MS-DOS 6.2 Defrag Uses XMS Memory When Available (103520)

The information in this article applies to:
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q103520


Microsoft MS-DOS 6.0 Defragmenter (Defrag) relies exclusively on conventional memory to hold all drive file allocation table (FAT) data and the disk directory structure.

Both MS-DOS 6.0, 6.2, and 6.21 Defrag use a 12,000-byte upper memory block (UMB) for data storage if it is available. MS-DOS 6.2 Defrag uses up to 384 kilobytes (K) of extended (XMS) memory, when available, to hold the FAT data for the drive. If you receive "out of memory" errors with MS-DOS 6.2 Defrag, increase conventional memory and/or XMS memory up to 384K.

NOTE: If /SKIPHIGH is specified, the 12,000-byte UMB and the 384K free XMS memory are not used.

If you have 384K of XMS memory and Defrag still does not run, free more conventional memory. If you cannot free more conventional memory by using a memory manager (such as EMM386.EXE) or by removing optional device drivers, you must reduce the number of files and directories on your drive to allow Defrag to run. This requires transferring, orbacking up and removing, files from your disk drive.


Modification Type: Major Last Reviewed: 11/19/1999
Keywords: KB103520