What Were The Other 2 Sizes Of Floppy Disks

8-inch, 5 ⁱ⁄₄ -inch, and iii ¹⁄_two -inch floppy disks

eight-inch, 5 ^ane⁄₄ -inch (full height), and 3 ¹⁄₂ -inch drives

A iii.5-inch diskette's "floppy" magnetic material, removed from its housing

A floppy disk, or diskette, is a disk storage medium equanimous 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 deejay drive (FDD).

Floppy disks, initially as viii-inch (200 mm) media and later on in 5.25-inch (133 mm) and 3.5-inch (90 mm) sizes, were a ubiquitous class of data storage and exchange from the mid-1970s well into the first decade of the 21st century. ^[one]

By 2010, computer motherboards were rarely manufactured with floppy drive support; iii ¹⁄_ii " floppies could be used as an external USB bulldoze, but 5 ^ane⁄₄ ", eight", and non-standard drives could only exist handled by former equipment.

While floppy disk drives still have some express uses, peculiarly with legacy industrial computer equipment, they have been superseded past data storage methods with much greater chapters, such as USB wink drives, portable external hard disk drive drives, optical discs, memory cards, and reckoner networks.

Contents

• 1 History
  • 1.i Ubiquity
  • 1.2 Pass up
  • 1.3 Use in the early 21st century
• 2 Blueprint
  • 2.1 Structure
  • 2.2 Operation
• 3 Sizes
  • three.1 eight-inch floppy disk
  • 3.2 5 ^ane⁄₄ -inch floppy disk
  • 3.iii 3 ^one⁄₂ -inch floppy disk ("Microfloppy")
  • 3.4 Other sizes
  • 3.5 Sizes, performance and chapters
• 4 See as well
• 5 References
• 6 Bibliography
• 7 External links

History

eight-inch disk drive with diskette (iii ^one⁄₂ -inch deejay for comparison)

3 ^ane⁄_ii -inch, high-density diskettes affixed with agglutinative labels

Principal article: History of the floppy disk

The earliest floppy disks, developed in the late 1960s, were 8 inches (200 mm) in diameter; ^[1] they became commercially bachelor in 1971. ^[2] These disks and associated drives were produced and improved upon past IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation. ^[3] The term "floppy disk" appeared in print as early as 1970, ^[4] and although in 1973 IBM announced its first media as "Blazon one Diskette" the industry continued to use the terms "floppy disk" or "floppy".

In 1976, Shugart Associates introduced the first 5 ^one⁄₄ -inch FDD. By 1978 at that place 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 5¼ inch format displaced the 8-inch one for most applications, and the hard sectored deejay 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 three.5" microfloppy disk on its Convertible laptop estimator and the 1.44 MB high density version with the PS/ii line in 1986. These disk drives could exist added to older PC models. In 1988 IBM introduced a drive for two.88 MB "DSED" diskettes in its top-of-the-line PS/2 models but this was a commercial failure.

Throughout the early on 1980s, limitations of the five ¹⁄₄ -inch format became clear. Originally designed to be more practical than the viii-inch format, it was itself too large; equally the quality of recording media grew, data could exist stored in a smaller area. ^[5] A number of solutions were developed, with drives at 2, 2 ¹⁄₂ , 3 and 3 ^one⁄₂ inches (and Sony's 90.0 mm �- 94.0 mm disk) offered by diverse companies. ^[v] They all shared a number of advantages over the old format, including a rigid example with a sliding write protection tab, protecting them from damage; the large market place share of the 5 ^one⁄_four -inch format made it difficult for these new formats to gain significant market share. ^[five] A variant on the Sony blueprint, introduced in 1982 by a big number of manufacturers, was then rapidly adopted; by 1988 the 3 ¹⁄₂ -inch was outselling the 5 ^ane⁄₄ -inch. ^[6]

By the end of the 1980s, the 5 ¹⁄₄ -inch disks had been superseded by the 3 ^one⁄₂ -inch disks. By the mid-1990s, the 5 ¹⁄₄ -inch drives had virtually disappeared as the 3 ¹⁄_two -inch disk became the predominant floppy disk. The advantages of the 3 ⁱ⁄₂ -inch disk were its smaller size and its plastic instance which provided better protection from clay and other environmental risks while the 5 ¹⁄_iv -inch disk was available cheaper per piece throughout its history, ordinarily with a price in the range of one third to two thirds of a 3 ^one⁄₂ -inch disk.^{[ citation needed ]}

Ubiquity

Imation USB floppy bulldoze, model 01946: an external bulldoze that accepts loftier-density disks

Floppy disks became ubiquitous in the 1980s and 1990s in their utilise with personal computers to distribute software, transfer data, and create backups. Earlier hard disks became affordable, floppy disks were often used to store a computer's operating organisation (Os). Near home computers had a primary Os and Bones stored as ROM, with the option of loading a more advanced disk operating arrangement from a floppy disk. By the early on 1990s, the increasing software size meant big packages similar Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were an estimated 5 billion floppy disks in utilize. ^[7] So, distribution of larger packages was gradually replaced by CD-ROM and online distribution (for smaller programs). An endeavour to continue the floppy disk was the SuperDisk in the late 1990s, with a capacity of 120 MB ^[8] and backward compatible with standard 3 ¹⁄₂ -inch floppies; a format war briefly occurred betwixt SuperDisk and other high density removable disc products, although ultimately flash memory, recordable CDs/DVDs, and online storage would return the matter moot. External USB-based floppy disk drives are still available; many mod systems provide firmware support for booting from such a drive.

