History of the floppy disk
Encyclopedia
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
a number of different formats were used. Floppy disks have now been largely superseded by other storage media and by network file transfer.
Origins, the 8-inch disk
In 1967, IBM gave their San Jose, CaliforniaSan Jose, California
San Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...
storage development center a task to develop a reliable and inexpensive system for loading microcode
Microcode
Microcode is a layer of hardware-level instructions and/or data structures involved in the implementation of higher level machine code instructions in many computers and other processors; it resides in special high-speed memory and translates machine instructions into sequences of detailed...
into their System/370
System/370
The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...
mainframe
IBM mainframe
IBM mainframes are large computer systems produced by IBM from 1952 to the present. During the 1960s and 1970s, the term mainframe computer was almost synonymous with IBM products due to their marketshare...
s in a process called Initial Control Program Load (ICPL). The System/370
System/370
The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...
was IBM's first computer system family to make extensive usage of volatile read/write semiconductor memory for microcode, so for most models, whenever the power was turned on the microcode had to be loaded (System/370's predecessor, System/360
System/360
The IBM System/360 was a mainframe computer system family first announced by IBM on April 7, 1964, and sold between 1964 and 1978. It was the first family of computers designed to cover the complete range of applications, from small to large, both commercial and scientific...
, generally used non-volatile read-only memory for microcode). IBM also wanted inexpensive media that could be sent out to customers with software updates.
IBM Direct Access Storage Product Manager Alan Shugart
Alan Shugart
Alan Field Shugart was an American engineer, entrepreneur and business executive whose career defined the modern computer disk drive industry.-Life:...
assigned the job to David L. Noble, who tried to develop a new-style tape for the purpose, but without success. Noble's team developed a read-only
Read-only
In computing, read-only can mean:* Read-only memory , a type of storage media* Read-only access to files or directories in file system permissions...
, 8 inches (203.2 mm) flexible diskette they called the "memory disk", holding 80 kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
s of data. The original 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. IBM introduced the diskette commercially in 1971.
The new device, developed under the code name Minnow and shipped as the 23FD, was a standard part of System 370 processing units (IBM internally used another device, code named Mackerel, to write boot disks for distribution to the field). It also was used as a program load device for other IBM products such as the 2835 Storage Control Unit.
Alan Shugart left IBM and moved to Memorex
Memorex
Memorex began as a computer tape producer and expanded to become a major IBM plug compatible peripheral supplier. It is now a consumer electronics brand of Imation specializing in disk recordable media for CD and DVD drives, flash memory, computer accessories and other electronics.Established in...
where his team in 1972 shipped Memorex 650, the first read-write floppy disk drive. The 650 had a data capacity of 175 kB, with 50 tracks, 8 sectors per track, and 448 bytes per sector. The Memorex disk was "hard-sectored", that is, it contained 8 sector holes (plus one index hole) at the outer diameter (outside data track 00) to synchronize the beginning of each data sector and the beginning of a track.
In 1973 IBM shipped its first read/write floppy disk drive, the 33FD, as a part of the 3740 Data Entry System, code named "IGAR", designed to directly replace IBM's punched card
Punched card
A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...
("keypunch") data entry machines. A significant feature of IBM's read/write disk media was the use of a teflon-lubricated fabric liner to lengthen media life. In 1976 media supplier Verbatim enhanced resilience further by adding a teflon coating to the magnetic disk itself. The new system used a different recording format that stored up to 250¼ kB on the same disks. 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 the Single Sided Single Density or SSSD format. It was designed to hold just as much data as one box of 2000 punch cards
Punched card
A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...
. The disk was divided into 77 tracks of 26 sectors, each holding 128 bytes. Note that 77 × 26 = 2002 sectors.
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
s 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
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
, originally shipped on 8-inch disks. However, the drives were still expensive, typically costing more than the computer they were attached to in early days, so most machines of the era used cassette tape instead.
Also in 1973, Shugart founded Shugart Associates
Shugart Associates
Shugart Associates was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the 5¼-inch minifloppy disk drive....
which went on to become the dominant manufacturer of 8-inch floppy disk drives
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
. Its SA800 became the industry standard for form factor and interface.
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 a Burroughs 1 MB unit failed to achieve any market presence.
The 5¼-inch minifloppy
An Wang
Dr. An Wang was a Chinese American computer engineer and inventor, and co-founder of computer company Wang Laboratories.-Early life and career:...
of Wang Laboratories
Wang Laboratories
Wang Laboratories was a computer company founded in 1951 by Dr. An Wang and Dr. G. Y. Chu. The company was successively headquartered in Cambridge , Tewksbury , and finally in Lowell, Massachusetts . At its peak in the 1980s, Wang Laboratories had annual revenues of $3 billion and employed over...
informed Shugart Associates
Shugart Associates
Shugart Associates was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the 5¼-inch minifloppy disk drive....
