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Q77178: Mylex 80486 EISA Motherboard and MS-DOS 5.0/6.0/6.2

Article: Q77178
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 
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SYMPTOMS
========

If you have a Tangent machine with a Mylex 80486 EISA motherboard, you may
experience erratic behavior when using Microsoft MS-DOS version 5.0 or 6.0,
especially when using the Mylex DCE cache controller.

Symptoms include the following:

- Machine stops responding (hangs).

- You can't access directories.

- You can't access the hard drive.

- Your file allocation table (FAT) may be corrupt.

The following application-specific problems have also been experienced with this
configuration:

- With MS-DOS 5.0 or 6.0 and Windows 3.0, erratic inability to find COMMAND.COM
  when exiting Windows.

- With Edit, QBasic, and 101-key keyboards, dedicated cursor keys operate as if
  the SHIFT key has been pressed (that is, they select blocks rather than
  moving the cursor).

- With EMM386.EXE, when attempting to use CTRL+ALT++ or CTRL+ALT+- to change
  the processor speed, an

  ILLEGAL INSTRUCTION : SYSTEM HALTED

  error occurs. The only way to recover from this error is with a cold boot.

- When running Memmaker from MS-DOS 6.0, the following error message is
  displayed:

  Illegal Instruction Trapped

RESOLUTION
==========

Mylex has confirmed this to be a problem with the Mylex 80486 EISA motherboard.
In addition, Mylex has confirmed that the Northgate/Mylex 80486 EISA motherboard
with BIOS version 6.04q is not compatible with EMM386.EXE. The newest revision
is 6.15, which is compatible with EMM386.EXE.

Contact Mylex for additional information or a BIOS upgrade.

The product included here is manufactured by vendors independent of Microsoft; we
make no warranty, implied or otherwise, regarding this product's performance or
reliability.

Additional query words: 6.22 3.00 5.00 milex dos 3rdparty emm386 win30 win31 6.00 6.20 5.00a

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