Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Amiga 1000 Abandonment
Message-ID: <21217@cbmvax.commodore.com>
Date: 3 May 91 15:34:17 GMT
References: <1991Apr25.042851.8912@uokmax.ecn.uoknor.edu> <20962@cbmvax.c <1991Apr29.042923.19672@mnemosyne.cs.du.edu> <21122@cbmvax.commodore.com> <928@cns.SanDiego.NCR.COM>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 43

In article <928@cns.SanDiego.NCR.COM> dltaylor@cns.SanDiego.NCR.COM (Dan Taylor) writes:
>In <21122@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes:

>>but the A1000 supports expansion, blessed by Commodore, while the early Macs
>>do not.

>Dave, why would Mac owners care if Commodore blessed their expansion? ;-)

They wouldn't.  But they would care if Apple did so, methinks.  If an expansion 
mechanism is designed for expansion, it has a tendency to work reliably.  If 
you're counting on processor sockets to support expansion towers, good luck, 
these may work, or may not; chip sockets are not designed to hold expansion 
boards.  Motherboards change regularly, and the hacked in expansion device 
that fits today may not fit tomorrow.  It may not work in all machines.  A 
defined expansion bus works today and tomorrow, it's on the shoulders of the
systems vendor and the card vendor to do things correctly so that this 
happens.

>Seriously, I built my own ZorroII expansion for my A1000, and then dropped
>the boards into my new 2500/30.  Now I'm planning to some of them, including
>the A2630, BACK.  Try putting NuBUS boards into an original Mac, or Plus.

Exactly.  Even today, Apple seems to be increasing the number of different,
incompatible expansion options, rather than reducing them.  That's not what
anyone needs.  There are only two reasons to make a machine-specific expansion
card.  The first generates things like A590s, which, for cost reasons, are
mechanically A500-specific.  But the electronic design, for all intents and
purposes, is Zorro II.  You build basic I/O and memory devices for all Amigas
based on Zorro II.  If Zorro II isn't fast enough, you can go to an A3000 and
Zorro III.  The other reason for machine-specifics is "it can't be done on
the general expansion bus".  That's where Coprocessor slots come in; you can,
of course, build a 680x0 board for Zorro II or III, but it can't act alone,
as the one processor in charge of the system.  So we define Coprocessor slots,
which, unlike the bus, can change as necessary between machine revisions.  This
is very specifically for coprocessor expansion only, nothing else.

>Dan Taylor


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      "That's me in the corner, that's me in the spotlight" -R.E.M.