PVM (Parallel Virtual Machine) (Parallel
Virtual Machine) is a software package that permits a heterogeneous collection of
Unix computers hooked together by a network to be used as a single large parallel
computer. Thus large computational problems can be solved more cost effectively by
using the aggregate power and memory of many computers. The software is very
portable. The source, which is available free through nettle, has been compiled on
everything from laptops to Crays.