In 1967 IBM gave their San Jose, California storage development center a new task: develop a simple and inexpensive system for loading microcode into their System/370 mainframes. The 370s were the first IBM machines to use semiconductor memory, and whenever the power was turned off the microcode had to be reloaded ('magnetic core' memory, used in the 370s' predecessors, the System/360 line, did not lose its contents when powered down). Normally this task would be left to various tape drives which almost all 370 systems included, but tapes were large and slow. IBM wanted something faster and more purpose-built that could also be used to send out updates to customers for $5.

David Noble, working under the direction of Alan Shugart, tried a number of existing solutions to see if he could develop a new-style tape for the purpose, but eventually gave up and started over. The result was a read-only, 8-inch (20 cm) floppy they called the "memory disk", holding 80 kilobytes. The original versions were simply the disk itself, but dirt became a serious problem and they enclosed it in a plastic envelope lined with fabric that would pick up the dirt. The new device, developed under the code name Minnow, became a standard part of the 370 in 1969.

A Japanese inventor, Yoshiro Nakamatsu (aka Dr. NakaMats), claims he independently came up with the floppy disk principle back in 1950, and so a sales license had to be acquired by IBM when they started manufacturing their floppy disk systems.

Alan Shugart left IBM, moved to Memorex where his team in 1972 shipped the Memorex 650, the first read-write floppy disk drive.

In 1973 IBM released a new version of the floppy, this time on the 3740 Data Entry System. The new system used a different recording format that stored up to 250¼ kB on the same disks, and was read-write. These drives became common, and soon were being used to move smaller amounts of data around, almost completely replacing magnetic tapes.

The IBM standard soft-sectored disk format was designed to hold just as much data as one box of punch cards. The disk was divided into 77 tracks of 26 sectors, each holding 128 bytes. Note that 77×26 = 2002 sectors, whereas a box of punch cards held 2000 cards.

When the first microcomputers were being developed in the 1970s, the 8-inch floppy found a place on them as one of the few "high speed, mass storage" devices that were even remotely affordable to the target market (individuals and small businesses). The first microcomputer operating system, CP/M, originally shipped on 8-inch disks. However, the drives were still expensive, typically costing more than the computer they were attached to in early days, so most machines of the era used cassette tape instead.

This began to change with the acceptance of the first standard for the floppy disk, ECMA-59, authored by Jim O'Reilly of Burroughs, Helmuth Hack of BASF and others. O'Reilly set a record for maneuvering this document through ECMA's approval process, with the standard sub-committee being formed in one meeting of ECMA and approval of a draft standard in the next meeting three months later. This standard later formed the basis for the ANSI standard too. Standardization brought together a variety of competitors to make media to a single interchangeable standard, and allowed rapid quality and cost improvement.

Shugart moved on in 1973 to found Shugart Associates. They started working on improvements to the existing 8-inch format, eventually creating a new 800 kB system. However, profits were hard to find, and in 1974 he was forced out of his own company.

Burroughs Corporation, meanwhile, was developing a high-performance dual-sided 8-inch drive at their Glenrothes, Scotland factory. With a capacity of 1 MB (MiB), this unit exceeded IBM's drive capacity by 4 times, and was able to provide enough space to run all the software and store data on the new Burrough's B80 data entry system, which incidentally had the first VLSI disk controller in the industry. The dual-sided 1MB floppy entered production in 1975, but was plagued by an industry problem, poor media quality. There were few tools available to test media for 'bit-shift' on the inner tracks, which made for high error rates, and the result was a substantial investment by Burroughs in a media tester design that they then gave to media makers as a quality control tool, leading to a vast improvement in yields.

In 1975, Burroughs' plant in Glenrothes developed a prototype 5¼-inch drive, stimulated both by the need to overcome the larger 8-inch floppy's asymmetric expansion properties with changing humidity, and to reflect the knowledge that IBM's audio recording products division was demonstrating a dictation machine using 5¼-inch disks. In one of the industry's historic gaffes, Burroughs corporate management decided it would be "too inexpensive" to make enough money, and shelved the program.

