PC is short for Personal Computer. These are affordable machines designed for a single user which are, however, far less powerful than the large, multi-user computer systems used, for example, within universities. In computing slang, "PC" is used to describe an IBM-compatible personal computer, while the alternative system produced by Apple Macintosh is called an Apple Mac or a Mac.

A personal computer consists of at least a screen or Visual Display Unit (VDU), a central processing unit (CPU), a keyboard and a printer. The user communicates with the PC using the keyboard, or, increasingly, a mouse or trackball. The PC will normally contain a hard disk drive inside the CPU, and may also have an external hard disk drive linked to the CPU by a lead. It will also have a floppy disk drive, and may have a CD Rom drive. It may also have speakers to play sound files, and a modem to connect it to the telephone network.

PCs came on to the market in the 1980s, and millions are now used worldwide in homes and offices. The majority are "IBM-compatible" - they meet the standards set by manufacturers IBM, although they may be made by a variety of different companies. A minority are made by Apple Macintosh; these are not normally compatible with IBM PCs, but in 1994 Apple Macintosh launched the Power PC, a hybrid machine which allows users to use programmes designed for either type of machine. In 1995 Apple Macintosh also allowed other manufacturers to make "clones" of the machines for the first time. In computing slang terms, "PC" is taken to refer to an IBM-compatible machine.

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