A floppy disk, also called a floppy, diskette or just disk, is a type of disk storage composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic enclosure lined with fabric that removes dust particles. Floppy disks are read and written by a floppy disk drive (FDD).

Floppy disks, initially as 8-inch media and later in 5¼-inch (133 mm) and 3½-inch (90 mm) sizes, were an ubiquitous form of data storage and exchange from the 1970s into the 2000s.[1] By the late 2000s, computers were rarely manufactured with installed floppy disk drives; 3½-inch floppy disks can be used with an external USB floppy disk drive, but USB drives for 5¼-inch, 8-inch, and non-standard diskettes are rare to non-existent. These formats are usually handled by older equipment.

While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity, such as USB flash drives, flash storage cards, portable external hard disk drives, optical discs, ROM cartridges and storage available through computer networks.


The first floppy disk was invented by Yoshiro Nakamatsu at the Tokyo Imperial University in 1950.[2][3] He later received a Japanese patent in 1952,[4][5] and a 1958 American patent, for a magnetic disk record sheet.[6] Nippon Columbia planned to commercialized his magnetic disc sheet recorder in 1960.[7] He licensed a number of patents to IBM,[4][8][9] reaching licensing agreements with them in the 1970s.[2][10][11]

Floppy disks became commercially available in 1971 as a component of IBM products and then were sold separately beginning in 1972 by Memorex and others.[12] These disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation.[13] The term "floppy disk" appeared in print as early as 1970,[14] and although in 1973 IBM announced its first media as "Type 1 Diskette" the industry continued to use the terms "floppy disk" or "floppy".

Sord Computer Corporation's M200 Smart Home Computer, released in 1977, was among the first home computers, and was an early personal computer to be integrated with a built-in floppy disk drive.[15]

Sony invented the 3½-inch floppy disk format, called the micro floppy disk. The first commercial micro floppy disk drive was the Sony OA-D30V, released in 1981.[16]


Different sizes of floppy disks are mechanically incompatible, and disks can fit only one size of drive. Drive assemblies with both 3½-inch and 5¼-inch slots were available during the transition period between the sizes, but they contained two separate drive mechanisms. In addition, there are many subtle, usually software-driven incompatibilities between the two. 5¼-inch disks formatted for use with Apple II computers would be unreadable and treated as unformatted on a Commodore. As computer platforms began to form, attempts were made at interchangeability. For example, the "Superdrive" included from the Macintosh SE to the Power Macintosh G3 could read, write and format IBM PC format 3½-inch disks, but few IBM-compatible computers had drives that did the reverse. 8-inch, 5¼-inch and 3½-inch drives were manufactured in a variety of sizes, most to fit standardized drive bays. Alongside the common disk sizes were non-classical sizes for specialized systems.

8-inch floppy diskEdit

The first floppy disk was 8 inches in diameter,[17] was protected by a flexible plastic jacket and was a read-only device used by IBM as a way of loading microcode.[18] Read/write floppy disks and their drives became available in 1972 but it was IBM's 1973 introduction of the 3740 data entry system[19] that began the establishment of floppy disks, called by IBM the "Diskette 1," as an industry standard for information interchange. Early microcomputers used for engineering, business, or word processing often used one or more 8-inch disk drives for removable storage; the CP/M operating system was developed for microcomputers with 8-inch drives.

The family of 8-inch disks and drives increased over time and later versions could store up to 1.2 MB;[20] many microcomputer applications did not need that much capacity on one disk, so a smaller size disk with lower-cost media and drives was feasible. The 5¼-inch drive succeeded the 8-inch size in many applications, and developed to about the same storage capacity as the original 8-inch size, using higher-density media and recording techniques.

5¼-inch floppy diskEdit

The head gap of an 80‑track high-density (1.2 MB in the MFM format) 5¼‑inch drive (a.k.a. Mini diskette, Mini disk, or Minifloppy) is smaller than that of a 40‑track double-density (360 KB) drive but can format, read and write 40‑track disks well provided the controller supports double stepping or has a switch to do such a process. 5.25-inch 80-track drives were also called hyper drives.

A blank 40‑track disk formatted and written on an 80‑track drive can be taken to its native drive without problems, and a disk formatted on a 40‑track drive can be used on an 80‑track drive. Disks written on a 40‑track drive and then updated on an 80 track drive become unreadable on any 40‑track drives due to track width incompatibility.

