Floppy Disks Are Developed for Computer Data Storage

Engineers at IBM’s San Jose laboratory developed the floppy disk drive, an inexpensive means of storing data and computer applications that would become the first major medium for distributing commercial software to personal-computer users.

Summary of Event

When International Business Machines International Business Machines (IBM) decided to develop computers for use by businesses in the 1950’s, it faced a problem that had troubled the earliest computer designers: how to store data reliably and inexpensively both during immediate processing and for later use. In the early 1940’s, during the early days of electro-mechanical computation, the English inventor Andrew D. Booth produced spinning paper disks on which he stored data by means of punched holes, only to abandon the idea because of the insurmountable engineering problems he foresaw. To work reliably, such disks would have to rotate quickly and in a stable fashion; in order to record enough data to be efficient and therefore economically feasible, the read/write head—the device that would encode and decode data on the spinning disk—would have to hover very close to the disk surface without actually touching it. The project was abandoned when these requirements were deemed impossible. Computers;external storage
Floppy disks
Magnetic storage devices
[kw]Floppy Disks Are Developed for Computer Data Storage (1967-1970)
[kw]Disks Are Developed for Computer Data Storage, Floppy (1967-1970)
[kw]Computer Data Storage, Floppy Disks Are Developed for (1967-1970)
[kw]Data Storage, Floppy Disks Are Developed for Computer (1967-1970)
Computers;external storage
Floppy disks
Magnetic storage devices
[g]North America;1967-1970: Floppy Disks Are Developed for Computer Data Storage[09130]
[g]United States;1967-1970: Floppy Disks Are Developed for Computer Data Storage[09130]
[c]Computers and computer science;1967-1970: Floppy Disks Are Developed for Computer Data Storage[09130]
[c]Science and technology;1967-1970: Floppy Disks Are Developed for Computer Data Storage[09130]
[c]Inventions;1967-1970: Floppy Disks Are Developed for Computer Data Storage[09130]
[c]Engineering;1967-1970: Floppy Disks Are Developed for Computer Data Storage[09130]
Shugart, Alan
Johnson, Reynold B.
Booth, Andrew D.

An alternative technology—punched cards and the punched-card reader—soon became the industry standard for storing data. The origin of punched cards dates back to 1801, when the French inventor Joseph-Marie Jacquard invented an automatic weaving loom for which patterns were stored in pasteboard cards. Charles Babbage Babbage, Charles , an early computing pioneer, refined this storage medium for his “analytical engine.” Then, as now, data were represented on a card by punched holes that corresponded to a letter or command. The virtue of such a device was its relative simplicity and reliability: At any given location on it, a card either had or did not have a punch. Two disadvantages—slow speeds (one might have to sift through a long sequence of cards to find what the computer needed) as well as low density of data storage—spurred the industry to look for other inexpensive, yet faster, means of retaining information for computer use.

When the Ampex Corporation Ampex Corporation demonstrated its first magnetic audiotape recorder after World War II, computer designers were quick to see the possibilities such a device could offer. Shortly after Ampex’s introduction, in August of 1949, the BINAC BINAC (Binary Automatic Computer) was introduced with a storage device that consisted of what appeared to be a large tape recorder. BINAC’s makers soon introduced a more advanced machine, the UNIVAC (Universal Automatic Computer), which used a strong metal tape instead of the plastic tape used by BINAC, which was subject to distortion by stretching or by breaking altogether.

The disadvantages of metal tape soon became apparent: It was considerably heavier, its edges were razor sharp and thus dangerous, and it created considerable friction and wear on the read/write head. Later advances offset these problems to some degree. The formulation of plastic tape eventually produced sturdy media, and IBM introduced a transport mechanism that used a vacuum to spool out lengths of tape not immediately passed by the read/write head in order to increase transport speed. As a consequence, magnetic tape became (and remains) a viable medium for storage computer use. Punched cards, however, were relegated to history.

The floppy disk was originally developed as an emergency rebooting device for the IBM System/370.

(International Business Machines Corporation)

Now that magnetism had demonstrated its feasibility as a means of storing electronic data, however, alternate ideas were proposed, including rapidly rotating drums whose construction allowed engineers to read data from them quickly. Whereas a tape might have to be fast-forwarded nearly to its end to locate a specific piece of data, a drum rotating at high speed had a short period of rotation. To achieve maximum flexibility, drums rotated at speeds up to 12,500 revolutions per minute and could store more than 1 million bits (or approximately 125 kilobytes) of data. To be sure, the physical demands of such a device moving at that speed were great; even faster speeds (necessary if increased capacity and transfer rates were to be achieved) presented difficult practical engineering problems.

In 1952, Reynold B. Johnson was hired by IBM’s San Jose laboratory to develop a means of transferring data from previously recorded magnetic media to punched cards. After reading a paper written by inventor Jacob Rabinow, who proposed a stack of independently rotating disks as a means of storing data, Johnson and his staff began development in earnest. By May, 1955, IBM announced the production of the hard disk Hard disk drives unit. It was part of the RAMAC 350, whose very name, “Random Access Method of Accounting and Control,” emphasized one very important feature of the hard disk device: its ability to access data randomly, not like a tape that moved either forward or backward to a given point.

