A cluster is a group of PCs (or other computers) that are connected together in such a way that they behave just like a single, much more powerful computer. Usually what happens is that the programs you run are divided between the machines. You don't see that, though. From your perspective, at whatever computer you're sitting at, it looks like everything is running on your machine. You see nothing different than that.... other than everything running much much faster.
One way you could use this sort of thing is if you've a bunch of really old PCs that all have network cards but just don't have the kind of speed you're looking for. Say they're half, or even quarter, the speed of a brand-new machine. All you need is four of them and you've got very nearly the same power as a modern machine. If you've already got the machines, or the local Internet Cafe is throwing some old machines out, you can build yourself something comparable to some of the more expensive PCs out there.
A second way it can be useful is if you've got some tasks that absolutely must not be interrupted (such as burning DVDs, relaying the cable TV picture of your favorite show to the screen or playing World of Warcraft) but other things must also take place (automatic checking for e-mail, printing school papers, surfing the web). You can build a cluster and farm the work out such that none of the critical stuff is going to be delayed. At the same time, because it acts like one machine, you don't need a multitude of monitors or a gigantic KVM switch. It's cheap and it's easy.
The third way to use this approach is to build something seriously extreme. Say you're a gamer with a decked-out extreme gaming PC which you use to crush your opponents at local LAN parties. You can't trick it out any more, you're already running it with as many cores as it'll handle, and the air cooling sounds like Concorde did on take-off. Can you go into the next Quake 9 tournament with something even more fearsome? Yes. By linking the machine up to other PCs in a cluster, you now get the total power of all the machines combined.
(In fact, if you look at some of the world's fastest computers, that's really all they are. Any school or college with 64 or so ordinary, run-of-the-mill PCs could get themselves onto the list of the 500 fastest computers. In fact, a very large fraction of the list is entries from colleges who have done just that. Even in the top 10, you see people who have just strapped hundreds, sometimes thousands, of standard desktop PCs together, to build machines capable of trillions of calculations a second.)
These days, there are programs you can get for free (for Linux) that'll do all of this and don't require a PhD in rocket science to install or use. If you can put a CD in, you've 99% of the skills required.
Aspies are notoriously geeky, and although it's easy, clusters are geek paradise. Aspies are also notoriously non-conformist, and clusters are definitely not an everyday thing, again even though they are easy. I cannot possibly imagine that the number of people who have built and used clusters here is any less than, say, on Slashdot (a notorious hive of nerdosity), simply because the density of truly obsessive geeks will always be highest amongst the Aspie community.
23 Jul 2007, 12:58 pm
"Do you have any thoughts of your own on this matter?"
