High Performance Computing 1
Accessing Distributed Memory
•Message Passing
–User transfers all data using explicit send/receive instructions
–synchronous message passing can be slow
–Programming with NEW programming model !
–User must optimize communication
–asynchronous/one-sided get and put are faster but need more care in programming
–Codes used to be machine specific -- Intel NEXUS etc. until  standardized to PVM (parallel virtual machine) and subsequently MPI (message passing interface)
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