Decline

Mechanically incompatible college-density disks were introduced, like the Iomega Nil disk. Adoption was limited by the contest between proprietary formats and the need to buy expensive drives for computers where the disks would be used. In some cases, failure in market place 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 former 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 becoming an established standard. Recordable CDs with even greater capacity, compatible with existing infrastructure of CD-ROM drives, made the new floppy technologies redundant. The CD-based media's lack of reusability was negated past their extremely low cost and eventually countered by re-writeable CDs. Networking, advancements in flash-based devices and widespread adoption of USB provided some other alternative that in turn made both floppy disks and optical storage obsolete for some purposes. The rise of file sharing and multi-megapixel digital photography encouraged the use of files larger than well-nigh 3 ¹⁄₂ -inch disks could agree. Floppy disks were commonly used every bit 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 take 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, pregnant it did not have to exist installed via external media. Apple tree introduced the iMac in 1998 with a CD-ROM bulldoze but no floppy drive; this made USB-continued floppy drives popular accessories as the iMac came without any writeable 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 operating system from CD-ROM early on. By 2002 most manufacturers yet provided Floppy Disk Drives as standard equipment to come across user demand for file-transfer and an emergency kicking device as well as the general secure feeling of having the familiar device. ^[9] Subsequently, enabled past the widespread back up for USB wink drives and BIOS boot, manufacturers and retailers progressively reduced the availability of floppy deejay drives as standard equipment. In February 2003, Dell announced floppy drives would no longer be pre-installed on Dell Dimension habitation computers, although they were still available as a selectable option and purchasable equally an aftermarket OEM add-on. ^[x] On 29 Jan 2007, PC World stated that only 2% of the computers they sold contained built-in floppy deejay drives; once present stocks were wearied, no more than standard floppies would be sold. ^[11] In 2009, Hewlett-Packard stopped supplying standard floppy drives on business desktops.^{[ citation needed ]}

Utilise in the early 21st century

A floppy hardware emulator, same size every bit a 3 ¹⁄_ii drive, provides a USB interface to the user.

Screenshot of the toolbar in OpenOffice.org, highlighting the Save icon, which depicts a floppy disk

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 tin can sometimes be used to perform a recovery. The music and theatre industries still use equipment requiring standard floppy disks (e.k. 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 non 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 can be used for flash drives; several manufacturers^{[ which? ]} make such emulators.

For more 2 decades, the floppy disk was the primary external writable storage device used. Almost computing environments before the 1990s were non-networked and floppy disks were the master ways of transferring data betwixt computers, a method known informally as sneakernet. Dissimilar hard disks, floppy disks are handled and seen; even a novice user can identify a floppy deejay. Because of these factors, a motion-picture show of a 3 ¹⁄_ii " floppy disk has become an interface metaphor for saving information. The floppy disk symbol is even so used by software on user interface elements related to saving files, such every bit the release of Microsoft Role 2010, even though such disks are largely obsolete. ^[12]

Blueprint

A disk notcher used to catechumen single-sided 5.25-inch diskettes to double-sided

Structure

The 5 ¹⁄₄ -inch disk has a large circular hole in the center for the drive's spindle and a pocket-sized oval aperture in both sides of the plastic to allow the bulldoze's heads to read and write data; the magnetic medium can be spun by rotating information technology from the eye pigsty. A small notch on the right of the deejay identifies that it is writable, detected by a mechanical switch or phototransistor above it; if it is non nowadays, the disk is read-merely. Punch devices were sold to convert read-only disks to writable ones and enable writing on the unused side of single sided disks; such modified disks became known as flippy disks. Tape may be used over the notch to protect writable disks from unwanted writing. This arrangement was the antipodal of the organization used on viii inch floppy discs where the notch had to exist covered before the disc could be written to.

Another LED/photo-transistor pair located about the center of the disk detects the index hole one time per rotation in the magnetic disk; it is used to detect the angular get-go of each rails and whether or not the disk is rotating at the correct speed. Early 8-inch and 5 ¹⁄₄ -inch disks had physical holes for each sector and were termed hard sectored disks. Subsequently soft sectored disks had but one alphabetize hole, and sector position was determined by the disk controller or low level software from patterns marking the showtime of a sector. Generally, the same drives were used to read and write both types of disks, with simply the disks and deejay controllers differing. Some operating systems utilizing soft sectors, such as Apple DOS, did not use the index pigsty; the drives designed for such systems often lacked the respective sensor; this was mainly a hardware toll-saving mensurate.

Inside the disk are two layers of fabric, with the medium sandwiched in the centre. The textile is designed to reduce friction between the medium and the outer casing, and grab particles of debris abraded off the disk to proceed them from accumulating on the heads. The outer casing is usually a one-role sheet, double-folded with flaps glued or spot-welded together. The 8-inch disk had read-only logic that was the reverse of the 5 ¹⁄₄ -inch deejay, with the slot on the side having to be taped over to allow writing.

The core of the 3 ^one⁄₂ -inch deejay is the same as the other two disks, only the front has only a label and a small aperture for reading and writing data, protected by the slider - 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 the spindle of the drive. Typical 3 ¹⁄_ii -inch disk magnetic coating materials are: ^[13]

• DD: ii µm magnetic atomic number 26 oxide
• HD: 1.ii µm cobalt doped fe oxide
• ED: iii µm Barium ferrite

2 holes at the bottom left and right indicate whether the deejay is write-protected and whether information technology is loftier-density; these holes are spaced every bit far apart as the holes in punched A4 paper, allowing write-protected high-density floppies to be clipped into standard ring binders. A notch at summit right ensures that the deejay is in the correct orientation and an arrow at top left indicating direction of insertion. The drive usually has a push button that when pressed ejects the disk with varying degrees of force, the discrepancy due to the ejection forcefulness provided past the bound of the slider comprehend. In IBM PC compatibles, a floppy disk may be inserted or ejected manually at whatever time. The bulldoze has a 'change switch' that detects when a disc is ejected or inserted. Failure of this mechanical switch is a common source of disc corruption if a disc is changed and the bulldoze (and hence the operating system) fails to notice.

