OPTI 486 Memory Chips Require Special AWARD BIOS (72304)
The information in this article applies to:
- Microsoft MS-DOS operating system 3.1
- Microsoft MS-DOS operating system 3.2
- Microsoft MS-DOS operating system 3.21
- Microsoft MS-DOS operating system 3.3
- Microsoft MS-DOS operating system 3.3a
- Microsoft MS-DOS operating system 4.0
- Microsoft MS-DOS operating system 4.01
- Microsoft MS-DOS operating system 5.0
- Microsoft MS-DOS operating system 5.0a
- Microsoft MS-DOS operating system 6.0
- Microsoft MS-DOS operating system 6.2
- Microsoft MS-DOS operating system 6.21
- Microsoft MS-DOS operating system 6.22
This article was previously published under Q72304 SUMMARY
There are some Pioneer and other 80486 motherboards that come equipped
with OPTI memory chips and an AWARD BIOS. Revisions A, B, and C of the
OPTI memory chips have a conflict with HIMEM.SYS and may return the
following error at bootup:
Cannot enable A20 handler
The following are the OPTI 486 Chip revisions and the necessary BIOS'
for use with HIMEM.SYS:
If you have OPTI
chip revision: You need to:
---------------- ------------
A Call Award Software at (415) 968-4433 for
more information.
B Obtain the OPTI Revision of AWARD BIOS 3.14.
C Obtain the OPTI Revision of AWARD BIOS 3.14.
D Your BIOS should be the correct revision.
MORE INFORMATION
Using alternate handlers with HIMEM.SYS will not work. The problem
lies in a conflict between the memory chips and the AWARD BIOS.
According to AWARD Software, there is a special revision of AWARD BIOS
3.14 that will correct this problem on the B and C releases of the
OPTI memory chips. Revision A of the OPTI memory chips may not allow
the A20 handler to be enabled regardless of BIOS version.
IMPORTANT: The AWARD BIOS revision offered to correct this
problem is NOT the standard AWARD BIOS 3.14. The BIOS must be
specified as the OPTI revision of the AWARD BIOS 3.14. If the
OPTI revision is not specified, then the standard BIOS upgrade
will be delivered and it WILL NOT correct the problem.
Revision D of the OPTI memory chips does not have this conflict and
should function normally with HIMEM.SYS.
For more information, contact AWARD Software at (415) 968-4433.
The products included here are manufactured by vendors independent of
Microsoft; we make no warranty, implied or otherwise, regarding these
products' performance or reliability.
Modification Type: | Major | Last Reviewed: | 5/12/2003 |
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Keywords: | KB72304 |
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