Lab 5-7 Creating a REAL Windows 98 ERD

As you probably know, both Windows 95 and Windows 98 allow you to create an emergency repair disk (ERD). However, if you've ever looked at the contents of this disk, you may have questioned its ability to help you out of a jam. For example, in some versions of Windows 95, this disk contains nothing more than the files necessary for booting to a DOS prompt from the disk. Although subsequent releases of Windows 95 and Windows 98 include more files on the ERD, you're still better off creating your own repair disk. In this article, we'll show you how to make a truly effective emergency repair disk.

What should an ERD be able to do?

Ideally, a good ERD should be able to recover any PC from any crash. However, such versatility is impossible because of limited disk capacity, and because it's impossible to predict every potential problem. Therefore, you need to make the best possible use of the space you do have on the disk. To do so, it helps to make a list of the main functionality you hope to gain from your ERD. Such a list may contain things like the following.

Bootable

Since the entire purpose of an ERD is to repair Windows, you must assume when you create the disk that Windows doesn't work. Therefore, it's important to make the disk bootable so that you can access the hard disk of a damaged computer via a DOS prompt.

Access CD-ROM drives

As you probably know, you can't access a CD-ROM drive through DOS unless you've loaded drivers for the CD-ROM drive. Because virtually all software ships on CD-ROM, it's extremely important for your ERD to be able to access your CD-ROM drive. You should also keep in mind that you'll probably be using this disk in a variety of PCs. Therefore, if possible, it's a good idea to set up a multiboot environment on your disk that allows you to use a menu to load the driver for any CD-ROM drive in your organization. Doing so isn't as difficult as you might think; we'll show you how to do this later on.

Repair a damaged hard disk

Because corrupted files cause many Windows problems, you should consider making a disk that's capable of scanning your hard disk for damaged files and directories.

Maintain files and disks

Because you'll be working in a DOS environment when using your ERD, it's especially helpful to include files for maintaining your hard disk and files for maintaining individual files. Although many commands such as COPY and ERASE are built into DOS, other, more powerful commands aren't. Later on, we'll show you which of these files you should include on your disk and why.

Edit text files

Some of Windows' most critical files are text based. When there's a problem with Windows, you need to be able to make changes to files such as Config.sys, Autoexec.bat, System.ini, Win.ini, and other configuration files. Making these changes is virtually impossible without a text editor. Therefore, it's important to include a text editor on your ERD.

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Our disk

So far, we've given you a general explanation of what functionality you should include in your ERD. Now it's time to go over the specifics of creating such a disk.

Making the disk bootable

To begin making your ERD, boot your computer in the usual manner and open an MS-DOS Prompt window. Next, insert a blank disk and type the command FORMAT A: /S

Doing so will create a bootable floppy disk.

Adding the CD-ROM driver

Once you've made a bootable disk, you need to add the CD-ROM drivers to it. If you look at your computer's Config.sys file, you should see a command similar to the following:

DEVICE=C:\CDROM\D011V110.SYS /D:MSCD0000

Because this command varies from computer to computer, yours may be slightly different. To add CD-ROM drivers to your ERD, copy your Config.sys file to the floppy disk. Now, edit the Config.sys file on your disk and remove each command except for the CD-ROM driver command. Then, change the path of the device driver from the C drive to the root directory of the A drive. For example, if your original CD-ROM driver command looked like our earlier example, you'd change it to

DEVICE=A:\D011V110.SYS /D:MSCD0000

Now, copy the file specified in your CD-ROM driver command from its original location on your hard disk to the root directory of the disk you're creating. For example, if your original command was the one we've been using, you'd copy the file D011v110.sys from C:\Cdrom to A:\.

The device driver is only half of the necessary CD-ROM files. Normally, Windows automatically loads another file to make the CD-ROM drive functional. However, in DOS you must manually load a similar file. To do so, copy the file Mscdex.exe from the \Windows\Command directory to your ERD's root directory. Next, create an Autoexec.bat file on your disk. Your Autoexec.bat file should contain a command similar to the following:

A:\MSCDEX /D:MSCD0000

The A:\MSCDEX portion of this command will work for all computers. The /D:MSCD0000 portion of the command will vary depending on your device driver. Notice that part of our device driver command contains /D:MSCD0000. Whatever your device driver command contains in this location, you'll attach to the end of your MSCDEX command. For example, if your Config.sys file contains the following command, you'd use the command below it in Autoexec.bat:

DEVICE=A:\BPCDDRV.SYS /D:BPCDDRV$
A:\MSCDEX /D:BPCDDRV$

Next, reboot your computer with the ERD and make sure you can access your CD-ROM drive. As we mentioned earlier, it's helpful to have your disk contain drivers for each type of CD-ROM drive in your company. For example, in Figure A, you can see that our disk boots to a menu we can use to select the driver that we want to use for the CD-ROM drive.

