Microsoft

Get IT Done: Tips for creating the perfect Windows boot disk

Configure a bootable USB storage device


Over the years, I’ve used emergency repair disks (also commonly called boot disks) to troubleshoot Windows 9x systems more times than I can count. Unfortunately, the repair disk that Windows allows you to build is mediocre at best. So it’s best to make your own.

Make it bootable
You’ll first need to make your disk bootable so you can boot from the disk and use it to access the hard drives on unbootable machines. Open a command prompt window and enter the command Format A: /S. However, you must consider what version of Windows is running on the machine that you’re using to make the disk.

Running the Format+ A: /S command copies the Io.sys, Msdod.sys, and Command.com files from the PC to the floppy. These files make the disk bootable and enable the disk to access the contents of a local hard drive. Just remember that different hard drives use different types of partitions. I recommend using a machine running either Windows Me or Windows 98 to create your boot disk. Both of these versions of Windows support FAT-16 and FAT-32 file systems. Although there are versions of Windows 95 that support FAT-32, you’re usually better off using a newer version of Windows for the repair disk creation. But no matter which of these Windows versions you choose, the disk won’t be able to access the contents of NTFS partitions, such as those created by Windows NT, Windows 2000, and Windows XP. If you need NTFS access, I recommend going to the Winternals Software Web site and checking out ERD Commander or NTFSDOS.

Add CD-ROM capabilities
Once you’ve created a bootable disk, you must next make the disk capable of accessing a CD-ROM drive. This is by far the most difficult part of the process, because it involves finding a suitable driver. You need a DOS-based driver that's universally compatible with all IDE CD-ROM drives. But some manufacturers don’t even include DOS drivers with their CD-ROM drives any more. I’ve had the best luck by calling up friends who have old PCs in their offices and copying drivers off of those machines.

I’ve been unable to find a single driver that works with every single drive, but I have a Hitachi driver that comes close. To get around the compatibility problem, I placed several different CD-ROM drivers on my emergency repair disk. I set the disk up so that when I boot the system, I get a boot menu that lists several different choices for drives.

Creating the Config.sys file
So how do you create the Config.sys file? Begin by copying the Mscdex.exe file from the Windows machine’s \WINDOWS\COMMAND folder to the disk. Next, copy the drivers you’ve selected to the disk. Then, create a Config.sys file on the disk that sets up the menu system.

Below is the actual Config.sys file from my emergency repair disk. The [MENU] section sets up the menu colors and the menu items. Notice that each menu item has a two-letter code followed by a description. The description is actually displayed. The code corresponds to one of the bracketed sections below. When you select a menu option, the operating system looks at the code associated with the option and jumps to that section of the file.

The [COMMON] section is reserved for any commands that should be processed regardless of menu choice.
[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


Creating the Autoexec.bat file
The contents of the Autoexec.bat file will differ widely depending on what you want your disk to do. If you need to be able to use a CD-ROM drive, the Autoexec.bat file must contain a line that loads the Mscdex.exe file.

Below, I’ve included my actual Autoexec.bat file. Notice that I’ve begun the file with a few common commands, followed by the Goto %Config% command. This command tells the file that the Config.sys file contained a menu. Below that line, you’ll see the same two letter codes that I used before. Below each code is the appropriate Mscdex.exe command for the given driver. At the end of the file is an End statement. This statement simply tells Autoexec.bat that this is the end of the menu choices, not the end of the file. So you can place additional commands that would be processed regardless of menu choice below the End command.
@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


Add utility files
The last step of the process is to put some files on the disk that will be beneficial to you in crisis situations. Ideally, it would be nice to include the entire contents of the \WINDOWS\COMMAND folder. However, a floppy disk has a very limited capacity, so you must pick and choose which files to include. I’ve experimented a lot over the years, and determined the following files to be of the most benefit to me:
  • Attrib.exe
  • Chkdsk.exe
  • Deltree.exe
  • Device.com
  • Diskcopy.com
  • Doskey.com
  • Edit.com
  • Edit.hlp
  • Extract.exe
  • Fdisk.exe
  • Format.com
  • Himem.sys
  • Mem.exe
  • Mode.com
  • More.com
  • Mscdex.exe
  • Scandisk.exe
  • Sys.com
  • Xcopy32.exe
  • Xcopy.exe

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