Computer

A computer is a digital electrical device that may be programmed to automatically perform sequences of arithmetic or logical operations (computation). Programs are the general sets of operations that modern computers can do. These applications allow computers to carry out a variety of activities. A computer system is a "complete" computer that consists of the necessary hardware, operating system (primary software), and peripheral devices for "complete" operation. This phrase may also refer to a set of interconnected and functionally interdependent computers, such as a computer network or computer cluster.

Computers are used as control systems in a vast array of industrial and consumer applications. Included are simple special-purpose devices such as microwave ovens and remote controls, factory equipment such as industrial robots and computer-aided design, and general-purpose devices such as personal computers and mobile devices such as smartphones. 

An early computer's only purpose was to do computations. Since antiquity, simple manual gadgets such as the abacus have assisted in computation. During the early stages of the Industrial Revolution, mechanical devices were constructed to automate laborious, time-consuming processes, such as directing patterns for looms. In the early 20th century, more complex electrical equipment performed specialised analogue computations. During World War II, the first digital electronic calculators were produced. The development of the silicon-based MOSFET (MOS transistor) and monolithic integrated circuit (IC) chip technology in the late 1950s led to the development of the microprocessor and the microcomputer revolution of the 1970s. Since then, the speed, power, and adaptability of computers have increased tremendously, along with the number of transistors (as anticipated by Moore's law), resulting in the Digital Revolution throughout the late 20th and early 21st centuries.

Conventionally, a contemporary computer consists of at least one processing device, often a central processing unit (CPU) in the form of a microprocessor, and some sort of computer memory, typically semiconductor memory chips. The processing element performs arithmetic and logical operations, and a sequencing and control unit may modify the sequence of operations based on information that has been previously stored. Input devices (keyboards, mouse, joysticks, etc.), output devices (monitors, printers, etc.), and input/output devices that do both roles are peripheral devices (e.g., the 2000s-era touchscreen). Peripheral devices enable the retrieval of information from an external source and the storage and retrieval of operation results.