly smaller than the source drive using a program

such as Disk Utility. Next, set the Volume Cloning tool to

use the File Sync Clone method, with the volume to be

optimizedasthesourceandthenewpartitionasthedes-

tination.ClickClonetoVolume...Thisprocessoptimizes

the data as it is copied.

After cloning is complete, verify the clone by holding ‘op-

tion’ at startup and verify that the clone starts up the Mac

as expected. Then, start up from an eDrive to complete the

process.

After starting up from the eDrive, return to the Cloning

tool, this time selecting the Duplicate Cloning method.

6.12

Reverse the source and destination, setting the clone as

the source and your original hard drive as the destination.

Click Clone to Volume... which will restore the data to the

originaldrive,maintainingitsoptimizedstate.

Disk Image Cloning

Disk Image cloning saves the clone to a le, rather than a

disk. To create a disk image clone, choose the source, the

type of disk image. Clicking Clone to Volume... will dislpay

a dialogue box in order to choose where to save the

resulting disk image le. TechTool Pro will then copy the

contents of the target drive to a .dmg le. Double-clicking

the resulting .dmg le will mount the image, giving the

user access to the les and folders contained within.

Read/Write - Choosing this option creates a .dmg le that

mounts as a virtual disk when opened. The .dmg le will

bethesamesizeasthediskbeingcloned,andlescanbe

added to it when it is mounted.

Read/Write“sparse”diskimage-Choosingthisoption

creates a .sparseimage le. It is the same as Read/Write

optionexceptthatthesizeoftheimagelewhenun-

mounted will be close to the amount of data contained in

theimage,ratherthanthesizeofthedisk.

Read/Write“sparse”diskbundle-Choosingthisoptioncre-

atesa.sparsebundlele.Itisthesameasthe“sparse”disk

image,exceptthattheleissavedin“blocks,”soastobe

more eciently backed up by tools such as Apple’s Time

Machine.

Read-Only disk image - Choosing this option creates a

.dmg le. It is the same as the Read/Write option except

that it cannot be modied when mounted.

Data Recovery

TechTool Pro’s data recovery routines are designed to help

you recover accidentally deleted les/folders or to recover

les/folders from a corrupted volume that no longer

mounts on the desktop. You should only try to recover

personal data that is not already backed up. Don’t try to

recover application or system les, since such les typical-

ly don’t operate properly by themselves. These les should

be restored from their original source.

The options in Data Recovery work in conjunction with

6.13

the data saved in TechTool Pro’s Directory Backup les

and Trash History. Directory Backup les are backups of a

volume’s directories. They contain important le location

data, allowing TechTool Pro to easily nd les that haven’t

already been overwritten. The Trash History is a record of

the location of deleted les. This information allows Tech-

Tool Pro to recover a deleted le, again assuming it hasn’t

already been overwritten. Directory Backup and Trash His-

tory are congured via the TechTool Protection pane in the

System Preferences. We strongly suggest enabling these

features since they dramatically increase the chance of

successful data recovery. However, even if the Protection

features were not enabled prior to a problem, TechTool Pro

may still be able to recover les from a corrupted drive by

scanning the entire drive for directory data.

TechTool Pro’s data recovery routines consist of

three parts:

• Protection—recoverles/foldersbasedonpreviouslysaved

Directory Backup les

• Drives—recoverles/foldersbasedonscavenged

directory data

• Trash—recoverdeletedlesbasedontheTrashHistory

These options are covered in detail below.

Protection

Use this data recovery option to try to recover les or fold-

ers from a corrupted volume when TechTool Protection

had been congured to save Directory Backup les for

the volume.

To display the Data Recovery Protection conguration

window, choose Data Recovery from the Tools category

and then click the Protection tab.

The left side of the conguration window shows the Direc-

toryBackupslist.Eachrecognizedvolumealongwithits

associated Directory Backup les indented beneath the

volume name is listed here. The Directory Backup les are

identied by the date and time they were created. Typi-

cally, you would select the most recent available Direc-

tory Backup le since it will most accurately represent the

state of the volume contents. TechTool Protection saves a

maximum of three Directory Backup les for each volume,

deleting the oldest one when necessary to save a new

one.

NOTE If a volume is badly corrupted, it is possible

that the Directory Backup les cannot be read on it and it

will not show up in this section of Data Recovery. In that

case, try scavenging the entire hard drive in the Drives

section.

6.14

Once you have selected a volume from which to recover

data, enter the search options on the right side of the con-

guration window. Enter a search string in the “Folder or

lenametolocate”eld(thesearchisnotcasesensitive).

Then select the desired Search Criteria from the bullet list.

The options are:

• Contains—searchforle/foldernamescontainingthespeci-

ed string

• StartsWith—searchforle/foldernamesbeginningwith

the specied string

• WholeWords—searchforle/foldernamesthatexactly

match the specied string

• EndsWith—searchforle/foldernamesendingwiththe

specied string

NOTE When searching for a le using the Whole

Words option, you must include the le’s extension (if

present) as a part of the le name. This is a three or four

letter identier (which is normally hidden by the Finder)

after a period at the end of the le name. If you don’t

know the extension for the le, you might consider using

the Contains search criterion instead. Press the Locate Files

button to begin the search.

As the search is performed, progress will be displayed on

the stage. When complete, the Data Recovery window will

appear listing all les and folders that were found based

on the search criteria, as well as other data about the

found item.

Select the le or folder of interest from the list. If the item

is displayed in black, it is still available on the volume via

the Finder. Click the Show button on the upper right to

display it in a Finder window. If the item is displayed in

red, it is not available via the Finder (the item has been

deleted, the volume is not mounted, etc.). In that case,

click the Restore button on the upper right to recover the

data. A save dialog box will appear letting you choose a

destination for the recovered items folder. The item will be

located in a subfolder whose name is the date and time of

the recovery.

NOTE Directory Backup les are copies of the volume

structures at an earlier time. Consequently they are not

a completely accurate map of the location of les and

folders on a volume. If a le has been moved or overwrit-

ten since the Directory Backup le was made, this will not

be reected in the Directory Backup le. In that case the

6.15

recovered le will be corrupt. Be sure to open or check

recovered les to be sure they are valid.

Drives

Use this data recovery option to try to recover les/fold-

ers from volumes for which no Directory Backup les are

available. It will be slower since the entire hard drive (not

just an individual volume) must be scanned for directory

information.

To display the Data Recovery Drives conguration win-

dow, choose Data Recovery from the Tools category and

then click the Drives tab.

The left side of the conguration window shows the

Driveslist.Eachrecognizeddriveislistedhere.

Once you have selected a drive from which to recover

data, enter the search options on the right side of the con-

guration window. Enter a search string in the “Folder or

lenametolocate”eld(thesearchisnotcasesensitive).

Then select the desired Search Criteria from the bullet list.

The options are:

• Contains—searchforle/foldernamescontainingthespeci-

ed string

• StartsWith—searchforle/foldernamesbeginningwith

the specied string

• WholeWords—searchforle/foldernamesthatexactly

match the specied string

• EndsWith—searchforle/foldernamesendingwiththe

specied string

NOTE When searching for a le using the Whole

Words option, you must include the le’s extension (if

present) as a part of the le name. This is a three or four

letter identier (which is normally hidden by the Finder)

following a period at the end of the le name. If you don’t

know the extension for the le, you might consider using

the Contains search criterion instead. Press the Locate Files

button to begin the search.

As the search is performed, progress will be displayed on

the stage. When complete, the Data Recovery window will

appear listing all les and folders that were found based

on the search criteria, as well as other data about the

found item.

6.16

Select the le or folder of interest from the list. If the item

is displayed in black, it is still available on the volume via

the Finder. Click the Show button on the upper right to

display it in a Finder window. If the item is displayed in

red, it is not available via the Finder (the item has been de-

leted, the volume is not mounted, etc.). In that case, click

the Restore button on the upper right to copy it to a folder

on the desktop named TechTool Pro 6 Recovered Files. The

item will be located in a subfolder whose name is the date

and time of the recovery.

Trash

Use this data recovery option to recover deleted les/fold-

ers. This will only work to undelete items from volumes

for which Trash History was active prior to the deletion

and which were deleted within the time frame congured

to record deleted les. . Trash History is congured in the

TechTool Protection pane of System Preferences. You must

run the installed copy of TechTool Pro when un-deleting

les, since the Trash History is maintained by the current

startup system. This option will not be available when

booted to another disk.

NOTE If the Finder is set to Empty Trash securely

(set via the Finder Preferences under the Finder menu), de-

leted les cannot be recovered since they are immediately

overwritten when the Trash is emptied.

To display the Data Recovery Trash conguration window,

choose Data Recovery from the Tools category and then

click the Trash tab.

Click the Show Trash History button to display the Trash

History window.

6.17

All items that were moved to the Trash within the time

frame congured for Trash History will be listed. If the item

is displayed in black, it is still available via the Finder on

the volume. Click the Show button on the upper right to

display it in a Finder window. If the item is displayed in

red, it is no longer available via the Finder (the item has

been deleted). In that case, click the Restore button on the

upper right to copy it to a folder on the desktop named

TechTool Pro Recovered Files. The item will be located in a

subfolder whose name is the date and time of the recov-

ery.

NOTE Be sure to open or check a recovered le to

verify that it is valid. Trash History keeps a record of the

location of les deleted from a volume. A le that has

been deleted from the Trash can be overwritten by the

le system at any time. If this happens, the le data is

unrecoverable by any standard means. When TechTool Pro

recovers such a le, it will most likely be unusable.

NOTE Trash History displays the deleted les for the

current user. If you want to recover les for a dierent user,

you must rst log into that user’s account and run Tech-

Tool Pro from there.

Wipe Data

When a le is saved to a disk an entry is made for the le in

the disk’s directory. This directory entry records where the

pieces of the actual le are stored on the disk. When a le

is deleted from the disk, only its directory entry is deleted.

The le data itself is still left on the drive and the locations

occupied by the data are made available to be used to

store other information. Until the data is actually overwrit-

ten by new information it is possible for the data to be

recovered using a data recovery tool such as TechTool Pro.

