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A reply to Mike Fischer's comments:
A brhef clarification: At the current time I do not see Lisp machines
replacing Apollos. A department may be able to afford $10K to $15K per
student, but it can't afford $50,000. I see Lisp machines as an alternative
for people whose programs are too large to run on Apollos.
1. What is the cost per node for all that speed? If a node that
costs twice as much runs 3-5 times as fast, is that really a good
deal, given that most of the time it sits practically idle doing
Some of us need more cpu cycles than others. In 1974, ten years ago, I had
access to a KL-10 (read "2060") evenings with few enough users that it was
efectively my own. Two years ago, one could come in in the evenings and run
on a similarly empty research machine. Today my T programs run 10 times more
slowly when they are not garbage collecting, and many orders of magnitude when
they are. For compute intensive research (e.g. machine learning experiments)
the apollos are a joke. The tern, at 3 times faster, will continue to be one
third the cycles available ten years ago. So much for progress.
In terms of cost, IFF Symbolics is willing to give us the kind of deals I was
quoted at AAAI this summer, 3640s should be cost competitive on a node per node
basis with terns. My estimate is that a 3640 OUGHT to be available at
under $50,000 per node.
2. What is the true cost of switching systems, once you factor in
the additional staff needed to support it and the increased difficulty
of interaction with others in the local community?
The point of the 3600's would be that, being for people who need cycles, those
people would be responsible for figuring them out for themselves. However,
since Drew maintains a NISP and a DUCK for the 3600, all his students can run
their code without change. Since 3600's have a company behind them, not a
graduate department in which each group would love to see the others go away,
software support should not be a problem. Hardware support has been quoted at
$7,000 per node-year: admittedly expensive.
3. How good is the software? Does it support transparent remote file
access? Mail? TeX? Scribe? Graphics? Yale-style editors? C?
It has a lot of software. It is claimed to support mail, transparent file
access, Zmacs (an Emacs style editor) (come on now, you aren't going to refuse
to let someone else use a system just because it doesn't support your favorite
editor, are you??), FORTRAN, and graphics, and might support scribe (don't
hold your breath).
Although it takes getting used to, the environment is quite nice. The
compiler is fast enough that exiting from the editor can go through the
compiler and still be reasonably fast: at about the cost of swapping in a
different "context" on a diskless node, one can debug compiled code.
4. How good is the Lisp? Does it have the clean semantics to
facilitate the development of large systems that T has? How long
does it take to learn to use effectively (i.e. what is its
"kludginess coefficient")? How many of our faculty and students
have the time to invest in learning to use it effectively?
Zetalisp is not T. Not by a long shot. It feels like returning to the stone
age. HOWEVER, it is possible to work in it, and it does support a
methodology, admitedly on the kludgey side, for developing large systems.
5. What is its growth path, i.e. if you take similar benchmarks in
two years' time, what will you expect to see? Is there any reason to
believe the Symbolics class of machines will remain faster than the
Apollo class? Maybe I hold out too much hope for the new T compiler,
but I had the impression that it might yield a speed increase of two
to three times. If so, the Tern running T would already approach the
First of all, neither terns NOR the new T compiler exist. Apollo has stopped
accepting orders for terns, and although the future promises DN300 size boxes
which are 6Mb Terns, that depends on both 256k chips and the 68020, neither of
which are available yet. The 3600 is here. Now. It is also a TWO YEAR OLD
machine; we saw a functioning prototype at AAAI two years ago. T 3.0 was to
have been here after a full summer of work by all involved. Now it is
promised for December. But most of the relevant people are no longer working on
it. (assigning blame here is ugly, so don't misinterpret me: I know its an
Both Symbolics and Apollo have new machines in the works. There is an
instruction pre-fetch unit which may speed up 3600s 20% to 50%. There are
semi-custom VLSI things in the works also. But even if the Tern can catch up
in speed with the 3600, the 3600 has a 27 bit cons cell address space, as
compared to 19 bits in the 68010, and 22 AT BEST IFF they pin out the existant
address lines in the 68020. (am I wrong here? Could the 68000 architecture
support 32 bits of byte address, and thus 27 or 28 bits of cons cells???)