Very-High-Performance Multiple-Instruction Multiple-Data Applications [and Discussion]

C. J. Elliott, J. H. Davenport
1988 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
The mimd (multiple instruction multiple data) class of multiprocessors offers, in principle, the capability to bring the resources of an arbitrary number of processors to a problem. This confers the dual advantages of very high performance and of faulttolerance. A number of successful applications will be presented, from which some general conclusions are drawn on the practical feasibility of the use of mimd machines. I n t r o d u c t io n High-performance multiple instruction multiple
more » ... am (mimd) computers have repre sented a 'holy grail' of computing research for many years. In this context, performance can be interpreted in terms of a number of attributes. Four such attributes are considered in this paper: (1) processing speed; (2) integrity; (3) verifiability; (4) flexibility. There has been a major technological development during this decade which has made the implementation of high-performance mimd computers feasible. This is the joint development of the Occam language and the Inmos transputer. The Occam language evolved from the concepts of Communicating Sequential Processes. Its key features are: (1) it is very simple; (2) parallelism is fundamental; (3) parallel processes do not share variables; (4) parallel processes communicate via tightly defined channels; (5) parallel processes only synchronize when they communicate. The Inmos transputer is a single chip computer designed to implement the Occam language. Its key features are: (1) hardware is included to allow interchip communications to be handled as interprocess communifcations; (2) context switch is done by simple hardware which imposes low processing overheads; (3) the central processor unit uses a RISC-like architecture to achieve high speed and efficient execution of compiled code; (4) transputer systems require a low chip count. This paper presents examples of high-performance mimd applications using Occam and transputers. It aims to provide an illustrated overview rather than a detailed description of each of the applications. All of the applications described are based on work by Smith Associates.
doi:10.1098/rsta.1988.0098 fatcat:y2rmaq4ezzdxfo2cp2lz2batji