The archive is tar-based, which sounds like UNIX. The documentation says it's FORTRAN 90/95.
Coupled GCMs (General Circulation Models) are resource hogs. You'll need a fast CPU. Today's PCs are not exactly up to the task, but they are close.
The resolution usually isn't enough to get concerned about. The vertical resolution divides the atmosphere into about 30 to 35 cells. The horizontal cell size is quite large--enough that whole cumulonimbus clouds (thunderstorms) are lost inside the cells.
You might try simpler models. Trenberth’s 1997 paper describes a simple global average model. His figure seven appears everywhere (including the last two IPCC reports).