MS DOS Command: MSCDEX.EXE

Reference from Microsoft MS-DOS cmd help

Description

Provides access to CD-ROM drives. MSCDEX can be loaded from your AUTOEXEC.BAT file or from the command prompt. (The device driver that came with your CD-ROM drive must be loaded from your CONFIG.SYS file. For more information, see Notes.)

The MSCDEX command should not be used after Windows has started.

Syntax

MSCDEX /D:driver [/D:driver2... ] [/E] [/K] [/S] [/V] [/L:letter] [/M:number]

Parameters

/D:driver1 [/D:driver2... ]	Specifies the driver signature of the first CD-ROM device driver. The driver1 parameter must match the parameter specified by the /D switch on the CONFIG.SYS command that starts the corresponding CD-ROM device driver The MSCDEX command must include at least one /D switch. To install additional CD-ROM device drivers, specify an additional /D switch for each device driver.
/E	Specifies that the CD-ROM driver be allowed to use expanded memory, if available, to store sector buffers.
/K	Specifies that MS-DOS should recognize CD-ROM volumes encoded in Kanji. By default, MS-DOS does not recognize Kanji CD-ROM volumes.
/S	Enables sharing of CD-ROM drives on MS-NET or Windows for Workgroups servers.
/V	Directs MSCDEX to display memory statistics when it starts.
/L:letter	Specifies the drive letter to assign to the first CD-ROM drive. If you have more than one CD-ROM drive, MS-DOS assigns additional CD-ROM drives subsequent available drive letters.
/M:number	Specifies the number of sector buffers.

Remarks

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:drivername 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 more information, see the SMARTDRV command.

Examples

Loading and enabling a single CD-ROM device driver

This example shows the relevant CONFIG.SYS and AUTOEXEC.BAT commands for a computer with one CD-ROM drive.

The CONFIG.SYS file contains the following DEVICE command:

device=c:\devices\cdromdrv.sys /d:mscd000

This command loads the device driver CDROMDRV.SYS, which came with the CD-ROM drive. The AUTOEXEC.BAT file contains the following MSCDEX command:

c:\dos\mscdex /d:mscd000 /l:g

This command enables the device driver that has the driver signature MSCD000. The /E switch specifies that the driver be allowed to use expanded memory, if available. The /L:G switch assigns the drive letter G to the CD-ROM drive.

Loading and enabling more than one CD-ROM device driver

This example shows the relevant CONFIG.SYS and AUTOEXEC.BAT commands for a computer that has two CD-ROM drives from two different manufacturers.

The CONFIG.SYS file contains the following DEVICE commands:

device = c:\aspi\aspicd.sys /d:mscd000

device = c:\cdrom\tslcdr.sys /d:mscd001

Each command loads the device driver that came with that CD-ROM drive. The AUTOEXEC.BAT file contains the following MSCDEX command:

c:\dos\mscdex /d:mscd000 /d:mscd001 /l:j

This command enables both device drivers. The first driver has the driver signature MSCD000; the second has the driver signature MSCD001. The /L:J switch specifies that the first CD-ROM drive, MSCD000, will be drive J and the second CD-ROM drive will be drive K.