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 variants
Commodore started its tradition of special disk formats with the 5¼-inch disk drives accompanying its PET/CBM, VIC-20 and Commodore 64 home computers, the same as the 1540 and 1541 drives used with the later two machines. The standard Commodore Group Coded Recording (GCR) scheme used in 1541 and compatibles employed four different data rates depending upon track position (see "zone bit recording"). Tracks 1 to 17 had 21 sectors, 18 to 24 had 19, 25 to 30 had 18, and 31 to 35 had 17, for a disk capacity of 170.75 KB (175 decimal kB). Unique among personal computer architectures, the operating system on the computer itself is unaware of the details of the disk and filesystem; disk operations are handled by Commodore DOS instead, which was implemented with an extra MOS-6502 processor on the disk drive. Many programs such as GEOS bypass Commodore's DOS completely, and replace it with fast-loading (for the time) programs in the 1541 drive.