Filename: CDROMDRV.TXT
WWW URL: http://www.firmware.com/support/bios/cdromdrv.htm
FTP URL: ftp://ftp.firmware.com/text/cdromdrv.txt
Revision: 08/27/99 TLS Micro Firmware Technical Support
Summary: General info on setting up CD-ROM drivers in CONFIG.SYS and
AUTOEXEC.BAT.
Under MS-DOS, two files are needed to access a CD-ROM drive: the driver for that particular drive (provided by the manufacturer) and MSCDEX.EXE, which is included with MS-DOS 6.x and all versions of WIN95/98.
The CD-ROM driver is loaded on bootup through CONFIG.SYS. MSCDEX.EXE is loaded on bootup through AUTOEXEC.BAT.
AUTOEXEC.BAT and CONFIG.SYS must both be located in the root directory of the boot drive, which may be a floppy drive (A:) or the first hard drive (C:). A PC will normally boot from drive C: unless there is a bootable disk in drive A:, in which case it will boot from that disk.
AUTOEXEC.BAT and CONFIG.SYS are both plain text files, which may be created and/or edited with any text editor, such as EDIT, which is provided with MS-DOS 6.x and all versions of WIN95/98.
To create or edit CONFIG.SYS in the root of drive C:, type EDIT CONFIG.SYS at the C:\> prompt. This may require that the EDIT command is present in the root directory or in a directory in the path or on a boot disk. Note that the EDIT.COM file with MS-DOS 6.x is only part of the editor - it actually uses QBASIC.EXE as an editor, so that file must be present as well. With WIN95/98, this is no longer true - EDIT.COM is the only file needed for the editor in WIN95/98.
The line to add to CONFIG.SYS would be:
DEVICE = C:\CDROM\driver.sys /D:MSCD001
(substitute the name of the driver for driver.sys in above example)
This assumes that there is a directory C:\CDROM and that the CD-ROM driver is located in this directory. You may need to create this directory and copy the driver to it. The /D: parameter is required. The D stands for device (has nothing to do with drive letter assigned to CD-ROM drive). The label after the colon can be any string as long as it matches the /D: label that is used on the MSCDEX line in AUTOEXEC.BAT. Also, this string cannot be a directory or file name. Some drivers may require additional parameters to indicate the port address and/or IRQ for the IDE interface where the CD-ROM drive is connected.
To create or edit AUTOEXEC.BAT in the root of drive C:, type EDIT AUTOEXEC.BAT at the C:\> prompt. The line to add to AUTOEXEC.BAT would be:
C:\CDROM\MSCDEX.EXE /D:MSCD001
This assumes that there is a directory called CDROM and that MSCDEX.EXE is present there. MSCDEX.EXE may also be located in the DOS directory or (on WIN95/98 systems) in the WINDOWS\COMMAND directory. The /D: parameter is required. The D stands for device (has nothing to do with drive letter assigned to CD-ROM drive). The label after the colon can be any string as long as it matches the /D: label that is used on the CD-ROM driver line in CONFIG.SYS.
After adding the above lines to AUTOEXEC.BAT and CONFIG.SYS on the boot drive, reboot the system and see if the CD-ROM drive is accessible. Test by inserting a CD-ROM into the drive (not an audio CD such as would be played in a stereo system) and do a DIR listing for that drive letter. If a DIR listing shows files on the CD-ROM, then the driver and MSCDEX loaded successfully. Also, watch for error messages from CONFIG.SYS and AUTOEXEC.BAT on bootup. An error such a "Bad command or filename" indicates that there is a spelling error in CONFIG.SYS or AUTOEXEC.BAT or a specified file or directory does not exist. An error message from MSCDEX may indicate that the driver in CONFIG.SYS did not successfully load, since it must load before MSCDEX will load. Sometimes the CD-ROM driver will give a specific error message, perhaps indicating that it cannot find the drive. This may indicate that the drive is not working or is not correctly installed or it may be that the driver requires some additional parameters on the line in CONFIG.SYS to tell it where the drive is.
Some CD-ROM drives come with a diskette that has an automatic installation program to install the needed driver. This diskette usually includes MSCDEX.EXE. It may be preferable to just run the installation program rather than following the above manual installation instructions. In many cases, the installation programs provided with CD-ROM drives have limitations or bugs, in which case the manual installation approach should work. Normally, the driver for the CD-ROM drive will be present on the diskette, perhaps in a subdirectory. In some cases the driver may be contained in a compressed file used by the install program. The driver will normally be a file with an extension of SYS.
If the driver for a particular CD-ROM drive has been lost, it is usually possible to download a driver from the manufacturer's web site. It may be necessary to open the case and have a look at the drive (which may require removing it) to determine the brand and model.
If you are installing a driver to access a CD-ROM drive just to install WIN95/98, you may be able to disable the driver after Windows is installed. WIN95/98 automatically supports most ATAPI CD-ROM drives. WIN95/98 will often change the path to MSCDEX.EXE in AUTOEXEC.BAT and may REM this line out. Usually, even though the driver is not required, it will not be disabled by the WIN95/98 installation. To disable the driver, edit CONFIG.SYS and add the letters REM (followed by a space) to the front of the line in CONFIG.SYS that loads the CD-ROM driver.
A WIN98 Startup disk may be able to access an ATAPI CD-ROM drive automatically, without having to configure any drivers for it.
ATAPI CD-ROM drives must be correctly jumpered as master or slave. Also, any other drives on the same cable must also be correctly jumpered as master or slave. Refer to manufacturers documentation or website for jumper info. Also, the colored edge of the ribbon cable must be matched to PIN 1 where it connects to the drive and to the IDE interface.
CD-ROM drives are not normally set up in CMOS setup. The setting for the drive would normally be left at NONE or NOT INSTALLED. Some newer BIOSes will have a setting for ATAPI or CD-ROM or may autodetect a CD-ROM drive. This feature is present in the BIOS just to support booting from a bootable CD-ROM. Even in such BIOSes the CD-ROM drive should still work if just set to NONE or NOT INSTALLED. The system BIOS normally has nothing to do with CD-ROM drives, execpt perhaps to enable the interface that the drive is plugged into. If a CD-ROM drive is plugged into an IDE interface on the motherboard, you may need to check and see if there is an option in CMOS setup to enable or disable this interface and make sure it is enabled.