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117-492: A floppy disk is a disk storage medium composed of a thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD). Floppy disks were an almost universal data format from the 1970s into the 1990s, used for primary data storage as well as for backup and data transfers between computers. In 1967, at an IBM facility in San Jose, California , work began on

234-520: A US$ 100 drive (equivalent to $ 540 in 2023). According to Massaro, Adkisson proposed a smaller size and began working with cardboard mockups before the Wang meeting. George Sollman suggests the size was the average of existing tape drives of the era. It is an urban legend that the physical size came about when they met with Wang at a bar in Boston; when he was asked what size would be appropriate, Wang pointed to

351-528: A 2.8-inch double sided disk type and a capacity of up to 20 sectors per side at 2.5 kB per sector, up to 100 kB per disk. Quick Disk as used in the Famicom Disk System holds 64 kB of data per side, requiring a manual turn-over to access the second side. Unusually, the Quick Disk utilizes "a continuous linear tracking of the head and thus creates a single spiral track along the disk similar to

468-498: A 3-inch single-sided, double-density (180 KB) drive in their CPC and some models of PCW . The PCW 8512 included a double-sided, quad-density (720 KB) drive as the second drive, and later models, such as the PCW 9512 , used quad-density even for the first drive. The single-sided double density (180 KB) drive was "inherited" by the ZX Spectrum +3 computer after Amstrad bought

585-455: A Teflon coating to the magnetic disk itself. 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

702-443: A button that, when pressed, ejects the disk with varying degrees of force, the discrepancy due to the ejection force provided by the spring of the shutter. In IBM PC compatibles , Commodores, Apple II/IIIs, and other non-Apple-Macintosh machines with standard floppy disk drives, a disk may be ejected manually at any time. The drive has a disk-change switch that detects when a disk is ejected or inserted. Failure of this mechanical switch

819-404: A cocktail napkin—there was no such meeting. The new drive of this size stored 98.5 KB, later increased to 110 KB by adding five tracks. The 5¼ drive was considerably less expensive than 8-inch drives, and soon started appearing on CP/M machines. Shugart's initial 5.25" drive was the 35-track, single-sided SA-400, which was widely used in many early microcomputers, and which introduced

936-429: A component of the 3740 Data Entry System , designed to directly replace IBM's punched card ("keypunch") data entry machines. The medium sold separately as "Diskette 1". The new system used a soft sector recording format that stored nearly 250 kB on a disk. Drives supporting this format were offered by a number of manufacturers and soon became common for moving smaller amounts of data. This disk format became known as

1053-542: A coupon had to be obtained and mailed in) and subsequent phaseout of stand-alone 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 predominant floppy disk. During the development of the Apple Lisa , Apple developed a disk format codenamed Twiggy , and officially known as FileWare . While basically similar to

1170-632: 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 can be used for flash drives. In May 2016, the United States Government Accountability Office released a report that covered the need to upgrade or replace legacy computer systems within federal agencies. According to this document, old IBM Series/1 minicomputers running on 8-inch floppy disks are still used to coordinate "the operational functions of

1287-428: A disk can be accessed, the drive needs to synchronize its head position with the disk tracks. In some drives, this is accomplished with a Track Zero Sensor, while for others it involves the drive head striking an immobile reference surface. In either case, the head is moved so that it is approaching track zero position of the disk. When a drive with the sensor has reached track zero, the head stops moving immediately and

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1404-658: A disk diameter of 8 inches (203.2 mm). Subsequently, the 5¼-inch (133.35 mm) and then the 3½-inch (88.9 mm) became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy disks were so common in late 20th-century culture that many electronic and software programs continue to use save icons that look like floppy disks well into

1521-466: A disk, some 3½-inch drives (notably the Macintosh External 400K and 800K drives ) instead use Constant Linear Velocity (CLV), which uses a variable speed drive motor that spins more slowly as the head moves away from the center of the disk, maintaining the same speed of the head(s) relative to the surface(s) of the disk. This allows more sectors to be written to the longer middle and outer tracks as

1638-469: A double-density disk (having lower coercivity media), the strongly magnetized oxide particles would begin to affect the magnetic charge of adjacent particles. The net effect is that the disk would begin to erase itself. On the other hand, the opposite procedure (attempting to format an HD disk as DD) would fail almost every time, as the high-coercivity media would not retain data written by the low-power DD field. High-density 3½-inch disks avoided this problem by

1755-557: A drive that led to the world's first floppy disk and disk drive. It was introduced into the market in an 8-inch (20 cm) format in 1971. The more conveniently sized 5¼-inch disks were introduced in 1976, and became almost universal on dedicated word processing systems and personal computers . This format was more slowly replaced by the 3½-inch format, first introduced in 1982. There was a significant period where both were popular. A number of other variant sizes were introduced over time, with limited market success. Floppy disks remained

1872-423: A fabric that removes dust particles from the spinning disk. The three most popular (and commercially available) floppy disks are the 8-inch, 5¼-inch, and 3½-inch floppy disks. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive ( FDD ) connected to or inside a computer or other device. The first floppy disks, invented and made by IBM in 1971, had

