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From: brooks@maddog.llnl.gov (Eugene Brooks)
Newsgroups: comp.arch
Subject: Re: Single user vs. shared (was Re: Killer Micros and vectorized code)
Message-ID: <52817@lll-winken.LLNL.GOV>
Date: 18 Mar 90 19:50:16 GMT
References: <51771@lll-winken.LLNL.GOV> <100598@convex.convex.com> <52661@lll-winken.LLNL.GOV> <1990Mar18.023523.4034@ultra.com>
Sender: usenet@lll-winken.LLNL.GOV
Reply-To: brooks@maddog.llnl.gov (Eugene Brooks)
Organization: Lawrence Livermore National Laboratory
Lines: 32

In article <1990Mar18.023523.4034@ultra.com> shj@ultra.com (Steve Jay) writes:
>If someone measured the time that I spend using the stapler, tape
>dispenser, or pocket calculator that I have in my office, they'd
>find that each sits idle 99.9...% of the time.  Does this mean that
>I shouldn't have exclusive use of these items, and I should have to
>go to some central facility whenever I want to staple, tape, or
>calculate?
The analogy people use here is comparing their car to their personal
computer.  The price tags are even comparable in this case.  The
argument does not hold water.  The car can't be switched between
users in milliseconds.  The computer is an entirely different animal.
You CAN have exclusive access to a CPU in a suitably parallel resource
composed of Killer Micros, yet efficiently share it with others.

By sharing your computer among a small group of people, large enough
to bring the utilization level up to perhaps 50%, you end up with
more computer, not less.  I do think that you should have your own
X display station, however, this can not be switched between users in
a millisecond or two.


>I'd be happy to have my CPU (with its maddening fan) in a remote location,
>where it could share power supplies, cooling, and disk space.  But I still
>want it to be mine. 
We are considering engraving users names on the cpu boards of our massively
parallel Killer Micro powered machine arriving here.  It will give them
that good feeling of ownership.  Last time I checked there were more processors
than users.  I think that we might also ask them to make the LTO payments for
the machine in return for this feeling of ownership...


brooks@maddog.llnl.gov, brooks@maddog.uucp