There are times when one needs to permanently delete

a le for security reasons. To permanently delete the data

from the drive it must be completely overwritten. This is

the purpose of Wipe Data. TechTool Pro oers a variety of

methods to securely overwrite the data.

Select Wipe Data from the Tools category to display the

6.18

Wipe Data conguration screen.

The following functions and controls are available from

the Wipe Data screen:

Overwrite Pattern

You may choose to overwrite selected data multiple times

with the following patterns:

• Binary0000–Overwritesthelewithallzeros.

• Binary1010–Overwritesthelewithalternatingones

andzeros.

• Binary1111–Overwritesthelewithallones.

• RandomASCIICharacters–Overwritesthelewithpseudo-

randompatternofzerosandones.Thiscanbehelpfulwhen

trying to hide the fact that a le has been wiped.

Overwrite Level

Select the number of times the selection will be overwrit-

ten. The higher the number, the more secure the overwrite

(and the longer the overwrite will take). Although over-

writing the data once is normally sucient to permanent-

ly erase the data, some government agencies specify that

data must be overwritten a specic number of times to be

considered securely deleted. The overwrite choices are:

• 1-PassOverwrite

• 3-PassOverwrite

• 7-PassOverwrite

• 35-PassOverwrite(referredtoastheGutmannmethod)

Select Item To Wipe… button

Click this button to select the item you wish to wipe. You

can choose a le, folder, or entire volume. If you choose a

volume, you can wipe either the entire volume or only the

volume’s unused free space. When you select an item its

full path name will appear in the eld below the buttons.

This allows you to verify what item will be wiped before

actually committing to the wipe.

Wipe Selection… button

Click this button to overwrite the selected le or folder

the specied number of times with the selected pattern.

Progress is displayed on the stage as the overwrite occurs.

Wipe Volume… button

Click this button to completely overwrite the entire volume’s

contents the specied number of times with the selected

pattern. Note that ALL data on the volume will be lost. Prog-

ress is displayed on the stage as the overwrite occurs.

6.19

Wipe Free Space… button

Click this button to overwrite the free unused space on

the selected volume the specied number of times with

the selected pattern. Progress is displayed on the stage as

the overwrite occurs.

WARNING Once the data is overwritten by TechTool

Pro’s Wipe Data routines there is no possibility of recover-

ing the data. Conrm that you have made the correct se-

lection by checking in the information eld at the bottom

of the Wipe Data Conguration screen before committing

to the wipe.

Volume Journaling

Journaling is a feature of the HFS+ le system that provides

protection against volume corruption and data loss. It is

supportedbyMacOSX10.2.2andabove.Whenjournal-

ing is enabled for a volume, the le system logs read/write

transactions as they occur. If the computer should unex-

pectedly quit, then the le system will have access to a re-

cordofincompletetransactionsinits“journal”onthedrive

and can quickly return the le system to a consistent state.

This protects against volume structure problems and the

need to test for or repair them after an improper shutdown.

Journaling adds a small amount of extra overhead to le

reads and writes. In most cases the performance degrada-

tion will not be noticeable. However, for les requiring

high transfer speeds, such as large video, graphics, or

audio les, the reliability provided by journaling may not

justify the performance slowdown when accessing the

data. For more a more technical explanation of volume

journaling, see the Macintosh File Systems section later in

the manual.

The Volume Journaling tool in TechTool Pro allows you to

turn journaling on or o for your HFS+ volumes. Choose

Volume Journaling in the Tools category to display the

Volume Journaling conguration screen.

Each available writable HFS+ volume will be listed in the

conguration screen. When you select a volume from the

list, the appropriate button on the lower right side of the

screen will activate so that you can toggle the state of

journaling for that volume.

6.20

Disk Permissions

TheMacintoshoperatingsystemisbasedontheUNIX

operatingsystem.LikeUNIX,itusespermissionsinthele

system. Every le and folder has a set of permissions as-

sociated with it that determine what users are allowed to

read from, write to, or execute it. Permissions may become

corrupt for one reason or another. Incorrect permissions

can cause a wide variety of problems. They can make les

or folders unavailable, they can keep applications from

launching or working properly, and if the incorrect permis-

sions are on system les, may even cause Finder problems

or make the computer unable to boot from that system.

Each system volume contains a Library/Receipts folder.

This folder holds package les that each contain a “Bill of

Materials”le(withextension.bom).TheseBillofMaterials

les store the correct permissions for the associated pack-

age—typically system and application packages. TechTool

Pro makes use of this information to verify and repair

permissions. Repairing permissions is easy to do and could

well solve an annoying problem with the computer or an

application.

To verify/repair the disk permissions for a volume, select

Disk Permissions from the Tools category. This opens the

Disk Permissions Conguration window.

In the conguration window, select the volume whose

permissions you would like to check or repair. Then click

the Verify Disk Permissions button to check the permis-

sions or the Repair Disk Permissions button to repair any

permissions that may be incorrectly set. Upon completion,

any les with incorrect permissions or whose permissions

were repaired will be listed in the Reports window.

Local Network

The Local Network tool displays what Bonjour en-

abled devices and services are running on your local

network. This tool lists the IP addresses of all network

devices as well as the port number of any services run-

ning on the selected device.

6.21

NOTE Handheld devices such as iPhones, iPod

touches and iPads will only appear in the Local Network

device list if they are running iOS 5 or later, which enables

Bonjour support.

The Local Network tool can be hepful in debugging net-

work problems (e.g. with a printer, AirPort Express, etc.). It

can also help with security issues by revealing what ports

are open and which applications are using them. Clicking

on a given network device will reveal a list of services and

their corresponding port numbers.

As a device becomes active or inactive, the green light will

blink. Once the device is active, the light will stay green.

NOTE If you switch networks or a device is no longer

partofthenetwork,pressthe“ClearHistory”button.

Video

The Video area includes options for checking your com-

puter’s display and iSight compatible cameras. Choose

Video in the Tools category to display the Video congura-

tion screen. Use the tabs at the top of the conguration

screen to choose either Video Geometry or iSight.

Video Geometry

Technicians use video geometry patterns and color

screens as an aid in calibrating a monitor and checking it

for defects. You may also nd them helpful for conrming

your monitor’s color output and for making adjustments if

your monitor has calibration controls.

Click the Video Geometry tab in the Video conguration

window to bring up the Video Geometry

conguration screen.

6.22

TechTool Pro oers a number of test screens. Each screen

is available via a button that shows the color/pattern that

will be displayed. Simply click on a button to display the

test pattern. Click again anywhere to return to the Video

conguration screen.

Use the Primary Colors area to choose among the follow-

ing solid colors:

• Red–Paintstheentirescreenred.

• Green–Paintstheentirescreengreen.

• Blue–Paintstheentirescreenblue.

• Yellow–Paintstheentirescreenyellow.

• White–Paintstheentirescreenwhite.

• Black–Paintstheentirescreenblack.

Use the Animate check box to turn on or o an animated

pattern within the solid colored screen.

Use the Test Patterns area to choose among the

following eects:

• Bars–Displaysaseriesofverticalcolorbars.

• Text–Displaysascreenfullofblackonwhitetextcharacters.

• Noise–Displaysaconstantlychangingrandomlycolored

noise pattern.

• Cycle–Displayschangingcolored,animatedtextonasolid

colored background.

iSight

Use the iSight tool to display the output from any at-

tached iSight compatible cameras. Output from up to four

cameras can be displayed simultaneously so that you can

compare the outputs from dierent cameras. You might

nd this tool handy to use in the case where a camera

does not appear to be providing a signal when used in

other software. TechTool Pro directly accesses the camera

signal and displays it if present.

To use the iSight tool, click the iSight tab in the Video con-

guration window to bring up the iSight

conguration screen.

When you press the Start button, a window will appear for

eachrecognizedcameradisplayingtheoutputfromthe

camera. Press the Stop button to terminate.

6.23

Audio

MacOSXdeliverstoday’sprofessionalstandardforaudio

resolution–24-bit,96KHz.CoreAudiomanagesallaudio

as 32-bit oating-point data. This allows your Mac to ef-

ciently handle 24/96 as well as higher resolutions that

may become common in the future. Core Audio also

delivershighlyoptimizedsamplerateconverterstoallow

programs that do not yet use this high-resolution format

toprovidedatatoMacOSXwithouttruncation.

MacOSXdeliversthebestaudioperformanceindesktop

computing. The most fundamental measure of audio per-

formance is throughput latency. That’s the time it takes for

audio to enter your Mac, travel through the system to your

application and then pass back out to your monitoring

system (speakers). Historically, Mac OS oered audio pros

excellent latency of about 10ms.

The Core Audio HAL (Hardware Abstraction Layer) pro-

vides ultra low latency communications between applica-

tions and I/O devices that is measurably more ecient

than previous solutions. M-Audio reports latency as low

as40samplesonMacOSXfromthecompany’saudioin-

terfaces. That translates into 1ms throughput latency–and

you get this performance in a full multi-channel environ-

ment.

TechTool Pro’s Audio tool lets you check the audio input

and output of your computer. Like the Video tests, all Au-

dio tests are non-qualied tests. This means that there are

no pass/fail marks. It is up to you to determine whether

the computer audio input or output is acceptable. The

audio tests require stereo output to test properly. Without

stereo output the tests will be monophonic.

Choose Audio in the Tools category to display the Audio

conguration screen.

From this screen you vary the audio signal and monitor

the outputs. The input and output sources are determined

by the setting in the Sound pane of the

System Preferences.

The left side of the conguration screen is the Audio Out-

put area. In this area you can set various output options.

The Sine Wave section has sliders that control the volume,

frequency, and balance of a sine wave. Use the Start/Stop

Tone button to begin or end the tone. To the right of the

Sine Wave area is the Chromatic Scales button. Press-

6.24

ing this button plays back a series of chromatic scales.

Beneath the above areas is the Speech Synthesis area. To

hearsynthesizedspeech,simplytypethetextyouwould

like to hear in the text eld and then press the

Say Text button.

The right portion of the Audio conguration screen dis-

plays a dynamic frequency bar graph of the audio

input signal.

