[[ROMDOS]] D20 80 track disks, which can store up to 256 files in a single directory user (confirmed using CP/M on a real CPC) are ideal to run On File. The 20 MB [[Dobbertin Harddisc]] or similar media which support more directory entries can also be used. Notice, that the amount of data that can be stored and accessed using Cosmos, On File and On File Register is really huge for the CP/M-80 world and resembles to the 16-bit world of computing([[Other Computers:16 bit computers]]).