On Wed, 10 Feb 1999 16:24:30 -0800, you wrote:

Since the A20 line is controlled by the chipset of the keyboard, if
that chipset is malfunctional, it is possible to have such error
message. Replaced another keyboard and see if this help.

>I'm teaching a computer hardware course at a community college and I
>have a bunch of old 486 VESA system boards that my students are learning
>on.  I have the same problem with a number of these boards, and so far
>have not been able to determine the cause.
>The problem is as follows:  When we boot up DOS 6.22 and the Himem.sys
>driver is loaded in Config.sys we get the message: "ERROR: Unable to
>control A20 line   XMS driver not loaded".
>Anyone familiar with this problem?  Thanks in advance for any advice.
>-Rick VanHeyst

Regards,
Michael

                Curious about the people moderating your
                   messages? Visit our staff web site:
                     http://nospin.com/pc/staff.html