One of the chief usability problems of the floppy disk is its vulnerability; even within a closed plastic housing, the disk medium is highly sensitive to dust, condensation and temperature extremes. Equally with all magnetic storage, it is vulnerable to magnetic fields. Blank disks have been distributed with an extensive set of warnings, cautioning the user not to expose information technology to unsafe atmospheric condition. Disks must not be roughly treated or removed from the drive while the magnetic media is even so spinning, since doing so is probable to cause impairment to the disk, drive head, or stored data. On the other hand, the 3 ⁱ⁄₂ -inch floppy has been lauded for its mechanical usability by HCI good Donald Norman: ^[fourteen]

"A unproblematic example of a good pattern is the 3½-inch magnetic diskette for computers, a small-scale circle of "floppy" magnetic material encased in hard plastic. Before 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 non in utilize 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 the machine, only one of which is correct. What happens if I do it wrong? I endeavor inserting the deejay sideways. Ah, the designer thought of that. A piddling study shows that the case really isn't square: it'south rectangular, and then you can't insert a longer side. I attempt astern. The diskette goes in only part of the way. Small protrusions, indentations, and cutouts, prevent the diskette from existence inserted backward or upside downwards: of the eight means one might attempt to insert the diskette, only one is correct, and merely that one will fit. An fantabulous design."

The spindle motor from a iii ¹⁄_two -inch unit of measurement

A read-write head from a 3 ⁱ⁄₂ -inch unit

Functioning

How the read-write head is practical on the floppy

Visualization of magnetic information on Floppy Disk (paradigm recorded with CMOS-MagView)

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 head(southward) along the surface of the deejay. Both read and write operations require the media to be rotating and the head to contact the deejay media, an action accomplished by a "disk load" solenoid. ^[xv] To write data, current is sent through a gyre in the head every bit the media rotates. The head's magnetic field aligns the magnetic particles straight below the head on the media. When the current is reversed the particles align in the opposite direction encoding the data digitally. To read data, the magnetic particles in the media induce a tiny voltage in the head ringlet as they pass under it. This small indicate is amplified and sent to the floppy disk controller, which converts the streams of pulses from the media into information, checks it for errors, and sends it to the host reckoner organization.

A blank "unformatted" diskette has a coating of magnetic oxide with no magnetic order to the particles. During formatting, the particles are aligned forming a pattern of magnetized tracks, each cleaved upward into sectors, enabling the controller to properly read and write information. The tracks are concentric rings around the center, with spaces betwixt tracks where no data is written; gaps with padding bytes are provided between the sectors and at the end of the track to allow for slight speed variations in the disk bulldoze, and to permit better interoperability with disk drives continued to other similar systems. Each sector of information has a header that identifies the sector location on the deejay. A cyclic redundancy check (CRC) is written into the sector headers and at the end of the user information and then that the disk controller tin detect potential errors. Some errors are soft and can be resolved past automatically re-trying 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 yet fail.

After a disk is inserted, a grab or lever at the front of the drive is manually lowered to forestall the deejay from accidentally emerging, engage the spindle clamping hub, and in ii-sided drives, engage the second read/write head with the media. In some five ¹⁄₄ -inch drives, insertion of the disk compresses and locks an ejection jump which partially ejects the disk upon opening the catch or lever. This enables a smaller concave surface area for the thumb and fingers to grasp the deejay during removal. Newer 5 ¹⁄₄ -inch drives and all iii ¹⁄₂ -inch drives automatically engage the spindle and heads when a disk is inserted, doing the reverse with the press of the eject push. On Apple Macintosh computers with built-in floppy drives, the ejection button is replaced by software controlling an eject motor which only does so when the operating organization no longer needs to access the drive. The user could elevate the prototype of the floppy bulldoze to the trash tin can on the desktop to eject the disk. The first such drives were the slim "Twiggy" drives of the late Apple Lisa. In the case of a power failure or drive malfunction, a loaded deejay can removed manually by inserting a straightened paper clip into a small-scale hole at the bulldoze's front panel, but as one would exercise with a CD-ROM drive in a similar situation. External three ¹⁄₂ -inch drives from Apple were equipped with eject buttons; the button was ignored when the drive was plugged into a Mac, but not if the drive was used with an Apple tree II, equally ProDOS did not support software-controlled ejection. Some other computer designs, such as the Commodore Amiga, poll for a new disk continuously and have button ejection mechanisms.

Sizes

Master manufactures: Floppy disk format and List of floppy deejay formats

Different sizes of floppy disks are mechanically incompatible, and disks can fit just one size of drive. Drives with 3 ¹⁄₂ -inch and 5¼-inch slots were available during the transition period betwixt the sizes, only they independent two divide drive mechanisms. In addition, at that place are many subtle, commonly software-driven incompatibilities between the two. 5 ⁱ⁄₄ -inch disks formatted for utilise with Apple Ii computers would be unreadable and treated as unformatted on a Commodore. As estimator platforms began to course, attempts were made at interchangeability. For instance, the "Superdrive" included from the Macintosh SE to the Power Macintosh G3 could read, write and format IBM PC-format three½-inch disks, just few IBM-compatible computers had drives that did the contrary. 8-inch, 5 ¹⁄_four -inch and 3 ^ane⁄₂ -inch drives were manufactured in a diversity of sizes, nigh to fit standardized drive bays. Alongside the common disk sizes were non-classical sizes for specialized systems.

