Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!husc6!hao!ames!pioneer!eugene From: eugene@pioneer.arpa (Eugene Miya N.) Newsgroups: comp.arch Subject: Re: What with these Vector's anyways? (oh really...) Message-ID: <2398@ames.UUCP> Date: Thu, 23-Jul-87 21:57:40 EDT Article-I.D.: ames.2398 Posted: Thu Jul 23 21:57:40 1987 Date-Received: Sat, 25-Jul-87 11:09:03 EDT References: <218@astra.necisa.oz> <142700010@tiger.UUCP> <363@astroatc.UUCP> <8344@utzoo.UUCP> Sender: usenet@ames.UUCP Reply-To: eugene@pioneer.UUCP (Eugene Miya N.) Organization: NASA Ames Research Center, Moffett Field, Calif. Lines: 32 In article <8344@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes: >If a program >is 90% vectorizable, than magically making the vector part of it *infinitely* >fast will only speed it up by a factor of ten. Too many of the pre-Cray >supercomputers did vectors really fast but were pigs on scalar computation. How many programs do you know which are 90% vectorizable? [as opposed to portions 90% vectorizable.] {Ref: G. M. Amdahl, SJCC,1967} Too many? I am only aware of one which was produced: the STAR-100. The Cyber 203 came PC: Post-Cray-1. Everything else could be considered a paper design. [^^ A new acronym for people in the know? ;-)] Pig is not a nice thing to say. >saying "our machines run your code real fast if you rewrite it somewhat" >doesn't have nearly the customer appear of saying "our machines run your >code real fast -- even faster if you rewrite it somewhat". Surprisingly, people do rewrite; there are over 40 Cyber 205 (The STAR follow on] sites and people do rewrite for those. You also have to distinguish between writing compiler directives and executable code. From the Rock of Ages Home for Retired Hackers: --eugene miya NASA Ames Research Center eugene@ames-aurora.ARPA "You trust the `reply' command with all those different mailers out there?" "Send mail, avoid follow-ups. If enough, I'll summarize." {hplabs,hao,ihnp4,decwrl,allegra,tektronix,menlo70}!ames!aurora!eugene I have begun to really learn that the people who say the most know the least in many cases.