Figure A: This menu lets us select the CD-ROM driver that our ERD will load.

Although creating such a menu may seem complex, it's actually quite simple. DOS has all of the menu commands built in—you need only make Config.sys and Autoexec.bat files that use this built-in functionality. Below is a sample Config.sys file. You can use our sample file to create your own multiboot environment.

Sample Config.sys

[MENU]
MENUCOLOR=15,1
MENUITEM=AZ, AZI CD-ROM Drivers
MENUITEM=HP, Goldstar CD-ROM Drivers for HP Vectra
MENUITEM=MC, Hitachi CD-ROM Drivers
MENUITEM=BP, Back Pack CD-ROM Drivers
MENUITEM=SY, Sony External CD-ROM Drivers
MENUITEM=NN, No CD-ROM Drivers
 
[COMMON]
device=himem.sys
device=drvspace.sys
 
[AZ]
REM AZI CD-ROM Drivers
DEVICEHIGH=a:\SGIDECD.SYS /D:MSCD000
 
[HP]
rem The following line is for the HP Vectra
DEVICEHIGH=a:\gscdrom.SYS /D:MSCD000
 
[MC]
REM Standard Hitache CD-ROM Drivers
DEVICEHIGH=a:\d011v110.SYS /D:MSCD000
 
[BP]
rem the following line is for the backpack CD-ROM
device=a:\bpcddrv.sys /d:bpcddrv$
 
[SY]
rem the following line is for the external Sony CD-ROM
DEVICE=SLCD.SYS /D:SONY_000 /B:340 /M:P /V /C /E:2
 
[NN]
rem No CD-ROM Drivers

Notice the MENUITEM commands at the beginning of the file. Each menu item contains two initials followed by a description that will appear on the actual menu. When the user selects a menu choice, the Config.sys file will process all instructions in the [COMMON] section and all instructions in the section whose initials match those specified in the MENUITEM command.

The Autoexec.bat file works in a similar manner. DOS processes the commands at the beginning of the Autoexec.bat file. When DOS reaches the GOTO %CONFIG% command, it causes the command interpreter to skip to the section of Autoexec.bat that matches the initials specified in Config.sys's MENUITEM command. Here is a sample Autoexec.bat file:

Sample Autoexec.bat

@echo off
prompt $p$g
path=a:\;c:\windows\command;c:\windows
GOTO %CONFIG%
 
:AZ
REM AZI CD-ROM Driver
mscdex /d:mscd000
GOTO END
 
:HP
REM Goldstar CD-ROM Driver for HP Vectra
mscdex /d:mscd000
GOTO END
 
:MC
REM Hitachi CD-ROM Driver
mscdex /d:mscd000
GOTO END
 
:BP
REM Back Pack CD-ROM Driver
MSCDEX /D:BPCDDRV$
GOTO END
 
:SY
REM Sony CD-ROM Driver
MSCDEX /D:SONY_000
GOTO END
 
:NN
REM No CD-ROM Driver
GOTO END
 
:END
Rem End of file

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Other files to add to your disk

When you have your CD-ROM driver or drivers working, you should add several other files to your ERD. Below is a list of these files and the reason for including them. Unless we've specified otherwise, each of these commands are available in the \Windows\Command directory.

Sys.com

The Sys.com command allows you to make any floppy disk or hard disk bootable. For example, if you were working on a computer whose boot sector had been destroyed by a virus, you might run the command SYS C: to add the Io.sys, Msdos.sys, and Command.com files to the hard disk.

Attrib.exe

The Attrib.exe program is critical for working with three types of files in a DOS environment. By following the ATTRIB command with a filename, a plus or minus sign, and the letter H, R, or S, you can add or remove the hidden, read-only, and system attributes, respectively from a file. For example, if you wanted to make every file in your current directory visible, you could type this command to remove the hidden attribute: ATTRIB *.* -h

To hide a visible file, you'd change the minus sign after the file name to a plus.

Mem.exe

The Mem.exe command is useful for viewing what's currently loaded in memory. To use this command, simply type MEM /C.

