Specifies definitions of essential concepts, the environment in which the characteristics shall be tested, the environments in which the cartridge shall be operated and stored, the mechanical, physical and dimensional characteristics of the case and of the optical disk, the optical characteristics and the recording characteristics for recording the information once and for reading it many times, so as to provide physical interchangeability between data processing systems, the format for the physical disposition of the tracks and sectors, the error correction codes, the modulation methods used for recording and the quality of the recorded signals.