By adjusting the varying the audio output you can subjec-

tively determine whether or not your audio circuitry and

speakers are working, whether the two audio channels

are balanced, and whether the full frequency and volume

range is being produced through each channel.

7.1

TechTool Protogo

7.2

The full functionality of TechTool Protogo is now included

as a part of TechTool Pro.

TechTool Protogo can create a bootable drive that contains

TechTool Pro as well as Disk Utility and several other utili-

ties. If you use a portable device, you can carry it with you

and have it readily available as needed. The device you

create can also be updated and additional software can be

added to it. You can think of it as the ultimate Macintosh

toolbox.

Using TechTool Protogo to create a diagnostic device is

easy. If you have an old iPod, a ash drive, a portable hard

drive,orjustastandard-sizedexternalharddrive,you

can use TechTool Protogo to congure it to be a bootable

device containing utility programs of your choice.

TechTool Protogo either ships on an installation DVD or as

a download. TechTool Pro is included with your Protogo

license. Protogo comes with proles for several standard

system/utility congurations so that you can easily set up

a device. Simply select the device, the desired device pro-

le, and press a single button. You can also create and save

your own proles that include the custom components

you desire (even including third party utilities). The stan-

dard proles range from a minimal bootable system with

TechTool Pro on it (such as used to come on the TechTool

ProDVD),toafull-blownMacOSXinstallationincludinga

Finder and multiple utility programs.

A device created by Protogo boots and runs software

much faster than from a DVD. It also includes memory

swap space for the Mac OS, which increases speed and

stability as well. In addition, you can re-congure the

device at any time to add new utilities, updated versions

of software, or newer Mac OS versions.

With TechTool Protogo, you can set up a

device to:

• Diagnoseandrepairharddriveproblems

• Testmajorcomputercomponents

• Predictdrivefailures

• Optimizeanddefragmentharddrivevolumes

• Rebuildvolumedirectories

• Recoverdatafromdamagedvolumes

• Repartitionharddriveswithoutlosingdata

• BootdierentMacOSversionsfrom

dierent partitions

• Runavarietyofutilities

TechTool Protogo gives you the power to create and main-

tain your own toolkit for the Macintosh–exactly the way

you want it–on one portable device. Just plug it in and all

your tools will be there at your ngertips.

7.3

The TechTool Protogo Interface

TechTool Protogo runs from an installation on your hard

drive. To launch the program, double-click the Protogo

icon. After the program has launched, you will see the

main TechTool Protogo window.

The main window is divided into three panes with a

button bar at the bottom. The upper pane is the Prole

Viewer. This is a visual summary of the currently selected

device and the prole. The two panes beneath the Prole

Viewer display information about the storage devices

attached to the computer and about the available device

proles, including any custom proles you may have cre-

ated. Use the New and Delete button below the Proles

pane to create or delete proles. Click the Edit button to

bring up the Prole Editor to set up a device prole the

way you wish. Click the Build TechTool Protogo button to

completely erase the selected device and congure it us-

ing the selected prole. These options are covered in more

detail below.

Prole Viewer

The upper pane in the Protogo window is the Profile Viewer. The

top left of the pane displays an icon for each Mac OS version

included in the profile. Beneath this is a series of icons indicating

the applications that are included on the volumes in the profile.

The application icons move across the screen and disappear into

an icon of the currently selected device. The lower portion of the

pane displays the profile name and the beginning of the profile

description. To view the full description, click the Edit button at

the bottom of the screen (or double-click the profile name in the

Profiles pane).

7.4

Devices Pane

The Devices pane is the lower left pane in the TechTool

Protogo window. It displays an icon for each device avail-

able for use by Protogo.

Click on a device icon to select it for use by the program.

Listed next to each device icon is its name, device type

andidentier(e.g.ExternalFireWire(disk1)),andsize.Click

on the Eject button beneath the Devices pane to eject the

selected device.

Proles Pane

The Proles pane is the bottom right pane in the TechTool

Protogo window.

A prole is a complete device conguration, including any

volumes (partitions) and their contents. Both the included

default proles and any custom proles you have cre-

ated will be displayed in the Proles pane. You can create

proles for use on devices ranging from 4GB ash drives

containing a minimal bootable system with one or two

utilities all the way up to large hard drives with full instal-

lationsofMacOSXalongwithmultipleutilitiesorother

software.

The Proles pane displays a Prole Strip for each available

prole.

7.5

Each Prole Strip includes the prole name, the number

of volumes on the prole, and a brief description of the

selected prole.

On the right side of the strip is a bar graph indicating the

amount of used and free space on

the device.

The graph colors indicate the following:

• green–spaceusedontheselecteddeviceby

the prole.

• white–freespaceavailableontheselecteddevice.

• red–insucientspaceontheselecteddevicetobuildthe

prole.

TechTool Protogo includes several default proles:

• MacOSXMinimalProle–createsabootableMacOSX

partition based on a minimal system installation that boots

Intel-based Macs (similar to a bootable CD or DVD with no

Finder).

• MacOSXBasicProle–createsasmallercopyoftheactive

MacOSXsysteminstallation.

• MacOSXFullCopyProle–willcreateafullcopyoftheac-

tiveMacOSXsysteminstallation.

•MacOSXRecoveryHDProle–BackupyourMacOSXLion

Recovery partition, along with TechTool Pro. (Available

onMacswithMacOSX10.7orlaterinstalledandavalid

Recovery HD.

NOTE: Only Intel-based Macs are supported by Protogo

All proles contain a default list of applications. For Mac

OS X, these are:

• TechToolPro

• Console

• DiskUtility

• SystemInformation

• Terminal

For the Recovery HD Prole, the partition will contain:

•TechToolPro  •DiskUtility

•ReinstallOSX •FirmwarePasswordUtility

•Console  •NetworkUtility

•Terminal  •Safari

•RestorefromTimeMachineBackup

7.6

Use the following buttons beneath the Proles pane to

work with proles:

• New–clickthisbuttontobringuptheProleEditorscreen

and create a new prole. Details about the Prole Editor are

covered below.

• Delete–clickthisbuttontodeletethe

selected prole.

• Edit–clickthisbuttontobringuptheProleEditorscreen

with information about the selected prole. You can then

alter the conguration as desired. Details about the Prole

Editor are covered below.

• BuildTechToolProtogoDevice–clickthisbuttontocopythe

contents of the selected prole to the selected device.

WARNING Be sure that any important data on the

device is backed up before choosing Build TechTool Pro-

togo Device, since the entire device, including all volumes

currently on it, will be completely erased. Any data on the

device will be lost.

Prole Editor

Click the New button or Edit button beneath the Proles

pane to bring up the Prole Editor. The Prole Editor is

where you create and/or congure a device prole to your

specications.

At the top of the screen is the Prole Name eld. Simply

enter the desired name for the prole into the eld.

On the right of the Prole Name eld is the Select Prole

to Copy pop-down menu. Use this menu if you wish to

copy an existing prole’s attributes into the Prole Edi-

tor so that you can produce a modied version of that

prole. This is often easier than creating a new prole from

scratch.

Beneath the Prole Name eld is the Description eld. En-

7.7

ter whatever you like in this eld for a prole description.

This information will be displayed in the Prole Viewer on

the main Protogo screen.

On the left, below the Description eld, is the Volume List.

This displays a Volume Strip for each volume currently

included in the prole.

The Volume Strip shows an icon for the device. To the

right of the icon are a number of elds:

• Name–enterthedesirednameforthevolume.

• System–choosewhatMacOSversion,ifany,toinstallonthe

volume from the pop-down menu.

• Format–choosethedesiredvolumeformatfromthepop-

down menu.

• DiskUsage–thiselddisplaysthetotalamountofdiskspace

used by the volume.

• AdditionalSpace–entertheamountofadditionalspaceyou

wish to include on the volume. Use the pop-down menu on

the right of the eld to choose whether this will be indi-

cated in MB (megabytes or million bytes) or GB (gigabytes

or billion bytes).

Click the Add Volume button beneath the Volume List to

add a new volume (partition) to the prole. Click the De-

lete Volume button to delete the selected volume (parti-

tion) from the prole.

To the right of the Volume List is the Content List. This dis-

plays a list of the utility programs on the selected volume.

Click the (+) button to bring up a File/Folder Selection

dialog to select a le or folder containing a utility you wish

to add to the selected volume. It will be placed in the Ap-

plications/Utilities folder on the volume. Click the (-) but-

ton to delete the currently selected le or folder from the

list. Click the Show File button to display a Finder window

showing the original location of the selected le or folder.

7.8

NOTE Not all application programs are self-con-

tained. If a program consists of multiple parts, then simply

copying a program le into a prole may not produce a

working program on the device.

Click the Save button on the lower right of the Prole

Editor to save the current state of the prole and return to

the TechTool Protogo window. Click the Cancel button to

cancel any changes made in the current Prole Editor ses-

sion and return to the TechTool Protogo window.

NOTETheprolesaresavedinthele“~/Library/Pref-

erences/com.micromat.protogo.proles.plist”(where“~”

refers to the current user’s folder).

Using a Protogo Device

Once Protogo has nished building a bootable device, it

can now be used to start up a Mac to perform a variety of

troubleshooting tasks. There are several ways to start up

from the new device.

Protogo Launcher

TostartupfromdevicescreatedusingtheMacOSXMini-

mal prole, double click the Protogo Launcher. The Mac

will then restart from the Protogo Device.

7.9

Startup Disk

Once Protogo has nished conguring your device, it will

be visible in the Startup Disk Preference Pane under Sys-

tem Preferences. Select the device to boot from, then click

the Restart... button.

Startup Manager

A Protogo device can also be selected using the Startup

Manager. To start up from a device in this way, do the fol-

lowing:

1. Startup or restart your Mac.

2. Immediately upon hearing the startup chime, hold

down the Option key until the Startup Manager ap-

pears. The Startup Manager is a screen which displays

the disks available that can start up your Mac.

3. Using the arrow keys, select the device you wish to

start up from.

4. Press the Return key.

The Mac will now start up from the selected device.

