Information technology -- 90 mm flexible disk cartridges -- 21 MBytes formatted capacity -- ISO Type 305
Specifies the mechanical, physical and magnetical characteristics of the cartridge, so as to provide physical interchangeability between data processing systems. It also specifies the method of recording, the quality of recorded signals, the track layouts and the track formats. Such flexible disk cartridges are identified as ISO type 305. Together with a standard for volume and file structure, for instance ISO/IEC 9293, it allows full data interchange between data processing systems.