Date: Tue, 13 May 1997 15:35:07 -0400 (EDT)
From: Pierre Phaneuf <pp AT 55-174 DOT hy DOT cgocable DOT ca>
Reply-To: pierre AT tycho DOT com
To: yeep <yeep AT xs4all DOT nl>
cc: OpenDOS Mailing List <opendos AT delorie DOT com>
Subject: Re: OpenDOS graphics drivers
In-Reply-To: <199705131701.TAA02371@magigimmix.xs4all.nl>
Message-ID: <Pine.LNX.3.95.970513153339.398A-100000@55-174.hy.cgocable.ca>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Precedence: bulk

On Tue, 13 May 1997, yeep wrote:

> > Nothing *really* fast will work on NT. On NT, ports and memory protection
> > prevents user space programs from access video hardware.
> 
> Well, the video-mem can be addressed as normal, by writing directly to
> 0xA000 (in a RM program), but the things is Windows NT doens't know any
> mode 13h !!!!!
> At least not in NT 3.51.
> You get 640x480 in stead!!!

Because it is all faked for DOS emulation. You're not really writing to
the video mem, but to a region of normal memory mapped at this address...
And it's almost normal to me that you get the wrong resolution for mode
13h (considering NT)! ;-) It gets you in mode 12h... Blarg!

Pierre Phaneuf