Information Systems - One- and Two-Sided, High-Density, Unformatted, 90-mm (3.5 in), 5,3-tpmm (135-tpi), Flexible Disk Cartridge for 15 916 bpr Use - General, Physical and Magnetic Requirements
4. This standard specifies the general, physical, and magnetic requirements for interchangeability of the one- and two-sided, high-density, 90-mm (3.5-in) (nominal) flexible disk cartridge for 15 916 bits-per-radian (bpr) use as required to achieve unformatted disk cartridge interchange among disk drives using 80 tracks per side and associated information processing systems. The one- and two-sided flexible disk enclosed ina protective case and having one or two recording surfaces is of the type intended specifically for use with digital recording and reproducing equipment employing access mechanisms capable of positioning to these data tracks.