8.1

TechTool Pro Reports

8.2

As TechTool Pro performs its various tests and other func-

tions, it keeps track of what is done and what results are

obtained. This information is saved in Reports. Detailed

results of every test can be displayed in the report, as well

as advice on how to proceed if problems are found. When

TechTool Pro is run from an installation on a hard drive, the

results are saved cumulatively into the Reports. You can go

back and refer to earlier results if desired. Having the re-

sults of previous tests available may allow you to pinpoint

when a problem developed and also be helpful as refer-

ence should you need to contact technical support.

The Reports are both sortable and searchable, making

it easy to locate results for specic tests, volumes, and

drives. For example, you can choose to display only test

failures if desired. The Report can be printed or saved as a

webarchive document if desired.

Choose the Reports category to display the

Reports window.

The Reports window is designed to provide convenient

access to details about each test that was performed.

The left side of the Report window contains the Report

Summary in a standard columnar database format. The

right side of the window displays the details for the item

selected in the Summary area.

If TechTool Pro has been run on more than one computer

(such as when booting and running the program from an

external hard drive), you can use the pop-down menu at

the top of the Summary area to choose the specic com-

puter whose results you wish to display in the Report.

8.3

Use the Job Selector pop-down menu to select among the

following:

• AllJobs

• FailedJobs

• CancelledJobsFromLastRun

• JobsFromLastRun

• FailedJobsFromLastRun

• OverallSummary

Type a string of characters in the eld to the right of the

Job Selector pop-down menu to search for specic items.

For example, you might want to display results for all

entriescontaining“SMART”or“Hitachi”.

Beneath the Job Selector pop-down menu is a colum-

nar list of all items meeting the chosen criteria. The four

columns are:

• TimeStamp—whenthetest/toolexecuted.

• Job—thetest/toolname.

• Status—test/toolresult(Passed,Failed,Canceled,etc.)

• Target—componenttested(volumename,harddrive

name, etc.)

The list can be sorted in either ascending or descending

order by clicking on the column descriptor at the top of

the column. For example, you might sort by Time Stamp

to see all tests run on a certain day or sort by Target to eas-

ily locate all tests performed on a certain volume. Columns

can be re-ordered if desired by dragging the column

descriptor left or right to the desired location.

To display further information about a specic item in the

list, simply click the list entry to select it. Details will be

displayed in the area to the right. These include specic

information about the item tested, results, and advice on

how to proceed in the case of a problem. You may need to

use the vertical scroll bar to view all the test/tools details.

The following buttons are available at the bottom of the

Reports window:

• ClearSelection—deletesthecurrentselectionfromthelist.

•Saveas…—savesareportasawebarchivedocument.

•Print—opensaprintdialogboxinordertosaveareport.

NOTE To select multiple consecutive items in the

Summary Report, hold down the shift key while clicking

on the items. To select multiple non-contiguous items,

hold down the command key while clicking on the items.

9.1

TechTool Protection

9.2

TechTool Pro oers a number of features you can congure

to run automatically in the background as your computer

operates. The features are controlled by TechTool Protec-

tion. (For details about installing TechTool Protection, see

the Installation and System Requirements earlier in this

manual.) You can congure TechTool Protection to monitor

the free space on your volumes, save pointers to deleted

les to assist in their later recovery, backup your volumes’

directories, check your hard drives’ built in SMART rou-

tines, and send you e-mail alerts in case problems are

detected. The automatic features are congured via the

TechTool Protection pane in the System Preferences.

At the top left of the TechTool Protection pane is a but-

ton to either Run or Stop TechTool Protection’s automatic

background routines. To the right of this button is a check-

box to control whether or not a TechTool Protection icon

appears in the menu bar. Clicking this icon shows a menu

displaying the status of TechTool Protection as well as an

option to open the TechTool Protection pane.

The various TechTool Protection features are described in

detail below.

Volume Usage

It is generally recommended that the amount of free

space on a volume not fall below about 15%. Lack of free

space can lead to serious volume corruption. TechTool

Protection can be congured to automatically monitor the

amount of free space on your volumes and to alert you it

exceeds a certain threshold.

9.3

Click the Volume Usage tab in the TechTool Protection

pane to bring up the Volume Usage screen.

Click the On button to turn on the Volume Usage options.

Check the box beside each volume you want monitored.

Use the Free Space Warning Threshold to set the free

space threshold for the selected volumes. If the free space

threshold is exceeded, a popup message appears on the

screen to alert you. If the E-mail Alerts option of TechTool

Protection is active, an e-mail will be sent to the cong-

ured address with a warning as well. Below the congura-

tion options is a graph showing the volume usage for the

selected volume. The graph’s bar will be green if the usage

is below the threshold and red if the threshold

is exceeded.

Directory Backup

The purpose of Directory Backup is to periodically save direc-

tory information for your volumes called Directory Backup

Files. These are backup les of critical volume structure data.

They are located in the main hard drive/Library/Application

Support/TechTool Protection folder. Directory Backup les

can greatly assist TechTool Pro with recovering data from cor-

rupted drives. They may also help recover les that have been

deleted if the Trash History in TechTool Protection was not

enabled when the les were deleted. The Directory Backup

screen allows you to select the volumes you wish to protect

and how frequently they are protected.

NOTE Directory Backup les are not backups of your

actual data. Rather, they are backups of the volume struc-

tures for the entire volume. It is very important to keep at

least one backup (preferably two) of your actual data on

another location to be safe.

NOTE Directory backups are not kept for drives en-

crypted by FileVault 2 for security reasons.

9.4

Click the Directory Backup tab in the TechTool Protection

pane to display the Directory Backup screen.

Click the On button to enable Directory Backup. Check the

box beside each volume you wish protect. Use the Backup

Interval eld to set the number of hours between directo-

ry backups. To backup the directories of the selected vol-

umes immediately, click the Backup Now button. To have

Directory Backup les saved to more than one location,

click on the Locations… button, then click the + button to

backup to another volume.

The Latest and Previous elds display the dates of the last

two directory backups (if present) for the currently select-

ed volume. TechTool Protection saves up to three directory

backups per volume. When newer directory backups are

done, the oldest is deleted.

WARNING Be sure that each of your volumes has a

unique name. This is especially important for removable

media. The Protection le uses the volume name as an

identier.

Trash History

TechTool Protection can save pointers to deleted les for

a specied number of days in a Trash History le. Assum-

ing a deleted le has not been overwritten since it was

deleted, you can use Data Recovery in the Tools category

toeasily“undelete”thele.

9.5

Use the Trash History eld to set the number of days for

which you would like to track the location of deleted les.

As long as a deleted le has not been overwritten, you

can undelete it within that time period. To undelete a le,

go to Data Recovery in the Tools category of TechTool Pro.

Click the Show Trash History button in the Trash section

to bring up the Trash History window for the current user.

Select the le you wish to undelete and click the Restore

button. The selected le will be saved to a folder named

TechTool Pro Recovered Files on the desktop.

NOTE If you have set the Finder Preferences to se-

curely delete les when you empty the Trash, then deleted

les are immediately overwritten and cannot be recovered

by any means–including using TechTool Pro. The same is

true if you empty the Trash using the Secure Empty Trash

option, or have FileVault 2 enabled.

SMART Check

TechTool Pro can automatically query your drive’s SMART

registry on a regular basis and alert you if problems are

developing. This may provide advance warning of drive

failures before they become catastrophic. More informa-

tion about SMART monitoring is available in the Tests

section of the manual under the SMART Check.

Click the SMART Check tab in the TechTool Protection

pane to bring up the SMART Check screen.

Click the On button to enable SMART Check. Click the

box beside the drive name of each drive you want to be

checked automatically. Use the Check Interval eld to

set the number of hours between SMART checks. To do a

SMART check immediately, click the Check Now button.

Below the Check Now button, the following information

is displayed:

• Driveidentier

• Connectiontype

• DateandtimeofthelastSMARTcheck

• ResultofthelastSMARTcheck(passedorfailed)

• Namesofvolume(s)onthedrive

9.6

When a SMART check failure occurs, a popup message ap-

pears on the screen to alert you. If the E-mail Alerts option

of TechTool Protection is active, an e-mail will be sent to

the congured address with a warning as well.

In the event of a SMART failure, you might consider run-

ning the SMART Check in the Tests category to get more

detailed information about which SMART parameter(s)

failed. This may help you determine the seriousness of the

issue and would be valuable information to provide the

drive manufacturer should you decide to contact them

for assistance.

E-mail Alerts

TechTool Pro can automatically send an e-mail mes-

sage alerting you if a volume exceeds the volume usage

threshold or if the SMART Check fails. This allows you to

monitor a computer even though you may not be physi-

cally present, providing an early warning of impending

problems. This alert may give you enough time to backup

your data and address the problems before experiencing a

catastrophic failure

Click the E-mail Alerts tab in the TechTool Protection pane

to bring up the E-mail Alerts screen.

Congure the following e-mail elds as required:

• E-mailSubject—SubjectlinetobeincludedinE-mailAlert,

Thedefaultsubjectis“TechToolProFailureAlert.”

• E-mailAddress—E-mailaddresswheretheAlerte-mail

should be sent.

• SMTPServer—SMTPservername.

• PortNumber—Portnumberusedbyoutgoinge-mail(de-

fault is 25).

• UseSMTPAuthentication—CheckthisboxifusinganSMTP

mail server and authentication is required.

9.7

• SMTPAccount—SMTPusernameifusing

SMTP authentication.

• Password—SMTPpasswordifusingSMTPauthentication.

•UseSSL/TLS-checkthisboxifyouremailserverrequiresSSL

or TLS authentication. (Not supported for all email services)

After entering the conguration information, click the

On button to enable E-mail Alerts. Check the appropriate

boxes to send e-mail alerts notifying you of Volume Usage

warnings and/or SMART Check failures.

Click the Send Test E-mail button to send an e-mail to

the specied address. Do this to verify that mail is work-

ing properly on the computer and that the E-mail Alerts

feature is properly congured.

If E-mail Alerts are enabled and a warning occurs in a se-

lected option, an e-mail will be sent to the specied e-mail

subject. The body of the e-mail will contain the following

information:

• DateandTimeoftheAlert.