8-inch floppy disk

The offset floppy disk was 8 inches in diameter, and was protected by a flexible plastic jacket. IBM used this size as a manner of loading microcode into mainframe processors, and the original 8 inch disk was not field-writeable. Rewriteable disks and drives became useful. Early microcomputers used for technology, business organization, or word processing often used one or more 8 inch deejay drives for removable storage; the CP/M operating system was developed for microcomputers with 8 inch drives.

An 8-inch deejay could store about a megabyte; many microcomputer applications didn't need that much capacity on 1 disk, then a smaller size disk with lower-cost media and drives was feasible. The five¼ inch drive succeeded the 8 inch size in many applications, and adult to about the same storage capacity as the original 8 inch size, using higher-density media and recording techniques.

five ¹⁄₄ -inch floppy disk

Uncovered 5 ¹⁄₄ -inch disk mechanism with disk inserted. The edge of the disk with the opening for the medium was inserted first, then the lever was turned to shut the machinery and engage the drive motor and heads

The caput gap of an eighty-rails high-density (1.2 MB in the MFM format) 5 ^ane⁄_iv -inch drive is smaller than that of a 40-track double-density (360 kB) drive simply tin format, read and write forty-track disks well provided the controller supports double stepping or has a switch to do such a process. A blank 40-rail disk formatted and written on an lxxx-track drive tin be taken to its native drive without issues, and a disk formatted on a xl-runway drive can be used on an fourscore-track drive. Disks written on a 40-track bulldoze and then updated on an 80 track drive get unreadable on any 40-track drives due to rail width incompatibility.

Unmarried sided disks were coated on both sides, despite the availability of higher-toll double sided disks. The reason unremarkably given was that double sided disks were certified error-complimentary on both sides of the media, only architectural differences amidst computer platforms negated this claim, with RadioShack TRS-80 Model I computers using one side and the Apple II machines the other. Double-sided disks could be used in drives for single-sided disks, 1 side at a fourth dimension, by turning them over (flippy disks); more expensive dual-caput drives which could read both sides without turning over were later produced, and afterwards became used universally.

Internal parts of a iii ¹⁄₂ -inch floppy disk.
1) A hole that indicates a high-chapters disk.
ii) The hub that engages with the bulldoze motor.
three) A shutter that protects the surface when removed from the drive.
iv) The plastic housing.
5) A polyester sheet reducing friction against the disk media every bit it rotates within the housing.
vi) The magnetic coated plastic disk.
7) A schematic representation of i sector of data on the disk; the tracks and sectors are not visible on actual disks.
8) The write protection tab (unlabeled) is upper left.

three ¹⁄₂ -inch floppy disk ("Microfloppy")

A 3 ^one⁄_two -inch floppy disk drive.

In the early on 1980s, a number of manufacturers introduced smaller floppy drives and media in various formats. A consortium of 21 companies eventually settled on a 3 ^one⁄₂ -inch floppy disk (actually 90 mm wide), like to a Sony design, just improved to back up both unmarried-sided and double-sided media, with formatted capacities of 360 KB and 720KB respectively. Single-sided drives shipped in 1983, ^[16] and double sided in 1984. What became the nearly common format, the double-sided, high-density (Hard disk) 1.44 MB disk drive, shipped in 1986.

The first Macintosh computers used single-sided 3.v inch floppy disks, but had 400 KB formatted capacity. These were followed in 1986 by double-sided 800 KB floppies. The higher capacity was achieved at the same recording density by varying the disk rotation speed with arm position so that the linear speed of the head was closer to constant. Later on Macs could too read and write 1.44 MB HD disks in PC format with stock-still rotation speed.

All 3 ¹⁄_ii -inch disks have a rectangular hole in i corner which, if obstructed, write-enabled the disk. The Hd ane.44 MB disks have 2nd, unobstructed pigsty in the oppoiste corner which identified them as being of that capacity.

In IBM-uniform PCs, the three densities of 3 ⁱ⁄₂ -inch floppy disks are backwards-compatible: college density drives can read, write and format lower density media. It is physically possible to format a deejay at the wrong density, although the resulting disk volition non work properly. Fresh disks manufactured as high density can theoretically be formatted at double density merely if no information has been written on the disk in loftier density, or the deejay has been thoroughly demagnetized with a bulk eraser, every bit the magnetic strength of a high density record is stronger and overrides lower density, remaining on the disk and causing issues.

Writing at different densities than disks were intended for, sometimes by altering or drilling holes, was possible but deprecated. The holes on the right side of a 3 ¹⁄_ii -inch deejay can be altered equally to brand some disk drives and operating systems treat the disk as one of higher or lower density, for bidirectional compatibility or economical reasons. Possible modifications include: ^{[17] [18]} Some computers, east.g. the PS/2 and Acorn Archimedes, ignored these holes altogether. ^[nineteen]

It is possible to brand a iii ¹⁄_two -inch floppy deejay drive be recognized past a system as a 5 ^one⁄₄ -inch 360 kB or 1200 kB drive, and to read and write disks with the same number of tracks and sectors as those disks; this had some application in data commutation with obsolete CP/M systems.^{[ citation needed ]}

Other sizes

Main article: floppy disk variants

Other smaller floppy size were proposed, particularly for portable or minor devices that needed a smaller storage device. 3" discs similar in construction to 3 ¹⁄_two " were manufactured and used for a time, particularly by Amstrad computers and word processors. A two-inch nominal size was introduced for compact pocket computers and was used with some electronic musical instrument controllers. Neither of these sizes became popular in personal computers.