1989-413: A hard-sectored disk, there are many holes, one for each sector row, plus an additional hole in a half-sector position, that is used to indicate sector zero. The Apple II computer system is notable in that it did not have an index hole sensor and ignored the presence of hard or soft sectoring. Instead, it used special repeating data synchronization patterns written to the disk between each sector, to assist

2106-418: A later special series of five games did include a protective shutter. Mitsumi's "3-inch" Quick Disk media were also used in a 3-inch×3-inch housing for many Smith Corona word processors. The Smith Corona disks are confusingly labeled "DataDisk 2.8-inch", presumably referring to the size of the medium inside the hard plastic case. The Quick Disk was also used in several MIDI keyboards and MIDI samplers of

2223-420: A loaded disk can be removed manually by inserting a straightened paper clip into a small hole at the drive's front panel, just as one would do with a CD-ROM drive in a similar situation. The X68000 has soft-eject 5¼-inch drives. Some late-generation IBM PS/2 machines had soft-eject 3½-inch disk drives as well for which some issues of DOS (i.e. PC DOS 5.02 and higher) offered an EJECT command. Before

2340-508: A market opportunity for such a device so came close to cancelling the project. A chance encounter in San Jose between IBM's Jack Harker and Don Stephenson the site manager of IBM's General Systems Division, Rochester MN, who needed a product to compete with Mohawk's key to tape system led to the production of IBM's first read/write FDD, the 33FD code named "IGAR." The 33FD first shipped in May 1973 as

2457-504: A master's degree in electrical engineering from Stanford University . "It isn't often someone gets an opportunity to see an industry get born. Or to participate in its beginning, participate in its formative years, and then still be around to see it become a major worldwide industry." —Jack Harker, 1987 Harker advanced through a series of positions at IBM to become the IBM San Jose Laboratory Director in 1972. He

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2574-452: A new high- coercivity oxide coating (after soft sector formatting became standard, previous increases in density were largely enabled by improvements in head technology; up until that point, the media formulation had essentially remained the same since 1976). In order to format or write to this high-coercivity media, the high-density drive switched its heads into a mode using a stronger magnetic field. When these stronger fields were written onto

2691-443: A number of advantages over the older format, including a small form factor and a rigid case with a slideable write protect catch. The almost-universal use of the 5 + 1 ⁄ 4 -inch format made it very difficult for any of these new formats to gain any significant market share. Some of these formats included Dysan and Shugart's 3 + 1 ⁄ 4 -inch floppy disk, the later ubiquitous Sony 3 + 1 ⁄ 2 -inch disk and

2808-404: A popular medium for nearly 40 years, but their use was declining by the mid- to late 1990s. The introduction of high speed computer networking and formats based on the new NAND flash technique (like USB flash drives and memory cards ) led to the eventual disappearance of the floppy disk as a standard feature of microcomputers , with a notable point in this conversion being the introduction of

2925-422: A record groove." 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. Floppy disk A floppy disk or floppy diskette (casually referred to as a floppy , a diskette , or a disk ) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with

3042-557: A recovery. The music and theatre industries still use equipment requiring standard floppy disks (e.g. 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 equipment may not be replaced due to cost or requirement for continuous availability; existing software emulation and virtualization do not solve this problem because

3159-429: 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 was considered risky by some as single sided disks were only certified by the manufacturer for single-sided use. The reasoning was that, when flipped, the disk would spin in the opposite direction inside its cover, so some of the dirt that had been collected by

3276-544: A see-through hole near the center spindle (used to ensure spindle clamping). Nintendo packaged the 2.8-inch magnetic media in a 3-inch×4-inch housing, while others packaged the same media in a 3-inch×3-inch square housing. The Quick Disk's most successful use was in Nintendo's Famicom Disk System (FDS). The FDS package of Mitsumi's Quick Disk used a 3-inch×4-inch plastic housing called the "Disk Card". Most FDS disks did not have cover protection to prevent media contamination, but

3393-468: A selectable option and purchasable as an aftermarket OEM add-on. By January 2007, only 2% of computers sold in stores contained built-in floppy disk drives. Floppy disks are used for emergency boots in aging systems lacking support for other bootable media and for BIOS updates, since most BIOS and firmware programs can still be executed from bootable floppy disks . If BIOS updates fail or become corrupt, floppy drives can sometimes be used to perform

3510-505: A single hole in the rotating floppy disk medium line up. This mechanism is used to detect the angular start of each track, and whether or not the disk is rotating at the correct speed. Early 8‑inch and 5¼‑inch disks also had holes for each sector in the enclosed magnetic medium, in addition to the index hole, with the same radial distance from the center, for alignment with the same envelope hole. These were termed hard sectored disks. Later soft- sectored disks have only one index hole in

3627-447: A small circle of floppy magnetic material encased in hard plastic. Earlier types of floppy disks did not have this plastic case, which protects the magnetic material from abuse and damage. A sliding metal cover protects the delicate magnetic surface when the diskette is not in use and automatically opens when the diskette is inserted into the computer. The diskette has a square shape: there are apparently eight possible ways to insert it into

