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From: fouts@orville (Marty Fouts)
Newsgroups: comp.arch
Subject: Re: Cost of Designing a New Computer (Software)
Message-ID: <167@ames.UUCP>
Date: Fri, 16-Jan-87 00:14:57 EST
Article-I.D.: ames.167
Posted: Fri Jan 16 00:14:57 1987
Date-Received: Fri, 16-Jan-87 21:39:57 EST
References: <950@husc6.UUCP> <666@instable.UUCP> <673@astroatc.UUCP> <976@husc6.UUCP> <1012@husc6.UUCP>
Sender: usenet@ames.UUCP
Reply-To: fouts@orville.UUCP (Marty Fouts)
Organization: NASA Ames Research Center, Mountain View, CA
Lines: 27
Keywords: hw, sw, micros, super-minis, unix
Summary: More on Cray 2 UniCos Experience


NASA Ames was the first site to run UniCos (on both the Cray 2 and on an
X/MP 12)  UniCos on the 2 is System V compatible, except for shared memory,
semaphores, and 'messages'.

The raw performance of the 2 is in the same range as that of the large
X/MP systems.  I have benchmarked UniCos I/O performance using simple
C programs under full CPU load which are capable of sustained transfer
rates of 7+ megabytes/second between memory and disk, using a disk drive
which is rated at 7.2 megabytes/second maximum transfer rate.

We have also seen the system run at nearly 100% cpu usage for weeks at
a time with less than 5% 'system overhead.' (time spent in the kernel
not directly accounted to user processes.)

It's not true that the software has to be complex to make the machine
perform well, and it doesn't take a huge development staff to make it
work -- if the machine is designed cleanly to begin with, and if the
software is well matched to the machine.

I also have a benchmark on which a Vax outperforms the Cray 2 by a factor
of ten; which I use to demonstrate that any computer can be misused.  (the
nature of the benchmark is left as an exercise to the reader.)

Disclaimer:  I don't work for CRI, my wife does.
             Any opinions stated here are not those
             of the federal government, NASA, or the mute Marine.