Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!cmcl2!ccnysci!alexis
From: alexis@ccnysci.UUCP (Alexis Rosen)
Newsgroups: comp.sys.mac
Subject: Re: Mac II and VGA  (icky-poo, IBM stuff)
Keywords: Zenith FTM Mac II Board RasterOps
Message-ID: <1885@ccnysci.UUCP>
Date: 7 May 89 04:58:43 GMT
References: <1531@jhunix.HCF.JHU.EDU> <8264@chinet.chi.il.us> <492@biar.UUCP> <1783@ccnysci.UUCP> <7848@batcomputer.tn.cornell.edu>
Reply-To: alexis@ccnysci.UUCP (Alexis Rosen)
Organization: City College of New York
Lines: 40

In article <7848@batcomputer.tn.cornell.edu> chow@tcgould.tn.cornell.edu (Christopher Chow) writes:
>What I'd always wanted to know was why Apple didn't support a 3-bit mode on
>their video card.  Why might one want a 3-bit graphics mode?  Well, 3-bits
>would be suffcient to render the colors found in the [non color] quickdraw
>programs and it should be faster than 4-bit mode since there's less bits to
>move around.

This does not make any sense to me. First off, why is having the same
number of colors as old quickdraw beneficial? Both run on a clor-capable
Mac anyway.

Second, I'll give you odds that three-bit is slower than four-bit (if you
could do it at all). With four bit color, your pixels are byte-aligned, but
with three-bit, you ALWAYS have to shift bits. Yuck.

Also, It's been two and a half years since I read leviticus (or whatever
the hell the early color-QD docs were called), but I seem to remember that
there are a few fundamental assumptions made for color-QD that the number of
bits is a power (or just multiple?) of two, though I could be wrong...

>In article <1783@ccnysci.UUCP> alexis@ccnysci.UUCP (Alexis Rosen) writes:
>.What about the huge number of people who bought 4-bit Apple boards? I
>.often see people using 4-bit color. If they couldn't they would be
>.very very unhappy.
>
>Interesting.  Although I agree with you that the 4-bit mode should be
>supported (if not for anything else, an 8-bit card should be able to double
>buffering in 4-bit mode), I haven't seen anyone with just a 4-bit card after
>the initial video-RAM crunch.  It seems that if one can afford a Mac
>II/IIcx/IIx one would be able to invest the extar $150 to get 8-bit video.

Not really relevant. Lots of people have machines bought by company (or
department) purchasing agent. They get color, because the PCs have color,
but nobody thinks they need more, so they don't specifically look for it on
the price lists. Also, it's just one more thing to think about.

---
Alexis Rosen
alexis@ccnysci.{uucp,bitnet}
alexis@rascal.ics.utexas.edu  (last resort)