• Computer’sUserName.

• Computer’sIPAddress(es).

• Computer’sMacOSXVersion.

• FailureCategory,VolumeorDrivename,andFailureType.

10.1

TechTool Pro Menu Options

10.2

When TechTool Pro is launched, a number of special Tech-

Tool Pro options are available from the menubar. They are:

TechTool Pro

This menu item contains the following choices:

About TechTool Pro

Select this option to display the TechTool Pro Information

screen. It displays the version number of the program as

well as copyright information.

Install TechTool Protection…

Selecting this option will install TechTool Protection.

Changes to Remove TechTool Protection if already in-

stalled. Choosing this option will then remove TechTool

Protection.

Check for Update…

Selecting this option will attempt to connect to the Mi-

cromat website and let you know if a newer version of the

program is available.

NOTE You must have an active connection to the

internet in order for this option to succeed.

Hide TechTool Pro

Select this option to hide the TechTool Pro windows.

Clicking the TechTool Pro icon on the dock will return the

windows to their previous state.

Quit TechTool Pro

Select this option to quit the TechTool Pro application.

Mode

Use the Options menu to select one of the four TechTool

Pro categories—Tests (command-1), Tools (command-2),

or Reports (command-3), Protogo (command-4).

Help

Use the Help menu when running an installed copy of

TechTool Pro to search or open TechTool Pro’s Help le.

10.3

11.1

Commonly Asked Questions

11.2

Can I start up (boot) the computer from a

TechTool Pro DVD?

Apple is no longer distributing a DVD that allows us to

create a startup DVD for TechTool Pro. We recommend us-

ing TechTool Pro to create an eDrive instead. Choosing an

external drive as the destination for the eDrive allows for

addtional security, should your primary internal drive fail.

Why can’t TechTool Pro do a volume test of the current

startup volume?

MacOSX10.2andaboveallowschangestothevolume

structures of the boot drive in the background as it is run-

ning. Hence, it is not possible to correctly test the volume

structures on the boot volume—and TechTool Pro will not

allow this (nor will Apple’s Disk Utility). You must boot the

computer and run the program from some other loca-

tion, such as the eDrive, in order to test/repair the volume

structures of your normal boot volume.

Is TechTool Pro able to check a UFS initialized volume?

No.TechToolProcanonlyworkonMacintoshinitialized

(HFS and HFS+) volumes.

Can TechTool Pro check a network volume?

No. TechTool Pro can only work on volumes of drives phys-

ically attached to the computer on which it is running.

How do I initialize a drive in Mac OS X?

MacOSXincludesautilityprogramcalledDiskUtilitythat

allowsinitializationofdisks.DiskUtilityistypicallylocated

in the Utilities folder (inside the Applications folder). After

launching Disk Utility, choose the Erase option. To check

for bad blocks and lock them out (if possible), select the

securityoptionto“zeroalldata.”Initializingwiththisop-

tion will take much longer, but will ensure that the drive is

in good shape.

How do I uninstall TechTool Pro?

The TechTool Pro Installer includes an uninstall option.

SelectCustomizeduringtheinstallprocess,andbesure

the“RemoveTechToolPro”checkboxischecked.Doing

an uninstall will delete all the TechTool Pro les from the

selected volume.

12.1

Tips, Short Cuts, and Hidden Features

12.2

Mac OS X Versions

MacOSX10.0:Cheetah(March24,2001)

MacOSX10.1:Puma(September25,2001)

MacOSX10.2:Jaguar(August23,2002)

MacOSX10.3:Panther(October24,2003)

MacOSX10.4:Tiger(April29,2005)

MacOSX10.5:Leopard(October26,2007)

MacOSX10.6:SnowLeopard(August28,2009)

MacOSX10.7:Lion(July20,2011)

OSX10.8:MountainLion(July25,2012)

OSX10.9:Mavericks(October22,2013)

OSX10.10:Yosemite(October16,2014)

TechTool Pro Key Commands

cmd-?: TechTool Pro Help

cmd-H: Hide TechTool Pro

cmd-Q: Quit TechTool Pro

cmd-1: Select the Tests category

cmd-2: Select the Tools category

cmd-3: Select the Reports category

Useful Apple Key Combinations

cmd-opt-P-Ratstartup:zapPRAM

opt at startup: select startup device

cmd-S at startup: boot into single user mode

cmd-V at startup: boot using verbose mode

shift at startup: boot into safe mode

shift at login: bypass user startup items

cmd-opt-O-F at startup: drop into open rmware on

PowerPC Macs

cmd-D at startup: start up in Apple Hardware Test if Install

DVD 1 is in the drive

cmd-T: start up in FireWire Target Disk mode

Basic Open Firmware Commands

(PowerPC Macs)

reset-nvram

set-defaults

reset-all

eject cd

dir hd:\

dir hd:\<pathname>

mac-boot

12.3

Handy Terminal Commands (for

Geeks only)

sudo diskutil enableJournal /: Enables journaling.

sudo diskutil disableJournal /: Disables journaling.

sudo sh /etc/daily: Runs the daily system cleanup tasks.

sudo sh /etc/weekly: Runs the weekly system

cleanup tasks.

sudo sh /etc/monthly: Runs the monthly system

cleanup tasks.

pwd: Displays the path name of the current

working directory.

cal: Displays a calendar for the current month.

cd: With no argument changes the working directory to

the user’s directory. When followed by a directory name it

changes the working directory to the specied directory.

ls: Lists the current directory’s les.

ls –a: Lists all les, including invisible les.

ls –l: Includes more information in the listing.

rm: When followed by a le name deletes the le.

12.4

rm –r: When followed by a directory name removes the

directory and all its subdirectories (be very careful, this is a

dangerous command).

rmdir: Removes an empty directory.

top: Provides a live display of currently running processes

(type“q”toquit).

sudo: Followed by a command, allows you to execute a

single command as root.

kill: Followed by a process ID, terminates that process.

13.1

Macintosh File Systems

13.2

Your Macintosh computer needs fast and easy access a

tremendous amount of information in order to function

and perform its various tasks. In particular, it must be able

to access the system les, application programs, and other

data as you work. This data may be stored on a variety of

physical devices, including hard drives, oppy drives, CD-

ROMs, memory cards, etc. In order to provide a consistent

interface to these various physical devices the Macintosh

File Systems were developed. To fully understand and

appreciate how your Macintosh works and some of the

things that may go wrong with it, you need to have some

understanding of the Macintosh File Systems. Although

this is a complex and somewhat technical subject, a

general overview of the le systems will make you a more

informed Macintosh user. In particular, the importance of

preventative maintenance and backups should become

apparent. You will also gain a better understanding of

what is going on with your computer and drives when

problems do develop.

The two most common Macintosh File Systems are the

original Hierarchical File System Standard (HFS Standard

or HFS) and the newer Hierarchical File System Extended

(HFS Extended, HFS Plus, or HFS+). The original HFS le

system was developed in the days of the original 400K

oppy disk. At that time a 20 MB hard drive was consid-

ered a huge storage device. The HFS Extended format was

developed primarily to make more ecient use of storage

space on large drives. It is now the format most commonly

used on the Macintosh and the format that we will focus

on here. However, before delving into HFS Extended we

will need to introduce a few basic concepts.

To allow computers to work in a consistent way with a

variety of physical devices, a number of abstractions have

been developed. Perhaps the most basic is the bit. A bit is

the smallest unit of information that can be accessed by a

computer and can be represented as a 0 or a 1. It may be

stored in dierent devices in dierent ways. For example,

a bit on a hard disk drive is stored as a magnetic trace,

whereas on a CD-ROM it is stored as a pit on the disk.

Within the computer circuitry a bit may be simply a pulse

of electricity. Larger chunks of information are the byte

and the word. A byte is simply eight bits and a word is two

bytes. All information in the computer is encoded in the

form of bits, bytes, and words.

The data storage device has been abstracted as a logical

devicecalledavolume.Thecomputerrecognizesavol-

umeasone“device”.Itmayactuallybeaoppydisk,one

partition on a hard drive, a CD-ROM drive, etc. Note that

one physical device, such as a single hard drive that has

been partitioned, can be seen as multiple volumes by the

le system. Data is stored on volumes in the form of les.

A le is simply a named collection of bits. It may contain

representations of user data, system data, programs, or

even the structures used to keep track of where other les

are stored.

13.3

Both HFS and HFS Extended are specications for how

data and the information necessary to retrieve that data

are stored on volumes. Volumes are divided into 512 byte

logical blocks called sectors. The sector is an abstraction

fromthe“sector”ofadiskplatter.Thetypicalharddrive

platter is divided into sectors of 512 bytes. Sectors are

numbered from 0 and continuing to the last one on the

volume. Space on a volume is allocated as a group of con-

secutivesectorscalledanallocationblock.Thesizeofthe

allocationblockissetatthetimethevolumeisinitialized.

Themostcommonallocationblocksizeis4K(8sectors).

There can be at most 2^32 allocation blocks on a volume.

The le system attempts to provide allocation blocks for

aleinaxedsizegroupcalledaclump.Alargerclump

sizetendstodecreaselefragmentation,butcanresult

in wasted space being left at the end of the le. Finally, a

series of contiguous allocation blocks that store a le on a

volume is called an extent of the le.

The rst block on a physical disk contains the driver

descriptor map. This holds information about the num-

ber and location of drivers on the disk. The second block

begins the disk’s partition map. It species the start,

length, and type of each partition (volume). The partition

typemaybeHFS+,AU/X,MS-DOS,etc.Thepartitionmap

is itself a partition and holds an entry for itself. The device

driver (if present) is typically located after the partition

map. Finally, the partitions themselves typically ll the

remainder of the disk space.

A number of data structures work together to keep track

of data on HFS Extended volumes. These include

the following:

• VolumeHeader

• CatalogFile

• ExtentsFile

• AttributesFile

• AllocationFile

• StartupFile

These structures will be described in more detail below.

They each consist of one or more allocation blocks.

