Article ID: 106419 - View products that this article applies to.
This article was previously published under Q106419
IntroductionThere are currently several different versions of MS-DOS in the personal-computer environment, both in the OEM-licensed versions and in the Microsoft packaged-product versions. The hard-disk-management capabilities of MS-DOS vary from one version to another. For example, MS-DOS versions 3.2 and 3.21 can address a single hard-disk partition of up to 32 megabytes (MB); MS-DOS version 3.3 can address multiple hard-disk partitions, with a primary DOS partition of up to 32 MB and an extended DOS partition containing logical drives of up to 32 MB each; and MS-DOS versions 4.0, 4.01, 5.0, 6.0, and 6.2 can address multiple hard-disk partitions with sizes up to 2 gigabytes (GB).
For those using versions of MS-DOS that have lesser levels of hard- disk support, such as MS-DOS versions 3.2 and 3.21, there are a number of third-party hard-disk-management software packages that allow MS- DOS to access multiple partitions and/or partitions in excess of 32 MB. However, these third-party packages may use non-DOS constructs to assist in managing the hard disk, possibly including non-DOS partitions. These non-DOS constructs can cause problems when you upgrade to later versions of MS-DOS because versions of MS-DOS earlier than 5.0 assume that non-DOS constructs are owned by another operating system and, therefore, do not use, delete, or change non-DOS partitions or other non-DOS constructs in any way.
To detect if your system makes use of Drive Overlay software, see the following article:
WARNING: Some computers require the use of third-party hard-disk- partitioning software because the system ROM BIOS does not fully support the drive parameters of the hard disk that is being used or because the hard disk has more than 1024 data cylinders. If you are unsure if your system supports your hard disk, consult your hardware manufacturer or the manufacturer of your partitioning software before proceeding.
(https://support.microsoft.com/kb/186057/EN-US/ )How to Tell If Drive Overlay Program Is Installed in Windows
Using Debug to Remove a Non-DOS PartitionThe Debug script on the following page, used with the MS-DOS Debug program, deletes non-DOS partitions when you upgrade to a new version of MS-DOS, enabling the entire hard disk to be used by MS-DOS. It does so, however, by clearing out the entire partition table on the hard disk, which results in the deletion of ALL partitions on the hard disk. You need to use this method if your current version of MS-DOS cannot delete non-DOS partitions.
There are two ways to use the following Debug script:
WARNING: Because all data on your hard disk will be destroyed by this procedure, you must back up your hard disk before using this Debug script.
For additional information on how to recreate a partition using the Fdisk utility, click the article number below to view the article in the Microsoft Knowledge Base:
255867Non-DOS partitions on your hard disk are also erased if you perform a low-level format. Consult your hardware manufacturer for specific instructions on performing a low-level format on your hard disk.
(https://support.microsoft.com/kb/255867/EN-US/ )How to Use Fdisk and Format to Partition or Repartition a Hard Disk
WARNING: Performing a low-level format will completely erase all data on your hard disk, including all defined partitions.
Article ID: 106419 - Last Review: November 14, 2003 - Revision: 2.0
Retired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.