In 1976 two of Shugart Associates's employees, Jim Adkisson and Don Massaro, were approached by An Wang of Wang Laboratories, who felt that the 8-inch format was simply too large for the desktop word processing machines he was developing at the time. After meeting in a bar in Boston, Adkisson asked Wang what size he thought the disks should be, and Wang pointed to a napkin and said "about that size". Adkisson took the napkin back to California, found it to be 5¼-inches (13 cm) wide, and developed a new drive of this size storing 98.5 kB later increased to 110 kB by adding 5 tracks.• This is believed to be the first standard computer media that was not promulgated by IBM.
The 5¼-inch drive was considerably less expensive than 8-inch drives from IBM, and soon started appearing on CP/M machines. At one point Shugart was producing 4,000 drives a day. By 1978 there were more than 10 manufacturers producing 5¼-inch floppy drives, in competing physical disk formats: hard-sectored (90 kB) and soft-sectored (110 kB). The 5¼-inch formats quickly displaced the 8-inch from most applications, and the 5¼-inch hard-sectored disk format eventually disappeared. These early drives read only one side of the disk, leading to the popular budget approach of cutting a second write-enable slot and index hole into the carrier envelope and flipping it over (thus, the "flippy disk") to use the other side for additional storage. This method was risky because, when flipped, the disk would spin in the opposite direction inside its cover, so some of the dirt that had been collected by the fabric lining in the previous rotations would be picked up by the disk and dragged past the read/write head.


Tandon introduced a double-sided drive in 1978, doubling the capacity, and a new "double density" format increased it again, to 360 kB.•

For most of the 1970s and 1980s the floppy drive was the primary storage device for microcomputers. Since these micros had no hard drive, the OS was usually booted from one floppy disk, which was then removed and replaced by another one containing the application. Some machines using two disk drives (or one dual drive) allowed the user to leave the OS disk in place and simply change the application disks as needed. In the early 1980s, 96 track-per-inch drives appeared, increasing the capacity from 360 to 720 kB. These did not see widespread use, as they were not supported by IBM in its PCs. (Another oddball format was used by Digital Equipment Corporation's Rainbow-100, DECmate-II and Pro-350. It held 400 kB on a single side by using 96 tracks-per-inch and cramming 10 sectors per track.)


Despite the available capacity of the disks, support on the most popular operating system of the early 80's—PC-DOS and MS-DOS—lagged slightly behind. In fact, the original IBM PC did not include a floppy drive at all as standard equipment—you could either buy the optional 5¼-inch floppy drive or rely upon the cassette port. With version 1.0 of DOS (1981) only single sided 160 kB floppies were supported. Version 1.1 the next year saw support expand to double-sided, 320 kB disks. Finally in 1983 DOS 2.0 supported 9 sectors per track rather than 8, for a total of 360 kB of disk space.• Along with this change came support for different directories on the disk (now commonly called folders), which came in handy when organizing the greater number of files possible in this increased space.

In 1984, along with the IBM PC/AT, the quad density disk appeared, which used 96 tracks per inch combined with a higher density magnetic media to provide 1200 kiB of storage (formerly referred to as 1.2 megabytes). Since the usual (very expensive) hard disk held 10–20 megabytes at the time, this was considered quite spacious.

By the end of the 1980s, the 5¼-inch disks had been superseded by the 3½-inch disks. Though 5¼-inch drives were still available, as were disks, they faded in popularity as the 1990s began. The main community of users was primarily those who still owned '80s legacy machines running MS-DOS that had no 3½-inch drive; the advent of Windows 95 (not even sold in stores in a 5¼-inch version; a coupon had to be obtained and mailed in) and subsequent phaseout of standalone MS-DOS with version 6.22 forced many of them to upgrade their hardware. On most new computers the 5¼-inch drives were optional equipment. By the mid-1990s the drives had virtually disappeared as the 3½-inch disk became the preeminent floppy disk.

