MiniDisc
MiniDisc (MD) is a magneto-optical disc-based data storage format offering a capacity of 60, 74 minutes and, later, 80 minutes, of digitized audio or 1 gigabyte of Hi-MD data. Sony brand audio players were on the market in September 1992.
Sony announced the MiniDisc in September 1992 and released it in November of that year for sale in Japan and in December in Europe, Canada, the USA and other countries.[1] The music format was originally based on ATRAC audio data compression, but the option of linear PCM digital recording was later introduced to meet audio quality comparable to that of a compact disc. MiniDiscs were very popular in Japan and found moderate success in Europe.[2]
Sony has ceased development of MD devices, with the last of the players sold by March 2013.[3]
Hi-MD
In January 2004, Sony announced the Hi-MD media storage format as a further development of the MiniDisc format.[4] With its release in later 2004, came the ability to use newly developed, high-capacity 1 gigabyte Hi-MD discs, sporting the same dimensions as regular MiniDiscs. The Hi-MD format can be considered obsolete as the last recorder/player was discontinued in 2011. The discs themselves were withdrawn from sale in September 2012.