The CD ROM device driver must be loaded
Your CONFIG.SYS file must include a DEVICE or DEVICEHIGH command
that loads the CD ROM device driver that came with your CD ROM
drive. The CD ROM driver's command line should include a /D:drivername
parameter. This parameter assigns a driver name (also called
a driver signature) to the CD ROM device driver
The MSCDEX command must include a /D:drivername parameter that
matches the /D: parameter on the CD ROM device driver's command
line. MSCDEX uses the /D: drivername parameter to identify the
correct CD ROM device driver. The driver name is usually a name
similar to MSCD000. Each CD ROM device driver currently in use
must have a unique driver name.
Limit on number of logical drives
The number of logical drive letters available on your computer
can limit the number of CD ROM drives you can have. The number
of logical drives is determined by the LASTDRIVE command in
your CONFIG.SYS file. By the time MSCDEX loads, some of the
available drive letters might be used by other programs, such
as a network, Drivespace, or Doublespace.
SMARTDrive and MSCDEX
If you use SMARTDrive, make sure the MSCDEX command appears
before the SMARTDRV command in your AUTOEXEC.BAT file. SMARTDrive
can significantly speed up your CD ROM drive by read-caching
it. By default, when SMARTDrive loads, it checks for the presence
of MSCDEX; if MSCDEX is present, cd rom caching is enabled.
For the complete help file, goto the utilities
page and download the OLD DOS UTILITIES.