Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: A rough future for the Amiga??? I think not.
Message-ID: <10765@cbmvax.commodore.com>
Date: 10 Apr 90 23:45:56 GMT
References: <16192@snow-white.udel.EDU> <1990Apr8.013940.12984@wam.umd.edu> <10715@cbmvax.commodore.com> <1990Apr10.023937.8350@wam.umd.edu>
Reply-To: daveh@cbmvax (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 30

In article <1990Apr10.023937.8350@wam.umd.edu> ddev@wam.umd.edu (Don DeVoe) writes:
>In article <10715@cbmvax.commodore.com> andy@cbmvax (Andy Finkel) writes:

>After all, the Z80 in the C128 only runs under C/PM, during which time the 
>6510 does nothing wrt i/o, right?

Actually, the Z-80 does use the 8502 in the C128 for some processing under
CP/M.  But you can only have one on at a given time.  Like most older
systems, that's really not a loss, since you're only doing one thing in
software at a time anyway.  So if an I/O operation must be done, let the
CPU best able to tackle it do the job.  The other's going to have to 
hang around waiting anyway...

In any Amiga, you can have 6502, 680x0, and blitter going at the same time.
I'm sure Mac use some kind of CPU in their keyboards these days.  The problem
with older Macs was that they basically used the CPU to read keyboard and
mouse at a really low level.  An I/O processor does a real good job at reading
things at this very low level.  Instead of that, an I/O chip can take such
low-level signals and cook them a bit before handing them off the the main
processor.  The Amiga's always done the latter, so it would benefit much
less from an IOP for keyboard and mouse control.

>Don DeVoe
>ddev@epsl.umd.edu


-- 
Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests"
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                    Too much of everything is just enough