Using PVM

	PVM = parallel virtual machine
		- set of library routines + pvm, pvmd commands

		- allows you to write c, fortran progs which communicate
		by passing messages

		- messages tagged with sender, type etc ID
 
		- intermediated by 'pvmd' daemons - handle all networking

		- very clean simple programmer interface

		- pvm command - start/halt the pvm - rudimentary job control
		and status checking - also fancy GUI interface 'xpvm'

		- library routines allow e.g. 'master' prog to spawn 'slave'
		processes

		- getting set up can be fiddly - see ~kaiser/imcat/pvmuse.html