In September 1975 ECMA issued Standard ECMA-45 for magnetic 12-disk packs with a density of 100 Mbytes. It corresponded to similar work undertaken in ANSI and ISO.
Further work was then started in these organizations and in ECMA on 12-disk packs with a density of 200 Mbytes. This Standard ECMA-52 defines the dimensional, physical and magnetic characteristics of such packs as well as a pre-initialization scheme, for procurement purposes.