Parallel Virtual Machine (PVM):

PVM (Parallel Virtual Machine) is portable message passing programming system which is designed to link different heterogeneous host machines to form a 'virtual machine' that is a single manageable parallel computing resource. Large computational problems like superconductivity studies, molecular dynamics simulations, distributed fractal computations, matrix algorithms can therefore be solved more cost effectively by employing the aggregate power and memory of several computers.

PVM was created by University of Tennessee "Oak Ridge National Laboratory and Emory University". The first version was released in year 1989, version 2 was released in 1991 and lastly version 3 was released in 1993. The PVM software enables a set of heterogeneous computer systems to be viewed as 'single parallel virtual machine'. It transparently handles all data conversion, message routing and task scheduling across a network of incompatible computer architectures. The programming interface of Parallel virtual machine (PVM) is very simple .The user writes his application like collection of cooperating tasks. Task accesses PVM resources by library of standard interface routines. These routines permit the beginning and termination of tasks across the network and communication as well as synchronisation between the tasks. Communication constructs involve those for transmitting and receiving data structures in addition high-level primitives like barrier synchronization and broadcast.