Editing Parallel Virtual Machine

{{Short description|Software tool for parallel networking of computers}}
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{{Infobox software
| logo                   = <!-- [[File: ]] -->
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| caption                =
| collapsible            =
| author                 = [[Oak Ridge National Laboratory]]
| developer              = [[University of Tennessee]]
| released               = 1989 <!-- {{Start date|YYYY|MM|DD}} -->
| discontinued           =
| latest release version = 3.4.6
| latest release date    = {{Start date and age|2009|02|02}}<ref>[http://www.netlib.org/pvm3/RELEASE_NOTES.txt Release Notes]</ref>
| latest preview version =
| latest preview date    = <!-- {{Start date and age|YYYY|MM|DD}} -->
| frequently updated     =
| programming language   = [[C (programming language)|C]]
| operating system       = Windows and Unix
| platform               =
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| genre                  =
| license                = [[BSD licenses|BSD]], [[GNU General Public License|GPL]]
| website                = https://www.epm.ornl.gov/pvm/pvm_home.html
}}

'''Parallel Virtual Machine''' ('''PVM''') is a [[computer software|software]] tool for parallel networking of [[computer]]s. It is designed to allow a [[computer network|network]] of heterogeneous Unix and/or Windows machines to be used as a single distributed [[parallel processor]].<ref>{{FOLDOC|Parallel+Virtual+Machine}}</ref> 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 code, available free through [[netlib]], has been compiled on everything from [[laptop]]s to [[Cray]]s.<ref name=PvmHome>{{cite web|url=http://www.csm.ornl.gov/pvm/|title=Parallel Virtual Machine (PVM) Homepage}}</ref>

PVM enables users to exploit their existing computer hardware to solve much larger problems at less additional cost. PVM has been used as an educational tool to teach [[parallel programming]] but has also been used to solve important practical problems.<ref name=PvmHome/> It was developed by the [[University of Tennessee]], [[Oak Ridge National Laboratory]] and [[Emory University]]. The first version was written at ORNL in 1989, and after being rewritten by University of Tennessee, version 2 was released in March 1991. Version 3 was released in March 1993, and supported [[fault tolerance]] and better [[portability (computer science)|portability]].

PVM was a step towards modern trends in [[distributed processing]] and [[grid computing]] but has, since the mid-1990s, largely been supplanted by the much more successful [[Message Passing Interface|MPI]] standard for message passing on parallel machines.   PVM is [[free software]], released under both the [[BSD License]] and the [[GNU General Public License]].

== Design ==

PVM is a software system that enables a collection of heterogeneous computers to be used as a coherent and flexible concurrent computational resource, or a "parallel [[virtual machine]]".

The individual computers may be shared-memory or local-memory [[multiprocessor]]s, [[Vector processor|vector]] [[supercomputer]]s, specialized [[CPU|graphics engines]], or [[Scalar processor|scalar]] [[workstation]]s and [[personal computer|PC]]s, that may be interconnected by a variety of [[computer network|network]]s, such as [[Ethernet]] or [[Fiber Distributed Data Interface|FDDI]].

PVM consists of a run-time environment and library for [[message passing]], task and resource management, and fault notification. While PVM will not automatically make a commercial software package run faster, it ''does'' provide a powerful set of functions for manually parallelizing an existing source program, or for writing new parallel/distributed programs.

The PVM software must be specifically installed on every machine that is to be used in a given "virtual machine". There is no "automatic" installation of [[executable]]s onto remote machines in PVM, although simply copying the <code>pvm3/lib</code> and <code>pvm3/bin</code> directories to another ''similar'' machine (and setting <code>$PVM_ROOT</code> and <code>$PVM_ARCH</code>) is sufficient for running PVM programs. [[compiler|Compiling]] or building PVM programs requires the full PVM installation.

User programs written in [[C (programming language)|C]], [[C++]], or [[Fortran]] can access PVM through provided library routines.

PVM also supports [[broadcasting (computing)|broadcasting]] (PVM_bcast) which sends to all processes in a group and multicasting (PVM_mcast) which sends to a specific list of processes.

== See also ==
{{Portal|Free and open-source software}}

* [[CORBA]]
* [[occam (programming language)|Occam programming language]]
* [[Ease (programming language)|Ease programming language]]
* [[Linda (coordination language)]]
* [[Calculus of communicating systems]]
* [[Calculus of Broadcasting Systems]]
* [[Message Passing Interface]] (MPI)

== References ==
{{Reflist}}

== External links ==
* {{official website|http://www.csm.ornl.gov/pvm/pvm_home.html}}
* {{webarchive |url=https://web.archive.org/web/20070321103208/http://www.parawiki.org/index.php?title=Parallel_Virtual_Machine&redirect=no |date=21 March 2007 |title=Parawiki: Parallel Virtual Machine }}
{{Oak Ridge National Laboratory|state=expanded}}
{{Parallel Computing}}

[[Category:Parallel computing]]
[[Category:Inter-process communication]]
[[Category:Virtualization software]]
[[Category:Software using the BSD license]]