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.
Floppy disk variants
The format was widely used by Amstrad in their CPC and PCW computers, and (after Amstrad took over manufacture of the line) the Sinclair ZX Spectrum +3. It was also adopted by some other manufacturers/systems such as Sega, the Tatung Einstein, and Timex of Portugal in the FDD and FDD-3000 disk drives. Despite this, the format was not a major success.