Sizes, performance and capacity

Main article: List of floppy disk formats

Floppy deejay size is ofttimes referred to in inches, fifty-fifty in countries using metric and though the size is defined in metric. The ANSI specification of 3 ¹⁄₂ -inch disks is entitled in part "90 mm (3.five in)" though 90 mm is closer to 3.54 inches. ^[20] Formatted capacities are generally set in terms of kilobytes and megabytes.

Historical sequence of floppy disk formats

Disk format	Year introduced	Formatted Storage chapters	Marketed capacity
8-inch: IBM 23FD (read-only)	1971	79.75 KB [21]	?
8-inch: Memorex 650	1972	175 KB	one.five megabit [22] [unformatted]
eight-inch: SSSD IBM 33FD / Shugart 901	1973	237.25 KB [21] [23]	3.1 Mbits unformatted
8-inch: DSSD IBM 43FD / Shugart 850	1976	500.5 KB [21]	6.2 Mbits unformatted
v 1⁄4 -inch (35 track) Shugart SA 400	1976 [24]	87.five KB [25]	110 kB
eight-inch DSDD IBM 53FD / Shugart 850	1977	980 KB (CP/M) - 1200 KB (MS-DOS Fat)	ane.two MB
5 1⁄4 -inch DD	1978	360 or 800 KB	360 kB
v ane⁄four -inch Apple Disk 2 (Pre-DOS 3.3)	1978	113.75 KB (256 byte sectors, 13 sectors/track, 35 tracks)	113 kB
5 1⁄4 -inch Atari DOS two.0S	1979	90 KB (128 byte sectors, 18 sectors/runway, forty tracks)	90 kB
v 1⁄iv -inch Apple tree Disk II (DOS 3.3)	1980	140 KB (256 byte sectors, xvi sectors/track, 35 tracks)	140 kB
iii ane⁄2 -inch HP single sided	1982	256�-sixteen�-70 = 280 KB	264 kB
five one⁄4 -inch Atari DOS 3	1983	127 KB (128 byte sectors, 26 sectors/rail, 40 tracks)	130 kB
3-inch	1982 [26] [27]	360 kB[ citation needed ]	125 kB (SS/SD), 500 kB (DS/DD) [27]
3 i⁄2 -inch SS (DD at release)	1983 [28]	360 KB (400 on Macintosh)	500 KB
3 one⁄2 -inch DS DD	1984	720 KB (800 on Macintosh, 880 on Amiga)	1 MB
5 1⁄4 -inch QD		720 KB	720 kB
5 one⁄4 -inch RX50 (SSQD)	Ca. 1982	400 kB[ citation needed ]	400 kB
v i⁄4 -inch Hard disk drive	1982 [29]	1155 KB	one.2 MB
iii-inch DD	1984[ citation needed ]	720 kB[ commendation needed ]	?
three-inch Mitsumi Quick Disk	1985	128 to 256 kB	?
2-inch	1989	720 kB [30]	?
2 1⁄2 -inch	1986 [31]	?	?
v 1⁄4 -inch Perpendicular	1986 [31]	ten MB[ commendation needed ]	?
3 1⁄two -inch HD	1987	1440 KB	1.44 MB (2.0 MB unformatted)
iii ane⁄two -inch ED	1987 [32]	2880 KB	2.88 MB
3 1⁄2 -inch Floptical (LS)	1991	20385 KB	21 MB
3 1⁄2 -inch LS-120	1996	120.375 MB	120 MB
3 ane⁄2 -inch LS-240	1997	240.75 MB	240 MB
3 i⁄ii -inch HiFD	1998/99	150/200 MB[ citation needed ]	150/200 MB
Abbreviations: SD = Single Density; DD = Double Density; QD = Quad Density; HD = High Density; ED = Extended Density; LS = Laser Servo; HiFD = High chapters Floppy Disk; SS = Unmarried Sided; DS = Double Sided
Formatted Storage Capacity is total size of all sectors on the deejay: For 8-inch see Table of 8-inch floppy formats IBM viii-inch formats. Spare, hidden and otherwise reserved sectors are included in this number. For 5 1⁄4 - and 3 i⁄2 -inch capacities quoted are from subsystem or arrangement vendor statements. Marketed Chapters is the capacity, typically unformatted, by the original media OEM vendor or in the example of IBM media, the first OEM thereafter. Other formats may get more or less capacity from the aforementioned drives and disks.

A box of nigh lxxx floppy disks together with one USB memory stick. The stick is capable of holding over 130 times equally much information as the entire box of disks put together.

Information is more often than not written to floppy disks in sectors (angular blocks) and tracks (concentric rings at a constant radius). For example, the Hd format of 3 ¹⁄₂ -inch floppy disks uses 512 bytes per sector, 18 sectors per rail, 80 tracks per side and 2 sides, for a full of one,474,560 bytes per disk. ^[33] Some disk controllers can vary these parameters at the user's request, increasing storage on the disk, although they may not exist able to exist read on machines with other controllers. For example, Microsoft applications were often distributed on 3 ¹⁄_ii -inch ane.68 MB DMF disks formatted with 21 sectors instead of eighteen; they could even so exist recognized past a standard controller. On the IBM PC, MSX and most other microcomputer platforms, disks were written using a Constant Angular Velocity (CAV) format, ^[32] with the disk spinning at a constant speed and the sectors hold the same amount of information on each rails regardless of radial location.

