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Q37241: Older Versions of FDISK Do Not Remove Non-DOS Partitions

Article: Q37241
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:2.x,3.x,4.x,5.0,6.0,6.2,6.21,6.22
Operating System(s): 
Keyword(s): 
Last Modified: 17-DEC-2000

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The information in this article applies to:

- Microsoft MS-DOS operating system versions 2.11, 3.1, 3.2, 3.21, 3.3, 3.3a, 4.0, 4.01, 5.0, 6.0, 6.2, 6.21, 6.22 
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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

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Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS321 kbMSDOS400 kbMSDOS320 kbMSDOS330a kbMSDOS621 kbMSDOS622 kbMSDOS620 kbMSDOS600 kbMSDOS310 kbMSDOS500 kbMSDOS330 kbMSDOS401 kbMSDOS211
Version           : MS-DOS:2.x,3.x,4.x,5.0,6.0,6.2,6.21,6.22

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