"If that doesn't work I could buy a cheap used computer like this one:"

Don't buy that as a cruncher.
The small form factor and puny power supply means you can't fit a high end Graphics card in there, and that's what gives you a serious cruncher. Using only an old CPU like that just gives you a small space heater. Useful if the weather gets cold, but that's about it.

Now buying a $100 refurb PC like that, but with a mini-tower case and a beefier 450w power supply, and then spending another $100 on a CUDA capable graphic card would get you something useful. Also makes a passable game machine for lan parties etc.

To make a "farm", just keep stacking them up. You can run them without screens and keyboards etc, just a lan connection and use remote desktop to sign in to the individual machines.

Once you get familiar with the innards of PCs you will know what you can mix and match to rebuild old machines. Often 3 dead PC's can be mixed n matched to get 2 working ones. You get a feel for the ones that are easy to rebuild.
No power at all? - Probably PSU, easy fix
Boots but comes up with a disk error? - Probably dead hard disk - relatively easy fix
Powers up but no picture - Who knows? But chances are you can recover a good PSU and HDD to fix the other 2....

Doesn't take long to build up a "farm", and if they can take CUDA cards, you can build something useful, without spending 1,000s of $$ on hardware.

Ian

Basically what I'm getting from this thread is that this idea I've been having is way beyond my skill level.

Maybe you should start reading here.

http://techreport.com/review/13671/how-to-build-a-pc

Basically what I'm getting from this thread is that this idea I've been having is way beyond my skill level.

You've got to start somewhere and if you've got an interest, but made it to university age without sticking your head into a computer to see how it ticks, there's no time like the present.

These things are stuck together on assembly lines. It isn't hard to stick all the parts in a box and make it work. Making the parts is beyond any of us. So you have to acquire the parts and assemble it like a kit.

Do you have any easily available source for an old computer? (old, but probably not older than a Pentium 4). How much room do you have for all of this? A desktop? A bookshelf?

Tell us what you were thinking more specifically and let's see if we can help you make the most of your time/money/energy.

BOINC farm = Big Electricity Bill :(

We have DC which is in effect a wave of infinite size, so we know there is no limit going this direction, except perhaps the age of the Universe if it is to be generated inside the Universe.

On the other end the plank length might be considered a limit. Such a wave would pack a lot of energy. At some point going smaller the wave/photon would consist of the entire energy of the universe and I assume that might be a real physical limit.