Single sided disks were coated on both sides, despite the availability of more expensive double sided disks. The reason usually given for the higher cost was that double sided disks were certified error-free on both sides of the media. Double-sided disks could be used in some drives for single-sided disks, as long as an index signal was not needed. This was done one side at a time, by turning them over (flippy disks); more expensive dual-head drives which could read both sides without turning over were later produced, and eventually became used universally.

3½-inch floppy diskEdit

In the early 1980s, a number of manufacturers introduced smaller floppy drives and media in various formats. A consortium of 21 companies eventually settled on a 3½-inch floppy disk (actually 90 mm wide) a.k.a. Micro diskette, Micro disk, or Micro floppy, similar to a Sony design. They supported both single-sided and double-sided media, with formatted capacities generally of 360 KB and 720 KB respectively. Single-sided drives shipped in 1983,[21] and double sided in 1984. What became the most common format, the double-sided, high-density (HD) 1.44 MB disk drive, shipped in 1986.

See also Edit

References Edit

  1. Fletcher, Richard (2007-01-30). PC World announces the end of the floppy disk. The Daily Telegraph. Retrieved on 2011-06-22.
  2. 2.0 2.1 G. W. A. Dummer (1997), Electronic Inventions and Discoveries, page 164, Institute of Physics
  3. Valerie-Anne Giscard d'Estaing (1990), The Book of Inventions and Discoveries, page 124, Queen Anne Press
  4. 4.0 4.1 Lazarus, David (April 10, 1995). "'Japan's Edison' Is Country's Gadget King : Japanese Inventor Holds Record for Patent". The New York Times. Retrieved 2010-12-21. 
  5. YOSHIRO NAKAMATSU – THE THOMAS EDISON OF JAPAN, Stellarix Consultancy Services, 2015
  6. Magnetic record sheet, Patent US3131937
  7. Graphic Arts Japan, Volume 2 (1960), pages 20-22
  8. Barron, James (Nov 11, 1990). "What a Stroke of ... Um, Ingenuity, Anyhow". The New York Times. Retrieved 2010-05-03. 
  9. Spy, December 1991, page 49
  10. Lidz, Franz (December 2012). "Dr. NakaMats, the Man With 3300 Patents to His Name". Smithsonian Magazine. Retrieved October 15, 2014. 
  11. Hornyak, Tim (January 2002). Dr. NakaMats: Japan's Self-Proclaimed Savior. Japan Inc. Retrieved on 2007-10-13.
  12. 1971: Floppy disk loads mainframe computer data. Computer History Museum.
  13. Five decades of disk drive industry firsts. ( Archived from the original on July 26, 2011. Retrieved on 2012-10-15.
  14. IBM's 370/145 Uncovered; Interesting Curves Revealed, Datamation, November 1, 1970
  15. 【Sord】 M200 Smart Home Computer Series, Information Processing Society of Japan
  16. SONY Micro Floppydisk Drive - Model OA-D30V
  17. The Designer's Guide to Disk Drives (1st ed.). Reston, Virginia, USA: Reston Publishing Company, Inc. / Prentice-Hall Company. 1985. ISBN 0-8359-1268-X. 
  18. Floppy Disk. Louisiana State University.
  19. IBM 3740
  20. The IBM Diskette General Information Manual
  21. "Shrinking drives increase storage". InfoWorld: 1, 7, 8, 9, 11. 1983-06-13. "Shugart is one of the major subscribers to the 3-1/2-inch micro-floppy standard, along with Sony and 20 other company... Its single-sided SA300 micro-floppy drive offers 500K of unformatted storage. Shugart's Kevin Burr said the obvious next step is to put another 500K of storage on the other side of the diskette and that the firm will come out with a double-sided 1-megabyte micro-floppy drive soon." 

Bibliography Edit

  • Weyhrich, Steven (2005). "The Disk II": A detailed essay describing one of the first commercial floppy disk drives (from the Apple II History website).
  • Immers, Richard; Neufeld, Gerald G. (1984). Inside Commodore DOS • The Complete Guide to the 1541 Disk Operating System. DATAMOST & Reston Publishing Company (Prentice-Hall). ISBN 0-8359-3091-2.
  • Englisch, Lothar; Szczepanowski, Norbert (1984). The Anatomy of the 1541 Disk Drive. Grand Rapids, Michigan, USA, Abacus Software (translated from the original 1983 German edition, Düsseldorf, Data Becker GmbH). ISBN 0-916439-01-1.
  • Hewlett Packard: 9121D/S Disc Memory Operator's Manual; printed 1 September 1982; part number 09121-90000.

External links Edit

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