For truly high speed clusters, the per port cost of the interconnect is a big piece of the puzzle. Thus you still want the maximum per processor performance. If you look at the Top 500 list you will see a number of highly ranked Intel machines. This is a very big recent development but they are all Xeon and Itanium systems, not budget Pentium 4s. So the G5 is price competitive, especially for floating point apps where PowerPC has always shined.
It would be a big coup if Apple can pull off even a top 10 finish, and it's not out of the question. If you'll look at the second decade of the Top 500 list you'll see several ~1000 processor pSeries 690 Turbo clusters. These are all 1.3GHz Power4 machines, the sister chip of the PPC970. Double the number of processors, each with roughly 1.5x clockspeed, and you're in the ballpark of a top 5 finish. The recently announced IBM FORTRAN compiler will help a lot with this. The open question will be whether the interconnect, which is rumored to be Infiniband, can keep up. If it works, this will sure sell a lot of G5 Xserves!
Since we're throwing out SPEC numbers, I thought I'd add some numbers I turned up on the SPEC WWW site.
Hardware Clockspeed(GHz) SPECint2k SPECfp2k
Athlon XP 3200+ 2.20 1044 873
Opteron 144 1.80 1170 1122
P4(533 MHz bus) 3.06 1089 1053
P4(800 MHz bus) 3.00 1164 1213
Itanium 1 0.80 314 645
Itanium 2 1.00 807 1356
UltraSparc IIIcu 1.20 642 1074
MIPS R14000 0.60 483 499
IBM Power4 1.70 1077 1598
These are actual measured values recorded at SPEC. I tried to pick the fastest of the listings for a given processor. Note that the Itanium I & II integer preformance problems are plainly evident as is the reason SGI is going to Itanium anyway. You can also see the benefits of the 800 MHz bus for the Pentium 4 and the reason why people question the 3200+ designation on the 2.2 GHz athlon.
We don't have measured SPEC numbers for the PPC970, but we can compare the Power 4 from which it is derived. To match the integer performance of the Opteron@1.8GHz or the Pentium4@3.00GHz would take roughly a 1.8 GHz Power4. If we then compare the FP performance of these same processors, the Power4 would win by 40% over the P4 and 50% over the Opteron. And the Power 4 doesn't have a vector unit.
The open question, which will probably be answered by IBM on Monday, is how well the PPC970 matches up with its sibling. Remember the main differences between the PPC970 and the Power4 are a smaller L2 cache, Altivec, and a very different main memory architecture, so the real question is how well the HyperTransport bus feeds the processor. Given the low memory bandwidth/flop of the Power4s we have at work, it's not impossible that the PPC970 will be as fast or faster. This would affect the FP performance more than the int performance and the rumors are that the IBM estimates quoted by Ace's are conservative at least for FP. But we'll have to wait and see (hopefully not long).
Certainly once these systems hit market, unlike today, Apple will have hardware which is competitive for key markets like video and image editing, without appealing to Altivec.
One of the most educational (and fiery) demos I ever saw was a demonstration of the effect of aeration on flame.
Take a large ladle and pack it full of a fine dry flammable. The demo I saw used fine sawdust, but flour (or coal dust!) should also work. Light the contents of the ladle, they will just smolder. Then swoosh the ladle hard through the air. The smoldering fine particulates will get mixed with air and a nice fireball will result. A great demo of how flame depends on oxygen as well as fuel.
Huh? Why would Apple include CUPS if GUI apps couldn't print via it. For their legion of command line users?
Since Mac applications can already spool PostScript and send it directly to LPR printers and CUPS is just an extention of this mechanism, what make you say that Mac applications won't be able to spool PostScript to CUPS servers?
I'm running XDarwin 1.0a3 successfully with Mac OS X.I. (Dual headed on a PowerBook G3 no less!) I had a little bit of problem, but it was easily fixed. OS X replaces the BSD subsystem, so I had to go back into the system tcsh login and add/usr/X11R6/bin back into the path.
A friend with an iBook had to reinstall XDarwin 1.0a3 to get it to work again.
Good Hunting!
