A computer is a machine that can be programmed to perform arithmetical or logical operations sequences automatically by computer programming. Modern computers are capable of following generic operating sets, called programs. These programs allow computers to perform a vast array of tasks. A “true” device may be referred to as a computer system, including the hardware, the operating system (main software), and the peripheral equipment required and used for full operation.
Computers are used as control systems for a wide range of consumer and industrial products. It includes simple, special-purpose devices such as microwave ovens and remote controls, manufacturing devices such as industrial robots and computer-aided design, as well as general-purpose devices such as personal computers and smartphones. Computers run the Internet and link hundreds of millions of other computers and their users.
Early computers were conceived simply as tools for calculation. Simple manual instruments such as the abacus have helped people do calculations since ancient times. In the early 20th century, more advanced electrical devices were doing complex analog calculations.
During World War II, the first digital electronic calculating machines were produced. In the late 1940s, the first semiconductor transistors were followed in the late 1950s by silicon-based MOSFET (MOS transistor). And monolithic integrated circuit (IC) chip technologies, leading to the microprocessor and microcomputer revolution in the 1970s. Since then, computer speed, power, and versatility have dramatically increased, with MOS transistor counts growing at a rapid pace (as predicted by Moore’s law), leading to the Digital Revolution in the late 20th to early 21st centuries.
A modern computer historically consists of at least one processing element, usually a central processing unit (CPU) in the form of a Metal-Oxide-Semiconductor (MOS) microprocessor, along with some kind of computer memory, generally MOS semiconductor memory chips.
The processing element performs arithmetic and logical operations. Peripheral devices include input devices (keyboards, buttons, joysticks, etc.).
Output devices include monitor screens, printers, etc. Peripheral devices allow the retrieval of information from an external source and permit the saving and retrieval of the product of the operations.