On 31 Mar 99, at 8:28, Roberto Safora wrote:
> I am dealing with four PCs with MOBO hot 591 p and AGP S3 trio
> 3D(86C365 chip). Every time I try to test the video with AMIDIAG ver
> 2.02 or similar the system hangs, mostly in the memory test. The
> error desapears if I put other video card model, lets say T9750 AGP.
> In the other hand. Windows 95 OSR-2 seems to be working properly. Any
> sugestion?
What does your COM port/modem configuration on these machines look like?
That probably looks like a strange question in this context, so a bit of
background is probably in order....
The year was 1987. In April, IBM unveiled their new PS/2 line,
including VGA and MicroChannel. And an optional better-than-VGA card
called the 8514/A.
Now although the "BIOS data area" had room to hold 4 COM port
addresses, no ROM BIOS had ever supported more than COM1 and COM2. IBM
had a plan of port addresses for COM3-COM8 (all to use IRQ 3), but they
failed to publicize it, and so third-part makers of serial ports went
ahead and created standard address and IRQ assignments for COM3 and
COM4 that we still use today. [For a time, there were lots of freeware
utilities around to detect and initialize these ports, because the BIOS
wouldn't. Virtually all modern BIOSes do, though, so these are not
often seen any more.]
This is where the problem comes in. While third parties were
standardizing on a COM4 address in an "unused" range, IBM was assigning
control ports for the 8514/A out of the same "unused" range. Oops.
I don't believe you can get the original 8514/A any more, but a few
manufacturers continue to emulate it in their video chipsets -- and one
of those is S3. So when you report that an S3 fails where a Trident
succeeds, I wonder if you have some device on COM4 that might be
confusing it.
David G
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