5.1. INTRODUCTION

Although the advent of computers in our everyday lives may seem very recent, the principles of the modern computer were established before the existence of any electronic or electromechanical technologies as we know them today, and electronic computers were beginning to take shape in laboratories in 1945.

The work of Charles Babbage, a Cambridge mathematician of the nineteenth century, in attempting to build an "analytical engine" from mechanical parts, remarkably anticipated several of the common features of today's electronic computers. His proposed design, had he been able to complete it and overcome mechanical engineering limitations of the day, would have had the equivalent of punched-card input and storage registers, the ability to branch according to results of intermediate calculations, and a form of output able to set numeric bits in type.

Many purely mechanical forms of analog computer have existed over the last few centuries. The most common of these is the slide rule, and other examples include mechanical integrators and even devices for solving simultaneous equations. Much of the development leading to modern electronic computers, both analog and digital, began during World War II with the intensified need to perform ballistics calculations. The development of radar at this time also provided the stimulus for new forms of electronic circuits that were to be adopted by the designers of computers. A further development of momentous importance to the technology of computers, as it was for so many branches of electronics, was...