Newsgroups: comp.sys.ibm.pc.hardware
Path: utzoo!censor!geac!itcyyz!xrtll!silver
From: silver@xrtll.uucp (Hi Ho Silver)
Subject: Re: Question about 1 meg VGA cards
Reply-To: silver@xrtll.UUCP (Hi Ho Silver)
Organization: Yeah, right.
Date: Sun, 13 Jan 91 00:26:12 GMT
Message-ID: <1991Jan13.002612.12450@xrtll.uucp>
References: <4839@umbc3.UMBC.EDU>
Sender:  Hi Ho Silver (Your Wildest Fantasy) 

In comp.sys.ibm.pc.hardware, chuck@umbc5.umbc.edu typed:
$Just thinking about the memory involved in displaying a 1024x768 256 color
$picture...
$1024 pixels x 256 colors = 1 K bytes per row
$1 K bytes x 768 rows = 768 K bytes

   Yeah, that's the correct answer, though the method isn't 100% on.  The
usual method of achieving more than one bit depth is to use bitplanes;
in this case, there would be a series of eight 1024x768x1 arrays.  Some
boards no doubt do it otherwise, though.

$What is done with the other 232K left over in the 1 meg of video memory?

   Which other 232K?  There's another 256K there.  Oh well, in any case,
nothing.  It's exactly the same as what happens with most other modes on
lesser boards (e.g. nearly half of 512K in 640x480x256 mode).  It's
hardly something to get worried about; the cost difference, if any, would
be quite small, and could even work to the advantage of a 1M board.

$Chuck Rickard
$(chuck@umbc5.umbc.edu)
$
$Chuck Rickard
$(chuck@umbc5.umbc.edu)

   BTW, your .signature is appearing twice.
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