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Q93234: How a CD-ROM Drive Letter Is Assigned

Article: Q93234
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:5.x,6.0,6.2,6.21,6.22
Operating System(s): 
Keyword(s): 
Last Modified: 17-DEC-2000

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The information in this article applies to:

- Microsoft MS-DOS operating system versions 5.0, 5.0a, 6.0, 6.2, 6.21, 6.22 
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SUMMARY
=======

The drive letter for a CD-ROM drive is assigned by the MSCDEX.EXE command in the
AUTOEXEC.BAT file, not by the device specific driver in the CONFIG.SYS file.
MSCDEX.EXE loads the Microsoft CD-ROM Extensions.

MORE INFORMATION
================

MSCDEX.EXE assigns a CD-ROM the next available drive letter. For example, if a
computer has two floppy drives (drives A and B) and one physical hard drive with
two partitions (drives C and D), then MSCDEX will assign the CD- ROM the drive
letter E. It is possible to specify a drive letter to the CD- ROM by using a
command line switch on the MSCDEX.EXE of /L:x, where x is the drive letter you
want to assign. To assign a CD-ROM the drive letter H, you would use the
following command:

  MSCDEX /L:H

When using a RAM Drive along with a CD-ROM, the RAM Drive will be assigned the
first available drive letter, because RAMDRIVE.SYS (which loads in the
CONFIG.SYS) is loaded before MSCDEX. The CD-ROM will then be assigned the second
available drive letter.

Additional query words: 6.22 cdrom ramdrive

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Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS621 kbMSDOS622 kbMSDOS620 kbMSDOS600 kbMSDOS500 kbMSDOS500a
Version           : MS-DOS:5.x,6.0,6.2,6.21,6.22

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