History of the floppy disk - Misplaced Pages Continue

3744-411: A small oblong opening in both sides to allow the drive's heads to read and write data and a large hole in the center to allow the magnetic medium to spin by rotating it from its middle hole. Inside the cover are two layers of fabric with the magnetic medium sandwiched in the middle. The fabric is designed to reduce friction between the medium and the outer cover, and catch particles of debris abraded off

3861-558: A smaller surface. Another problem was that the 5 + 1 ⁄ 4 -inch disks were simply scaled down versions of the 8-inch disks, which had never really been engineered for ease of use. The thin folded-plastic shell allowed the disk to be easily damaged through bending, and allowed dirt to get onto the disk surface through the opening. A number of solutions were developed, with drives at 2-inch , 2 + 1 ⁄ 2 -inch, 3-inch and 3 + 1 ⁄ 2 -inch (50, 60, 75 and 90 mm), all being offered by various companies. They all shared

3978-564: A standard 5 + 1 ⁄ 4 -inch disk, the Twiggy disk had an additional set of write windows on the top of the disk with the label running down the side. The drive was also present in prototypes of the original Apple Macintosh computer, but was removed in both the Mac and later versions of the Lisa in favor of the 3 + 1 ⁄ 2 -inch floppy disk from Sony. The drives were notoriously unreliable and Apple

4095-475: Is a common source of disk corruption if a disk is changed and the drive (and hence the operating system) fails to notice. One of the chief usability problems of the floppy disk is its vulnerability; even inside a closed plastic housing, the disk medium is highly sensitive to dust, condensation and temperature extremes. As with all magnetic storage , it is vulnerable to magnetic fields. Blank disks have been distributed with an extensive set of warnings, cautioning

4212-533: Is best known for his leadership of the 1311 Disk File project, but he considered the 1350/1360 (Cypress) Image Storage System his most challenging assignment and the creation of the Technology and Advanced Development Group (TAD) in 1969 amongst his most important accomplishments. After graduating from Berkeley he was hired in 1952 by Reynold B. Johnson as the eighteenth employee of the new IBM design laboratory in San Jose, California, United States. An early project

4329-451: Is correctly aligned. For a drive without the sensor, the mechanism attempts to move the head the maximum possible number of positions needed to reach track zero, knowing that once this motion is complete, the head will be positioned over track zero. Some drive mechanisms such as the Apple II 5¼-inch drive without a track zero sensor, produce characteristic mechanical noises when trying to move

4446-428: Is still used by software on user-interface elements related to saving files even though physical floppy disks are largely obsolete. Examples of such software include LibreOffice , Microsoft Paint , and WordPad . The 8-inch and 5¼-inch floppy disks contain a magnetically coated round plastic medium with a large circular hole in the center for a drive's spindle. The medium is contained in a square plastic cover that has

4563-547: The Type 1 Diskette in 1973, the industry continued to use the terms "floppy disk" or "floppy". In 1976, Shugart Associates introduced the 5¼-inch floppy disk drive. By 1978, there were more than ten manufacturers producing such drives. There were competing floppy disk formats , with hard- and soft-sector versions and encoding schemes such as differential Manchester encoding (DM), modified frequency modulation (MFM), M FM and group coded recording (GCR). The 5¼-inch format displaced

4680-491: The 1970s and 1980s, the floppy drive was the primary storage device for word processors and microcomputers . Since these machines 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

4797-401: 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 1980s legacy machines (PCs running DOS or home computers ) that had no 3½-inch drive; the advent of Windows 95 (not even sold in stores in a 5¼-inch version;

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4914-398: The 1990s were non-networked, and floppy disks were the primary means to transfer data between computers, a method known informally as sneakernet . Unlike hard disks, floppy disks were handled and seen; even a novice user could identify a floppy disk. Because of these factors, a picture of a 3½-inch floppy disk became an interface metaphor for saving data. As of 2024 , the floppy disk symbol

5031-469: The 21st century, as a form of skeuomorphic design . 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 data storage capacity and data transfer speed , such as USB flash drives , memory cards , optical discs , and storage available through local computer networks and cloud storage . The first commercial floppy disks, developed in

5148-469: The 3-inch format: The 3-inch floppy drive itself was manufactured 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 , Schneider , Tandy , Godexco and Dixons ), but "no-name" disks with questionable quality have been seen in circulation. Amstrad included

5265-444: The 34-pin interface that would become an industry standard. It could be used with either a hard or soft sectored controller, and storage capacity was listed as 90k (single density) or 113k (double density). The drive went on sale in late 1976 at a list price of $ 400, with a box of ten disks at $ 60. The new, smaller disk format was taken up quickly, and by 1978 ten different manufacturers were producing 5¼-inch drives. At one point, Shugart

5382-518: The 720 KB double density 3½-inch microfloppy disk on its Convertible laptop computer in 1986 and the 1.44 MB (1,474,560 bytes) high-density version with the IBM Personal System/2 (PS/2) line in 1987. These disk drives could be added to older PC models. In 1988, Y-E Data introduced a drive for 2.88 MB Double-Sided Extended-Density (DSED) diskettes which was used by IBM in its top-of-the-line PS/2 and some RS/6000 models and in

