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 format
Single-sided disks began to become obsolete after the introduction of IBM PC DOS 1.1 in 1982, which added support for double-side diskette drives with capacity of 320 KB to the IBM 5150 PC. In 1983 PC DOS 2.0 pushed the formatting capacity to 180 KB single-sided or 360 KB double-sided by utilizing 9 instead of only 8 sectors per track.