Parallel architectures

Parallel or concurrent operation has many different forms within a computer system. Using a model based on the different streams used in the computa-tion process, we represent some of the different kinds of parallelism available. A stream is a sequence of objects such as data, or of actions such as instruc-tions. Each stream is independent of all other streams, and each element of a stream can consist of one or more ob-jects or actions. We thus have four com-binations that describe most familiar parallel architectures: (1) SISD: single instruction, single dat