5499-530: The 8-inch one for most uses, and the hard-sectored disk format disappeared. The most common capacity of the 5¼-inch format in DOS-based PCs was 360 KB (368,640 bytes) for the Double-Sided Double-Density (DSDD) format using MFM encoding. In 1984, IBM introduced with its PC/AT the 1.2 MB (1,228,800 bytes) dual-sided 5¼-inch floppy disk, but it never became very popular. IBM started using

5616-450: The A/C line and spun constantly. Other later models used a DC motor with corresponding changes to the interface to start and stop the motor. In a 1976 meeting, An Wang of Wang Laboratories informed Jim Adkisson and Don Massaro of Shugart Associates that the 8-inch format was simply too large and expensive for the desktop word processing machines he was developing at the time, and argued for

5733-925: The DPQ-280 Quickdisk for the Daewoo/Dynadata MSX1 DPC-200, in the Dragon 32/64 machine, in the Crescent Quick Disk 128, 128i and 256 peripherals for the ZX Spectrum, and in the Triton Quick Disk peripheral also for the ZX Spectrum. The World of Spectrum FAQ reveals that the drives did come in different sizes: 128 to 256 kB in Crescent's incarnation, and in the Triton system, with a density of 4410 bits per inch, data transmission rate of 101.6 kbit/s,

5850-555: The IBM 23FD Floppy Disk Drive System (code name Minnow). The disk is a read-only, 8-inch-diameter (200 mm) flexible diskette called the "memory disk" and holding 80 kilobytes of data. Initially the disk was bare, but dirt became a serious problem so they enclosed it in a plastic envelope lined with fabric that would remove dust particles. The Floppy Disk Patent #3,668,658 was issued on June 6, 1972, with named inventors Ralph Flores and Herbert E. Thompson. The Floppy Disk Drive Patent #3,678,481

5967-475: The MSX computer in 1984. The Quick Disk format is referred to in various size references: 2.8-inch, 3-inch×3-inch and 3-inch×4-inch. Mitsumi offered this as OEM equipment, expecting their VAR customers to customize the packaging for their own particular use; disks thus vary in storage capacity and casing size. The Quick Disk uses a 2.8-inch magnetic media, break-off write-protection tabs (one for each side), and contains

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6084-458: The PC. By 1977 Shugart had been purchased by Xerox, who closed the operations in 1985 and sold the brand to a third party. In 1978 I.T.C. (later called Verbatim), had approximately 35 percent of the estimated $ 135 million floppy disk market and sold 5¼-inch disks in large quantities for $ 1.50 each (equivalent to $ 7 in 2023). Apple purchased bare SA-400 drive mechanisms for their Disk II drive, which

6201-489: The Single Sided Single Density or SSSD format. It was designed to hold the same amount of data as 3000 punch cards . In 1973, Shugart founded Shugart Associates which went on to become the dominant manufacturer of 8-inch floppy disk drives. Its SA800 became the industry standard for form factor and interface. In 1976, media supplier Information Terminals Corporation enhanced resilience further by adding

6318-469: The Sony design, introduced in 1983 by many manufacturers, was then rapidly adopted. By 1988, the 3½-inch was outselling the 5¼-inch. Generally, the term floppy disk persisted, even though later style floppy disks have a rigid case around an internal floppy disk. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks. During this time, PCs frequently came equipped with drives of both sizes. By

6435-636: The United States' nuclear forces". The government planned to update some of the technology by the end of the 2017 fiscal year. Use in Japan's government ended in 2024. Windows 10 and Windows 11 no longer come with drivers for floppy disk drives (both internal and external). However, they will still support them with a separate device driver provided by Microsoft. The British Airways Boeing 747-400 fleet, up to its retirement in 2020, used 3½-inch floppy disks to load avionics software. Sony, who had been in

6552-401: The addition of a hole in the disk cartridge so that the drive could determine the appropriate density. However, the coercivity rating between the 3½-inch DD and HD formats, 665 and 720 oersteds , is much narrower than that for the 5 + 1 ⁄ 4 -inch format, 600 versus 300 oersteds, and consequently it was possible to format a 3½-inch DD disk as HD with no apparent problems. By the end of

6669-522: The application disks as needed, or to copy data from one floppy to another. In the early 1980s, “quad density” 96-track-per-inch drives appeared, increasing the capacity to 720 KB. RX50 was another proprietary format, used by Digital Equipment Corporation 's Rainbow 100 , DECmate II , and Professional 300 Series . It held 400 KB on a single side by using 96 tracks per inch and cramming 10 sectors per track. Floppy disks were supported on IBM's PC DOS and Microsoft's MS-DOS from their beginning on

6786-409: The computer in finding and synchronizing with the data in each track. The later 3½-inch drives of the mid-1980s did not use sector index holes, but instead also used synchronization patterns. Most 3½-inch drives used a constant speed drive motor and contain the same number of sectors across all tracks. This is sometimes referred to as Constant Angular Velocity (CAV). In order to fit more data onto

6903-464: The computer they were attached to in early days, so most machines of the era used cassette tape instead. In 1976, IBM introduced the 500 KB Double Sided Single Density (DSSD) format, and in 1977 IBM introduced the 1–1.2 MB Double Sided Double Density (DSDD) format. Other 8-inch floppy disk formats such as the Burroughs 1 MB unit failed to achieve any market presence. At the end of 1978