Volume Header

The HFS Extended Volume Header contains critical infor-

mation about the volume as a whole. It corresponds to the

Master Directory Block (MDB) of an HFS volume. A partial

list of the information stored in the Volume

Header includes:

• locationandsizeoftheothervolumestructurecomponents

• totalnumberoffoldersandlesonthedrive

• sizeoftheallocationblocksinbytes

• totalnumberofallocationblocksonthevolume

• nextfreeallocationblock

• defaultclumpsizefordataandresourceforks

• nextunusuedcatalogIDnumber

13.4

• date/timeofthevolume’screationandlastmodication

• languagetousetodisplayleandfoldernames

• whetherthevolumeiswrite-protected

The Volume Header is always located at the volume’s

second sector. Note that this may not be the actual second

physical sector on a physical disk. Because the data in the

Volume Header is so important, a copy of it is kept at the

second to last sector on the volume. This is called the Al-

ternate Volume Header. It is one of the few pieces of data

on a volume that may not reside in an allocation block.

This could occur if the second to last sector falls outside

an allocation block. The Alternate Volume Header may be

used by disk utilities such as TechTool Pro in the case of

damage to the main Volume Header.

The Volume Header may become corrupt if the computer

quits unexpectedly and the Volume Header has not been

properly updated. This could also happen if a bad block

were to develop in the Volume Header. If both the Volume

Header and the Alternate Volume Header are incorrect,

this can pose a challenge for repair utilities. Such damage

may not be repairable. If the corruption to the Volume

Header is severe enough, it may not even be possible to

access data on the drive using standard software.

B-Trees

The Catalog le, Extents le, and Attributes le all make

use of a data structure called a B-tree (Balanced tree) to

store their information. A B-tree is a data structure spe-

cically designed for fast retrieval of information. Using

B-trees in the volume structures allows the File System to

locate data on a volume containing hundreds of thou-

sands of les in a reasonable length of time.

A B-tree le contains a series of nodes. Each node contains

records. A record contains a key used to identify the record

and also some data. The keys are unique and ordered

so that the particular key for an individual record can be

located via a search. The data may include pointers (links)

to other nodes as well as other data associated with that

particular key.

The nodes give the B-tree its structure and come in

four types:

• headernode(theentrypointintothetree)

• mapnode(holdsallocationdataifthemaprecordinthe

header gets full)

• indexnode(holdspointerrecords)

• leafnode(holdsthedataassociatedwithakey)

13.5

A node has the following structure:

Offset to record 0

Offset to record 1

Offset to free space

Node Descriptor

Record 0

Record 1

Free space

offset

data

Structure of a Node

The node descriptor indicates the type of node, the num-

ber of records it contains, where it belongs in the tree, and

contains links to previous or next nodes.

A simple B-tree is illustrated below:

First leaf node

pointer

Root node

pointer

Last leaf node

pointer

112

17 12 20

key/pointerkey/data

13 71011121620

Header Node

Index Nodes

Leaf Nodes

Structure of a B-Tree

In the above example it is clear that it will only be nec-

essary to search at most three nodes to nd the record

associated with any key.

Damage to a B-tree may occur in the key eld, pointer

eld, or data eld. If damage occurs in a key eld, then a

record or whole sub-tree may not be able to be found.

If in the data eld of an index node (a pointer), then the

sub-tree pointed to could be orphaned. Finally, if damage

occurs to the data eld of a leaf node, then the actual data

itself for that key would be invalid. The type of damage to

the le system will depend on whether the B-tree is hold-

13.6

ing the Catalog, Extents, or Attributes data and also on

which type of node is damaged.

Catalog File

One of the most important les of the volume structures is

the Catalog le. The Catalog le keeps track of the hierar-

chy of les and folders on a volume. The rst extent of the

Catalog le is stored in the Volume Header. This means

that the Catalog header, or entry point into the Catalog,

is stored in the Volume Header. If the Volume Header is

damaged, then the Catalog Header may not be able to

be found and it may not be possible to even locate the

Catalog le.

Each le and folder in the Catalog le is assigned a unique

identier called the Catalog Node ID or CNID. For a le this

is called the File ID and for a folder the Folder ID. For each

le or folder the Parent ID is the CNID of the folder con-

taining that item. Some important reserved CNID’s follow:

• 1–parentIDoftherootfolder

• 2–CNIDoftherootfolder

• 3–CNIDoftheExtentsle

• 4–CNIDoftheCatalogleitself

• 5–CNIDofthebadblockle(aspecialledescribedbelow)

• 6–CNIDoftheAllocationle

• 7–CNIDoftheStartuple

• 8–CNIDoftheAttributesle

Every B-tree record must contain a key in order for the

le system to be able to traverse the tree and locate that

record. In the Catalog B-tree there are two possibilities for

the key:

• foraleorfolderrecordthekeycontainstheCNIDofthe

parent and the name of the le and folder

• forathreadrecord(alink)thekeycontainstheCNIDofthe

le or folder itself and no name

There are four types of Catalog leaf nodes:

• folderrecord–containsinformationaboutaparticularfolder

• lerecord–containsinformationaboutaparticularle

• folderthreadrecord–linksafoldertoitsparentfolder

• lethreadrecord–linksaletoitsparentfolder

Some of the more important information stored in the

Catalog folder record includes the CNID of the folder, the

number of les and folders in the folder, the creation and

modication dates, the backup date, and the

folder’s permissions.

Information stored in the Catalog le record includes the

CNID of the le, the creation and modication dates, the

backup date, whether the le is locked, the location of the

rst eight extents of each fork, and the le’s permissions.

The CNID and name of a le or folder allows the informa-

tion for that item to be easily located in the Catalog B-tree.

Corruption in the Catalog le can cause loss of the le

or folder information contained in the Catalog records

13.7

as well as incorrect placement of les and folders in the

folder hierarchy. For example, if you were to suddenly nd

some of your les scattered about at the root level of the

hard drive instead of in their correct folders, this could

indicate damage to the Catalog le.

Extents File

When a le is saved, the le system assigns space on the

volume to hold the le. This space consists of one or more

allocation blocks. Each set of contiguous allocation blocks

is called an extent. The le record of each le in the Cata-

log le holds the locations of the rst eight extents of each

fork in the le. The locations of any additional (or over-

ow) extents that make up a le’s forks are maintained by

the Extents le (also called the Extents overow le).

The Extents le is stored as a simple B-tree. A record key

in the Extents B-tree includes the CNID of the le, the

type of fork (whether resource or data), and the oset in

allocation blocks to the extent. Each extent location is

represented as a pair of numbers: the rst allocation block

of the extent and the number of allocation blocks in the

extent. This information is stored in the Extents le data

record and allows a le fork’s actual data to be located on

the volume.

When the Extents B-tree is searched the information in the

keys is compared in the following order: CNID, fork type, o-

set. Thus, the extents for each fork are grouped together and

are located next to the extents for the other fork of the le.

Corruption in the Extents le could cause the le system

to lose track of the locations of portions of the data in one

or both forks of a le. This could cause les to be truncated

or result in garbage data to appear in a le. If the Extents

le itself cannot be located, then any data beyond the

rst eight extents of each le’s fork, which is stored in the

Catalog le, would be lost.

The Extents le holds information about a special le

called the bad block le. If a sector is found to be bad, in

other words it cannot hold data reliably, then the entire

allocation block containing that sector is added to the bad

block le. This ensures that the space occupied by the bad

block will not be used to store data.

A bad block on a hard disk indicates an actual physical

defect in the media surface at that location. Bad blocks are

locatedduringaninitializationofthedriveusingthe“zero

alldata”option.Theymayalsobediscoveredbythedrive

itself as data is written to and read from the drive.

The bad block le is dierent than standard les. It does

not have a record in the Catalog le and is not referenced

in the Header le. The bad block le has a CNID of 5 for use

as an identier in the Extents le. Bad block extents are

considered data forks. When a bad block is entered in the

Extents le, its allocation block is marked as used in the Al-

location le (see below). This prevents it from being used

in the future. Keeping track of a bad block’s location in the

Extents le allows for consistency checks in the Allocation

le. Every location marked as used in the Allocation le

13.8

should correspond to an extent of some le.

An interesting aside is that when an HFS Extended volume

is contained within an HFS wrapper (see HFS Wrapper

below), all the extents of the HFS Extended volume are

entered into the HFS volume’s bad block le. This ensures

that if the HFS wrapper volume mounts when using a ver-

sion of the Mac OS that does not support HFS Extended,

then the space occupied by the HFS Extended volume will

not be written to.

Allocation File

The Allocation le keeps track of whether or not each

allocation block in the volume is being used by the le

system. It is a simple list with an entry for each allocation

block indicating whether or not it is used. If an allocation

block is marked as unused, then the le system may assign

it to hold data for a new le. When a le is deleted, the

allocation blocks occupied by that le are marked as free

and they may be reused to hold other data at any time.

The allocation information for an HFS volume is stored in a

special location on the volume called the Volume Bitmap,

instead of being stored in an actual le.

Corruption in the Allocation le or the Volume Bitmap can

cause the le system to think that areas actually storing

data are available for use by another le. In that case the

data in the original le may be overwritten and corrupted.

If an unused area is marked as already allocated, then the

le system will report that the volume has less free space

available than it actually has.

Attributes File

The Attributes le is new to the HFS Extended specica-

tion. Like the Catalog and Extents les, the Attributes le

is dened to be a B-tree. The Attributes File stores three

types of 4 KB records: Inline Data Attribute records, Fork

Data Attribute records and Extension Attribute records.

Inline Data Attribute records store small attributes that

can t within the record itself. Fork Data Attribute records

contain references to a maximum of eight extents that

can hold larger attributes. Extension Attributes are used

to extend a Fork Data Attribute record when its eight

extent records are already used. Extended Attributes

enable metadata to be associated with computer les

not interpreted by the le system itself, whereas regular

attributes have a purpose dened by the le system itself

(such as permissions or records of creation and modica-

tion times). As an example, Extended Attributes are used

by Apple’s Safari browser to add security to the Macintosh

operating system. When an application is downloaded by

Safari, this information is stored as an Extended Attribute.

The rst time an attempt is made to launch the applica-

tion, a dialog appears warning the user that they are

about to open a downloaded application for the rst time

and requesting permission to proceed.

