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From: donn@rice.EDU (Donn Baumgartner)
Newsgroups: comp.unix.wizards
Subject: AT *speed* (was Re: 4.3 bsd for PC/AT)
Message-ID: <9338@brl-adm.ARPA>
Date: Wed, 16-Sep-87 18:52:17 EDT
Article-I.D.: brl-adm.9338
Posted: Wed Sep 16 18:52:17 1987
Date-Received: Sat, 19-Sep-87 11:52:52 EDT
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In response to my claim that the AT (roughly) benches above the vax,
Larry McVoy basically complained that he had seen just the opposite,
albeit "only a little tiny bit slower", and proceeded to give standard numbers
associated with AT machine's disk speeds, cpu speeds, and memory count.
The jist being that an AT running some non-BSD un*x system appeared to be
slower than a vax 750 (probably not running xenix).

To this, Ron Natalie (basically) responds that Larry's comparison is not
a fair one.
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Apples and oranges?  Maybe.  Let me clarify just a little:
  (1) the benchmarks are not comprehensive, and did not include disk bench
      marks (I said simple benchmarks, and I meant it);
  (2) a standard AT disk has a '28 ms' random access time, it's sequential
      read time (for loading, etc.) is typically 2 to 3 times that;
  (3) if you spent as much money on an AT disk as you will for a vax disk,
      the AT would fly;
  (4) an AT with only 1.5Mb of RAM running BSD or any other un*x is a crippled
      machine (how much memory did your vax 750 have?) (I should mention that
      AT RAM is considerably cheaper than vax RAM);
  (5) the 4.3 port to the AT is using the bsd fast filesystem - theoretically
      that will make it faster than your average xenix filesystem
  (6) the drystone benchmark (a pseudo-typical C program) shows one very
      important thing, that not all C compilers are created equal.  I have
      run that benchmark under DOS (3 compilers), PC/IX (it's compiler), and
      a xenix (it's compiler); all the times were different, with pc/ix taking
      top honors at '1215' (8MHz AT)... some of the times were slower than the
      vax time on the same code (but *different* compiler).
  (7) the simple bench we used for comparison ... a shell scipt which spawns
      /bin/echo many times in a loop, runs faster on the AT than the vax.
      The usefulness of that bench is also questionable.

OK, so what's my jist?  Well, first, I only use the vax for comparison because
it has in some sense become a standard to compare against.  My point was that
an AT running 4.3 bsd should make a cost effective, reasonably fast, personal
work station.  It's not a vax, or a sun, and should not be directly compared
with either (especially on pricing :-).  And then there's my bias; why would
I tell you negative things about the machine I'm helping port 4.3 to...

- Donn Baumgartner