Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!ames!mailrus!tut.cis.ohio-state.edu!rutgers!rochester!pt.cs.cmu.edu!cadre!pitt!darth!liber
From: liber@darth.UUCP (Eric Liber)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Paradise VGA Plus undocumented video modes
Message-ID: <418@darth.UUCP>
Date: 15 Dec 88 19:04:48 GMT
References: <247@shockeye.UUCP>
Organization: Darth Software, Allison Park, Pa.
Lines: 28

> interrupts. Imagine my puzzlement when I read (under the BIOS set video
> mode int) that my Paradise VGA Plus board has a 640x480 256-color mode!
> I looked in the little booklet you get with the board, and there's not
> mention of it. It's not advertised anywhere I've seen either. So I played
> with it. 640 x 480 x 256 > 128K. Problem. How do you get access to the
           ^^^^^^^^^^^^^^^

I have the Paradise VGA 16 plus and i didn't know about this either but...
Let's think about this for a minute.  These boards (8 and 16) come with 
256k of ram on board.  To get 256 colors requires 8 bits (a byte). 
If we multiply the pixel counts 640 x 480 = 307200 (or 300K).  It looks to me
like we are short 56k from filling the screen.  If you devide 256K (262144)
by 640 lines we can get 409 lines with 256 colors.  And lo and behold there
is indeed a supported resolution of 640 x 400 x 256!  

What I think is happening here is that Paradise also makes a VGA professional
board that does have a 640 x 480 x 256 color resolution.  (Actually it will
go to 800 x 600 x 256 ).  ( 800 x 600 = 480000 bytes necessary).  While 
looking at the board (VGA 16 plus) i noticed an unused ram row and position
for one support chip on the board... Is it just possible that the professional
board is just the VGA 16 plus with more ram?   If so It would make sense that
the BIOS would probably be the same for all of the boards.  Any paradise 
people out there to verify or deny this?

Before you flame paradise for holding out on us this is very common in the
electonic hardware arena.  Make one board and firmware and simply do or do 
not include some chips to provide the level of price/performance you want.
It makes a lot of sense from a marketing and production standpoint.
good luck .. Eric (the red) Liber