CF-2 Compact Floppy Disk
The CF-2 Compact Floppy Disk was one of several odd-sized floppy formats that never caught on. It was 3 inches in width, and larger in height (of the casing unit the users saw; the actual disk inside is round as usual). It was released around the same time as the 3 1/2" disk, attempting a "VHS vs. Betamax" or "BluRay Disc vs. HD-DVD" style format war. It was used in some Amstrad and Sinclair computers, and a few others. Some of the drives were double-sided, reading/writing both sides of the medium, while others used only one side but could be flipped.