Yoshiro Nakamatsu
Among Nakamatsu's early inventions is the Shoyu Churu Churu, a siphon pump used in the home to move soy sauce from large containers to smaller vessels for cooking and serving. His patented inventions include:
Based upon a patent issued in 1952, Nakamatsu claims to have invented the first floppy disk well before IBM's floppy disk patent was filed in 1969. However, what Nakamatsu patented in 1952 was a paper for optical sound player. In contrast to a floppy disk, this Nakamatsu patent discloses the use of printed paper for storage instead of the magnetic material of a floppy disk. It is not rewritable and lacks most elements of the IBM floppy disk patent. Since the paper was 'floppy' material, he claims he had invented the floppy disk (sometimes he uses the phrase "floppy media"); however, it should be noted that flexible magnetic recording media was well known prior to 1952, in tape and wire recording.
Floppy disk
Data is generally written to floppy disks in sectors (angular blocks) and tracks (concentric rings at a constant radius). For example, the HD format of -inch floppy disks uses 512 bytes per sector, 18 sectors per track, 80 tracks per side and two sides, for a total of 1,474,560 bytes per disk. Some disk controllers can vary these parameters at the user's request, increasing storage on the disk, although they may not be able to be read on machines with other controllers. For example, Microsoft applications were often distributed on -inch 1.68 MB DMF disks formatted with 21 sectors instead of 18; they could still be recognized by a standard controller. On the IBM PC, MSX and most other microcomputer platforms, disks were written using a constant angular velocity (CAV) format, with the disk spinning at a constant speed and the sectors holding the same amount of information on each track regardless of radial location.