Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!bcm!dimacs.rutgers.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: 040 boards
Message-ID: <18284@cbmvax.commodore.com>
Date: 29 Jan 91 22:04:34 GMT
References: <15988@sdcc6.ucsd.edu>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 36

In article <15988@sdcc6.ucsd.edu> rblewitt@sdcc6.ucsd.edu (Richard Blewitt) writes:

>  Since it is possible to have both the 040 and the 030 running at
>the same time, would it be possible to make an 040 board that has
>an expansion slot for the addition of more 040 boards all running
>together?  

Sounds like a good idea, but you would be extremely hard pressed to fit more
than a 68040, interface logic, and your choice of RAM, Cache, or possibly 
a Yet Undefined Goody (like the PP&S compression chip) in the relatively tight
space allocated for a coprocessor board.

If you want to think in more general multiprocessing terms, you could 
theoretically build Zorro III boards with multiple processors on them.  The
Zorro III bus doesn't currently have any hardware cache consistency protocol,
but it does provide for bus locking and other things you would need in a
multiprocessor environment.  The real trick is software.

The main reasons for the Coprocessor Slot:

	[a] A Coprocessor Slot device can completely take over the Amiga 
	    system itself, without any special software.  A Zorro III device
	    would at the very least need the main CPU to handle interrupts.
	[b] A Coprocessor Slot device can be very tightly coupled to the A3000
	    motherboard.  So it's generally more efficient than a Zorro III
	    device.  But don't expect it to plug into your A4000 or whatever 
	    new thing comes along someday, whereas the Zorro III board would
	    travel just fine to a more advanced 32 bit Amiga system.

>Rick


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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	"What works for me might work for you"	-Jimmy Buffett