This International Standard specifies the characteristics of 90 mm Flexible Disk Cartridges of 10 MByte formatted capacity, recorded at 33157 ftprad using modified frequency modulation recording and sector servo tracking on 255 data tracks on each side. Such Flexible Disk Cartridges are identified as ISO Type 304. It specifies the mechanical, physical and magnetic characteristics of the cartridge, so as to provide physical interchangeability between data processing systems. It also specifies the method of recording, the quality of the recorded signals, the track layout and the track format of data tracks and servo tracks. Together with a standard for volume and file structure, for example International Standard ISO 9293, this International Standard provides for full data interchange between data processing systems.