Homemade computer calculates pi to 10 trillion digits
npr.org
npr.org
To think, if he had used this for bitcoin mining instead, he could be a hundredaire.
I am working on a similar brute-force analysis, but I have access to a datacenter with many machines. Not so impressive.
"For large computations, the bottleneck is either memory bandwidth or disk bandwidth depending on the number of hard drives and their configuration."
Calculating pi is a fairly reasonable way of measuring CPU performance though. I've seen Anandtech and the like use SuperPi for this purpose.
In my first year of university we had to do (in Pascal) a library of arbitrary-precision functions for the arithmetic operations. It was really interesting at the time. If you measure something to a trillion digits you need a pretty good library for this. You also may not have the entire number of memory at a time (although a trillion digits is 0.5TB BCD-encoded so that's not inconceivable) so the problem itself has a lot of interesting aspects to it.
Just think about it. If that's true, the whole universe is described inside Pi with any precision you want, with any time precision you want. Somewhere in Pi your whole life is stored.