Date: Wed, 14 May 1997 14:04:12 -0400 (EDT)
From: Pierre Phaneuf <pp AT 55-174 DOT hy DOT cgocable DOT ca>
Reply-To: pierre AT tycho DOT com
To: OpenDOS Mailing List <opendos AT delorie DOT com>
Subject: Re: OpenDOS graphics drivers
In-Reply-To: <199705140533.PAA05313@solwarra.gbrmpa.gov.au>
Message-ID: <Pine.LNX.3.95.970514130343.17340A-100000@55-174.hy.cgocable.ca>
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On Wed, 14 May 1997, Leath Muller wrote:

> Even though a DOS 16bit program doesn't have scheduling to worry about,
> it still only runs at half the speed of a 32bit program; under NT and Win95
> you can also set the priority of a program to 'real-time' which pretty much
> takes over the operating system completely.

32 bit isn't double the speed of a 16 bit program! The *main* advantage
that you can access larger areas of memory at once. For example, you can
use a linear frame buffer, instead of using 4 segments and bank switching
to access the video card. This is a *bit* faster since you don't have to
bank switch, not because of using 32-bit instructions. Of course, using
32-bit instruction will help a bit too. Under NT, an ordinary user cannot
set a priority to real-time BTW.

> > There's a Quake version for S3 ViRGE chipsets, this is what you should
> > compare a WinQuake using DirectX 3.0 drivers, on the same system (using a
> > ViRGE video card, of course!). 
> 
> Are you talking about 3D acceleration in hardware? I Don't have that yet... :)
> I am talking sheer CPU power...

The only two advantages of DirectX is that it gives any program access to
all the features of hardware acceleration (which is interesting) and
overcome the GDI, which is a GUI-only concern, since there's no GDI to
overcome in DOS. 

Pierre Phaneuf