Raph
Links to Better Sources of Supernova Info
on
Star In A Jar
·
· Score: 3
OK Folks-
There are a lot of explanations going around this thread about how core collapse supernovae occur. Some good, some terrible, none quite right. Rather than correct what's been said, I'll instead point y'all to a few of the sources of real info out there.
A friend in the business maintains a page full of links to SN pages. Many of these are links to research groups, but there are also links to general education and image catalogs.
BTW, in case you don't believe that I know of what I speak, follow this link
Slashdot Mirror
For truly high speed clusters, the per port cost of the interconnect is a big piece of the puzzle. Thus you still want the maximum per processor performance. If you look at the Top 500 list you will see a number of highly ranked Intel machines. This is a very big recent development but they are all Xeon and Itanium systems, not budget Pentium 4s. So the G5 is price competitive, especially for floating point apps where PowerPC has always shined.
It would be a big coup if Apple can pull off even a top 10 finish, and it's not out of the question. If you'll look at the second decade of the Top 500 list you'll see several ~1000 processor pSeries 690 Turbo clusters. These are all 1.3GHz Power4 machines, the sister chip of the PPC970. Double the number of processors, each with roughly 1.5x clockspeed, and you're in the ballpark of a top 5 finish. The recently announced IBM FORTRAN compiler will help a lot with this. The open question will be whether the interconnect, which is rumored to be Infiniband, can keep up. If it works, this will sure sell a lot of G5 Xserves!
We don't have measured SPEC numbers for the PPC970, but we can compare the Power 4 from which it is derived. To match the integer performance of the Opteron@1.8GHz or the Pentium4@3.00GHz would take roughly a 1.8 GHz Power4. If we then compare the FP performance of these same processors, the Power4 would win by 40% over the P4 and 50% over the Opteron. And the Power 4 doesn't have a vector unit.
The open question, which will probably be answered by IBM on Monday, is how well the PPC970 matches up with its sibling. Remember the main differences between the PPC970 and the Power4 are a smaller L2 cache, Altivec, and a very different main memory architecture, so the real question is how well the HyperTransport bus feeds the processor. Given the low memory bandwidth/flop of the Power4s we have at work, it's not impossible that the PPC970 will be as fast or faster. This would affect the FP performance more than the int performance and the rumors are that the IBM estimates quoted by Ace's are conservative at least for FP. But we'll have to wait and see (hopefully not long).
Certainly once these systems hit market, unlike today, Apple will have hardware which is competitive for key markets like video and image editing, without appealing to Altivec.
One of the most educational (and fiery) demos I ever saw was a demonstration of the effect of aeration on flame.
Take a large ladle and pack it full of a fine dry flammable. The demo I saw used fine sawdust, but flour (or coal dust!) should also work. Light the contents of the ladle, they will just smolder. Then swoosh the ladle hard through the air. The smoldering fine particulates will get mixed with air and a nice fireball will result. A great demo of how flame depends on oxygen as well as fuel.
Huh? Why would Apple include CUPS if GUI apps couldn't print via it. For their legion of command line users?
Since Mac applications can already spool PostScript and send it directly to LPR printers and CUPS is just an extention of this mechanism, what make you say that Mac applications won't be able to spool PostScript to CUPS servers?
Hang in there, it can work.
/usr/X11R6/bin back into the path.
I'm running XDarwin 1.0a3 successfully with Mac OS X.I. (Dual headed on a PowerBook G3 no less!) I had a little bit of problem, but it was easily fixed. OS X replaces the BSD subsystem, so I had to go back into the system tcsh login and add
A friend with an iBook had to reinstall XDarwin 1.0a3 to get it to work again.
Good Hunting!
Raph
There are a lot of explanations going around this thread about how core collapse supernovae occur. Some good, some terrible, none quite right. Rather than correct what's been said, I'll instead point y'all to a few of the sources of real info out there.
A good place to start is the NASA Observatorium page on Stellar Evolution and Death
A friend in the business maintains a page full of links to SN pages. Many of these are links to research groups, but there are also links to general education and image catalogs.
BTW, in case you don't believe that I know of what I speak, follow this link