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Few technological advances have had such a decisive effect on human society as the invention of the computer (it has been described as a second industrial revolution), and yet computing is still in its infancy. Ever since computer technology became portable and cheap with the invention of the silicon chip in the late 1960s, the industrialized way of life has been completely revolutionized. Everything has changed, from the factory floor to music, from banking to the prevention of crime.
The reason that the computer has been able to cause such far-reaching changes is that it is so versatile. The whole story of the industrial revolution until the computer has been that of the production of more and more specialized machines, to the point where car assembly lines need to be substantially altered when the model of car to be produced is changed. Now, the computer can not only be used for millions of different applications (so that, for example, the same computer could run accounts and check production standards), but the computer system itself does not usually need to be changed; just the program that tells it what to do.
There are essentially two types of computer (others are hybrids of these types). Analog computers have as their inputs physical quantities (such as a voltage down a wire or pressure on a lever) which the internal workings process to give an output in the form of other physical quantities. They have major drawbacks. First, their accuracy is low and is limited by insuperable physical problems such as friction. Second, the accuracy of the results also depends on the apparatus used to measure them (such as a voltmeter) and on the observer\'s ability to use them correctly. Third, they are often designed with a specific problem in mind and are useless once that problem is solved. (An example would be the model used by a civil engineer to see if the bridge he intends building will collapse in high winds—it is totally pointless once the bridge is built.)
Such devices have been rendered virtually obselete by the successful design of digital computers since the 1940s. A digital computer accepts input in the form of numbers, processes them inside by means of a program, and presents the output in terms of numbers. Such computers solve (or at least alleviate) all the problems with analog computers mentioned above. The results can be presented in an easy to read form such as a numerical display or printout; their accuracy is limited only by the accuracy of the figures entered in and the amount of time the operator wishes to spend allowing the computer to improve the accuracy of the result; and they can solve other problems by means of altering their internal program, which is far easier than on those analog machines which were designed to solve general problems. SMcL
Further reading T. Forester, The Microelectronics Revolution. |
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