Microsoft KB Archive/71318

CHKDSK Fails on RAM Disk with More Than 512 Directory Entries PSS ID Number: Q71318 Article last modified on 07-14-1993 PSS database name: O_MSDOS

4.00 4.01 4.01a

MS-DOS

Summary:

A RAM disk created with the RAMDRIVE.SYS device driver can have up to 1024 root directory entries. The MS-DOS versions 4.x CHKDSK command, however, cannot handle a RAM disk with more than 512 root directory entries. When the CHKDSK command is executed on such a RAM disk, it gives the error “Invalid media type” and may cause the machine to stop (hang).

Workarounds
  Use the RAMDRIVE.SYS device driver only with 512 or fewer root directory entries and subdirectories created for any additional files. -or-   Do not run the CHKDSK command on the RAM disk. 

Microsoft has confirmed this to be a problem with MS-DOS versions 4.00, 4.01, and 4.01a. This problem does not occur in later versions of MS-DOS.

Additional reference words: 4.00 4.01 4.01a noupd

Copyright Microsoft Corporation 1993.