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From: farren@well.UUCP (Mike Farren)
Newsgroups: net.micro.amiga
Subject: Re: interlace mode
Message-ID: <538@well.UUCP>
Date: Thu, 23-Jan-86 05:46:01 EST
Article-I.D.: well.538
Posted: Thu Jan 23 05:46:01 1986
Date-Received: Fri, 24-Jan-86 22:16:22 EST
References: <570@amiga.amiga.UUCP> <877@h-sc1.UUCP> <511@well.UUCP> <1271@gitpyr.UUCP>
Organization: Whole Earth Lectronic Link, Sausalito, CA
Lines: 31

I wrote:
>>you describe isn't an easy job. (Before I hear anything about the Atari ST
>>and its 640X400, 70Hz screen, let me remind you that that is a one-bit-per-
>>pixel monochrome screen.  It's ONLY color option is 320X200.  If you are
>>willing to accept THAT limitation, then the problem isn't too hard.  If you
>>want a color screen such as the Amiga's, at a reasonable cost, compromises
>>have to be made.)
And Steve Tynor replied:
> Medium res (high res color) on the atari st is 640x200.

   Thanks for the information.  I hadn't realized there was a med-res mode.
It still doesn't change things, though.  The limitation is the number of
bytes you're shoving through the graphics hardware every frame, and I
would believe that med-res mode on the Atari cuts the number of colors
displayable in half?  Twice the resolution = half the colors = same number
of bytes/line.

   It might be possible, by limiting the bit-planes to one (or possibly 2),
to get the bandwidth you'd need to put out a 640X400 non-interlaced screen,
as someone else suggested.  The secondary problem that that brings up is
simple:  you need a different monitor.  A monitor that will handle 640X400
is forced to operate with a MUCH higher horizontal frequency, and would    
either be much more expensive (if color), or incompatible with the lower
resolution modes (rendering a lot of software incompatible), or both.
I'm pretty sure this is the reason the STs have two non-intermixable
monitors.

-- 
           Mike Farren
           uucp: {your favorite backbone site}!hplabs!well!farren
           Fido: Sci-Fido, Fidonode 125/84, (415)655-0667