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more on Interlisp-VAX

Mail-from: ARPANET host USC-ISIB rcvd at 17-Jan-82 1647-PST
Date: Sun, 17 Jan 1982 20:49:00 -0000
From: Dave Dyer       <DDYER at USC-ISIB>
Subject: Interlisp-VAX report
To: feigenbaum at SUMEX-AIM, lynch at USC-ISIB, balzer at USC-ISIB,
    bengelmore at SRI-KL, nilsson at SRI-AI
cc: rbates at USC-ISIB, saunders at USC-ISIB, voreck at USC-ISIB, mcgreal at USC-ISIB,
    ignatowski at USC-ISIB, hedrick at RUTGERS, admin.mrc at SU-SCORE,
    jsol at RUTGERS, griss at UTAH-20, bboard at RUTGERS, reg at SU-AI

	Addendum to Interlisp-VAX: A report

		Jan 16, 1982

  Since Larry Masinter's "Interlisp-VAX: A Report" is being
used in the battle of LISPs, it is important that it be as
accurate as possible.  This note represents the viewpoint of
the implementors of Interlisp-VAX, as of January 1982.

  The review or the project, and the discussions with other
LISP implementors, that provided the basis for "Interlisp-VAX:
A report", were done in June 1981.  We were given the opportunity
to review and respond to a draft of the report, and had few
objections that were refutable at the time of its writing.

  We now have the advantage of an additional 6 month's development
effort, and can present as facts what would have been merely
counter arguments at the time.

  We believed at the time, and still believe now, that Masinter's
report is largely a fair and accurate presentation of Interlisp-VAX,
and of the long term efforts necesary to support it.  However,
a few very important points he made have proven to be inaccurate.


  Interlisp-VAX has been in beta test, here at ISI and at several
sites around the network, since November 13 (a friday - we weren't worried).
We are planning the first general release for February 1982 - ahead
of the schedule that was in effect in June, 1981.

  The current implementation incudes all of the features of Interlisp-10
with very minor exceptions.  There is no noticable gap in functionality
among Interlisp-10, Interlisp-D and Interlisp-VAX.

   Among the Interlisp systems we are running here are KLONE, AP3,


   Masinter's analysis of the problems of maximizing performance,
both for Interlisp generally and for the VAX particularly was excellent.
It is now reasonable to quantify the performance based on experiance
with real systems.   I don't want to descend into the quagmire of
benchmarking LISPs here, so I'll limit my statements to the most basic.

  CPU speed (on a vax/780) is currently in the range of 1/4 the speed
of Interlisp-10 (on a KL-10), which we believe is about half the
asymptoticaly acheivalbe speed.

   Our rule of thumb for real memory is 1 mb. per active user.