Creating a bootable disk with CD-ROM support

In order for your CD-ROM (also used in this article to mean DVD-ROM, CD-RW, CD-R, DVD-RW, DVD-R and other similar optical drives) drive to function in a MSDOS environment, that is when none of the Windows components or Windows drivers are loaded, you need to load a real mode CD-ROM driver and a small program (MSCDEX.EXE) that initializes it and assigns it a drive letter. In summary, this is done by specifying a line in the CONFIG.SYS file that loads the driver, with a switch that assigns an “alias” to it. Next, a line in the AUTOEXEC.BAT file loads MSCDEX.EXE with the switch that references the alias defined in CONFIG.SYS for the CD-ROM driver.

Note: If all you need to do is get the CD-ROM drive to work so you can install or reinstall windows and you just don’t want to deal with all this, scroll down to download a .ZIP file to be extracted to a bootable floppy disk that will allow you to install Windows 95 from the CD-ROM. The driver will work with most IDE CD-ROM drives. If you are running Windows 98, separate (and easier) instructions are provided below as well.

Here is a typical example of loading a CD-ROM driver in the CONFIG.SYS file. Note the drive and path, you must change this to the correct path and filename of your real mode CD-ROM driver. Typically, it will have the file extension of .SYS as do most drivers that load in this manner.


Note that the /D: switch is NOT to assign a drive letter, think of that switch as “Driver” and the IDECD001 is the “alias” that we are assigning to the driver. Its importance will be apparent soon.

Here is an example of a line that loads MSCDEX.EXE in AUTOEXEC.BAT:


Note the usage of the /D: switch again. The alias (in this case IDECD001 must be identical to the one specified in the CONFIG.SYS file. When you go to edit these configuration files, look at your AUTOEXEC.BAT file and you may see that the MSCDEX line is already there, but is prefaced with “REM – BY WINDOWS SETUP”. This is because Windows 9x setup comments out that line because real mode drivers should not load with Windows, which has protected mode CD-ROM drivers of its own. In many cases you simply need to remove the REM – BY WINDOWS SETUP from the command and reboot to command prompt only, and you will have DOS CD-ROM support. Be sure to add REM in front of the line before you boot back into Windows 9x, as MSCDEX.EXE should not load with Windows 9x.

If you are lucky, or if your CD-ROM uses proprietary drivers, you may have a driver disk that came with your computer or CD-ROM drive. In that case all you will have to do is put the disk in the drive and type “setup” or “install”, (whichever the case may be, look for setup.exe or install.bat or install.exe etc. on the disk) and the setup will take care of this mess for you.

Now, why do you want CD-ROM support in DOS? If you need it to install windows, it would be best to set this up on a boot disk. If you want CD-ROM support because you want to play games, then additional commands/devices will be required in the configuration files and it would be probably easiest to set this up on the hard drive, (though you can use a boot disk for games too). I will provide some information for both, so scroll down for what is appropriate for you.

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glenda says

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