Amdek released the AmDisk-3 Micro-Floppy-disk cartridge system in December 1982.• Originally designed for use with the Apple II Disk II interface card, it has also been connected to other computers successfully.•

The drive itself was originally designed by Hitachi, Matsushita and Maxell. Only Teac outside this "network" is known to have produced drives. Similarly, only three manufacturers of media (Maxell, Matsushita and Tatung) are known (sometimes also branded Yamaha, Amsoft, Panasonic, Tandy, Godexco and Dixons), but "no-name" disks with questionable quality have been seen in the wild.

Amstrad incorporated a 3-inch single-sided drive into their CPC and PCW lines, and this format and the drive mechanism was later "inherited" by the ZX Spectrum +3 computer after Amstrad bought Sinclair. Later models of the PCW featured double-sided, double density drives.

While all 3-inch media were double-sided in nature, single-sided drive owners were able to flip the disk over to use the other side. The sides were termed "A" and "B" and were completely independent, but single-sided drive units could only access the upper side at one time.

The disk format itself had no more capacity than the more popular (and cheap) 5¼-inch floppies. Each side held 180 kiB for a total of 360 kiB per disk, and later 720 kiB for the PCW range.• Unlike 5¼-inch or 3½-inch disks, the 3-inch disks were designed to be reversible and sported two independent write-protect switches. It was also more reliable thanks to its hard casing (some reviews at the time reported driving over them with no problems).

3-inch drives were also used on a number of exotic and obscure CP/M systems such as the Tatung Einstein and occasionally on MSX systems in some regions. Other computers to have used this format are the more unknown Gavilan Mobile Computer and Matsushita's National Mybrain 3000. The Yamaha MDR-1 also used 3-inch drives.

Not a bad format in its own right, but the main problems were the high prices, due to the quite elaborate and complex case mechanisms. However, the tip on the weight was when Sony in 1984 convinced Apple Computer to use the 3½-inch drives in the Macintosh 128K model, effectively making it a de-facto standard.

Another 3-inch format was Mitsumi's Quick Disk format. The Quick Disk format is referred to in various size references: 2.8-inch, 3-inch×3-inch and 3-inch×4-inch. Confusing when trying to categorize the disk but perhaps not when understood that Mitsumi offered this as OEM equipment, expecting their VAR customers to customize the packaging for their own particular use. Nintendo packaged the 2.8-inch magnetic media in a 3-inch×4-inch housing, while others packaged the same media in a 3″×3″ housing. This explains the different numbering labels, while here we generically call the Mitsumi Quick Disk a 3-inch format.

The Quick Disk's most successful use was in Nintendo's Famicom Disk System. The FDS package of Mitsumi's Quick Disk used a 3-inch×4-inch plastic housing called the "Disk System Card". Most FDS disks did not have cover protection to prevent media contamination, but a later special series of five games did include a protective shutter.•

The World of Spectrum FAQ• This has led some to compare it more to a "tape-stream" unit than typically what is thought of as a random-access disk drive.•

Sony introduced their own small-format 90.0 × 94.0 mm disk, similar to the others but somewhat simpler in construction than the AmDisk. The first computer to use this format was the HP-150 of 1983, and Sony also used them fairly widely on their line of MSX computers. Other than this the format suffered from a similar fate as the other new formats; the 5¼-inch format simply had too much market share. Things changed dramatically in 1984 when Apple Computer selected the format for their new Macintosh computers. By 1988 the 3½-inch was outselling the 5¼-inch.

The 3½-inch disks had, by way of their rigid case's slide-in-place metal cover, the significant advantage of being much better protected against unintended physical contact with the disk surface than 5¼-inch disks when the disk was handled outside the disk drive. When the disk was inserted, a part inside the drive moved the metal cover aside, giving the drive's read/write heads the necessary access to the magnetic recording surfaces. Adding the slide mechanism resulted in a slight departure from the previous square outline. The irregular, rectangular shape had the additional merit that it made it impossible to insert the disk sideways by mistake as had indeed been possible with earlier formats.

