Subject:	Re: DV/X support of video hardware
To:	dsg AT iac DOT es (Diego Sierra)
Date:	Thu, 6 May 93 11:23:05 EDT
From:	Stephen Turnbull <turnbull AT ecolan DOT sbs DOT ohio-state DOT edu>
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu (DJ's GPP mailing list)

For DV/X questions, you can email to 'support AT qdeck DOT com'.  You should
include your customer number or serial number if you have one.  There
are also forums on the commercial services (bix, compuserve), and on
the usenet (comp.os.msdos.desqview, I think).
    Regarding the Trident (and various other boards): Look in
...\dvx\server\screens.txt.  This will document which boards are
supported, and in what modes.  For performance reasons, DV/X's server
accesses the hardware directly.  (Ie, it recognizes chipsets, not
boards.)  Furthermore, the hardware support is hardcoded into the
server.  There are *no* drivers for DV/X.  (Not in the sense of 'plug
and play' anyway.)  This is done because it is apparently extremely
difficult to get anything resembling decent performance while
supporting Windoze in non-full-screen windows.  The Trident in
particular is *not* supported above standard VGA, or maybe to 640x480
256 colors and 800x600 16 colors.
    The DV/X server also supports anything supporting DGIS.  I believe
this is done via software drivers.  You take a slight performance hit.
Maybe the Trident has DGIS drivers?
    Quarterdeck's unofficial advice (they don't endorse any particular
board, you see) is to get an ATI Ultra series board.  (The official
line is get a 8514A *register*-compatible board.  Only the Ultra
series has this.  Everyone else uses software drivers.  Not even IBM
sells the original 8514A boards, and they were Micro-channel only
according to ATI tech support.)  The reason for this is that the 8514A
register-compatible boards have a video-memory aperture feature, and
you can put *all* of the video memory into extended memory addresses.
Thus DV/X can access the memory directly (a slight performance boost
by avoiding bank switching), and QEMM can use VIDRAM to recover an
additional 96KB for your DV windows.
    Personal experience says the old STB Powergraph is plug and play
to 1024x768 256 colors.  Great for xdvi and xv'ing the swimsuit issue
and Voyager photos of Titan and Mars.  This should extend to any Tseng
4000-based product.  The new STB Powergraph is I believe S3-based and
therefore *not* supported above standard VGA.  Ditto the Diamond
Speedstar.
    Caveat:  this is all based on my imperfect understanding of what
the not necessarily fully-informed tech supports at Quarterdeck,
Diamond, and ATI say.
--

Stephen Turnbull
The Ohio State University, Department of Economics
410 Arps Hall, 1945 N. High St., Columbus, OH  43210-1172  USA
Phone: (614) 292-0654  Fax: ...-3906  Email: turnbull DOT 1 AT osu DOT edu

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