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From: bing@galbp.UUCP (Bing Bang)
Newsgroups: net.micro.pc
Subject: Re: CGA vs EGA
Message-ID: <689@galbp.UUCP>
Date: Tue, 14-Oct-86 10:19:59 EDT
Article-I.D.: galbp.689
Posted: Tue Oct 14 10:19:59 1986
Date-Received: Fri, 17-Oct-86 10:02:49 EDT
Reply-To: bing@galbp.UUCP (Bing Bang)
Distribution: net
Organization: Lanier Business Products, Inc., Atlanta, Georgia
Lines: 39

In article <> uchuck@ecsvax.UUCP (Charles Bennett) writes:
>
>We are currently getting ready to purchase new IBM PC/AT's for the
>programming staff here.  We utilize the machines in a variety of ways
>both for microcomputing and accessing mainframes via async communications
>and will be adding an IRMA-X type board for 3279 emulation.  We have a
>large investment in software, most of which uses color but not
>necessarily pure graphics.  The question is this; what, if any, are
>the incompatablities between the CGA board and the EGA board (with
>appropriate monitor, of course).  Rumor postulates two completely
>different circumstances; 1) CGA software does not run on the EGA, and
>2) CGA software runs on the EGA but in CGA mode without special
>intervention.  ????WHAT IS THE STORY????  !!!!PLEASE!!!!
>-- 
> 
> 
>                   -Chuck Bennett-
>                    919-966-1134
>...              ...!(decvax|akgua)!mcnc!ecsvax!uchuck

Here's what I have been able to find out on my own. Most EGA cards make
atleast a half-hearted attempt to be CGA compatible. Most maker will claim
BIOS compatibility, and they achieve this in varying degrees. This means
programs that are well behaved, i.e. use the BIOS calls to do everything will
most likely run on any good EGA board. However, there are many programs that
talk directly to the graphics board and if these programs talk to the EGA
board as if it were a CGA board, the result is a scrambled screen. I know of
only one EGA card that claims total hardware compatiblity with the CGA (and
MDA and hercules and platronics) board. I have it and it works great with all
the software I have so far. The board is made by Paradise Inc. called the
"Autoswitch EGA". I hope this helps out.


---
Bing H. Bang
Gun for Hire
"Have gun, will travel."

...akgua!galbp!bing