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Drawings from IBM Floppy Disk Drive Patents. IBM's decision in the late 1960s to use semiconductor memory as the writeable control store for future systems and control units created a requirement for an inexpensive and reliable read only device and associated medium to store and ship the control store's microprogram and at system power on to load the microprogram into the control store.
IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. [1] [2] Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. [3]
8-inch floppy disk, inserted in drive, (3½-inch floppy diskette, in front, shown for scale) 3½-inch, high-density floppy diskettes with adhesive labels affixed The first commercial floppy disks, developed in the late 1960s, were 8 inches (203.2 mm) in diameter; [4] [5] they became commercially available in 1971 as a component of IBM products and both drives and disks were then sold ...
A Maxell-branded 3-inch Compact Floppy Disk. The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. [1] Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and ...
Common floppy disk formats, logical characteristics by platform Platform Size Density Sides Tracks/ side Sectors/ track Bytes/ sector Sectoring Capacity rpm Encoding Note Acorn: 5 1 ⁄ 4 inch Single 1 40 10 256 soft 100 kB 300 FM 80 200 kB Double 1 40 16 256 160 kB MFM 80 320 kB 2 640 kB 3 1 ⁄ 2 inch Double 2 80 16 256 640 kB 300 MFM
The system included an eight-inch floppy drive that could also read floppies from the IBM 3740 family. Only one side of the 77-track floppy diskette was used. Each track held 26 128-byte sectors. An extended format was offered by IBM, and it permitted 512 bytes per sector. Even so, that came to an 8-inch floppy holding less than one third of a ...
According to Nakamatsu, IBM reached licensing agreements with him in the late 1970s. [3] [27] He also says to have licensed his floppy disk to IBM in 1979, [28] but that the details are "confidential". [6] An IBM spokesman, Mac Jeffery, confirmed that the company did license some of his patents, but said that they were not for the floppy disk ...
For IBM-compatible floppy controllers, a twist in the cable reverses the order of conductors 10 through 16 for the second connector. This allows two drives connected to the same cable to be addressed by the host controller without having to select drive assignments with jumpers on the drives themselves.