NAME

Introduction to Digital PVM

DESCRIPTION

Digital PVM is an implementation of the Parallel Virtual Machine (PVM) message-passing system. It supports SMP AlphaServers and AlphaServer MEMORY CHANNEL clusters. 

User programs, written in C or Fortran, access the PVM function calls through a single library, libdpvm.a or libdpvm.so.  Digital PVM comprises a Digital PVM daemon (dpvmd) and a Digital PVM console (dpvm), and operates only in a shared memory or MEMORY CHANNEL environment. 

ENVIRONMENT VARIABLES

You can set environment variables in the .cshrc or .profile files. The following environment variables are used in Digital PVM:

PVM_EXPORT

Defines the names of environment variables inherited from a parent task by a child task when using PVM_SPAWN.  Environment variables should be separated by ’:’. 

DPVM_DEBUGGER

When spawning a task under a debugger, the delegate shell-script used is /usr/bin/dpvmdbg.  An alternative dpvmdbg script can be printed to by using the DPVM_DEBUGGER variable. 

PVM_BUF_SIZE

Sets the size of the shared memory buffer used by Digital PVM. This should be at least as big as the largest message to be sent (default = 256000). 

PVM_MC_CHAN_SIZE

Specifies the size, in bytes, of the MEMORY CHANNEL communications channel (default = 204800). 

PVM_SM_CHAN_SIZE

Specifies the size, in bytes, of the shared memory communications channel (default = 204800). 

PVM_FRAG_SIZE

Specifies the size of the PVM fragments used when constructing large messages. 

PVM_NUM_BUFS

Specifies the number of communication channels to open (default = 100). 

SEE ALSO

DPVM(1DPVM), DPVMD(1DPVM)