Summary on Communication etc.
Distributed Shared Memory machines have communication features of both distributed (messages) and shared (memory access) architectures
Note for distributed memory, programming model must express data location (HPF Distribute command) and invocation of messages (MPI syntax)
For shared memory, need to express control (openMP) or processing parallelism and synchronization -- need to make certain that when variable updated, “correct” version is used by other processors accessing this variable and that values living in caches are updated