Author: Robert Hyatt
Date: 15:00:42 06/13/99
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On June 13, 1999 at 17:10:06, Heiko Mikala wrote: >On June 13, 1999 at 16:05:28, Robert Hyatt wrote: > >>On June 13, 1999 at 14:48:49, leonid wrote: >> >>>What was the hardware of Cray Blitz in 1983? >> >>A dual processor Cray-XMP with 1M words of memory (8 Mbytes). We were >>searching about 20-30K nodes per second back then, when the micros were >>doing only a couple of hundred nodes per second... > >Hi Bob! > >This is a question which I thought about often during the last weeks: When you >say, that the Cray-XMP had 8 MB of memory and Cray Blitz searched about 20-30K >nodes per second, do you think that todays normal PC's are faster than the >super-computers of that time? For raw integer scalar computing, todays micros blast the cray... the first SMP (1983 machine) had a 8.5ns cycle time cpu, which is just over 100mhz... But when you do vector computing (if you have large arrays of data) that old cray will fry the spots off of any microprocessor built today... because that old machine could do 2 memory reads and one memory write (24 bytes total) in one cycle, per cpu. With 2 cpus, that is 48 bytes per cycle, which at 10ns/cycle (to make the math easy) that turns into 48 X 10^8 bytes per second. No 20 pcs can produce even a fraction of that... > >I was thinking much about this thing, because at work we have an "old" Vax and >an old HP mainframe, which are fascinating me - these machines did cost a *huge* >amount of money when they were bought only some years ago, but don't seem to be >faster than a normal Pentium (HP) or a medium-fast Pentium II (Vax). > >Of course, these machines are built to work forever - they're still in full use, >24 hours a day, every day... main thing is you need a code with big arrays and many iterations, like weather forcasting, seismic analysis, etc... > > >Another question, which I would like to ask you: > >During the last 1-2 years you sometimes mentioned, that you tested some >positions on Cray Blitz and compared the results to Crafty. Do you still have >access to Cray Blitz? Is it still alive? And what happened to the other Cray >Blitz team-members? > Bert Gower lives about 75 miles north of me in Huntsville Alabama. We chat regularly and he drops by ICC often to check on Crafty. Harry still lives in Livermore, but has retired from the Lab there... We chat maybe once every year or so, still. Crays are still being shipped, and I have the source, so I do occasionally test things against cray blitz for fun... but machine time is difficult to get and I don't do it much.. > >Greetings from an "old" fan, who learned much from your articles about Cray >Blitz, > >Heiko. thanks... those were fun years battling Slate/Atkin and Ken Thompson (among others)... :)
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