Q. PVM communication model?

A nonblocking receive as soon as returns with either data or a flag that data hasn't arrived while a blocking receive returns only when data is in receive buffer. The model supports the multicast to a set of tasks too as well as broadcast to a user-defined group of tasks. There are functions to carry out global sum, global max etc too across user-defined group of tasks. Wildcards may be specified in receive for source and label allowing either or both of these contexts to be ignored. A routine may be called to return information about received messages. 

The PVM model assures that message order is preserved. If task 1 transmits message A to task 2 then task 1 transmits message B to task 2 and message A will arrive at task 2 before message B. Furthermore if both messages arrive before task 2 does a receive then a wildcard receive would always return message A.

• int bufid = pvm_mkbuf( int encoding )

encoding specifying the buffer's encoding scheme. creates a new message buffer.