Command-Line Switches for MSCDEX.EXE (87165)

The information in this article applies to:
    Microsoft MS-DOS operating system
    Microsoft Windows 3.0
    Microsoft Windows 3.0a
    Microsoft Windows 3.1
    Microsoft Windows 3.11
    Microsoft Windows for Workgroups
    Microsoft Windows 95
    Microsoft Windows 98
    Microsoft Windows Millennium Edition

This article was previously published under Q87165


This article describes the command-line switches for Microsoft's CD-ROM Extension, Mscdex.exe, versions 2.21, 2.22, and 2.95.

Mscdex.exe is available from CD-ROM vendors, with the MS-DOS 6 Upgrade, 6.2 Upgrade, and 6.21 Upgrade, and with Windows 95/98.


Mscdex.exe is a CD-ROM "redirector." It hooks into the MS-DOS or Windows operating system the same way the network redirector does to obtain access to files that are not on local hard or floppy disks. As far as MS-DOS or Windows is concerned, CD-ROM drives look just like network drives. MSCDEX splices itself in front of the network redirector and takes requests belonging to CD-ROM drives and passes the rest to redirectors (such as network redirectors).

Command Line Switches

The following is the command line for MSCDEX.EXE:

MSCDEX.EXE: /D:x /M:n /E /V /L:x /S /K

The following table defines the MSCDEX.EXE command-line switches:
Switch                  Definition

/D:<device name>        - Allows you to specify a name for the device
                          driver. This name must be identical to the
                          device name used in the CONFIG.SYS file.

/M:<n>                  - Specifies the number of sector buffers used
                          to cache the path table of a CD-ROM disk.
                          Typically, each drive should have a minimum
                          of four to five buffers. The larger this
                          number is, the less your computer will have
                          to read directly from the CD-ROM drive.

/E                      - Tells MSCDEX.EXE to use expanded memory if
                          your system is using expanded memory.

/V                      - Displays information on memory usage
                          when you boot your PC.

/L:<drive letter>       - Allows you to specify the letter you want
                          to assign to the first CD-ROM drive.

/S                      - Allows the CD-ROM to be shared on MS-NET
                          based systems.

/K                      - Tells MSCDEX.EXE to use any KANJI (Japanese)
                          file structures, if present, rather than the
                          default of alphanumeric file structures.

Modification Type: Major Last Reviewed: 5/28/2003
Keywords: kbinfo TP_CS KB87165