Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!husc6!necntc!ames!ucbcad!ucbvax!certes.UUCP!doug From: doug@certes.UUCP Newsgroups: comp.sys.amiga Subject: Re: 12 - 50 Mip Amiga 2000 CoProcessor? Message-ID: <8707181011.AA14226@unisoft.UNISOFT> Date: Sat, 18-Jul-87 02:11:02 EDT Article-I.D.: unisoft.8707181011.AA14226 Posted: Sat Jul 18 02:11:02 1987 Date-Received: Sat, 18-Jul-87 21:04:24 EDT Sender: uucp@ucbvax.BERKELEY.EDU Lines: 33 Chuck McManis ponders: >You realize of course that the I/O bandwidth on the IBM PC bus is about 5 >megabytes per second? Even having a 2 MIP machine on it can be a waste if >you can't talk to it at any decent speed. 100 MIP co-processor would be a >waste of money on that bus. Not to mention the big steel box you would >need to shield it. Yes, it's awkward having crumby I/O bandwidth, but it's hardly "a waste of money". Consider a ray tracer running at 100MIPS for twelve hours on that board before it *needs* to use the bus (once it's done). There's always some good uses for horsepower. 100Mhz clocks cause lots of logic design problems, but steel boxes are the least of the worries. Signal paths need to follow waveguides with exacting geometries to handle phase distortion, reflections etc. Noise susceptability is a bugbear throughout, as is capacitance. After all that, if you need to wrap a faraday cage around the thing, no big deal. In fact, there's a faraday cage inside of Amiga 1000's, but nobody complains about *it* being a big steel box. Many products these days use a conductive plastic shell to help with FCC RF shielding, btw. Your implied point remains valid: high end machines have good I/O bandwidth, which is another reason that a 100 MIP Amiga wouldn't eat Suns for lunch. >>Copyright 1987 Douglas R. Merritt. All rights reserved. >Portions of this message were extracted from a copyrighted work and were >used without permission. I'm sure reasonable Usenet quotes fall under the "fair use" provisions of the copyright law! :-) Public Domain Posting, copyright abandoned 1987 Douglas R. Merritt Doug Merritt {ucbvax,sun}!unisoft!certes!doug