Parallel architectures for computer systems

Abstract

People frequently do more than one thing at a time: Driving a car while listening to the radio, cooking a meal so that several dishes are ready at once, or playing two lines of melody on a piano are all familiar examples. On a larger scale, many human activities, such as building a house or complicated experimental apparatus, or putting out a magazine, are separated into what might be called “units of activity” that are performed separately by people working in parallel. On a smaller scale, our brains control separately—but in a coordinated fashion—breathing, heartbeat and several different kinds of motor activity. In each of these cases, separate units of activity are carried out by separate processors (different people or different parts of the brain, for example) that work simultaneously (at the same time, but not in lockstep) and interact to produce the final effect or product.