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Own a Piece of An Apple-Based Supercomputer
Graff writes "Now that Apple has come out with the Xserve G5, Virginia Tech has been swapping out parts of their 'System X' supercomputer for the more compact 1U Xserves. MacMall is selling some of those System X component G5 systems with an approximate $200 savings and an extra 512 megs of RAM over a normal G5. You can read more about it at MacCentral."
on the contrary. My 4 years experience with clusters show that after the first two months of burn-in where many components fail, you aftewards have a higher MTBF than with PCs used "normall", because in the Beowulf case the AC power is regulated, the machine is almost never switched on and off (major cause of damage because at startup every component consumes power at the same time, voltage drops, and damage occurs), temperature is kept constant, the machine is kept in a safe room where nobody ventures more often than once a week because of the cold and the noise, therefore there is no dust in the machines or grease on the contacts.
Google passes Turing test : see my journal
I'm going to have to disagree with you concerning the amount of wear and tear.
Most computers fail either in the first month or so of use or after many years of good use. In the first case it's usually a bad component that slipped by quality control. In the latter it is simply the ravages of time. Longer quality control "burn-in" times would eliminate many of those first month failures, but the vendor really doesn't have the time/space for long burn-ins.
Now, the Number One way to shorten the life of your computer is to turn it on and off frequently. The computer heats up when you run it and cools when it's off. The expansion and contraction of components associated with these temperature changes stresses every solder joint on every component -- and may even stress the chip-level components themselves. To lengthen the life of your hardware (at the cost of extra electricity), leave your system on unless you aren't going to be using it for a significant length of time (i.e.: don't power cycle more than once a day).
These G5's have been on for approximately six months straight in a very well-controlled temperature environment. This is a burn-in that virtually guarantees that there were no manufacturing defects. However, since they weren't power-cycling on a regular basis, it was actually a VERY low-stress environment.
Life is short: void the warranty.
You can do some good high speed networking using firewire.
It's available in Mac OS and Linux.
http://www.homenethelp.com/network/firewire.asp
400mbps isn't to be sneezed at. With repeaters it'd probably make a decent fail-over network in case the main gigabit link failed.
Worst
What I heard is that VT isn't removing the identification stickers. I don't know if MacMall is removing them or not.
First of all, how is this profiteering? They are trading in their G5s to upgrade their cluster, Virginia Tech is not selling the "old" ones, MACMALL IS! Virginia Tech is simply trading them in. So you would rather have Virginia Tech eat all the money that they spent to purchase the original lot of 1,100 instead of making them look much better to potential customers who want to purchase the use of their cluster, by leveraging the money they have already spent? It is in business to make a profit, like it or not, it is not their primary main objective (Chinpokomon!) but it can not be ignored, either. I respect your opinion that some of the G5s should have been kept around for use in labs, by students, etc. Then again, we don't know if VT traded ALL of their G5s, they just might have kept some for the uses that you and I laid out. I suppose this just shows, on a grand scale, the high resale value of Apples!
I hate sigs.
The G5 was the clear winner out of all the chips on the market, and Apple was the clear winner of the platforms considered, and they considered *ALL* of them worth considering.
The success of the venture simply proves the superiority of keeping an open mind and not bringing tired old pre-conceptions (Apple's slow, Apple sux, etc.) to your work.
Actually, FireWire supports transfers of up to 3.2Gbps depending on the interconnect used.
mbbac
I'm fairly sure Virginia Tech wanted the 1u cases all along (makes more sense). However, they needed the cluster up in time to make the Top 100 list. Being on that list brings in _lots_ of research money. So yes, they did need them.
Why?
Actually the list is updated every 6 months, but the one in November is the bigger of the two because that is the time for the annual supercomputing conference.
Just called, no need to call.. they're all gone.. shucks.
-Jim
Not every. But most. Solving ODE's usually boils down to iterating a (possibly implicit) linear system. Solving PDE's with finite differences does too. Or with finite elements. Or spectral methods. Lots of statistical computations do too.
Certainly there *are* scientific applications that don't involve multiply-adds, it's just that the vast bulk of scientific computations that are suitable for parallelization really boil down to solving linear systems, some kind of linear iteration, least-squares problems, or some combination. All of which are solved using lots of multiply-adds. So, while linpack isn't the end-all and be-all of hpc benchmarks, i'd say that it's a pretty good guideline; i'd also say that the speed of multiply-adds matters a whole hell of a lot for scientific computing.