Back in 2004, Apple hobbyist/guru [Michael Mahon] built a cluster of Apple IIe main boards dubbed the “AppleCrate” as an experiment in parallel computing. Now that a few years have passed, he is back with a new iteration of the device, aptly named AppleCrate II.
AppleCrate II was built to address some of the design limits of his first cluster project as well as to expand his parallel computing capabilities. His gripes with the first model were primarily structural in nature. The new system is organized in horizontal layers, using metal standoffs between each main board, rather than relying on a shaky wooden superstructure to keep things together. He also found his previous 8-processor configuration a bit limiting, so the AppleCrate II has 17 nodes – 16 slaves and one main board dedicated to running the operation. The cluster even uses his own homebrew networking stack known as NadaNet to enable communications between the boards.
The project is pretty impressive, so be sure to swing by his site if you want to learn more. He has a ton of technical details there, as well as copies of all of the software he used to get the cluster up and running.