INTRODUCTION OF ADVANCED COMPUTER ARCHITECTURE AND PARALLEL PROCESSING :
Computer architects have always strived to increase the performance of their computer architectures. High performance may come from fast dense circuitry, packaging technology, and parallelism. Single-processor supercomputers have achieved unheard of speeds and have been pushing hardware technology to the physical limit of chip manufacturing.
However, this trend will soon come to an end, because there are physical and architectural bounds that limit the computational power that can be achieved with a single-processor system. In this book we will study advanced computer architectures that utilize parallelism via multiple processing units.
Parallel processors are computer systems consisting of multiple processing units connected via some interconnection network plus the software needed to make the processing units work together. There are two major factors used to categorize such systems: the processing units themselves, and the interconnection network that ties them together.
The processing units can communicate and interact with each other using either shared memory or message passing methods. The interconnection network for shared memory systems can be classified as bus-based versus switch-based. In message passing systems, the interconnection network is divided into static and dynamic. Static connections have a fixed topology that does not change while programs are running. Dynamic connections create links on the fly as the program executes.
The main argument for using multiprocessors is to create powerful computers by simply connecting multiple processors. A multiprocessor is expected to reach faster speed than the fastest single-processor system.
In addition, a multiprocessor consisting of a number of single processors is expected to be more cost-effective than building a high-performance single processor. Another advantage of a multiprocessor is fault tolerance. If a processor fails, the remaining processors should be able to provide continued service, albeit with degraded performance.