This was not the most efficient way to use the disk surface with available drive electronics;^{[ citation needed ]} because the sectors have constant athwart size, the 512 bytes in each sector are compressed more near the disk'south center. A more than infinite-efficient technique would be to increment the number of sectors per track toward the outer edge of the disk, from xviii to thirty for instance, thereby keeping constant the amount of concrete disk space used for storing each sector; an instance is zone chip recording. Apple tree implemented this in early Macintosh computers past spinning the deejay slower when the head was at the border, while maintaining the data rate, allowing 400 kB of storage per side and an extra 160 kB on a double-sided disk.^{[ commendation needed ]} This higher capacity came with a disadvantage: the format used a unique drive machinery and control circuitry, significant that Mac disks could not be read on other computers. Apple eventually reverted to constant angular velocity on Hd floppy disks with their subsequently machines, still unique to Apple tree as they supported the older variable-speed formats.

Deejay formatting is ordinarily done past a utility program supplied by the computer OS manufacturer; generally, information technology sets upwards a file storage directory system on the disk, and initializes its sectors and tracks. Areas of the deejay unusable for storage due to flaws can be locked (marked every bit "bad sectors") then that the operating system does not effort to use them. This was time consuming so many environments had quick formatting which skipped the error checking procedure. When floppy disks were often used, disks pre-formatted for popular computers were sold. A formatted floppy disk does not include the sector and runway headings of an unformatted disk; the difference in storage betwixt them depends on the bulldoze's application. Floppy disk bulldoze and media manufacturers specify the unformatted capacity (for instance, 2 MB for a standard 3 ¹⁄₂ -inch HD floppy). It is implied that this should non exist exceeded, since doing so will most likely result in functioning issues. DMF was introduced permitting 1.68 MB to fit onto an otherwise standard 3 ¹⁄₂ -inch deejay; utilities and then appeared allowing disks to be formatted as such.

Mixtures of decimal prefixes and binary sector sizes require intendance to properly calculate total chapters. Whereas semiconductor memory naturally favors powers of ii (size doubles each time an address pin is added to the integrated circuit), the capacity of a disk drive is the production of sector size, sectors per rail, tracks per side and sides (which in difficult disk drives tin can exist greater than ii). Although other sector sizes have been known in the past, formatted sector sizes are now almost always fix to powers of two (256 bytes, 512 bytes, etc.), and in some cases, disk capacity is calculated as multiples of the sector size rather than in simply bytes, leading to a combination of decimal multiples of sectors and binary sector sizes. For example, 1.44 MB 3 ⁱ⁄₂ -inch HD disks take the "Thou" prefix peculiar to their context, coming from their chapters of two,880 512-byte sectors (1,440 KiB), inconsistent with either a decimal megabyte nor a binary mebibyte (MiB). Hence, these disks hold i.47 MB or 1.41 MiB. Usable information capacity is a function of the disk format used, which in plow is determined by the FDD controller and its settings. Differences between such formats tin result in capacities ranging from approximately one,300 to 1760 KiB (1.80 MB) on a "standard" three ¹⁄₂ -inch loftier density floppy (and up to nearly ii MB with utilities such as 2MGUI). The highest chapters techniques require much tighter matching of drive head geometry between drives, something not always possible and unreliable. For example, the LS-240 bulldoze supports a 32 MB capacity on standard iii ¹⁄₂ -inch Hard disk disks,^{[ citation needed ]} but information technology is, however, a write-once technique, and requires its own drive.

The raw maximum transfer rate of iii ¹⁄₂ -inch Hard disk floppy drives and interfaces, disregarding overheads, is as much as k kilobit/s, or approximately 83% that of single-speed CDROM (71% of sound CD). This represents the speed of raw data bits moving under the read head; even so, because of the very high corporeality of overhead in the system (apply of soft sectors with headers, sync problems preventing sequential reads of an unabridged 18-sector track in a unmarried rotation, etc.), the actual user data read/write speed is much lower. In fact, a DSHD diskette formatted with an efficient non-sequential (interleaved or "twist") sector layout could sync and read an boilerplate of only slightly more than iii double-sided pairs of 512-byte sectors per 0.2s revolution, or a lilliputian over 15 sectors/second, for an effective data rate of approximately 125 kbit/southward. At this speed, a single, deejay-filling file would accept a skilful 90 seconds to transfer; smaller and/or fragmented files further reduced transfer speed because of the slow head seek speed and the requirement to re-read the FAT from Track 0 forth with any folder data, as removable media is rarely cached. Unusually, when compared to hard disks, optical drives and archive tapes, the floppy disk standard proper did not receive any further successful speed or capacity upgrades throughout its period of relevance, from the mid-80s introduction of DSHD through to its eventual death more than than 20 years later.

Yet, some developments did seek to improve this, but with express success. Double-sided extended-density (DSDue eastD) iii ¹⁄_ii -inch floppy disks, introduced by Toshiba in 1987 and adopted by IBM on the PS/2 in 1994, doubled the number of sectors per track, thereby providing double the data rate and capacity of conventional DSHD 3 ¹⁄₂ -inch drives. ^[32] Although information technology was not enabled by default, both the MSDOS/Windows 3.1 "Smartdrive" caching TSR and the system cache of afterward Windows versions can be configured to cache removable drives, including floppy disks. Similarly, some USB floppy drives use caching to increment performance while being congenital from standard speed drives; alternatively, the X10 accelerated floppy bulldoze was an attempt to physically increase floppy functioning by increasing spindle RPM.

More successfully, a number of (typically QIC-standard) tape-based backup drives that interfaced via the floppy drive controller were developed and sold by manufacturers such as Travan and Iomega. These fabricated better utilize of the available bandwidth, and somewhen pushed the 500/1000 kbit/s limits of standard (DD/HD) motherboard floppy disk controllers; higher cease models could brand apply of the 2000 kbit/s bandwidth of DSED controllers, and plug-in "high speed" adapter cards were offered for PCs defective this capability. Though inadequate by modern standards, their speed was competitive with early CD recorders and Zip drives, and was sufficient for overnight backups of a contemporary dwelling house or minor role users' difficult drive.

