Date: Wed, 24 May 95 13:01:02 EDT
From: peprbv AT cfa0 DOT harvard DOT edu (Bob Babcock)
To: junaid AT barney DOT eng DOT monash DOT edu DOT AU
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Compiling gdb, dpmi DS:VRAM hack.
Reply-To: rbabcock AT cfa DOT harvard DOT edu

> Well here it is; how to access video ram at 0xa0000 without using
> a segment overide (ie using the current process's DS). Works well
> under MS Windows 3.1 in a full screen DOS box.
>    This program works by removing the segment limit on DS and
> using 32-bit wrap around in the linear address space to access
> memory at linear address 0xa0000.

Nice trick!  Your test program seems to also work under OS/2.