7020-606: The control store's microprogram and at system power on to load the microprogram into the control store. The objective was a read only device costing less than $ 200 and medium costing less than $ 5. IBM San Jose's Direct Access Storage Product Manager, Alan Shugart , assigned the job to David L. Noble, who tried to develop a new-style tape for the purpose, but without success. The project was reassigned to Donald L. Wartner, 23FD Disk Drive manager, and Herbert E. Thompson, 23FD Disk manager, along with design engineers Warren L. Dalziel, Jay Brent Nilson, and Ralph Flores; and that team developed

7137-406: The corresponding sensor; this was mainly a hardware cost-saving measure. The core of the 3½-inch disk is the same as the other two disks, but the front has only a label and a small opening for reading and writing data, protected by the shutter—a spring-loaded metal or plastic cover, pushed to the side on entry into the drive. Rather than having a hole in the center, it has a metal hub which mates to

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7254-577: The cost in the 1980s to add 5 + 1 ⁄ 4 -inch drives was still quite high, the Mitsumi Quick Disk was competing as a lower cost alternative packaged in several now obscure 8-bit computer systems. Another non-inclusive list of Quick Disk versions: QDM-01, QDD (Quick Disk Drive) on French Thomson micro-computers, in the Casio QD-7 drive, in a peripheral for the Sharp MZ-700 & MZ-800 system, in

7371-399: The current is reversed the magnetization aligns in the opposite direction, encoding one bit of data. To read data, the magnetization of the particles in the media induce a tiny voltage in the head coil as they pass under it. This small signal is amplified and sent to the floppy disk controller , which converts the streams of pulses from the media into data, checks it for errors, and sends it to

7488-399: The disk media, an action originally accomplished by a disk-load solenoid. Later drives held the heads out of contact until a front-panel lever was rotated (5¼-inch) or disk insertion was complete (3½-inch). To write data, current is sent through a coil in the head as the media rotates. The head's magnetic field aligns the magnetization of the particles directly below the head on the media. When

7605-442: The disk shell are not quite square: its width is slightly less than its depth, so that it is impossible to insert the disk into a drive slot sideways (i.e. rotated 90 degrees from the correct shutter-first orientation). A diagonal notch at top right ensures that the disk is inserted into the drive in the correct orientation—not upside down or label-end first—and an arrow at top left indicates direction of insertion. The drive usually has

7722-466: The disk to keep them from accumulating on the heads. The cover is usually a one-part sheet, double-folded with flaps glued or spot-welded together. A small notch on the side of the disk identifies whether it is writable, as detected by a mechanical switch or photoelectric sensor . In the 8-inch disk, the notch being covered or not present enables writing, while in the 5¼-inch disk, the notch being present and uncovered enables writing. Tape may be used over

7839-414: The early 1980s, falling prices of computer hardware and technological advances led to the near-universal adoption of soft sector, double density disk formats. In addition, more compact half-height disk drives began to appear, as well as double-sided drives, although the cost of them meant that single-sided remained the standard for most home computers, and 80-track drives known as "quad density". For most of

7956-406: The eight ways one might try to insert the diskette, only one is correct, and only that one will fit. An excellent design. A spindle motor in the drive rotates the magnetic medium at a certain speed, while a stepper motor-operated mechanism moves the magnetic read/write heads radially along the surface of the disk. Both read and write operations require the media to be rotating and the head to contact

8073-509: The engineering manager and then Program Manager for development and delivery of the IBM 1350 Photo Image Retrieval System / 1360 Photo-Digital Storage System . The IBM 1360 was the first " trillion-bit " data storage system (about 160  GB ). It was developed for the Atomic Energy Commission. From 1969 to 1972 he was Direct Access Storage Product Manager responsible for what was then IBM's most profitable line of business. During

8190-687: The existing 3½-inch designs was the SuperDisk in the late 1990s, using very narrow data tracks and a high precision head guidance mechanism with a capacity of 120 MB and backward-compatibility with standard 3½-inch floppies; a format war briefly occurred between SuperDisk and other high-density floppy-disk products, although ultimately recordable CDs/DVDs, solid-state flash storage, and eventually cloud-based online storage would render all these removable disk formats obsolete. External USB -based floppy disk drives are still available, and many modern systems provide firmware support for booting from such drives. In

8307-720: The fabric lining in the previous rotations would be picked up by the disk and dragged past the read/write head. Although hard sectored disks were used on some early 8" drives prior to the IBM 33FD (May 1973), they were never widely used in 5¼-inch form, although North Star clung to the format until they went bankrupt in 1984. Tandon introduced a double-sided drive in 1978, doubling the capacity, and this new “double sided double density” (DSDD) format increased capacity to 360 KB. By 1979, there were also 77-track 5¼-inch drives available, mostly used in CP/M and other professional computers, and also found in some of Commodore's disk drive line. By

8424-486: The field. Other suppliers recognized the opportunity for a read/write FDD in applications such as key entry and data logging. Shugart, by then at Memorex shipped the Memorex 650 in 1972, the first commercially available read-write floppy disk drive. The 650 had a data capacity of 175 kB, with 50 tracks and 8 sectors per track. The Memorex disk was hard sectored, that is, it contained 8 sector holes (plus one index hole) at

