standards - storage media - technical definition

Over the years, there have been many varieties of disk cartridges, floppy disks, reel-to-reel tapes, tape cartridges and tape cassettes. Each one has has had its own shape and size and could be used only in drives designed to accommodate them. With all storage devices, the physical shape is half the standards issue. The other half is the recording pattern, which is invisible to the human eye and is written onto the tape or disk by the drive. Most of the time, the media cannot be inserted into the wrong drive. See magnetic disk, magnetic tape and optical disc.