Yoshiro Nakamatsu
Nakamatsu claims IBM reached licensing agreements with him in the late 1970s. He also claims to have licensed his floppy disk to IBM in 1979, but that the details are "confidential". An IBM spokesman, Mac Jeffery, confirmed that the company did license some of his patents, but claimed they were not for the floppy disk, which he claimed IBM invented on its own. Another IBM spokesman, Brian Doyle, said they licensed 14 patents from Nakamatsu, but also claimed that they do not have anything to do with the floppy disk.
History of the floppy disk
Shugart's initial 5.25" drive was the 35-track, single-sided SA-400, which was widely used in many early microcomputers, and which introduced the 34-pin interface that would become an industry standard. It could be used with either a hard or soft-sectored controller and storage capacity was listed as 90k (single density) or 113k (double density). The drive went on sale in late 1976 at a list price of $400, and $60 for a box of ten disks. The new, smaller disk format was taken up quickly, and by 1978 there were ten different manufacturers producing 5.25" drives. At one point, Shugart was turning out 4000 drives a day, but their ascendancy was short-lived and the company's fortunes declined in the early 1980s. Part of this was their failure to develop a reliable 80-track drive, increasing competition, and the loss of several lucrative contracts--Apple by 1982 had switched to using cheaper Alps drive mechanisms in their computers, and IBM chose Tandon as their sole supplier of disk drives for the PC. By 1977, they had been purchased by Xerox, who closed the operations in 1985 and sold the Shugart brand to a third party.