Computer

A computer is a device that can beinstructedto carry out an arbitrary setofarithmeticorlogicaloperations automatically. The ability of computers to follow generalized sequences of operations, calledprograms, enable them to perform a wide range of tasks.Such computers are used ascontrol systemsfor a very wide variety ofindustrialandconsumer devices. This includes simple special purpose devices likemicrowave ovensandremote controls, factory devices such asindustrial robotsandcomputer assisted design, but also ingeneral purpose devices likepersonalcomputersandmobile devicessuch assmartphones. TheInternetis run on computers and it connects millions of other computers.Since ancient times, simple manual devices like theabacusaided people in doing calculations. Early in theIndustrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns forlooms. More sophisticated electrical machines didspecializedanalogcalculations in theearly 20th century. The firstdigitalelectronic calculating machines weredeveloped duringWorld War II. The speed, power, and versatility of computers has increased continuously and dramatically since then.Conventionally, a modern computer consists of at least oneprocessing element, typically acentral processing unit(CPU), and some form ofmemory. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the orderof operations in response to storedinformation.Peripheral devicesinclude input devices (keyboards, mice, joystick, etc.), output devices (monitor screens, printers, etc.), and input/output devices that perform both functions (e.g., the 2000s-eratouchscreen). Peripheral devices allow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved.