Desktop computers

A desktop computer is a personal computer designed for regular use at a single location on or near a desk or table due to its size and power requirements. The most common configuration has a case that houses the power supply, motherboard (a printed circuit board with a microprocessor as the central processing unit (CPU), memory, bus, and other electronic components), disk storage (usually one or more hard disk drives, optical disc drives, and in early models a floppy disk drive); a keyboard and mouse for input; and a computer monitor, and, often, a printer for output. The case may be oriented horizontally or vertically and placed either underneath, beside, or on top of a desk.

An all-in-one desktop computer typically combines the case and monitor in one unit.

Prior to the widespread use of microprocessors, a computer that could fit on a desk was considered remarkably small; the type of computers most commonly used were minicomputers, which were themselves desk-sized. Early computers took up the space of a whole room. Minicomputers generally fit into one or a few refrigerator-sized racks.

The very first "programmable calculator/computer" was marketed in the second half of the 1960s, starting with the Italian machinery Programma 101 (1965) computer at typewriter size. More desktop models were introduced in 1971, leading to a model programmable in BASIC in 1972. This one used a smaller version of a minicomputer design based on read-only memory (ROM) and had small one-line LED alphanumeric displays. They could draw computer graphics with a plotter.

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