13.9

Startup File

The Startup le is intended for use by systems that do not

have built-in ROM support for booting from HFS Extended

volumes. It is similar to the Boot Blocks of an HFS volume.

The rst eight extents of the Startup File are stored in the

Volume Header. This makes them easy to locate and read

into memory. This le contains information formerly used

by the computer’s ROM to determine what program will

boot the computer. For newer Macs, this is handled by the

HFS Wrapper.

HFS Wrapper

Most HFS Extended volumes are embedded inside a

locked HFS volume called the HFS wrapper. However,

newerMacmodelsarebeginningtosupport“pure”HFS

Extended (wrapperless HFS Extended) format.

Embedding HFS Extended volumes in an HFS wrapper

makes it possible for a computer with HFS (but not HFS

Extended) support in ROM to boot from an HFS Extended

volume. Additionally, if an HFS Extended volume is at-

tached to a computer with HFS (but not HFS Extended)

support, the HFS wrapper can be mounted and provide a

message indicating that the computer does not support

HFS Extended volumes. This was especially important

during the years immediately after the introduction of the

HFS Extended format. At that time many people were still

using Mac OS 8.0 or earlier, which did not support HFS Ex-

tended volumes. When using a wrappered HFS+ volume

under Mac OS 8.1 or above, the HFS Extended volume

itself will mount and the HFS wrapper will not be visible.

The HFS wrapper contains an invisible minimal System

and Finder le. The root folder of the wrapper is set as a

“blessed”foldersothatitcanbeusedforstartup.When

starting up from that volume, the computer will begin the

startup sequence from the special System on the wrapper

volume,recognizeandmounttheHFSExtendedvolume,

and then continue starting up from the System on the HFS

Extended volume.

The HFS wrapper is locked so that its contents cannot

be altered. This protects it from inadvertent corruption.

It typically contains a text le named “Where_have_all_

my_les_gone?”IfawrapperedHFSExtendedvolumeis

attached to a computer that does not have support for the

HFS Extended format, the HFS wrapper will mount and

that text le will show up on the volume. The contents of

the text le explain why the HFS Extended volume is

not appearing.

Damage to the HFS wrapper can cause the HFS Extended

volume to not be accessible or make it unable to startup

the computer.

13.10

Journaling

MacOSX10.2.2addedanewfeaturetotheHFSExtended

le system called journaling. Journaling is part of a set

of incremental enhancements to the HFS Extended le

system and is backward compatible with earlier versions

of that le system.

Journaling makes the le system more robust and helps

protect against data loss. When journaling is enabled, the

le system logs transactions as they occur. If your comput-

er fails in the middle of an operation (which might occur

due to a crash or power failure), disk reads and writes may

be interrupted. This can cause discrepancies between the

le system directory and the actual location and structure

of stored les. In an unjournaled le system, volumes may

be left in a corrupted state after an unexpected shutdown.

Ifjournalingwasenabled,thelesystemcan“replay”the

information in its log and complete the interrupted opera-

tions when the computer restarts. Although there may

be minor loss of data that was buered at the time of the

failure, the le system itself will be returned to a consistent

state. This allows the computer to restart much faster since

the volume structures will not need to be repaired

during startup.

Journaling adds a small amount of extra overhead to le

reads and writes. In most cases, the impact of journal-

ing upon data access performance will not be noticed.

However, for les requiring high transfer speeds, such as

large video, graphics, or audio les, the reliability provided

by journaling may not justify the performance loss when

accessing the data.

14.1

Glossary

14.2

AirPort: AirPort is Apple’s name for the IEEE 802.11 wireless

networking standard. The original AirPort based on the

802.11b standard has a maximum transmission speed of

11 Mbps. The newer AirPort protocols are based on the

802.11g standard with a maximum speed of 54 Mbps and

the 802.11n standard with a maximum speed of 248 Mbps.

Allocation Block: The space on a volume is allocated as a

group of consecutive sectors called an allocation block.

Allocation File: This le in the volume structures keeps

track of the blocks that are used and those that are free.

AltiVec: AltiVec is a technology built into most PowerPC

processors that provides increased performance for cer-

tain types of high-bandwidth data processing functions.

Apple Sound Chip: The Apple Sound Chip, or ASC, is a cus-

tom manufactured sound chip made for Apple by Sony.

Often referred to as a DAC, or Digital to Analog Converter,

the ASC provides the Macintosh with advanced sound

creation capabilities.

ASC: See Apple Sound Chip.

ASCII: American Standard Code for Information Inter-

change. A numeric ID assigned to every number, letter,

or other symbol that enables dierent programs and

dierent computers to consistently share information. The

standard code consists of an 8-bit coded number.

AT Attachment Packet Interface: This is an interface,

commonly known at ATAPI, between the computer and

attached CD-ROM drives and tape backup drives. ATAPI

adds additional commands to the IDE interface (see IDE/

ATA below) needed for controlling CD-ROM and tape play-

ers. ATAPI is part of the Enhanced IDE (EIDE) interface, also

known as ATA-2.

AT Attachment Standard: This is a standard electronic in-

terface, commonly called ATA or IDE, between a computer

and its mass storage devices that specify how peripherals

communicate with the computer.

The following chart shows the maximum data transfer rate

for the various ATA versions:

ATA (original) 4 Mb/sec

ATA-2 16.6 Mb/sec

ATA-3 16.6 Mb/sec

ATA-4 (Ultra ATA/33) 33.3 Mb/sec

ATA-5 (Ultra ATA/66) 66.6 Mb/sec

ATA-6 (Ultra ATA/100) 100.0 Mb/sec

ATA: See AT Attachment Standard.

ATAPI: See AT Attachment Packet Interface.

Attributes File: This le in the volume structures, if present,

tracks the attributes of a le—such as whether the le is

locked or not.

14.3

Backup: An exact copy of computer information. In case

of data loss or corruption, the original data can be re-

trieved from the backup.

Benchmark Test: In a given conguration, the test used to

evaluate the performance of computer software

and hardware.

Bit: A bit is the smallest unit of information that can be

storedbyacomputer.Itisrepresentedasazerooraone.

Booting: The term booting originated from bootstrap. It is

the process by which the computer starts itself and reads

the Operating System. When you boot from a CD you are

starting and reading the OS from the CD.

Bundle Bit: A bundle bit is a resource located in most

Macintosh applications. If active, it indicates that the le

contains icon information.

Bus: A bus is the path that transmits information between

a computer and connected devices. An example is the USB

bus, which connects the computer to USB devices such as

keyboards and mice.

Byte: A byte is a unit of information stored in the com-

puter. A byte consists of eight bits. An ASCII character

consists of one byte.

Cache: A high-speed intermediate buer memory that lies

between the processor and main memory in the compu-

ter’s memory hierarchy. It can reduce memory access time.

Catalog File: The Catalog File is a part of the Volume Struc-

tures. It keeps track of the les and folders on a volume.

Central Processor Unit: The Central Processor Unit or Main

Processor Unit is a chip that maintains the processing and

sequencing facilities for machine-related functions such as

initial program booting and instruction execution.

Chip:A“chip,”orIntegratedCircuit,isaminiatureelectron-

iccomponentwithspecializedfunctionswithin

the computer.

Circuit: A conductor through which an electric current

can ow; the entire course traversed by an electric current.

Parts and components assembled to function together in

an electric or electronic device or system.

Clump: The le system attempts to provide allocation

blocksforaleinaxedsizegroupcalledaclump.

Contiguous: Joining or touching in a continual, consecu-

tive, unbroken order to a common edge or boundary.

CPU: See Central Processing Unit.

CRT: CRT is an acronym for cathode Ray tube. It is the

element that produces the image on most computer and

television screens.

Device: A device is any piece of equipment that can be at-

tached to a computer. These might include a monitor, disk

drive, printer, etc. Devices are also known as peripherals.

14.4

DIMM: See Dual Inline Memory Module.

Directory: Another term for the volume structures.

Disk: A disk is a at circular device for storing computer

data. The data might be stored magnetically or optically.

The most common disks are CD-ROM disks made of sti,

translucent plastic.

Disk Drive: A device for controlling and accessing data

stored on a disk or disk stack.

Disk Driver: A driver for a block transfer device (see Driver

below) such as a hard disk drive, oppy drive, or CD-ROM

drive. It is a software plug-in that implements a hardware

abstraction layer for the device.

Drive: A drive is a computer peripheral that stores data.

It might use a tape cartridge, a disk, or other medium. A

drivemaybe“readonly”or“read/write.”

Driver: A driver (or device driver) is software that lets a

computer communicate with a device such as a printer,

hard drive, etc. When you purchase a new device, its driver

is usually provided as part of the software that comes

with it.

Driver Descriptor Map: The Driver Descriptor Map holds

information about the number and location of drivers on

a disk.

Dual Inline Memory Module: A DIMM, or Dual Inline

Memory Module, is a memory unit used by the computer.

It contains RAM chips mounted on a small printed circuit

board that plugs into DIMM slots making for easy installa-

tion and removal.

EIDE: See Enhanced Integrated Drive Electronics.

Enhanced Integrated Drive Electronics: This is a standard

electronic interface, commonly called EIDE, between a

computer and its mass storage devices. EIDE is an en-

hancement to IDE (see below) which makes it possible to

address a hard drive larger than 528 MB. It also provides

faster access to the hard drive, support for Direct Memory

Access (DMA), and support for additional drives, including

CD-ROM drives and tape drives.

Ethernet: A popular networking protocol originally

developedatXerox.Standardethernetcommunicatesat

10Mbps and fast ethernet communicates at 100Mbps

or 1 GB.

Extents File: This le in the volume structures contains

the extent data for the volume. Extents are the separate

components of a fragmented le.

File System: Every volume uses a le system to organ-

izetheinformationitstores.Alesystemkeepstrackof

where les are located on the volume. The Macintosh typi-

cally uses either the HFS or HFS+ ling system.

