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Q74730: Erratic Keyboard Behavior Using HIMEM.SYS

Article: Q74730
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

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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 
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SUMMARY
=======

You may encounter erratic keyboard behavior when using HIMEM.SYS driver on
certain systems. Symptoms may include a variety of problems interpreting the
state of the SHIFT, CAPS LOCK, NUM LOCK, ALT, and CTRL keys.

If you encounter this kind of problem, setting the /CPUCLOCK: switch to ON may
alleviate the problem. If not, use the HIMEM /machine:xxxx switch to specify an
alternative value for the A20 handler. Switches which have been found to be most
likely are 11, 12, and 13 (in that order). These switches represent
progressively longer delays in the switch state of the A20 line compared to the
default handler 1.

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

Another workaround is to include the following line in your AUTOEXEC.BAT file.

  c:\dos\keyb us,,c:\dos\keyboard.sys

KEYB replaces the ROM BIOS INT 09h keyboard interrupt handler with its own
routine. This may allow handling of the keyboard in a manner that does not
conflict with A20 handling.


Additional query words: 6.22 5.00 5.00a 6.00 6.20 101 key extended enhanced

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

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