A MiniDisc (MD) is a disc-based data storage device for storing any kind of data, usually audio. The technology was announced by Sony in 1991 and introduced January 12, 1992. Along with Philips' Digital Compact Cassette (DCC) system, MiniDisc was targeted as a replacement for analogue cassette tapes as the recording system for Hi-Fi equipment. What became a very brief format war ended when DCC was phased out in 1996.
MD Data, a version for storing computer data was announced by Sony in 1993, but it never gained significant ground, so today MDs are used primarily for audio storage.
The disc is permanently housed in a cartridge (68 × 72 × 5 mm) with a sliding door, not unlike 3.5 in floppy diskettes. The audio discs can either be recordable (blank) or premastered. Recordable MiniDiscs use a magneto-optical system to record data.