Computers

A computer is a machine (Abre numa nova janela) that can be programmed to carry out (Abre numa nova janela) sequences of arithmetic (Abre numa nova janela) or logical operations (Abre numa nova janela) (computation (Abre numa nova janela)) automatically. Modern digital electronic (Abre numa nova janela) computers can perform generic sets of operations known as programs (Abre numa nova janela). These programs enable computers to perform a wide range of tasks. A computer system is a nominally complete computer that includes the hardware (Abre numa nova janela), operating system (Abre numa nova janela) (main software (Abre numa nova janela)), and peripheral (Abre numa nova janela) equipment needed and used for full operation. This term may also refer to a group of computers that are linked and function together, such as a computer network (Abre numa nova janela) or computer cluster (Abre numa nova janela).

A broad range of industrial (Abre numa nova janela) and consumer products (Abre numa nova janela) use computers as control systems (Abre numa nova janela). Simple special-purpose devices like microwave ovens (Abre numa nova janela) and remote controls (Abre numa nova janela) are included, as are factory devices like industrial robots (Abre numa nova janela) and computer-aided design (Abre numa nova janela), as well as general-purpose devices like personal computers (Abre numa nova janela) and mobile devices (Abre numa nova janela) like smartphones (Abre numa nova janela). Computers power the Internet (Abre numa nova janela), which links billions of other computers and users.

Early computers were meant to be used only for calculations. Simple manual instruments like the abacus (Abre numa nova janela) have aided people in doing calculations since ancient times. Early in the Industrial Revolution (Abre numa nova janela), some mechanical devices were built to automate long, tedious tasks, such as guiding patterns for looms (Abre numa nova janela). More sophisticated electrical machines did specialized analog (Abre numa nova janela) calculations in the early 20th century. The first digital (Abre numa nova janela) electronic calculating machines were developed during World War II (Abre numa nova janela). The first semiconductor (Abre numa nova janela) transistors (Abre numa nova janela) in the late 1940s were followed by the silicon (Abre numa nova janela)-based MOSFET (Abre numa nova janela) (MOS transistor) and monolithic integrated circuit (Abre numa nova janela) chip technologies in the late 1950s, leading to the microprocessor (Abre numa nova janela) and the microcomputer revolution (Abre numa nova janela) in the 1970s. The speed, power and versatility of computers have been increasing dramatically ever since then, with transistor counts (Abre numa nova janela) increasing at a rapid pace (as predicted by Moore's law (Abre numa nova janela)), leading to the Digital Revolution (Abre numa nova janela) during the late 20th to early 21st centuries.

Conventionally, a modern computer consists of at least one processing element (Abre numa nova janela), typically a central processing unit (Abre numa nova janela) (CPU) in the form of a microprocessor, along with some type of computer memory (Abre numa nova janela), typically semiconductor memory (Abre numa nova janela) chips. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the order of operations in response to stored information (Abre numa nova janela). Peripheral devices include input devices (keyboards, mice, joystick (Abre numa nova janela), etc.), output devices (monitor screens, printers (Abre numa nova janela), etc.), and input/output devices that perform both functions (e.g., the 2000s-era touchscreen (Abre numa nova janela)). Peripheral devices allow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved.

Etymology