Now let us relate the basic message-passing ideas to a cluster of computers(cluster computing). There have been software packages for cluster computing, originally described as for network of workstations. Perhaps, the first widely adopted software for using a network of workstations as a multicomputer platform was PVM(Parallel Virtual Machine) developed by Oak Ridge National Laboratories in the late 1980s and used widely in the 1990s. PVM provides a software environment for message-passing between homogeneous or heterogeneous computers and has a collection of library routines that the user can employ with C or Fortran programs. PVM became widely used, partly because it was made readily available at no charge. PVM used dynamic process creation from the start.
Parallel Programming – Techniques and Applications 2th Edition, Barry Wilkinson