🚀 go-pugleaf

In Alan Karp's summary of the recent ARO conference at Stanford on medium
scale parallel computers he left the impression that 
"there is currently a dearth of commercially available, shared memory systems. "
We would like to offer a different impression of the availability and usefulness
of shared memory parallel computers that one can purchase commercially today.

In addition to the Alliant, Flex32, and Elxsi systems that were mentioned
there are a number of other very successful shared memory machines including

     BBN Butterfly (256 processors)
     Sequent Balance 16000 (24 processors)
     Encore Multimax (20 processors)
     CRAY X-MP-4 (4 processors)
     CRAY 2 (4 processors)

We also must remember that while the Denelcor HEP was a commercial failure,
it certainly was a success in terms of providing a parallel computer that
was programmable and capable of doing real computations.  We have had experience
with the Alliant, Sequent, Encore, CRAY X-MP and Denelcor machines.  All of 
these computers out perform existing cubes and in our view are easier to program
and debug.  If you want to account for cost/performance place Sequent and
Encore against the Intel's iPSC and Alliant against Ncube.  Moreover, these 
systems (Alliant, Sequent, Encore)  are stand alone minicomputers that can 
perform the ordinary computing one would normally does on say a VAX system 
including sharing resources among a number of users.  For these reasons we fail
to see any dominance of the cube architecture at this moment. 

>From the standpoint of developing algorithms, the hypercube does provide 
an interesting architecture to investigate.  


               Jack Dongarra     Dan Sorensen