8541-555: The flexibility of floppy disks combined with greater capacity, but remained niche due to costs. High-capacity backward compatible floppy technologies became popular for a while and were sold as an option or even included in standard PCs, but in the long run, their use was limited to professionals and enthusiasts. Flash-based USB thumb drives finally were a practical and popular replacement, that supported traditional file systems and all common usage scenarios of floppy disks. As opposed to other solutions, no new drive type or special software

8658-457: The floppy disk business since 1983, ended domestic sales of all six 3½-inch floppy disk models as of March 2011. This has been viewed by some as the end of the floppy disk. While production of new floppy disk media has ceased, sales and uses of this media from inventories is expected to continue until at least 2026. For more than two decades, the floppy disk was the primary external writable storage device used. Most computing environments before

8775-475: The floppy-less iMac in 1998. After 2000, floppy disks were increasingly rare and used primarily with older hardware, especially with legacy industrial and musical equipment. Sony manufactured its last new floppy disks in 2011. 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

8892-512: The general population, floppy disks were often used to store a computer's operating system (OS). Most home computers from that time have an elementary OS and BASIC stored in read-only memory (ROM), with the option of loading a more advanced OS 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 standard floppy disks in use. An attempt to enhance

9009-431: The greater capacity, compatibility with existing CD-ROM drives, and—with the advent of re-writeable CDs and packet writing—a similar reusability as floppy disks. However, CD-R/RWs remained mostly an archival medium, not a medium for exchanging data or editing files on the medium itself, because there was no common standard for packet writing which allowed for small updates. Other formats, such as magneto-optical discs , had

9126-407: The heads past the reference surface. This physical striking is responsible for the 5¼-inch drive clicking during the boot of an Apple II, and the loud rattles of its DOS and ProDOS when disk errors occurred and track zero synchronization was attempted. All 8-inch and some 5¼-inch drives used a mechanical method to locate sectors, known as either hard sectors or soft sectors , and is the purpose of

9243-460: The high price, due to the quite elaborate and complex case mechanisms. However, the final tip of the scale was when Sony in 1984 convinced Apple Computer to use the 3 + 1 ⁄ 2 -inch drives in the Macintosh 128K model, effectively making the 3 + 1 ⁄ 2 -inch drive a de facto standard. Another 3-inch (75 mm) format was Mitsumi 's Quick Disk format, originally released for

9360-450: The host computer system. A blank unformatted diskette has a coating of magnetic oxide with no magnetic order to the particles. During formatting, the magnetizations of the particles are aligned forming tracks, each broken up into sectors , enabling the controller to properly read and write data. The tracks are concentric rings around the center, with spaces between tracks where no data is written; gaps with padding bytes are provided between

9477-499: The late 1960s, were 8 inches (203.2 mm) in diameter; they became commercially available in 1971 as a component of IBM products and both drives and disks were then sold separately starting in 1972 by Memorex and others. 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 IBM announced its first media as

9594-424: The machine, only one of which is correct. What happens if I do it wrong? I try inserting the disk sideways. Ah, the designer thought of that. A little study shows that the case really isn't square: it's rectangular, so you can't insert a longer side. I try backward. The diskette goes in only part of the way. Small protrusions, indentations, and cutouts prevent the diskette from being inserted backward or upside down: of

9711-399: The media. In some 5¼-inch drives, insertion of the disk compresses and locks an ejection spring which partially ejects the disk upon opening the catch or lever. This enables a smaller concave area for the thumb and fingers to grasp the disk during removal. Newer 5¼-inch drives and all 3½-inch drives automatically engage the spindle and heads when a disk is inserted, doing the opposite with

9828-400: The medium, and sector position is determined by the disk controller or low-level software from patterns marking the start of a sector. Generally, the same drives are used to read and write both types of disks, with only the disks and controllers differing. Some operating systems using soft sectors, such as Apple DOS , do not use the index hole, and the drives designed for such systems often lack

9945-687: The mid-1980s. A non-inclusive list includes: the Roland S-10 , Roland S-220 , and MKS100 samplers, the Korg SQD1, the Korg SQD8 MIDI sequencer , Akai 's 1985 model MD280 drive for the S-612 MIDI sampler, Akai's X7000 / S700 (rack version) and X3700, and the Yamaha MDF1 MIDI disk drive (intended for their DX7/21/100/TX7 synthesizers, RX11/21/21L drum machines, and QX1, QX21 and QX5 MIDI sequencers). As

10062-493: The mid-1990s, 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 higher capacity, its smaller physical size, and its rigid case which provided better protection from dirt and other environmental risks. Floppy disks became commonplace during the 1980s and 1990s in their use with personal computers to distribute software, transfer data, and create backups . Before hard disks became affordable to

10179-479: The mid-1990s, mechanically incompatible higher-density floppy 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 the release of higher-capacity versions of the drive and media being not backward-compatible with

