Parallel Computing BY

Parallel computing has developed in an attempt to satisfy the constant demand forgreater computational power than is available from the fastest processorsof the time.This has evolved from parallelism within a single Central ProcessingUnit to thousandsof CPUs working together.The developmentof both novel hardware and software forparallel multiprocessor systemsis presentedin this thesis. A general introduction to parallel computing is given in Chapter 1. This covers thehardware design conceptsused in the field such as vector processors,array processorsand multiprocessors. The basic principles of software engineering for parallelmachines (i. e. decomposition, mapping and tuning) are also discussed. Part 1 (Chapters 2,3 and 4) is concerned with the development of hardware formultiprocessor systems. Some of the concepts used in digital hardware design areintroduced in Chapter 2. These include the fundamentalsof digital electronics such aslogic gates and flip-flops as well as the more complicated topics of rom andprogrammablelogic. It is often desirable to change the network topology of a multiprocessor machine to suita particular application. The third chapter describes a circuit switching scheme thatallows the user to alter the network topology prior to computation. To achieve this,crossbar switches are connected to the nodes, and the host processor (a PC) programsthe crossbar switches to make the desired connections between the nodes. Thehardware and software required for this system is described in detail. Whilst this design allows the topology of a multiprocessor system to be altered prior tocomputation, the topology is still fixed during program run-time. Chapter 4 presents asystem that allows the topology to be altered during run-time. The nodes sendconnection requests to a control processor which programs a crossbar switch connectedto the nodes. This system allows every node in a parallel computer to communicatedirectly with every other node. The hardware interface between the nodes and thecontrol processor is discussed in detail, and the software on the control processor isalso described.