Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!mordor!sri-spam!ames!pasteur!agate!aurora!amelia!orville.nas.nasa.gov!fouts
From: fouts@orville.nas.nasa.gov (Marty Fouts)
Newsgroups: comp.arch
Subject: Re: Cray 2 has 2GW address
Message-ID: <308@amelia.nas.nasa.gov>
Date: 29 Feb 88 21:28:55 GMT
References: <416@micropen> <3534@killer.UUCP> <305@amelia.nas.nasa.gov>
Sender: news@amelia.nas.nasa.gov
Reply-To: fouts@orville.nas.nasa.gov (Marty Fouts)
Organization: NASA Ames Research Center, Moffett Field, CA
Lines: 24

In article <305@amelia.nas.nasa.gov> msf@amelia.nas.nasa.gov (Michael S. Fischbein) writes:

>If I remember correctly (I've got the reference here somewhere, but I'm
>sure I'll get flamed if I'm far off -- or even just a little off), tests
>on the first Ames Cray-2 showed twenty SIMULATED hot-and-heavy interactive
>edits used about 8% of one cpu.  These were all running as canned scripts.
>Unfortunately, they also simulated using more than half of the available
>"outside world" i/o bandwidth.
>

Actually we never ran those tests.  I believe that numbers from a test
like this were derived at the University of Minnesota, although I
don't know their results.  In attempting to drive the machine with
character traffic from a Vax, we couldn't drive it hard enough to have
a noticable impact using 4 11/780s doing nothing but sending one
character packets to the 2.  The Vaxen just couldn't sent packets fast
enough.

Back when we had an engineering branch they did some simulations that
could be interpretted as showing that interactive editing was very
expensive, but of course these started with assumptions that could be
loosely stated "interactive editing will be very expensive" and went
on to prove precisely that.

We don't have an engineering branch anymore. (;-)