This International Standard specifies the characteristics of a 130 mm optical disk cartridge (ODC) of Type WORM (Write Once Read Many) with a capacity of 5,2 Gbytes. Type WORM ODCs use writing effects that are inherently irreversible. Written marks cannot be erased and attempted modification of the written marks are detectable. This International Standard specifies — the conditions for conformance testing and the Reference Drive; — the environments in which the cartridges are to be operated and stored; — the mechanical, physical and dimensional characteristics of the cartridge, so as to provide mechanical interchange ability between data processing systems; — the format of the information on the disk, both embossed and user-written, including the physical disposition of the tracks and sectors, the error correction codes, the modulation methods used; — the characteristics of the embossed information on the disk; — the recording characteristics of the disk, enabling processing systems to write data onto the disk; — the minimum quality of user-written data on the disk, enabling data processing systems to read data from the disk. This International Standard provides for interchange between optical disk drives. Together with a standard for volume and file structure it provides for full data interchange between data processing systems.