Ontrack Disk Manager Support for MS-DOS Partitions (73198)

The information in this article applies to:
    Microsoft MS-DOS operating system 3.1
    Microsoft MS-DOS operating system 3.2
    Microsoft MS-DOS operating system 3.21
    Microsoft MS-DOS operating system 3.3
    Microsoft MS-DOS operating system 3.3a
    Microsoft MS-DOS operating system 4.0
    Microsoft MS-DOS operating system 4.01
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a

This article was previously published under Q73198


Ontrack Disk Manager partitioning software supports a primary MS-DOS compatible boot partition. Disk Manager can create these partitions to be compatible with FDISK. The compatibility of this partition with various MS-DOS versions depends upon the version of Disk Manager used to create the partition.

Do not delete Disk Manager partitions; doing so can reduce the usable size of the partition.


Disk Manager versions 3.x are compatible with MS-DOS versions 3.x. Therefore, the same partitioning limitations apply--that is, Disk Manager versions 3.x support a maximum of 32 MB for an MS-DOS compatible partition.

Disk Manager versions 4.x are compatible with MS-DOS versions 5.0 and earlier. If you use the /4 switch when invoking Disk Manager, it can create partitions up to the limitations of DOS 4.0x--that is, the BIOS limitation of 1024 cylinders by 256 heads by 63 sectors per track maximum. This partitioning scheme is also compatible with MS-DOS 5.0.

Disk Manager also creates non-DOS partitions for use in working around the 3.x 32 MB logical drive limit. Disk Manager can also be used to to support a hard drive type that is not supported by the BIOS. This commonly occurs with the following configurations:
    A hard drive with more than 1024 cylinders, 63 sectors per track, or 255 heads -or-

    An XT system with a hard drive larger than 20 MB
If Disk Manager is being used to support a drive not supported by the BIOS, deleting the partition will disable Disk Manager's support and reduce the usable hard drive space.

The product included here, Disk Manager, is manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

For more information on installing MS-DOS on a Disk Manager partition, query on the following words here in the Microsoft Knowledge Base:


Modification Type: Major Last Reviewed: 11/26/2003
Keywords: KB73198