XCOPY*.*

XCOPY*.* includes all Xcopy and Xcopy32 files. The XCOPY command works exactly like the COPY command. However, you can add the /S switch to copy subdirectories, while the COPY command can copy only the current directory. For example, if you wanted to copy the current directory and all of its subdirectories to the D drive, you'd type XCOPY *.* /S D:

Deltree.exe

If you've ever tried to delete a large directory structure from the DOS prompt, you know how tedious it can be. You must remove the contents of each subdirectory individually before you can erase the main directory. For example, suppose you had a directory called Letters that contained the subdirectories A, B, and C. Using the normal DOS commands, you'd have to type the following sequence of commands to remove the Letters directory:

CD\LETTERS\A
ERASE *.*
CD..
RD A
CD B
ERASE *.* 
CD..
RD B
CD C
ERASE *.*
CD..
RD C
ERASE *.*
CD..
RD LETTERS

This long sequence of commands can be easily replaced by typing the simple command DELTREE LETTERS. Needless to say, the DELTREE command is a big timesaver.

EDIT.*

The Edit files allow you to use the MS-DOS EDIT program. The EDIT program is a text editor that you can use to alter system files such as Config.sys, Autoexec.bat, and System.ini, to name a few.

Chkdsk.exe

Although CHKDSK's repair capabilities are obsolete, using the CHKDSK command is still the quickest method in a DOS environment to check your hard disk size and remaining free space. To do so, simply type CHKDSK followed by the letter of the drive you want to check.

Format.com

The FORMAT command is useful for formatting blank floppies. You can also use it to reformat a damaged hard disk.

Diskcopy.com

The DISKCOPY command duplicates a floppy disk. To use this command, type DISKCOPY followed by the source drive and the destination drive. For example, you might type

DISKCOPY A: A:

Extract.ext

If you've ever looked at the contents of your Windows CD, you probably know that all the files that make up Windows are stored in a compressed format within CAB files. If you need to replace a damaged Windows file, you can use the EXTRACT command to decompress the file you need. For detailed instructions on using this utility, type EXTRACT /?.

Mode.com

Occasionally, a problem may result in your not being able to read the screen. If this happens to you, you can use the mode command to return the screen to a readable state. For example, to view a standard DOS format screen you'd type MODE CO80.

Scandisk.exe

If you've used Windows for any time at all, you're probably already familiar with the Scandisk utility. Scandisk allows you to correct hard disk problems.

Fdisk.exe

The FDISK command can be used to repartition your hard disk. You should be cautious when using FDISK, because once you delete a partition, you can't recover it through conventional means.

Doskey.com

The DOSKEY command allows you to repeat commands you've already typed by pressing the up arrow. This shortcut is especially handy if you're doing a complex procedure with a lot of repetitive typing.

More.com

Using the MORE command causes the computer to show you only one screen full of information at a time. For example, suppose you have a long text file called Readme.txt. If you type the command TYPE README.TXT the computer will display the file too quickly to read. However, typing TYPE README.TXT |MORE will cause the computer to display the file while pausing after each screen full of information.

Himem.sys

You may have noticed that we used the Himem.sys command in Config.sys. We did this to load our CD-ROM drivers into high memory and preserve precious conventional memory. You can use Himem.sys to load a variety of drivers into high memory.

PKZIP and PKUNZIP

Many times, when trying to repair a malfunctioning computer, you'll have to use a patch that's stored in ZIP format. Under normal circumstances, you'd probably use a utility like WinZip to decompress such a file. However, if Windows won't load, you won't be able to use WinZip. PKZIP and PKUNZIP offer similar functionality to WinZip, but they work in a DOS environment. You can download these utilities from http://www.pkware.com .

What about XP and Vista?? Since Windows 2000 the CD ROM has served as the Emergency Repair Disk. You can insert and boot from the CD and then run the command console to repair, delete, and replace files. We will use the command console more in Networking.

Keep this disk for your lab test! Now take the ERD quiz on Examview!

1. Create a Windows 98 emergency startup disk.

2. Copy the cabinet file to a new directory on the disk.

3. Get a printed list of the files in the cabinet file.

4. Extract all files from the cabinet file into the new directory.

5. Get a printed list of the files in the new directory.

Requirement	Completed (10)	Incomplete (5)	Not attempted (0)
Create a Windows 98 startup disk
Extracted cabinet files
Created new directory
List of files in the new directory

So…what is a cabinet file?