FireWire: FireWire is Apple’s name for the high speed

IEEE 1394 bus standard. It can handle data rates of up to

400Mbps and is commonly used to connect hard drives

14.5

and video cameras to the Macintosh. The newer IEEE

1394b specication, which Apple calls FireWire 800, han-

dles data rates of 800Mbps.

Firmware: This is software that has been permanently

recorded into ROM (Read Only Memory). It is a cross be-

tween hardware and software.

GB: See Gigabyte.

Gigabyte: A Gigabyte consists of 1,024 Megabytes.

Head: A mechanism that reads, writes, or erases data on a

storage medium.

Head Crash: A Head Crash refers to contact between a

read/write head and a oppy or a hard disk surface. This

usually results in damage to the disk surface and loss

of data.

HFS: HFS stands for Hierarchical Filing System and is also

known as Macintosh OS Standard Format. It is a method of

formatting storage devices for Macintosh computers.

HFS+: Macintosh OS Extended Format is a method of for-

matting storage devices attached to Macintosh comput-

ers. Compared to the earlier HFS it supports more les and

increases the eciency of storage on larger drives.

I/O: An acronym for input/output.

IDE: See Integrated Device Electronics.

IEEE: See Institute of Electrical and Electronics Engineers.

Initialize:Initializationisaprocessofpreparingastorage

mediumtoholddata.Duringinitialization,thevolume

structures for a volume are created specifying locations

forstoringdata.Initializationerasesdirectoryinformation.

However; the data in les themselves may be left on

the volume.

Institute of Electrical and Electronics Engineers: Often

referred to as IEEE (I-triple-E), this is a professional organi-

zationthatsetsmanystandardsusedinthecomputer

and electronics industries. For example, AirPort is another

name for the IEEE 802.11b networking standard.

Integrated Device Electronics: This is a standard electronic

interface, commonly called IDE, between a computer and

its mass storage devices. IDE devices (sometimes called

ATA devices) conform to the ATA (AT Attachment Standard,

see reference earlier in the Glossary) which species how

peripherals communicate with the computer.

Journaling: Journaling is a feature available for HFS+

volumesunderMacOSX10.2.2andabove.Ifjournaling

is enabled on a volume then the le system maintains a

transaction log of reads and writes. This makes the le

system more robust and helps protect against data loss in

the event of an unexpected shutdown.

Kb: Kilobit or 1024 bits.

KB: Kilobyte or 1024 bytes.

Kbps: Kilobits per second.

14.6

KBps: Kilobytes per second.

LAN: See Local Area Network.

Local Area Network: A Local Area Network, or LAN,

consists of a group of computers and peripherals in close

proximity that have been set up so that they can com-

municate with one another. Macintosh computers usually

connect via Ethernet or LocalTalk.

Logic Board: The logic board is the main component of

any computer system. It might even be called the brain of

the computer since it contains all the parts necessary to

perform the many calculations that computers perform.

This is where the CPU, the memory, and the main compo-

nents of the computer are located.

Logical Unit Number: The SCSI bus identication number.

Low-Level Format: Low-level formatting removes and then

recreatesthemarkersthatorganizethedataonadrive.All

data on the drive is usually erased. Low-level formatting is

usuallyfollowedbyinitializing.

LUN: See Logical Unit Number.

MAC address: see Media Access Control address.

Mb: See Megabit.

Mbps: Megabits per second.

MB: See Megabyte.

MBps: Megabytes per second.

MHz:SeeMegahertz.

Media Access Control address: The Media Access Control

address, or MAC address, of an ethernet interface is a

unique 48-bit address that is encoded directly into the

ethernet adapter hardware by the manufacturer. It con-

sists of 6 hexadecimal numbers separated by colons. For

example: 00:00:c0:34:f1:52.

Megabit: A unit of measure for storage capacity. One

megabit is equivalent to 1,048,576 bits.

Megabyte: A unit of measure for storage capacity. One

megabyte is equivalent to 1,048,576 bytes.

Megahertz:Ameasureoffrequency—onemillioncycles

per second.

Mount Point: The mount point of a volume is the location

in the directory hierarchy that the volume appears. The

volume appears as a sub-directory of the mount point. In

MacOSXthisistypically/Volumes.

OS: OS stands for Operating System. This is the software

that allows you to interact with your computer and that

keeps track of les, peripherals, programs, networks, etc.

14.7

Parallel: Parallel, the converse of serial, is a method of

transmitting simultaneous bits of information over a

multi-paired connector. This is much faster than serial

communication since multiple bits of data can be trans-

mitted at once. The SCSI port is a parallel port.

Partition: Disks contain sections called partitions. A parti-

tion is a block of addresses on a drive that the disk driver

assigns to a specic volume.

Partition Map: The partition map holds information about

the start, length, and type of each partition on a disk.

Parameter RAM: Also called PRAM. This is a dedicated chip

that holds information that is vital to the Macintosh com-

puter. A battery supplies power to the PRAM so that when

the Macintosh is shut down it will retain this information.

Information contained in this chip includes keyboard set-

tings, mouse settings, and the startup device.

PCI: The standard bus on the newer Macintosh comput-

ers. It supersedes NuBus.

PRAM: See Parameter RAM.

PRAM Battery: The PRAM battery is a 3 to 4 1/2 volt battery

that supplies the parameter RAM chip with power once

the Macintosh has been turned o.

Protocol: A set of rules that dictate the operations of com-

puters to allow them to communicate.

QuartzExtreme:QuartzExtremeisthenameforenhanced

graphics routines (such as high quality animations) that

AppleaddedinMacOSX10.4.Itissupportedbythevideo

subsystem on faster G4 and later Mac models. The Graph-

ics/Displays area of System Proler will indicate whether

ornotthecomputersupportsQuartzExtreme.

RAID: See Redundant Array of Independent Disks

RAM: See Random Access Memory.

Random Access Memory: RAM is an acronym for Random

Access Memory. This is memory that stores the data and

programs used by your computer. Its contents are lost

when the computer is turned o. RAM generally comes in

packages called DIMMs and SIMMs.

Read Only Memory: ROM is dedicated chips that perma-

nently store information. In the Macintosh the chips con-

tain operational routines that the computer employs. ROM

does not lose its information when the power is turned o.

The information is permanent and cannot be changed.

14.8

Redundant Array of Independent Disks: Usually referred

to as RAID. RAID software allows multiple physical hard

drives to be combined so as to appear as one or more

volumes. This allows for faster and/or more reliable disk

access. The most common RAID standards are RAID0 (or

striped) where data is distributed in parallel across mul-

tiple drives for increased speed and RAID1 (or mirrored)

where the same data is written simultaneously to multiple

drives for reliability.

Refresh Rate: This is the rate at which an image is repeated

on a display surface such as a monitor.

Resolution: A measurement of the sharpness of an image;

either by the number of pixels or the number of lines and

columns on the display screen.

RGB: RGB is a video format standing for Red, Green and

Blue providing color images on a CRT. By combining dif-

ferent levels of the red, green, and blue signals almost any

color can be displayed on a monitor.

ROM: See Read Only Memory.

Root Directory: The top level of a volume’s directory. It

may contain subdirectories (otherwise known as folders).

SCC: See Serial Communication Controller.

SCSI: See Small Computer System Interface.

SCSI Chip: The SCSI Chip allows the Macintosh to com-

municate with SCSI devices. Most Macintosh computers

equipped with SCSI use the 8530 SCSI chip.

SCSI Conict: A SCSI Conict occurs when two or more

SCSI devices share the same ID number on the same bus.

This can keep the devices from working reliably or from

working at all.

Sector: A Sector is a portion of a disk drive’s track and

typically contains 512 bytes of data.

Self-Monitoring Analysis and Reporting Technology: .This

is a technology built into most modern hard drives. It is an

industry standard that employs predictive diagnostics and

analysis to help foresee a drive failure BEFORE it happens.

Serial: Serial is a communication format for sending infor-

mation in consecutive bits of data, in contrast to parallel

in which multiple bits of data are sent simultaneously. The

advantage of using this format is that it requires less data

lines, usually two, whereas parallel can require up to 50.

Serial Communication Controller: The Serial Communica-

tion Controller or SCC is an integrated circuit that super-

vises all serial processing on the Macintosh.

Small Computer System Interface: Also known as SCSI, this

is a parallel interface standard that species how periph-

erals communicate with the computer. There are several

varieties of SCSI. The transfer rate for standard SCSI built

into SCSI-equipped Macs is 4MBps. The maximum rate for

14.9

SCSI is 80MBps.

SIMM: See Single Inline Memory Module.

Single Inline Memory Module: A SIMM, or Single Inline

Memory Module, is a memory unit used by the computer.

It contains RAM chips mounted on a small printed circuit

board that plugs into SIMM slots allowing for easy installa-

tion and removal.

S.M.A.R.T: see Self-Monitoring Analysis and

Reporting Technology

Startup File: This le in the volume structures, if present,

contains information used by the ROM to determine what

program will boot the computer.

Termination: A technique of capping the end of a signal

bus to prevent resonance from occurring within a signal. A

SCSI bus requires a terminator at each end.

USB: USB or Universal Serial Bus is a medium speed proto-

col for connecting devices to a computer. It has supersed-

ed ADB on Macintosh computers. USB is hot-swappable

and has a maximum transfer rate of 12Mbps. The new USB

2.0 standard has a raw data rate at 480Mbps.

Versatile Interface Adapter: Versatile Interface Adapter or

VIA is an integrated circuit used to control user input on

the Macintosh. The VIA is attached to the ADB circuitry, as

well as the NuBus, to control signal timing.

Volume: A volume refers to a logical storage unit seen

by the computer as a single item. This may be a oppy

disk, an entire hard drive, or one or more partitions on

hard drives. Although a partition is typically seen as one

volume, a RAID volume may consist of more than one

partition on more than one drive.

Volume Header: This portion of the volume structures

contains important data about the volume as a whole.

Included is the volume name, number of les and folders,

and amount of free space.

Volume Structures: A collection of data structures on a vol-

umethatisusedbythelesystemtoorganizethestorage

of data on the volume. They include the Volume Header

and Catalog.

VRAM: VRAM, or Video RAM, is the memory that holds the

information that is displayed on your computer’s screen.

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