Microsoft KB Archive/37241

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Older Versions of FDISK Do Not Remove Non-DOS Partitions

Article ID: 37241

Article Last Modified on 5/12/2003



APPLIES TO

  • Microsoft MS-DOS 2.11 Standard Edition
  • Microsoft MS-DOS 3.1
  • Microsoft MS-DOS 3.2 Standard Edition
  • Microsoft MS-DOS 3.21 Standard Edition
  • Microsoft MS-DOS 3.3 Standard Edition
  • Microsoft MS-DOS 3.3a
  • Microsoft MS-DOS 4.0 Standard Edition
  • Microsoft MS-DOS 4.01 Standard Edition
  • Microsoft MS-DOS 5.0 Standard Edition
  • Microsoft MS-DOS 6.0 Standard Edition
  • Microsoft MS-DOS 6.2 Standard Edition
  • Microsoft MS-DOS 6.21 Standard Edition
  • Microsoft MS-DOS 6.22 Standard Edition



This article was previously published under Q37241

SUMMARY

In MS-DOS versions 5.0 and later, FDISK.EXE allows non-DOS partitions to be deleted. For more information on this subject, query on the following words:

MS-DOS and 5.0 and FDISK and non-DOS and partition


The remaining information in this article applies to Microsoft MS-DOS versions 2.x, 3.x, and 4.x, but not 5.0 or later.

MORE INFORMATION

As a security measure, the MS-DOS FDISK.EXE utility will not remove or modify a partition made by another non-DOS operating system (such as XENIX). If your system contains another operating system in another partition (in addition to MS-DOS), this implies that this operating system understands about disk partitions. Instead of trying to get the MS-DOS FDISK.EXE utility to work with this other operating system, you should instead rely on the partitioning tools available with the non-DOS operating system.

For safety purposes, the MS-DOS FDISK.EXE utility prevents you from modifying non-DOS partitions; however, it is still possible to accidentally or intentionally modify the partition (or data) of this other operating system by using the ROM BIOS interrupt 13H (Disk I/O), or MS-DOS interrupt 25H/26H (Absolute Disk Read/Write).

If you are using MS-DOS version 4.01 or earlier and the non-DOS operating system does not have the ability to modify its own partition, a program that uses the ROM BIOS interrupt 13H could be used to modify the partition.

Another method of removing a non-DOS partition is to perform a low-level format of the disk, thus removing partition information from the disk.


Additional query words: appnote 6.22 2.x 3.00 3.10 3.20 3.21 3.22 3.30 3.30a 4.00 4.00a 4.01 4.01a 5.00 5.00a 6.00 6.20

Keywords: KB37241