什么是电脑

computer

Programmable machine that can store, retrieve, and process data. Today's computers have at least one CPU that performs all calculations and includes a main memory, a control unit, and an arithmetic logic unit. Auxiliary data storage is usually provided by an on-board hard disk and may be supplemented by other media such as floppy disks or CD-ROMs. Peripheral equipment includes input devices (e.g. keyboard, mouse) and output devices (e.g. monitor, printer), as well as the circuitry and cabling that connect all the components. Generations of modern computers are characterized by their technology. First-generation computers, developed mostly in the U.S. after World War II, used vacuum tubes and were enormous. The second generation, introduced c. 1960, used transistors and were the first successful commercial computers. Third-generation computers (late 1960s and 1970s) were characterized by miniaturization of components and use of integrated circuits. The microprocessor chip, first introduced in 1974, defines fourth-generation computers. The fifth generation emphasizes artificial intelligence, focusing on machine reasoning and logic programming languages. Early machines were analog computers, but most today are digital computers. In the last 50 years computers have changed the way people live and work, and their development has made the information age possible.