Digital Computers: Their History, 

 Operation, and Use 



By E. M. McCoRMicK 



National Science Foundation 



INTRODUCTION 



In the past 15 years digital computers have emerged as an interest- 

 ing and extremely useful tool not only for scientists but for workers 

 in many other fields of human endeavor. Their use has been so wide- 

 spread as to suggest that they may be the basis for another revolution 

 comparable in significance to the industrial revolution. Their appeal 

 and usefulness are due largely to the fact that they perform tasks 

 which heretofore have required "intellectual" effort for their ac- 

 complislmient. Much has been said about the ability of computers 

 to perform in relatively short periods of time tasks which otherwise 

 might require the brainpower of many humans working over long 

 periods of time. Since computers do work which man normally does 

 mentally, in contrast to doing jobs which require musclepower, there 

 is some confusion and misconception about digital computers and 

 their use. Man does not know nearly as much about intellectual activi- 

 ties as he does about physical. Further, he is less able to judge them 

 by measures which are commonly understood. 



First impressions of digital computers are impressive and perhaps 

 confusing. Computers are expensive devices costing thousands or 

 even millions of dollars. They consist of hundreds of thousands of 

 electronic components interconnected in what appears to be a vei-y 

 complicated manner. Some of the equipment for putting information 

 into or taking information out of computers is perhaps familiar, since 

 commonly used electric typewriters and business accoimting machines 

 have been adapted for this purpose. However, much of the rest of 

 the equipment is unfamiliar. 



Digital computers are information-processing devices. The infor- 

 mation is generally represented by numbers and the processing in- 

 volves the performing of simple arithmetic operations such as adding, 

 subtracting, multiplying, and dividing. Scientists use digital com- 



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