This part of ISO 8378 specifies the quality of recorded signals, the track layout, and a track format to be used on 130 mm (5.25 in) flexible disk cartridges intended for data interchange between data processing systems.

NOTE - Numeric values in the SI and/or Imperial measurement system in this part of ISO 8378 may have been rounded off and therefore are consistent with, but not exactly equal to, each other. Either system may be used, but the two should be neither intermixed nor reconverted. The original design of this part of ISO 8378 was made using SI units.

Conformance
A flexible disk cartridge shall be in conformance with ISO 8378 when it meets all the requirements either of parts 1 and 2 or of parts 1 and 3 of ISO 8378.