Computing Science Technical Report No. 99 a History of Computing Research* at Bell Laboratories (1937-1975)
Computing Science Technical Report No. 99 A History of Computing Research* at Bell Laboratories (1937-1975) Bernard D. Holbrook W. Stanley Brown 1. INTRODUCTION Basically there are two varieties of modern electrical computers, analog and digital, corresponding respectively to the much older slide rule and abacus. Analog computers deal with continuous information, such as real numbers and waveforms, while digital computers handle discrete information, such as letters and digits. An analog computer is limited to the approximate solution of mathematical problems for which a physical analog can be found, while a digital computer can carry out any precisely specified logical proce- dure on any symbolic information, and can, in principle, obtain numerical results to any desired accuracy. For these reasons, digital computers have become the focal point of modern computer science, although analog computing facilities remain of great importance, particularly for specialized applications. It is no accident that Bell Labs was deeply involved with the origins of both analog and digital com- puters, since it was fundamentally concerned with the principles and processes of electrical communication. Electrical analog computation is based on the classic technology of telephone transmission, and digital computation on that of telephone switching. Moreover, Bell Labs found itself, by the early 1930s, with a rapidly growing load of design calculations. These calculations were performed in part with slide rules and, mainly, with desk calculators. The magnitude of this load of very tedious routine computation and the necessity of carefully checking it indicated a need for new methods. The result of this need was a request in 1928 from a design department, heavily burdened with calculations on complex numbers, to the Mathe- matical Research Department for suggestions as to possible improvements in computational methods.
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