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From: eugene@pioneer.arpa (Eugene Miya N.)
Newsgroups: comp.arch
Subject: Re: was 360  (now comparisons)
Message-ID: <2601@ames.arpa>
Date: Wed, 26-Aug-87 23:47:23 EDT
Article-I.D.: ames.2601
Posted: Wed Aug 26 23:47:23 1987
Date-Received: Sat, 29-Aug-87 05:39:55 EDT
References: <855@tjalk.cs.vu.nl> <2683@hoptoad.uucp>
Sender: usenet@ames.arpa
Reply-To: eugene@pioneer.UUCP (Eugene Miya N.)
Organization: NASA Ames Research Center, Moffett Field, Calif.
Lines: 40

Hugh LaMaster (just down stairs and down the hall) wrote:
>2)  Be careful to compare oranges and oranges. [Or apple to apples].

Great...  I'm literary trying to write down just what this person-hood
(Mother-hood went out years ago) statement means.  Yeah we want
consistency.  But, it is not as simple to achieve as people think.
One thing I have found in certain ego benchmarks is that when you get an
"apples-to-apples" comparison, people say, "You can't compare Golden
Delicious to Macs."  The problem may ultimately be unsolveable.

What I am working on is along the lines of what I call "equivalent
machines."  Such that I can substitute, by linear transformations, one
measure for another.  Consider that Dongarra's linpack has what many
consider constrains: 64-bit fixed size (orignally 100x100 dense system).
floating point "intensive."  64-bit is typically derailed by some
marketing types by, "Well, in case you don't need the precision, we
offer 32-bit..."  The means then becomes what's a 32-bit derived-number
versus a 64-bit rate.  The logic might go: well the ratio is 1:2, so
that should be the ratio between any two 32 to 64-bit comparisons,
right?  The problem is things like this don't scale.  I am also
thinking about what I might call, a "minimally equivalent machine"
and a "minimally equivalent benchmark," and I'm trying to think of this
stuff as I go along.  Give it a try.

Try comparing a 36-bit computer to a 32-bit computer.  Set explicitly
aside certain consistency assumptions: like identical cycle time.  What,
you've never work on a 36-bit [32-bit] computer.  Well go give it a try!
You might get your thinking warped, but seriously.  Tell me how you
think you would do some of these apples-to-oranges comparisons [note:
both use the same DNA, therefore, it's just the number of genomes
right?].

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