Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!mit-eddie!ll-xn!ames!pasteur!ucbvax!hplabs!hpl-opus!hpccc!baryeka
From: baryeka@hpccc.HP.COM (Jarek Baryeka)
Newsgroups: comp.sys.amiga.tech
Subject: Re: BridgeBoard & VGA problems
Message-ID: <1760002@hpccc.HP.COM>
Date: 6 Sep 88 16:31:26 GMT
References: <1760001@hpccc.HP.COM>
Organization: HP Corporate Computing Center
Lines: 35


 daveh@cbmvax.UUCP (Dave Haynie) says:

>But what you just said sounds impossible.  At least as I understand it,
>the PC-XT, being 8088 based, is limited to a total of 1 meg normal address
>space, plus 64K or so I/O space.  The MDA, CGA, EGA, and the various other
>cards sit up in higher memory and by default must take less than the space
>that's left over in the PC.  If VGA really takes up 512K of directly
>addressable memory, it must either be unsuitable to an XT compatible, or
>use some generally unused addressing mode, like the 16 bit I/O addressing
>that the Z-80 can do, but generally doesn't do.

The VGA needs only 256K (the 512K are used for some modes going beyond
the VGA resolution).

>There are jumpers on the bridge card to turn off it's CGA or MDA emulation;
>the manual should explain this.  

I have managd to get a german manual but they are talking about 8-pin jumper -
 my jumperhas only 6 pins.

>This is all a prime example of what's broken on PC[lone] machines....

I agree, but in this case the BridgeBoard seems to be even more broken than 
the PCs - the card works with other PC-XT clones.

>-- 
>Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
>   {ihnp4|uunet|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
>		"I can't relax, 'cause I'm a Boinger!"
>----------
 
Thanks for your help,
   
   Jarek Baryeka.