Sonyís 20GB Rewritable Disc

Sony Corporation has demonstrated to the Japanese trade press a prototype of a 12cm, rewritable optical disc with a 0.30 micron track pitch and a 20 gigabyte (GB) capacity, in its efforts to develop a disc with sufficient capacity for HDTV recording. Sony is not yet satisfied with the discís overwrite performance in which performance deteriorates after several hundred rewrites, due to cross erasing or distortion of recording marks on neighboring tracks (caused by heat). According to Sony, an 18GB disc with a broader track pitch of 0.33 micron will enable data to be overwritten several thousand times.