The shutter mechanism was not without its problems, however. On old or roughly treated disks the shutter could bend away from the disk. This made it vulnerable to being ripped off completely (which does not damage the disk itself but does leave it much more vulnerable to dust), or worse, catching inside a drive and possibly either getting stuck inside or damaging the drive. On disks with the cover bending away the best option is to rip the cover off (to make sure it does not catch in the drive) and then immediately copy the data off it. Most modern floppies have a springy plastic cover that does not tend to bend away from the disk.

Like the 5¼-inch, the 3½-inch disk underwent an evolution of its own. When Apple introduced the Macintosh in 1984, it used single-sided 3½-inch disk drives with an advertised capacity of 400 kB. The encoding technique used by these drives was known as GCR, or Group Code Recording. Somewhat later, PC-compatible machines began using single-sided 3½-inch disks with an advertised capacity of 360 kB (the same as a single-sided 5¼-inch disk), and a different, incompatible recording format called MFM (Modified Frequency Modulation). GCR and MFM drives (and their formatted disks) were incompatible, although the physical disks were the same. In 1986, Apple introduced double-sided, 800 kB disks, still using GCR, and around the same time, 720 kB double-sided double-density MFM disks began to appear on PC-compatibles.

A newer "high-density" format, displayed as "HD" on the disks themselves and storing 1440 kB of data, was introduced in 1987. These HD disks had an extra hole in the case on the opposite side of the write-protect notch. IBM used this format on their PS/2 series introduced in 1987. Apple started using "HD" in 1988, on the Macintosh IIx, and the HD floppy drive soon became universal on virtually all Macintosh and PC hardware. Apple's HD drive was capable of reading and writing both GCR and MFM formatted disks, and thus made it relatively easy to exchange files with PC users. Apple marketed this drive as the "SuperDrive." Interestingly, Apple began using the SuperDrive brand name again around 2003 to denote their all-formats CD/DVD reader/writer.

Another advance in the oxide coatings allowed for a new "extended-density" ("ED") format at 2880 kB introduced on the second generation NeXT Computers in 1991, and on IBM PS/2 model 57 also in 1991, but by the time it was available it was already too small in capacity to be a useful advance over the HD format and never became widely used. The 3½-inch drives sold more than a decade later still use the same 1.44 MB HD format that was standardized in 1989, in ISO 9529-1,2.

The 8-inch, 5¼-inch and 3-inch formats can be considered almost completely obsolete. 3½-inch drives and disks are still widely available. As of 2006 3½-inch drives are still available on many desktop PC systems, although it is usually now an optional extra or has to be bought and installed separately. HP has recently dropped supplying floppy drives as standard on business desktops. The majority of ATX and Micro-ATX PC cases are still designed to accommodate at least one 3.5" drive that can be accessed from the front of the PC (although this can be used for other devices than just floppy drives). As of 2006, HD floppy disks are still quite commonly available in most computer and stationery shops, although selection is usually very limited.

Floppy disks still maintain a stronghold when it comes to emergency boots, BIOS updates and as maintenance program carriers, in general, as many BIOS and firmware update/restore programs are still designed to be executed from a bootable floppy disk, and the legacy support for alternate bootable media such as CD-ROMs and USB devices is still problematic in some configurations.

However, the advent of other portable storage options, such as USB storage devices and recordable or rewritable CDs, and the rise of multi-megapixel digital photography have encouraged the creation and use of files larger than most 3½-inch disks can hold. In addition, the increasing availability of broadband and wireless Internet connections is decreasing the utility of removable storage devices overall. The 3½-inch floppy is growing as obsolete as its larger cousin became a decade before. However, the 3½-inch floppy has been in continued use longer than the 5¼-inch floppy.

Some manufacturers have stopped offering 3½-inch drives on new computers as standard equipment. The Apple Macintosh, which popularized the format in 1984, began to move away from it in 1998 with the iMac model—possibly prematurely, since the basic model iMac of the time only had a CD-ROM drive, giving users no easy access to removable media. This made USB-connected floppy drives a popular accessory for the early iMacs. In February 2003, Dell, Inc. announced that they would no longer include floppy drives on their Dell Dimension home computers as standard equipment, although they are available as a selectable option for around $20 and can be purchased as an aftermarket OEM addon anywhere between $5 and $25.