Can a large RS/6000 easily replace a Convex?

[raymond thomas pierrehumbert]

> (questions about 550 vs. Convex, esp. multi-user performance)

I think that replacing a Convex with a cluster of 550's could be
a big win.  I benchmarked the R6000 series against a number of
other number crunchers, and found that the performance is 
pretty much as claimed.  Code that is very vectorizable
but with no possibility of re-use of data may still do
better on a vector machine like the Convex though;  code in
this category may be rarer than you think.

Multi-user performance?  I ran four copies of a 2D fluid code, and
then did a big makefile.  It worked fine.  I think 8 users wouldn't
be any problem, as long as you have enough memory.  If it gets 
to be a problem, buy a couple extra 550's!  For the price differential,
you can afford this vis a vis 1 Convex.

Gee, I wish IBM would come out with a four-processor shared memory
version of the R6000.  Now THAT would be a really fine cruncher.
.
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