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Path: utzoo!linus!cca!decvax!harpo!seismo!hao!hplabs!sri-unix!SJOBRG.ANDY%MIT-OZ@mit-mc
From: SJOBRG.ANDY%MIT-OZ%mit-mc@sri-unix.UUCP
Newsgroups: net.micro.cpm
Subject: Re: S-100 Unix
Message-ID: <1756@sri-arpa.UUCP>
Date: Sat, 4-Jun-83 10:19:00 EDT
Article-I.D.: sri-arpa.1756
Posted: Sat Jun  4 10:19:00 1983
Date-Received: Tue, 7-Jun-83 02:48:00 EDT
Lines: 25

Because it hasn't been done yet, there are a number of considerations:

1) The 68k isn't the ultimate 16bitter on the market. If you want to
	have >real< unix* (Berkeley unix), then you need to have a good
	virtual memory scheme. For this, if you want to stick with the
	68000 family, you would need to go with a 68010 and a number of
	68451 (memory management) chips - about 16 or so to be useful.
	As you see, this implementation can take up a lot of board space,
	so...

2) Drop the 68k and go with National's 16032. It is more orthogonal in its
	instruction set, and it handles virtual memory in the proper way,
	with >fast< context switching (which happens a lot in multi-user
	operating systems like unix). The chip is also about as fast as
	a vax (according to National's literature, using the prime number
	program that was in (I think) Sept 81 Byte), and the benchmark
	that they used can be optimised for even more speed (so, according
	to my guesses and testing it out on our 68ks at work, it would
	end up being as fast as a vax).

	Long live unix!
	-andy
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*Unix is a trademark of Bell Laboratories
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