See also

• dd (Unix)
• Deejay epitome
• Don't Re-create That Floppy
• Semi-virtual diskette

References

1. ^ ^{a b} Fletcher, Richard (2007-01-thirty). "PC World announces the end of the floppy disk". Telegraph.co.uk. http://world wide web.telegraph.co.u.k./finance/2803487/PC-Earth-announces-the-end-of-the-floppy-disk.html . Retrieved 2011-06-22.
2. ^ "20th century disk storage chronology". IBM Archives. http://www-03.ibm.com/ibm/history/exhibits/storage/storage_chrono20.html . Retrieved 2011-07-nineteen.
3. ^ "Five decades of disk drive industry firsts". Disktrend.com (web.archive.org). http://web.archive.org/spider web/20110726102519/http://world wide web.disktrend.com/5decades2.htm . Retrieved 2012-10-15.
4. ^ IBM's 370/145 Uncovered; Interesting Curves Revealed, Datamation, November 1, 1970
5. ^ ^{a b c} "The Microfloppy—Ane Key to Portability," Thomas R. Jarrett, Calculator Applied science Review, Winter 1983 (Jan 1984), pp 245–7
6. ^ 1991 Disk/Trend Report, Flexible Disk Drives, Figure 2
7. ^ Reinhardt, Andy (Baronial 12, 1996). "Iomega's zip drives demand a chip more zip". Business organisation Week (The McGraw-Hill Companies) (33). ISSN 0007-7135. http://www.businessweek.com/1996/33/b3488114.htm.
8. ^ "floppy". Linuxcommand.org. 2006-01-04. http://linuxcommand.org/man_pages/floppy8.html . Retrieved 2011-06-22.
9. ^ Bound, Tom (2002-07-24). "What Has Your Floppy Bulldoze Done for You Lately? PC makers are still continuing past floppy drives despite vanishing consumer demand.". PC World. http://www.pcworld.com/article/103037/what_has_your_floppy_drive_done_for_you_lately.html . Retrieved 2012-04-04.
10. ^ "R.I.P. Floppy Disk". BBC News. 2003-04-01. http://news.bbc.co.uk/1/hi/uk/2905953.stm . Retrieved 2011-07-19.
11. ^ Derbyshire, David (2007-01-30). "Floppy disks ejected as demand slumps". Daily Telegraph. http://www.telegraph.co.britain/news/main.jhtml?xml=/news/2007/01/30/nfloppy30.xml . Retrieved 2011-07-nineteen.
12. ^ Landphair, Ted (ten March 2007). "So Long, Faithful Floppies". VOA News (Vocalism of America). http://voanews.com/english/archive/2007-03/2007-03-10-voa3.cfm . Retrieved 25 December 2008.
13. ^ "Dice Hardware-Bastelkiste" (in German language). (M)TRONICS SCS. http://www.hardware-bastelkiste.de/floppy.html . Retrieved 2011-07-19.
14. ^ Norman, Donald (1990). "Chapter 1". The Blueprint of Everyday Things. New York: Doubleday. ISBN 0-385-26774-vi.
15. ^ Jim Porter, ed. (2005). "Oral History Panel on eight inch Floppy Disk Drives" (PDF). pp. 4. http://archive.computerhistory.org/resources/access/text/Oral_History/102657926.05.01.acc.pdf . Retrieved 2011-06-22.
16. ^ Shea, Tom (June 13, 1983). "Shrinking drives increment storage". InfoWorld: ane,vii,8,9,xi. http://books.google.com/books?id=zS8EAAAAMBAJ&pg=PA8&lpg=PA8&dq=shugart+SA300+introuced&source=bl&ots=rW9E1UjbJf&sig=8GnYHwEL1n1F1KauyVoCiXT6zao&hl=en&sa=Ten&ei=vY7lULHAEPOs0AGLmICgCQ&ved=0CEkQ6AEwBA#5=onepage&q=shugart%20SA300%20introuced&f=false. "Shugart is one of the major subscribers to the 3-1/2-inch micro-floppy standard, along with Sony and 20 other visitor... Its single-sided SA300 micro-floppy drive offers 500K of unformatted storage. Shugart's Kevin Burr said the obvious next step is to put another 500K of storage on the other side of the diskette and that the business firm will come out with a double-sided 1-megabyte micro-floppy bulldoze shortly. (p. viii)"
17. ^ "Managing Disks". http://www.carolrpt.com/disks.htm . Retrieved 2006-05-25.
18. ^ "A question of floppies". http://www.jlaforums.com/viewtopic.php?p=22991294 . Retrieved 2011-02-20.
19. ^ "Formatting 720K Disks on a i.44MB Floppy". Floppy Bulldoze . http://ohlandl.ipv7.net/floppy/floppy.html#Format_720K_On_144MB . Retrieved 2011-02-11.
20. ^ ANSI X3.137, Ane- and Two-Sided, Unformatted, 90-mm (3.v-in) five,iii-tpmm (135-tpi), Flexible Disk Cartridge for 7958 bpr Use. General, Physical and Magnetic Requirements.
21. ^ ^{a b c} http://www.research.ibm.com/journal/rd/255/ibmrd2505ZE.pdf
22. ^ "Memorex 650 Flexible Disc File" (PDF). http://corphist.computerhistory.org/corphist/documents/md-4407890383ae1.pdf . Retrieved 2011-06-22.
23. ^ http://www.research.ibm.com/journal/rd/255/ibmrd2505ZB.pdf
24. ^ Sollman, George (July 1978). "Evolution of the Minifloppy (TM) Production Family". Magnetics, IEEE Transactions on xiv (4): 160–166. doi:ten.1109/TMAG.1978.1059748. ISSN 0018-9464.
25. ^ "Shugart SA 400 Datasheet". Swtpc.com. 2007-06-25. http://www.swtpc.com/mholley/SA400/SA400_Index.htm . Retrieved 2011-06-22.
26. ^ "Chronology of Events in the History of Microcomputers − 1981–1983 Business organisation Takes Over". http://nikkicox.tripod.com/comp1981.htm . Retrieved 1008-10-04.
27. ^ ^{a b} "Three-inch floppy disk product announced". http://csdl.estimator.org/plugins/dl/pdf/mags/mi/1982/02/04070788.pdf . Retrieved 1008-10-04.
28. ^ Infoworld Media Group, Inc (Nov i, 1982). "Tandon announces tiny only powerful iii½ inch disk drive". InfoWorld (InfoWorld Media Group, Inc.) iv (43): p.11. ISSN 0199-6649. http://books.google.com/?id=EzAEAAAAMBAJ&pg=PA11.
29. ^ per 1986 Disk/Trend Report, Flexible Disk Drives
30. ^ "Viability of two-Inch Media Standard for PCs in Doubt". InfoWorld 11 (31): p.21. July 31, 1989. http://books.google.com/books?id=tjAEAAAAMBAJ&pg=PT20&lpg=PT20&dq=panasonic+2-inch+floppy&source=bl&ots=beIUYo48Jj&sig=0ilCpHCMAfDUKJl50jjYkdWPj_A&hl=en&ei=L85ATs6IG4XtrQe4zPimBw&sa=Ten&oi=book_result&ct=result&resnum=1&ved=0CCAQ6AEwAA#v=onepage&q=panasonic%202-inch%20floppy&f=false.
31. ^ ^{a b} "The Future of Mass Storage". Atarimagazines.com. http://world wide web.atarimagazines.com/compute/issue70/054_1_THE_FUTURE_OF_MASS_STORAGE.php . Retrieved 2011-06-22.
32. ^ ^{a b c} Mueller, Scott (2004). Upgrading and Repairing PCs, 15th Anniversary Edition. Que Publishing. p. 1547. ISBN 0-7897-2974-1. http://books.google.com/books?id=E1p2FDL7P5QC&pg=PA1380&lpg=PA1380&dq=Floppy+disk+format+CAV&source=bl&ots=M2lgFb44eB&sig=MZNPhGkEwbhAQDjMF4YcLq5PYYM&hl=en&ei=ZwoiTq3_FafWiALkhOTEAw&sa=X&oi=book_result&ct=result&resnum=5&sqi=2&ved=0CDcQ6AEwBA#5=onepage&q=Floppy%20disk%20format%20CAV&f=false . Retrieved 2011-07-sixteen.
33. ^ "Computer Peripherals". http://www.lintech.org/comp-per/08FDK.pdf . Retrieved 2011-07-xvi.