10296-526: The notch to change the mode of the disk. Punch devices were sold to convert read-only 5¼" disks to writable ones, and also to enable writing on the unused side of single-sided disks for computers with single-sided drives. The latter worked because single- and double-sided disks typically contained essentially identical actual magnetic media, for manufacturing efficiency. Disks whose obverse and reverse sides were thus used separately in single-sided drives were known as flippy disks . Disk notching 5¼" floppies for PCs

10413-485: The old format, including a rigid case with a sliding metal (or later, sometimes plastic) shutter over the head slot, which helped protect the delicate magnetic medium from dust and damage, and a sliding write protection tab, which was far more convenient than the adhesive tabs used with earlier disks. The large market share of the well-established 5¼-inch format made it difficult for these diverse mutually-incompatible new formats to gain significant market share. A variant on

10530-468: The original IBM PC . With version 1.0 of PC 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, providing 180 KB on a (formatted) single-sided disk and 360 KB on a double-sided. In 1984, IBM introduced the 5¼ high density disk format with its new IBM AT machines. The 5¼ HD drive

10647-492: The original drives, dividing the users between new and old adopters. Consumers were wary of making costly investments into unproven and rapidly changing technologies, so none of the technologies became the established standard. Apple introduced the iMac G3 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. Recordable CDs were touted as an alternative, because of

10764-412: The outer diameter (outside data track 00) to synchronize the beginning of each data sector and the beginning of a track. Most early 8" disks were hard sectored, meaning that they had a fixed number of disk sectors (usually 8, 16, or 32), marked by physical holes punched around the disk hub, and the drive required the correct media type for its controller. IBM was developing a read/write FDD but did not see

10881-409: The press of the eject button. On Apple Macintosh computers with built-in 3½-inch disk drives, the ejection button is replaced by software controlling an ejection motor which only does so when the operating system no longer needs to access the drive. The user could drag the image of the floppy drive to the trash can on the desktop to eject the disk. In the case of a power failure or drive malfunction,

10998-403: The read operation; other errors are permanent and the disk controller will signal a failure to the operating system if multiple attempts to read the data still fail. After a disk is inserted, a catch or lever at the front of the drive is manually lowered to prevent the disk from accidentally emerging, engage the spindle clamping hub, and in two-sided drives, engage the second read/write head with

11115-495: The rights from Sinclair . The Oric-1 and Atmos systems from Oric International also used the 3-inch floppy drives, originally shipping with the Atmos, but also supported on the older Oric-1. Since 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

11232-651: The second-generation NeXTcube and NeXTstation ; however, this format had limited market success due to lack of standards and movement to 1.44 MB drives. Throughout the early 1980s, limits of the 5¼-inch format became clear. Originally designed to be more practical than the 8-inch format, it was becoming considered too large; as the quality of recording media grew, data could be stored in a smaller area. Several solutions were developed, with drives at 2-, 2½-, 3-, 3¼-, 3½- and 4-inches (and Sony 's 90 mm × 94 mm (3.54 in × 3.70 in) disk) offered by various companies. They all had several advantages over

11349-502: The sectors and at the end of the track to allow for slight speed variations in the disk drive, and to permit better interoperability with disk drives connected to other similar systems. Each sector of data has a header that identifies the sector location on the disk. A cyclic redundancy check (CRC) is written into the sector headers and at the end of the user data so that the disk controller can detect potential errors. Some errors are soft and can be resolved by automatically re-trying

11466-413: The small hole in the jacket, off to the side of the spindle hole. A light beam sensor detects when a punched hole in the disk is visible through the hole in the jacket. For a soft-sectored disk, there is only a single hole, which is used to locate the first sector of each track. Clock timing is then used to find the other sectors behind it, which requires precise speed regulation of the drive motor. For

11583-408: The spindle of the drive. Typical 3½-inch disk magnetic coating materials are: Two holes at the bottom left and right indicate whether the disk is write-protected and whether it is high-density; these holes are spaced as far apart as the holes in punched A4 paper, allowing write-protected high-density floppy disks to be clipped into international standard ( ISO 838 ) ring binders . The dimensions of

11700-444: The surface using the air flow from the disk underneath instead of the pressurized air from an air compressor as used by RAMAC. Hard disk drives today continue to use self-acting air bearings. Harker led the IBM 1311 project as the engineering manager for the first successful removable disk drive. He was instrumental in inventing the removable disk pack. From 1960 to 1969 he was first

11817-518: The time, work was put into place that led to the “Winchester” magnetic recording components and thin film recording structures. In 1972, Harker first became the director, San Jose Development Laboratory. During this time as Product Manager and then as Laboratory Director, he oversaw development and release of many important and innovative storage systems such as: Harker later held the positions of Director of Technology for IBM and later, again Director of

11934-693: The track length increases. While the original IBM 8-inch disk was actually so defined, the other sizes are defined in the metric system, their usual names being but rough approximations. Jack Harker Jack Harker was born in San Francisco in 1926 and during World War II enlisted in the navy, becoming an electronics repair specialist, serving on board in both the Atlantic and Pacific. He received his BA in mechanical engineering from Swarthmore in 1950 and master's degree in mechanical engineering from University of California Berkeley in 1952. In 1962 he received

