A compact digital audio disc from Sony that comes in read-only and rewritable versions. Introduced in late 1993, the MiniDisc has been most popular in Japan. The read-only 2.5" disc stores 140MB compared to 650MB on a CD, but holds the same 74 minutes worth of music due to Sony's Adaptive Transform Acoustic Coding (ATRAC) compression scheme, which eliminates inaudible signals. MD discs store disc and track titles displayed by the player. Used for music recording, rewritable MiniDiscs employ magneto-optic technology and come in 60 and 74-minute cartridges. The MiniDisc drive for computers (MD DATA) never caught on.