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From: mjm@cantor.UUCP (Michael Markowitz)
Newsgroups: net.micro.pc
Subject: Re: Enhanced Graphics Adapter on PC-AT in high-res mode
Message-ID: <164@cantor.UUCP>
Date: Thu, 10-Oct-85 00:03:31 EDT
Article-I.D.: cantor.164
Posted: Thu Oct 10 00:03:31 1985
Date-Received: Sat, 12-Oct-85 15:37:13 EDT
References: <381@eneevax.UUCP>
Distribution: net
Organization: Loyola Univ. of Chicago Dept. of Math
Lines: 42

Naba Barkakati has posted the following:

> ========================================================================
> 
> I am using an IBM PC-AT with enhanced color display + enhanced graphics
> adapter (EGA). I would like to use the display in its highest resolution
> graphics mode (640x350) through the ROM-BIOS video services. By using
> video mode 14, I could get 640X200 resolution, but mode 15 (which
> supposedly means the EGA in extra high resolution) only messed up the 
> screen.
> 
> I would appreciate hearing from anyone who has used the EGA in the
> 640x350 resolution. 
> 
> Thanks in advance.
> 
>                              Naba Barkakati
> 
> ARPA:  enee!naba@maryland.ARPA
> UUCP:  [seismo,allegra]!umcp-cs!eneevax!naba 

You might want to check out the April '85 issue of PC Tech Journal.  It
contains an article with a lot of technical info on the EGA.

Anyway, I believe that your problem is that mode 15 (0fh) is intended to
be used only for 50Hz monochrome displays--it won't work on the enhanced 
display.  Try mode 16 (10h) for 640x350 graphics on that display.  I 
recently rewrote one of the Mandelbrot set generating programs to work in
this mode and the results are spectacular.  With 128K on the EGA I get
16 colors.

Unfortunately I haven't yet figured out how to dump the graphics memory 
(~112K) to disk so that the images can be stored, but if you like 
I would be willing to mail you a copy of what I've done to date.

Hope this helps.

					Michael Markowitz
					Department of Math. Sciences
					Loyola University of Chicago

UUCP: ihnp4!gargoyle!cantor!abel!mjm