SIMD processors-expanding its horizons by emulating others

Parallel processing has established itself as the key enabling technology for the future of high performance computing. A parallel machine can be abstracted as a collection of processing elements (PEs) connected using some form of communication network. Parallel machines have been built along two major architectural formats: multiple-instruction streams multiple-data streams (MIMD) machines and single-instruction stream multiple-data streams (SIMD) machines. The hardware differences and general programming models for SIMD and MIMD processors have led many to believe each can solve only limited types of problems. SIMD machines, for instance, are often used in applications such as image processing. In that application, the same set of operations are performed on many different pieces of data. MIMD machines are commonly used when the control flow needs vary in correspondence with differences in data, such as parallel simulation.