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From: bert@helix.nih.gov (Bert Tyler)
Newsgroups: comp.windows.ms
Subject: IBM's XGA and Windows
Message-ID: <859@nih-csl.nih.gov>
Date: 23 Jan 91 21:21:01 GMT
Sender: news@nih-csl.nih.gov
Organization: National Institutes of Health, Bethesda
Lines: 39

> Is there a windows driver available for XGA? 
 
My XGA adapter arrived with drivers for Windows (2.x and 3.0), OS/2,
Autocad, and one that emulates the 8514/A API.  I tested the Windows 3.0
drivers and the 8514/A API driver (I don't have Autocad or OS/2)
 
The Windows drivers are kind of interesting.  There are two Windows 3.0
drivers, labelled "high-rez" and "low-rez".  I first installed the "low rez"
driver with a low-rez VGA monitor attached.  Then I powered down the machine,
switched to a high-rez monitor, brought it back up - and Windows came up
in high resolution but using the (now tiny) low-rez fonts!  I switched to
the "high-rez" driver and Windows switched to high-rez (8514/A-style) fonts.
I haven't yet had the guts to put the low-rez monitor back online and see
what happens when I fire up Windows with a low-rez monitor and the high-rez
driver active.
 
The 8514/A driver cautions that programs that run on single-monitor
setups and rely on the fact that the 8514/A video memory and the VGA video
memory are distinct and remain intact during mode switches won't work,
because the XGA adapter uses the same memory for both functions.  CSHOW
had no problems, but my own Fractint program failed miserably because we
*do* make that assumption.  Not a big deal, because the next release of
Fractint will include native XGA drivers.

...which brings up an off-topic question.  I have written some simple routines
that I intend to give away as freeware that autodetect the presence of an
XGA adapter (including its available memory and what kind of monitor it is
attached to), throw the XGA into any of its text or graphics modes, and
read/write pixels to the adapter in those modes.  I am having problems with
the 65536-color mode (a mode which the preliminary copy of the XGA Hardware
Users Guide discusses but does not include sample code for) - I can throw the
adapter into and out of that mode, and sling pixels at it, but the colors are
wrong.  I have looked for an area on USENET to post questions about this
beastie, but can't find any likely suspects.  Can someone post me a private
message telling me where to go?  (No, no, not *there* - somewhere on USENET
<grin>.)

Bert Tyler
Bert@helix.nih.gov