Q73416: Uninstall Disk Must Be the Same Media as Drive A

Article: Q73416
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:5.x,6.0,6.2,6.21,6.22
Operating System(s): 
Keyword(s): 
Last Modified: 17-DEC-2000

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft MS-DOS operating system versions 5.0, 5.0a, 6.0, 6.2, 6.21, 6.22 
-------------------------------------------------------------------------------

SUMMARY
=======

If the Uninstall disk you create (labeled "Uninstall Disk") is not the same
media (density) as drive A, you receive the following error message:

  error reading or writing to drive a:

MORE INFORMATION
================

Because Uninstall Disk 1 must be a bootable disk, it must be the same density as
drive A. For example, if drive A is a 1.2-megabyte floppy disk drive, only a
high-density 1.2-megabyte disk should be used for the Uninstall Disk 1.

The ROM bootstrap routine is executed when the computer is booted. It checks to
see if a disk is in drive A; if there is no disk in drive A, it checks the
active partition on the hard disk drive. Note that it never checks drive B;
therefore, it is not possible to boot from drive B.

This behavior is a function of the BIOS, not MS-DOS.

For more information on the ROM bootstrap routine, query on the following word in
the Microsoft Knowledge Base:

  " bootstrap " (without the quotation marks)

Additional query words: 6.22 5.00 5.00a 6.00 6.20 low density, double "Uninstall Disk 1" 2" 720K, 360K, error reading or writing to drive a:

======================================================================
Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS621 kbMSDOS622 kbMSDOS620 kbMSDOS600 kbMSDOS500 kbMSDOS500a
Version           : MS-DOS:5.x,6.0,6.2,6.21,6.22

=============================================================================