Bibliography

• Weyhrich, Steven (2005). "The Disk Two": A detailed essay describing one of the first commercial floppy disk drives (from the Apple 2 History website)
• Immers, Richard; Neufeld, Gerald Yard. (1984). Inside Commodore DOS. The Complete Guide to the 1541 Disk Operating System. DATAMOST, Inc & Reston Publishing Visitor, Inc. (Prentice-Hall). ISBN 0-8359-3091-2.
• Englisch, Lothar; Szczepanowski, Norbert (1984). The Anatomy of the 1541 Deejay Bulldoze. Chiliad Rapids, MI: Abacus Software (translated from the original 1983 German edition, Düsseldorf: Information Becker GmbH). ISBN 0-916439-01-i.
• Hewlett Packard: 9121D/Due south Disc Memory Operator'due south Transmission; Printed one September 1982; Part No. 09121-90000

External links

• Programming Floppy Disk Controllers
• HowStuffWorks: How Floppy Disk Drives Work
• Calculator Hope: Information nigh computer floppy drives
• NCITS (mention of ANSI X3.162 and X3.171 floppy standards)
• Floppy Drive Tech Info
• Floppy disk drives and media technical information

Magnetic storage media
Wire (1898) Tape (1928) Pulsate (1932) Ferrite core (1949) Hard disk (1956) Stripe card (1956) MICR (1956) Thin film (1962) CRAM (1962) Twistor (~1968) Floppy disk (1969) Bubble (~1970) MRAM (1995) Racetrack (2008)

Basic estimator components
Input devices	Keyboard Epitome scanner Microphone Pointing device Graphics tablet Joystick Low-cal pen Mouse Pointing stick Touchpad Touchscreen Trackball Webcam Softcam
Output devices	Monitor Printer Speakers Plotter
Removable data storage	Optical disc drive CD-RW DVD+RW Disk pack Floppy disk Memory card USB flash bulldoze
Computer case	Central processing unit (CPU) Hard disk / Solid-state drive Motherboard Network interface controller Power supply Random-admission memory (RAM) Sound carte du jour Video card
Information ports	Ethernet FireWire (IEEE 1394) Parallel port Serial port Universal Serial Motorcoach (USB)

Standards of Ecma International
AIT ANSI escape code C++/CLI C# CD-ROM CDFS CLI DDS DLT E4X ECMAScript Eiffel Fat FD HVD NFC Office Open XML OpenXPS Super DLT U3D UDF UDO Ultrium-ane UMD UWB VXA
List of Ecma standards

What Were The Other 2 Sizes Of Floppy Disks,

Source: http://kuliahkaryawan.widyakartika.ac.id/IT/en/3077-2963/floppy-disk_1971_kuliahkaryawan-widyakartika.html

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