There seems to be a problem with the power consumption requirement of 3 MW, which is stated in the presentation material. If you estimate that each of the 2200 cpus consumes 100 W, that makes only 0.22 MW, a factor of 10 difference. Where is the rest (90%) of the electrical power needed?

I was a bit sceptical about the latency and speed of the communications network, but there is some serious technology involved. According to an expert, the Infiniband technology is in the same class as Myrinet - in the middle category both in speed and price. It will be interesting to see how the communications scales up in the G5 cluster.

Here is some background in the partnership of the project where Virginia Tech Builds Top 10 InfiniBand SuperComputer for $5M: "Virginia Tech[base ']s partners for building this supercomputer in less than three months are Apple, Mellanox, Cisco, and Liebert. Mellanox is the leading provider of the InfiniBand semiconductor technology, the primary communications fabric, drivers, cards, and switches for the project. Cisco[base ']s Gigabit Ethernet switches were the choice for the secondary communications fabric to interconnect the cluster. Cisco provided a significant educational discount to support the project. Liebert, a division of Emerson Network Power, known for its comprehensive range of protection systems for sensitive electronics, provided the cooling system."

But what is "Déjà vu", which was reported to make it possible to carry on computations even when a node of the system fails. It seems that Déjà vu is a migratable version of MPI, and allows a task to be migrated to another node of the system. (See a pdf presentation about this.)

On the Cray T3E supercomputer there was this possibility: you could migrate tasks between nodes, and also suspend task when a higher-priority task had to be started. (An example: the weather forecast system has to be executed several times a day within a certain time limit.) If Déjà vu really works and does not need programmer intervention, this is really great news for all computational clusters.

In any case, it is time to forget the notion that Apple hardware is more expensive than other brands. When comparing similarly configured high-end systems, Apple may turn up cheaper, because a lot of the required functionality comes as options on other systems.

There is a lot of data available about the Virginia Tech G5 cluster at the Terascale Cluster page. If you are interested in technical details, see the slides (in PDF).

Dell joins UT's $38M supercomputer project: "With the purchase of 300 computer servers from Round Rock-based Dell Inc., the new "Lonestar" computing cluster gives UT scientists and engineers the power of more than 3 trillion computer operations per second, or 3 teraflops." See also: Cost of supercomputer only part of $38 million.

Here are my choices: Linux kernel development, Mozilla, XFree86, Apache, and OpenSSH. On the other hand, all these are doing rather well already.

How about, for example, the SourceForge projects for posting Xmeeting and MPlayer to Mac OS X, or the Fink and DarwinPorts projects?

A company might not be interested in the MPlayer port, depending of course on the business it is involved in. The other projects are good investment choices for almost any enterprise, even for Microsoft.