Recordable Blank Media - Data Media - MINIDISC (MD DATA) - MiniDiscs were announced in 1991 by Sony as a disc based digital medium for recording and distributing consumer audio that is "near CD'' in quality. In 1993 Sony announced MD Data, a version of the MiniDisc for storing computer data. Recordable MDs, can be recorded on repeatedly and employ magneto-optical technology. The disc itself is enclosed in a small (7cm x 7cm), convenient, cartridge.