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
By the early 1980s, falling prices of computer hardware and technological advances led to the near-universal adoption of soft-sector, double density disk formats. In addition, more compact half-height disk drives began to appear, as well as double-sided drives, although the cost of them meant that single-sided remained the standard for most home computers, and 80-track drives known as "quad density".