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From: vg55611@ihuxy.ATT.COM (gopal)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Moving from CGA to MONO
Message-ID: <2108@ihuxy.ATT.COM>
Date: Tue, 1-Sep-87 15:12:28 EDT
Article-I.D.: ihuxy.2108
Posted: Tue Sep  1 15:12:28 1987
Date-Received: Sat, 5-Sep-87 04:39:36 EDT
References: <2839@hoptoad.uucp> <1325@faline.bellcore.com>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 20
Summary: If programs write directly to screen memory, there is nothing you can do

In article <1325@faline.bellcore.com>, gtchen@faline.bellcore.com (George T. Chen) writes:
> I have several public domain programs (no source though) that send its
> output through the CGA screen (memory 0xb8000000).  Unfortunately, I only
> have a Mono screen.  Since I know the output doesn't require the color
> screen and will be just as readable in monochrome, does anyone know of
> any programs that will change all references from 0xb8000000 to 0xb000000 ?
> I've used debug to change a few programs but it's a painful procedure
> without the source code.

If programs write directly to screen memory, there is no way to intercept it/
redirect it - you have to patch the program (debug or whatever).  (Actually,
there is a way - modify the hardware so that addresses B8000h - to BFFFFh
actually select your memory at B0000h to B7fffh).  

With programs that uses interrupt 10h functions solely, a redirect may be
possible.  In these cases, I don't see a good solution except writing 
a custom interrupt 10h driver to do this.

Venu P. Gopal
ihnp4!ihuxy!vg55611