12051-466: The typical floppy disk price per piece was $ 5 (equivalent to $ 23 in 2023) to $ 8 (equivalent to $ 37 in 2023). Sales in 1978 for all types of drives and media were expected to reach $ 135 million for media and $ 875 million for drives. The 8" floppy disk drive interface standard as developed from the Shugart Associates drives involved a 50-pin interface and a spindle motor that ran directly from

12168-449: The upper side at one time. The disk format itself had no more capacity than the more popular (and cheaper) 5 + 1 ⁄ 4 -inch floppies. Each side of a double-density disk held 180 KB for a total of 360 KB per disk, and 720 KB for quad-density disks. Unlike 5 + 1 ⁄ 4 -inch or 3 + 1 ⁄ 2 -inch disks, the 3-inch disks were designed to be reversible and sported two independent write-protect switches. It

12285-442: The user not to expose it to dangerous conditions. Rough treatment or removing the disk from the drive while the magnetic media is still spinning is likely to cause damage to the disk, drive head, or stored data. On the other hand, the 3½‑inch floppy disk has been lauded for its mechanical usability by human–computer interaction expert Donald Norman : A simple example of a good design is the 3½-inch magnetic diskette for computers,

12402-479: Was also more reliable thanks to its hard casing. 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. The main problems with this format were

12519-441: Was as a mechanical engineer on the original team developing the IBM 350 RAMAC disk storage unit, the world's first hard disk drive. After RAMAC his next project was working for Alan Shugart on the IBM 1301 . Harker led development of the first self flying disk heads. As Air Bearing Development Manager, Harker led the development effort for self-acting air bearings, which lowered the disk heads and relied on flying them over

12636-410: Was criticized for needlessly diverging from industry standards. Throughout the early 1980s, the limitations of the 5 + 1 ⁄ 4 -inch format were starting to become clear. Originally designed to be smaller and more practical than the 8-inch format, the 5 + 1 ⁄ 4 -inch system was itself too large, and as the quality of the recording media grew, the same amount of data could be placed on

12753-410: Was essentially a scaled-down 8" drive, using the same rotation speed and bit rate, and it provided almost three times as much storage as the 360k format, but had compatibility issues with the older drives due to the narrower read/write head. Except for labeling, 5¼-inch high-density disks were externally identical to their double-density counterparts. This led to an odd situation wherein the drive itself

12870-409: Was generally only required where users wanted to overwrite original 5¼" disks of store-bought software, which somewhat commonly shipped with no notch present. Another LED/photo-transistor pair located near the center of the disk detects the index hole once per rotation in the magnetic disk. Detection occurs whenever the drive's sensor, the holes in the correctly inserted floppy's plastic envelope and

12987-458: Was issued July 18, 1972 with named inventors Warren L. Dalziel, Jay. B. Nilson, and Donald L. Wartner. IBM introduced the diskette commercially in 1971. The new device first shipped in 1971 as the 23FD, the control store load device of the 2835 Storage Control Unit. and then as a standard part of most System 370 processing units and other IBM products. Internally IBM used another device, code named Mackerel , to write floppy disks for distribution to

13104-468: Was little financial incentive to omit the device from a system. Subsequently, enabled by the widespread support for USB flash drives and BIOS boot, manufacturers and retailers progressively reduced the availability of floppy disk drives as standard equipment. In February 2003, Dell , one of the leading personal computer vendors, announced that floppy drives would no longer be pre-installed on Dell Dimension home computers, although they were still available as

13221-481: Was no need of hard sectored disks or even the index hole. Commodore also elected to use GCR recording (although a different variation not compatible with Apple's format) in their disk drive line. Tandy however used industry-standard FM on the TRS-80's disk drives, with stock Shugart SA-400s, and so had a mere 85k of storage. These early drives read only one side of the disk, leading to the popular budget approach of cutting

13338-416: Was producing 4,000 drives a day, but their ascendancy was short-lived; the company's fortunes declined in the early 1980s. Part of this was due to their failure to develop a reliable 80-track drive, increasing competition, and the loss of several lucrative contracts—Apple by 1982 had switched to using cheaper Alps drive mechanisms in their computers, and IBM chose Tandon as their sole supplier of disk drives for

13455-443: Was required that impeded adoption, since all that was necessary was an already common USB port . By 2002, most manufacturers still provided floppy disk drives as standard equipment to meet user demand for file-transfer and an emergency boot device, as well as for the general secure feeling of having the familiar device. By this time, the retail cost of a floppy drive had fallen to around $ 20 (equivalent to $ 34 in 2023), so there

13572-532: Was then equipped with a custom Apple controller board and the faceplate stamped with the Apple logo. Steve Wozniak developed a recording scheme known as Group Coded Recording which allowed 140k of storage, well above the standard 90–113k, although the price of double density controllers fell not long after the Disk II's introduction. GCR recording used software means of detecting the track and sector being accessed, hence there

13689-409: Was unable to determine the density of the disk inserted except by reading the disk media to determine the format. It was therefore possible to use a high-density drive to format a double-density disk to the higher capacity. This usually appeared to work (sometimes reporting a small number of bad sectors)—at least for a time. The problem was that the high-density format was made possible by the creation of

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