The processor in modern PCs has multiple cores. Earlier PC models had two cores, but later PCs typically have four cores, each running at GHz speeds, thus making it possible for you to test/debug the same MPI programs you will be running on your eight-node, 32-core Pi supercomputer. Initially, you will utilize the CPU in your main PC as a one node supercomputer. This step will give you a quick introduction to and demonstration of the MPI protocol. Incidentally, the author's PC has an i7, four-core processor, each core running at 4 GHz, and can run two processing threads per physical core. The initial MPI runs included in this book were done using this 4 GHz machine.