A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles. They are read and written by a floppy disk drive (FDD).
Invented by IBM, floppy disks in 3.5-inch (89 mm), 5.25-inch (133 mm) and 8-inch (200 mm) forms were an ubiquitous form of data storage and exchange from the mid-1970s to the 2000s.
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floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity, such as USB flash drives, portable external hard disk drives, optical discs, memory cards, and computer networks.
The earliest floppy disks, invented in the late 1960s, were 8 inches (200 mm) in diameter; they became commercially available in 1971. These disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation.The term "floppy disk" appeared in print as early as 1970,and although in 1973 IBM announced its first media as "Type 1 Diskette" the industry continued to use the terms "floppy disk" or "floppy".
In 1976, Shugart Associates introduced the first 5¼-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs. There were competing floppy disk formats, with hard and soft sector versions and encoding schemes such as FM, MFM and GCR. The 5 1/4 inch format displaced the 8-inch one for most applications, and the hard sectored disk format disappeared. In 1984, IBM introduced the 1.2 MB dual sided floppy disk along with its AT model. IBM started using the 720 kB double density 3.5" microfloppy disk on its Convertible laptop computer and the 1.44 MB high density version with the PS/2 line in 1986. These disk drives could be added to older PC models. In 1988 IBM introduced a drive for 2.88 MB "DSED" diskettes in its top-of-the-line PS/2 models; it was a commercial failure.
Throughout the early 1980s, limitations of the 5¼-inch format became clear. Originally designed to be more practical than the 8-inch format, it was itself too large; as the quality of recording media grew, data could be stored in a smaller area. A number of solutions were developed, with drives at 2, 2½, 3 and 3½ inches (and Sony's 90.0 mm × 94.0 mm disk) offered by various companies. They all shared a number of advantages over the old format, including a rigid case with a sliding write protection tab, protecting them from damage; the large market share of the 5¼-inch format made it difficult for these new formats to gain significant market share. A variant on the Sony design, introduced in 1982 by a large number of manufacturers, was then rapidly adopted; by 1988 the 3½-inch was outselling the 5¼-inch.
By the end of the 1980s, the 5¼-inch disks had been superseded by the 3½-inch disks. By the mid-1990s the 5¼-inch drives had virtually disappeared as the 3½-inch disk became the predominant floppy disk. The advantages of the 3½-inch disk were its smaller size and its plastic case which provided better protection from dirt and other environmental risks.
Floppy disks became ubiquitous in the 1980s and 1990s in their use with personal computers and home computers to distribute software, transfer data, and create backups. Before hard disks became affordable, floppy disks were often used to store a computer's operating system (OS). Most home computers had a primary OS and BASIC stored as ROM, with the option of loading a more advanced disk operating system from a floppy disk. By the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were an estimated five billion floppy disks in use. Then, distribution of larger packages was gradually replaced by CD-ROM and online distribution (for smaller programs). An attempt to continue the floppy disk was the SuperDisk in the late 1990s, with a capacity of 120 MB and backward compatible with standard 3½-inch floppies. External USB-based floppy disk drives are available; many modern systems provide firmware support for booting from such a drive.
Mechanically incompatible higher-density disks were introduced, like the Iomega Zip disk. Adoption was limited by the competition between proprietary formats and the need to buy expensive drives for computers where the disks would be used. In some cases, failure in market penetration was exacerbated by release of higher-capacity versions of the drive and media not backward compatible with the original drives, dividing the users between new and old adopters. A chicken or the egg scenario ensued, with consumers wary of making costly investments into unproven and rapidly changing technologies, resulting in none of the technologies being able to prove themselves and stabilize their market presence. Recordable CDs with even greater capacity, compatible with existing infrastructure of CD-ROM drives, made the new floppy technologies redundant, their reusability diminished by their extremely low cost and countered by re-writable CDs. Networking, advancements in flash-based devices and widespread adoption of USB provided another alternative that made optical storage obsolete for some purposes. The rise of file sharing and multi-megapixel digital photography encouraged the use of files larger than most 3½-inch disks could hold. Floppy disks were commonly used as sneakernet carriers for file transfer, but the broad availability of LANs and fast Internet connections provided a simpler and faster method of transferring such files. Other removable storage devices have advantages in both capacity and performance when network connections are unavailable or when networks are inadequate.
In 1991, Commodore introduced the CDTV, with a CD-ROM drive in place of the floppy drive. The kickstart of AmigaOS was stored in ROM as in other Amigas, making CDTV still booting from floppy rather than from CD-ROM, like other Amigas. Apple introduced the iMac in 1998 with a CD-ROM drive but no floppy drive; this made USB-connected floppy drives popular accessories as the iMac came without any writable removable media device. This transition from standard floppies was relatively easy for Apple, since all Macintosh models originally designed to use a CD-ROM drive could boot and install their OS from CD-ROM early on. PC manufacturers were initially reluctant to remove the floppy drive because many IT departments appreciated the Sneakernet built-in file-transfer mechanism that always worked and required no device driver to operate properly. Then, manufacturers and retailers progressively reduced the availability floppy drives and disks; widespread support for USB flash drives and BIOS boot support helped them. In February 2003, Dell announced floppy drives would no longer be pre-installed on Dell Dimension home computers, although still available as a selectable option and purchasable as an aftermarket OEM add-on. On 29 January 2007, PC World stated that only 2% of the computers they sold contained built-in floppy disk drives; once present stocks were exhausted, no more standard floppies would be sold. In 2009, Hewlett-Packard stopped supplying standard floppy drives on business desktops.
Floppy disks are used for emergency boots in aging systems lacking support for other bootable media, and for BIOS updates since most BIOS and firmwareprograms can still be executed from bootable floppy disks. If BIOS updates fail or become corrupt, floppy drives can be used to perform a recovery. The music and theatre industries still use equipment requiring standard floppy disks (i.e. synthesizers, samplers, drum machines, sequencers, and lighting consoles). Industrial automation equipment such as programmable machinery and industrial robots may not have a USB interface; data and programs are then loaded from disks, damageable in industrial environments. This may not be replaced due to cost or requirement for continuous availability; existing software emulation and virtualization do not solve this problem because no operating system is present or a customized operating system is used that has no drivers for USB devices. Hardware floppy disk emulators can be made to interface floppy disk controllers to a USB port that for flash drives; several manufacturers make such emulators.
For more than two decades, the floppy disk was the primary external writable storage device used. Most computing environments before the 1990s were non-networked and floppy disks were the primary means of transferring data between computers. Unlike hard disks, floppy disks are handled and seen; even a novice user can identify a floppy disk. Because of these factors, the image of the floppy disk has become a metaphor for saving data. The floppy disk symbol is still used by software on user interface elements related to saving files, such as the release of Microsoft Office 2010, even though such disks are increasingly obsolete.