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Path: utzoo!linus!decvax!decwrl!spar!baba
From: baba@spar.UUCP (Baba ROM DOS)
Newsgroups: net.micro.68k,net.arch
Subject: Re: Multiple 68020's on VME ?
Message-ID: <552@spar.UUCP>
Date: Mon, 30-Sep-85 14:56:08 EDT
Article-I.D.: spar.552
Posted: Mon Sep 30 14:56:08 1985
Date-Received: Wed, 2-Oct-85 20:45:12 EDT
References: <442@rna.UUCP>
Organization: The Institute for Impure Science
Lines: 18
Xref: linus net.micro.68k:1107 net.arch:1622

> 
> 	We would like to hear from people who know about or who have
> used multiple 680XX's on a bus. We are tentatively considering a ~10
> processor machine using 68020's on VME for a particular real-time
> data collection, analysis and display application.
> 
> 
> 					Cheers,
> 					Dan Ts'o

The August 1, 1985 issue of Computer Design contains a rather interesting
article on metastability problems in multiprocessor VME systems.  It appears
to be a little trickier than expected to design VME bus and memory arbitration 
logic that is not vulnerable to metastability problems in synchronization.  In
particular, some folks at CMU's robotics lab discovered that "as few as two"
8-MHz Motorola VM02 68000 boards would lock up "within 4 to 10 minutes".

						Baba ROM DOS