Types of computers

The two basic types of computers are analog and digital. Analog computers simulate physical systems. They operate on the basis of an analogy to the process that is being studied. For ex-

Английский язык. Основы компьютерной грамотности 58

ample, a voltage may be used to represent other physical quan­tities such as speed, temperature, or pressure. The response of an analog computer is based upon the measurement of signals that vary continuously with time. Hence, analog computers are used in applications that require continuous measurement and control.

Digital computers, as contrasted with analog computers, deal with discrete rather than continuous quantities. They count rather than measure. They use numbers instead of analogous physical quantities to simulate on-going, or real-time processes. Because they are discrete events, commercial transactions are in a natural form for digital computation. This is one reason that digital computers are so widely used in business data processing.

Machines that combine both analog and digital capabilities are called hybrid computers. Many business, scientific, and in­dustrial computer applications rely on the combination of ana­log and digital devices. The use of combination analog devices will continue to increase with the growth in applications of mi­croprocessors and microcomputers. An example of this growth is the trend toward installing control systems in household ap­pliances such as microwave ovens and sewing machines. In the future we will have complete indoor climate control systems and robots to do our housecleaning. Analog sensors will provide in­puts to the control centres of these systems, which will be small digital computers.