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From: ags@pucc-i (Seaman)
Newsgroups: net.arch
Subject: Re: lets talk supercomputer micro-archit - (nf)
Message-ID: <259@pucc-i>
Date: Tue, 1-May-84 01:41:09 EDT
Article-I.D.: pucc-i.259
Posted: Tue May  1 01:41:09 1984
Date-Received: Fri, 4-May-84 00:38:50 EDT
References: <255@houxk.UUCP> <5600014@uiuccsb.UUCP>
Organization: Purdue University Computing Center
Lines: 26

>  A person from NEC gave a talk here about their >1 gigaflop machine.  The
>  machine had 16 pipeline units.  The machine did get a gigaflop if all 16
>  units were operating, but I doubt if a real program exists which has enough
>  computation in parallel to sustain 16 pipeline units for any length of time.
>  I certainly haven't seen anything to indicate they know more than Cray about
>  supercomputing.
>  
>  
>  Harlan Husmann
>  University of Illinois at Urbana-Champaign

I can assure you that there are programs running on our Cyber 205 at Purdue
which have "enough computation in parallel" (i.e. long enough vectors) to
keep the pipes busy.  By the way, "vector length" and "number of pipes"
are orthogonal concepts on the 205.  Vector lengths can go up to 65,535.
All vector instructions (regardless of the vector length) use all available
pipes in parallel.  We have only two pipes, but if we somehow had 16 we
could still keep them all busy for over 4000 clock cycles (=200 microseconds)
with a single instruction.
-- 

Dave Seaman
..!pur-ee!pucc-i:ags

"Against people who give vent to their loquacity 
by extraneous bombastic circumlocution."