pvm_intro(1)

NAME

PVM - Parallel Virtual Machine System Version 3

DESCRIPTION

PVM is a software system that enables a collection of heterogeneous computers to be used as a coherent and flexible concurrent computational resource.

The individual computers may be shared- or local-memory multiprocessors, vector supercomputers, specialized graphics engines, or scalar workstations, that may be interconnected by a variety of networks, such as ethernet, FDDI.

User programs written in C, C++ or Fortran access PVM through library routines (libpvm3.a and libfpvm3.a).

Daemon programs (pvmd3) provide communication and process control between computers.

MACHINE ARCHITECTURE

In the PVM system, machines are assigned a short string to identify their architectures (this includes operating system type as well as CPU type). The types currently predefined in the distribution are:

ENVIRONMENT VARIABLES

The following environment variables are read by PVM and may be set in order to customize your PVM environment. To set them, you can add commands to your .cshrc or .profile file. See the manual page for the shell you normally use for information about how to do this.

For csh users: Note that setting them in .login does not have the same effect. .login is only read when you are actually logging in, whereas .cshrc is read every time csh starts up. PVM needs to have environment variables set when it starts a slave pvmd with "rsh host pvmd ...", so they must be set in .cshrc.

[v3.3.10 and later] For those using a shell that doesn't always read a startup script (e.g. sh, ksh), there is another way to set environment variables for PVM. Before running the PVM executables, the pvm and pvmd startup scripts source any commands in $HOME/.pvmprofile if this file exists. You will still need to use pvmd host file options (e.g. dx=) or environment variables (PVM_DPATH) on the master host to tell PVM where things are installed on slave hosts.

PVM_ROOT

The path where PVM libraries and system programs are installed, for example /usr/local/pvm3 or $HOME/pvm3. This variable must be set on each host where PVM is used in order for PVM to function. There is no default value.

PVM_EXPORT

Names of environment variables to export from a parent task to children tasks through pvm_spawn(). Multiple names must be separated by ':'. If PVM_EXPORT is not set, no environment is exported.

PVM_DEBUGGER

The debugger script to use when pvm_spawn() is called with PvmTaskDebug set. The default is $PVM_ROOT/lib/debugger.

PVM_DPATH

[v3.3.2 and later] The path of the pvmd startup script (default is $PVM_ROOT/lib/pvmd). It is overridden by host file option dx=.

This variable is useful if you use a shell that doesn't automatically execute a startup script (such as .cshrc) to allow setting PVM_ROOT on slave (added) hosts. If you set it to the absolute or relative path of the pvmd startup script (for example /usr/local/pvm3/lib/pvmd or pvm3/lib/pvmd), the script will automatically set PVM_ROOT. Note that for this to work, you must set it to run the pvmd script, not the pvmd3 executable itself.

PVMDLOGMAX

[v3.3.8 and later] Sets the maximum length of the pvmd error log file. Default value is the PVMDLOGMAX parameter in the source, 1 Mbyte.

PVMDDEBUG

[v3.3.8 and later] Sets the default pvmd debugging mask (as does the pvmd -d option). Value can be in hexadecimal (0x...), octal (0...) or decimal. Used to debug the pvmd (not intended to be used to debug application programs).

PVMTASKDEBUG

[v3.3.8 and later] Sets the default libpvm debugging mask (as does pvm_setopt(PvmDebugMask, x)). Value can be in hexadecimal (0x...), octal (0...) or decimal. Used to debug libpvm (not intended to be used to debug application programs).

PVMBUFSIZE

Sets the size of the shared memory buffers used by libpvm and the pvmd. The default value is 1048576. If your program composes messages longer than this size, you must increase it.

PVMKEY

PVM uses this value, combined with the process id, to generate shared-memory segment keys. The default value is your numeric uid. PVM automatically detects collisions when generating a key and picks a new key, so it should almost never need to be set explicitly.

The following environment variables are used by PVM internally. With the exception of PVM_ARCH, their values should not be modified. This is for information only.

PVM_ARCH

The PVM architecture name of the host on which it is set, used to distinguish between machines with different executable (a.out) formats. Copies of a program for different architectures are installed in parallel directories named for PVM architectures.

PVMSOCK

Is passed from pvmd to spawned task, and gives the address of the pvmd local socket.

PVMEPID

Holds the expected process id of a spawned task exec'd by the pvmd. This is a magic cookie used by the task to identify itself when reconnecting to the pvmd, in order to get the correct task slot.

PVMTMASK

[v3.3 and later] The libpvm trace mask, passed from the pvmd to spawned tasks.

SEE ALSO

aimk(1PVM), pvm(1PVM), pvmd3(1PVM), PVM 3.3 User's Guide and Reference Manual

AUTHORS

A. L. Beguelin [4,5], J. J. Dongarra [1,2], G. A. Geist [2], W. C. Jiang [1], R. J. Manchek [1], B. K. Moore [1], V. S. Sunderam [3]

1. University of Tennessee, Knoxville TN.
2. Oak Ridge National Laboratory, Oak Ridge TN.
3. Emory University, Atlanta GA.
4. Carnegie Mellon University, Pittsburgh PA
5. Pittsburgh Supercomputer Center, Pittsburgh PA