ok, we have had some discussions, let me add my views / facts.
8 of top 10 of the top500 supercomputers TODAY are linux based. was not like
this historically. if you go back, say 5 years (yeah, some of us have been
interested in top 500 for that long, heck, maybe even longer), vendor flavours
of unix was king. ibm, sgi etc were big players, so aix, irix and such figured
prominently. the sponsors then were the same government laboratories and there
was no issue with source code. users were quite happy (well, maybe, maybe not)
with vendor supplied non-open-source os machines as long as the parallel tools
ran as per user expectations. it was common for vendors to tweak their
networking code and parallel tool (mpi) code, but as hardware and network
architechture kept changing, this was more and more tricky. also, specialty
networking like myrinet and infiniband added its own twist to this tale. sorry,
but i believe that the shift to linux is not for any real 'technical merit'
reason but just incidental. high performance users dont really want to see the
networking source code - they want to use parallel tools like mpi and want their
code to run FAST. in any case, the top500 listing is based on linpack benchmark
using mpi (only), so parallel performance using mpi is all that counts.
there was also some comment about param padma. param padma is an ibm p-series
(risc) smp box based machine - basically ibm supplied hardware with some cdac
special networking. the previous param 10000 was a similar construct with sun
hardware. cdac's contribution in both cases was in special networking. the
'real' indian entry into the top 500 (no longer current) was from imsc
(matscience) with its xeon linux cluster. of course, now we have more entries,
including the centre for biochemical technology delhi (i guess institute of
genomics blah blah is the correct name).
sriram
