Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!genrad!mit-eddi!smh From: smh@mit-eddi.UUCP (Steven M. Haflich) Newsgroups: net.arch Subject: Re: Cray vs ICs, continued Message-ID: <242@mit-eddi.UUCP> Date: Wed, 15-Jun-83 02:01:02 EDT Article-I.D.: mit-eddi.242 Posted: Wed Jun 15 02:01:02 1983 Date-Received: Wed, 15-Jun-83 17:56:56 EDT References: <3018@utzoo.UUCP> utcsrgv.1531 Lines: 24 Last week I was visited by an old friend who now works in Gallium Arsenide (GAs) logic research for a large west coast company. Unless I have my figures entirely scrambled, he told me that work is proceding on ECL compatible gate array logic operating at gate delays approaching 50 picoseconds. (Well, he did admit that the gates were only probabilistically digital at these speeds, but the bugs were being worked out.) In case you have forgotten, 50 picoseconds fits into a microsecond about 20,000 times! Anyone who has dabbled in microwaves will realize that such frequencies give new meanings to terms like "parasitic capacitance" and "transmission line effects." When one builds a radio transmitter operating at a mere couple hundred MHz, one must give careful consideration to the shape and path of simple conductors connecting circuit elements; at such frequencies, there ARE no simple conductors! Now imagine that the conductors have to be made of/in epitaxial GAs, and must operate at two orders of magnitude higher frequency. It is no coincidence that my friend got into the GAs business directly from microwave work. Don't bother asking me for more info -- I have pretty much exhausted my understanding of the field. However, it appears that swallowing IC's will soon be even a worse idea than it is now. Steve Haflich, genrad!mit-eddie!smh