The hard disk unit consisted of fifty platters, each two feet in diameter, mounted permanently on a spindle rotating at twelve hundred revolutions per minute; a read/write head was moved to the appropriate disk and then positioned on the one side of the disk that held data in order to read the information required. To speed things even more, the next version of the device, similar in design, employed one hundred read/write heads—one for each of its fifty double-sided disks. Computer designers and users now had what they had long awaited: flexible, mass data storage at a reasonable price (in terms of mainframe computers), even if the size of IBM’s first commercial unit earned it the nickname “jukebox.”

The development of the floppy disk drive was a logical evolutionary outgrowth of the introduction of the hard disk drive. Work began in 1967, when Alan Shugart and David Noble Noble, David undertook the project. It succeeded by 1970, and the product was announced a year later in 1971, when the first commercial floppy disk drive was deployed as an emergency rebooting device for the IBM System/370 mainframe computer. At first, the floppy disk drive seemed to be a step back, because it operated more slowly than a hard disk drive and did not store as much data.

Initially, a floppy disk was a single thin plastic disk eight inches in diameter. It was developed without the protective envelope in which it is now universally seen. The addition of that jacket gave the floppy disk its single greatest advantage over the hard disk: portability with reliability. Another advantage soon proved itself: The floppy disk is resilient to damage. In a hard disk drive, the read/write heads must hover thousandths of a centimeter over the disk surface in order to attain maximum performance. Should even a small particle of dust get in the way or should the drive unit be bumped too hard, the head may “crash” into the surface of the disk and ruin its magnetic coating; the result is a permanent loss of data. Because the floppy disk drive operates with the read/write head in contact with the flexible plastic disk surface, individual particles of dust or other contaminants are not nearly as likely to cause such a failure.

The first floppy disks were 8 inches in diameter. They were eventually superseded by these smaller, plastic-encased disks with sliding metal flanges.


As a result of its advantages, the floppy disk was the logical choice for mass storage in personal computers (PCs), which were developed a few years after the floppy disk’s introduction. Because the conditions under which it operates are less stringent than those of the hard disk (which, to achieve the density of data storage of which it is capable, must be assembled in a “clean-room” environment), the floppy disk drive is relatively inexpensive to produce. Because the disks themselves were inexpensive, moreover, they could be used as a distribution medium for software, enabling the creation of a market for games, hobbyist applications, and other personal computer applications. Without such a cheap distribution medium, only mission-critical business applications might have been developed for mass distribution, since it would have been difficult to justify the expense of purchasing other types of software were the expense of distribution too prohibitive.


While still of use in the world of mainframe computer operation, the floppy disk and disk drive had their greatest impact in the realm of the personal computer. There is little doubt that the history of personal computing would have been very different were it not for the availability of inexpensive floppy disk drives. While the hard disk had been in existence for some years before the first floppy disk drive was announced and had reached a high level of sophistication, hard disk drives were quite expensive to produce. As a result, they were initially built in a fixed format of multiple platters in order to keep costs (relative to data storage capacity) reasonably low. Later developments in hard-drive technology allowed for removable disk packs, still made of units containing multiple platters (usually more than ten), but these devices required large, washing-machine-sized drives which, among other things, could create a partial vacuum in the disk chamber. Such technology was unsuitable for the office or home environment; only large research organizations had a great enough need for it to sustain the necessary expenditure.

Floppy disks provided more than merely economical data storage. Since they were built to be removable (unlike early hard drives), they represented a very basic means of transferring data between machines of like architecture. Indeed, prior to the popularization of local area networks (LAN) for the interchange of computer data, the floppy disk was known as a “sneaker” network: One merely carried the disk by foot to its destination computer. They remained the primary means of distributing new software to users until they were replaced by the CD-ROM and the Internet. Computers;external storage
Floppy disks
Magnetic storage devices

Further Reading

  • Ceruzzi, Paul E. A History of Modern Computer. 2d ed. Cambridge, Mass.: MIT Press, 2003. Survey of historical developments in computer technology and their practical consequences.
  • Friedman, Ted. Electric Dreams: Computers in American Culture. New York: New York University Press, 2005. A history of computers and computing that focuses on its effects upon the cultural history of the United States.
  • Kean, David W. IBM San Jose: A Quarter Century of Innovation. San Jose, Calif.: International Business Machines, 1977. Provides somewhat technical discussion of design and implementation of the floppy disk drive. Well documented.
  • Sobel, Robert. IBM vs. Japan: The Struggle for the Future. New York: Stein & Day, 1985. While concentrating on the similarities and differences in corporate styles in IBM and in Japanese organizations, this text provides a useful and revealing early history of the origins of the IBM personal computer series.
  • Thompson, Robert Bruce, and Barbara Fritchman Thompson. PC Hardware in a Nutshell: A Desktop Quick Reference. Cambridge, Mass.: O’Reilly, 2000. Useful reference explaining the fundamentals of all major PC components. Includes chapters on floppy disk drives and their replacements, as well as hard disk drives and other types of storage devices.
  • Time-Life Books. Understanding Computers: Memory and Storage. Alexandria, Va.: Author, 1987. Provides a very clear discussion of how modern mass storage devices work (including disk drives, tape drives, and optical media). Good illustrations. Contains a bibliography, as well as a glossary of terms related to storage and memory functions.

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