Computers

A computer is a device or machine for making calculations or controlling operations that are expressible in numerical or logical terms. Computers are constructed from components that perform simple well-defined functions. The complex interactions of these components endow computers with the ability to process information. If correctly configured (usually by programming) a computer can be made to represent some aspect of a problem or part of a system. If a computer configured in this way is given appropriate input data, then it can automatically solve the problem or predict the behavior of the system.

The discipline which studies the theory, design, and application of computers is called computer science.

The word Computer was originally used to describe a person who performed arithmetic calculations and this usage is still valid (although it is becoming quite rare in the United States). The OED2 lists the year 1897 as the first year the word was used to refer to a mechanical calculating device. By 1946 several qualifiers were introduced by the OED2 to differentiate between the different types of machine. These qualifiers included analogue, digital and electronic. However, from the context of the citation, it is obvious these terms were in use prior to 1946.

Computing devices have doubled in capacity (instructions processed per second per $1000) every 18 to 24 months since 1900. Gordon E. Moore, co-founder of Intel, first described this property of computer development in 1965. His observation has become known as Moore's Law, although it of course is not actually a law, but rather a significant trend. Hand-in-hand with this increase in capacity per unit cost has been an equally dramatic process of miniaturization. The first electronic computers, such as the ENIAC (announced in 1946), were huge devices that weighed tons, occupied entire rooms, and required many operators to function successfully. They were so expensive that only governments and large research organizations could afford them and were considered so exotic that only a handful would ever be required to satisfy global demand. By contrast, modern computers are orders of magnitude more powerful, less expensive, smaller and have become ubiquitous in many areas. The exponential progress of computer development makes classification of computers problematic since modern computers are many orders of magnitude more powerful than earlier devices.