🚀 go-pugleaf

    In article <1210@ogcvax.UUCP> pase@ogcvax.UUCP (Douglas M. Pase) writes:

	. . . However, machines like the iPSC were designed to do heavy
	computing, and NOT a lot of resource sharing.  . . .
	The hypercube is set up to do number crunching, with lots of
	operations per byte of I/O.

    In article <ames.362> eugene@pioneer.UUCP (Eugene Miya N.) responds:

	Hypercubes were not designed to do a lot of heavy computing.  You would
	be putting them into the Cray class of processor, and everyone's
	experience has been to the contrary.

Agreed, the iPSC is not intended to compete with the Cray - at ~1 Mflop per
32 node tower, it hasn't near the horsepower of a Cray.  Crays are especially
good at problems which are vectorizable and require huge amounts of memory.
The iPSC is not.  (However, just try to pick up a Cray for under $200,000.)

(Miya)	Heavy computing requires a well thought out (balanced) structure to
	prevent things like an I/O bottleneck.  A hypercube is far from a
	typical end-user machine.

Again I agree, but whether a machine architecture is "balanced" or not depends
alot on its intended application.  If a huge volume of communication is
required, the iPSC is probably not appropriate.  Geoffrey Fox of CalTech
presented a paper in one of the 1984 conferences extolling some of the virtues
of a hypercube architecture (NOTE: NOT an iPSC - the iPSC is based on Fox's
design) for computing.  The article was called "Concurrent Processing for
Scientific Calculations".  It was in an IEEE conference, but I don't remember
which one.  BTW, just about any new architecture is "far from a typical
end-user machine."

(Miya)	The marketing hype which has surrounded hypercubes astounds me.  It
	turns out the ONLY person I have heard a level-headed response from was
	Justin Rattner of Intel who stated that these machines are research
	machines to provide exposure to people on the problems of doing parallel
	programming.

Perhaps you're too easily astounded, or maybe you think it's of no use because
it's of no use to you...

(Miya)	They are not designed to replace Crays or compete with
	them.  To believe so would involve a great deal of misunderstanding.

Again, I don't disagree - it was never my contention.

(Miya)	There are now five (if not more) companies selling hypercube
	architectures out there, I doubt if any will survive in the long term
	(in the hypercube market).  Don't hold your breath for software either.
	Don't expect to take you dusty deck C or Fortran and have it
	automatically parallelize it (when it does, we will have achieved true
	AI 8-).

No question but that algorithms for the iPSC require a different approach than
Von Neumann style machines; hence dusty decks won't work.  This is no suprise
to me, as there is a big difference between an MIMD architecture and a SISD
architecture, and only a little difference between vector/scaler and SISD
architectures.  Does that mean they'll never succeed?  Well, we'll see...

One Last Word:
I'm glad you subscribe to this newsgroup Eugene; I enjoy your postings.  Please
keep them coming.
-- 
Doug Pase   --   ...ucbvax!tektronix!ogcvax!pase   or   pase@Oregon-Grad