Shared Versus Distributed Memory Multiprocessors

The question of whether multiprocessors should have shared or distributed memory has attracted a great deal of attention. Some researchers argue strongly for building distributed memory machines, while others argue just as strongly for programming shared memory multiprocessors. A great deal of research is underway on both types of parallel systems. This paper puts special emphasis on systems with a very large number of processors for computation intensive tasks and considers research and implementation trends. It appears that the two types of system will likely converge to a common form for large scale multiprocessors.