' Jim Adkinson and Don Massaro, that the 8-inch format was simply too large for the desktop word processing
Word processing
Word processing is the creation of documents using a word processor. It can also refer to advanced shorthand techniques, sometimes used in specialized contexts with a specially modified typewriter.-External links:...
machines he was developing at the time. Adkinson and Massaro proposed a 5¼-inches wide format which Wang accepted. Shugart Associates then developed a new drive of this size storing 98.5 KB later increased to 110 KB by adding 5 tracks.
The 5¼-inch drive was considerably less expensive than 8-inch drives from IBM, and soon started appearing on CP/M machines. At one point Shugart was producing 4,000 drives a day. By 1978 there were more than 10 manufacturers producing 5¼-inch floppy drives, in competing physical disk formats: hard-sectored (90 KB) and soft-sectored (110 KB). The 5¼-inch formats quickly displaced the 8-inch for most applications, and the 5¼-inch hard-sectored disk format eventually disappeared.
Apple introduced the 5¼-inch Disk II
Disk II
The Disk II Floppy Disk Subsystem was a 5¼-inch floppy disk drive designed by Steve Wozniak and manufactured by Apple Computer. It was first introduced in 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the controller card and cable...
for the Apple II in 1978, using GCR encoding to store 35 tracks of 13 sectors of 256 bytes (113KB). An upgrade to a more sophisticated GCR scheme in 1980 increased track capacity to 16 sectors (140KB for the disk).
These early drives read only one side of the disk, leading to the popular budget approach of cutting a second write-enable slot and index hole into the carrier envelope and flipping it over (thus, the “flippy disk
Flippy disk
A flippy disk is a double-sided 5¼" floppy disk, specially modified so that the two sides can be used independently in single-sided drives...
”) to use the other side for additional storage. This was considered risky by some, for the reason that single sided disks would only be certified by the manufacturer for single sided use. In reality, since some single-head floppy drives had their read/write heads on the bottom and some had them on the top, disk manufacturers routinely certified both sides of disks for use, thus the method was perfectly safe. An alternate 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 the fabric lining in the previous rotations would be picked up by the disk and dragged past the read/write head.
Tandon
Tandon Corporation
Tandon Corporation was a disk drive and PC manufacturer founded in the mid-1970s by "Jugi" Tandon. The company's original purpose was to provide magnetic read-write heads for the then-burgeoning floppy-drive market. Due to the labor-intensive nature of the product, production was carried out in...
introduced a double-sided drive in 1978, doubling the capacity, and a new “double density” format increased it again, to 360 KB.
For most of the 1970s and 1980s the floppy drive was the primary storage device for word processor
Word processor
A word processor is a computer application used for the production of any sort of printable material....
s and microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
s. 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 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
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
's Rainbow-100, DECmate-II and Pro-350. It held 400 KB on a single side by using 96 tracks per inch and cramming 10 sectors per track.
Floppy disks were supported on IBMs PC-DOS
PC-DOS
IBM PC DOS is a DOS system for the IBM Personal Computer and compatibles, manufactured and sold by IBM from the 1980s to the 2000s....
and Microsoft's MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
from their beginning on the original IBM PC. With version 1.0 of DOS (1981) only single sided 160 KB floppies were supported. Version 1.1 the next year saw support expand to double-sided
Double-sided disk
In computer science, a double-sided disk is a disk of which both sides are used to store data.Early floppy disks only used one surface for recording. The term "single sided disk" was not common until the introduction of double-sided disks, which offered double the capacity in the same physical size...
, 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, along with the IBM PC/AT, the high density disk appeared, which used 96 tracks per inch combined with a higher density magnetic media to provide 1,200 KB of storage (formally referred to as 1.2 megabytes). Since the usual (very expensive) hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
held 10–20 megabytes at the time, this was considered quite spacious. High-density drives could also read and write to double-density disks, allowing an easy upgrade path.
Except for labelling, 5¼-inch high-density disks were externally identical to their double-density counterparts. This led to an odd situation wherein the drive itself 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 a new high-coercivity
Coercivity
In materials science, the coercivity, also called the coercive field or coercive force, of a ferromagnetic material is the intensity of the applied magnetic field required to reduce the magnetization of that material to zero after the magnetization of the sample has been driven to saturation...
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 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 the addition of a hole in the disk cartridge so that the drive could determine the appropriate density.
By the end of the 1980s, the 5¼-inch disks had been superseded by the 3½-inch disks. Though 5¼-inch drives were still available, as were disks, they faded in popularity as the 1990s began. The main community of users was primarily those who still owned '80s legacy machines (PCs running MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
or home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
s) that had no 3½-inch drive; the advent of Windows 95
Windows 95
Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
(not even sold in stores in a 5¼-inch version; a coupon had to be obtained and mailed in) and subsequent phaseout of standalone MS-DOS with version 6.22 forced many of them to upgrade their hardware. On most new computers the 5¼-inch drives were optional equipment. By the mid-1990s the drives had virtually disappeared as the 3½-inch disk became the predominant floppy disk.
The "Twiggy" disk
During the development of the Apple LisaApple Lisa
The Apple Lisa—also known as the Lisa—is a :personal computer designed by Apple Computer, Inc. during the early 1980s....
, Apple developed a disk format codenamed Twiggy, and officially known as FileWare
Apple FileWare
FileWare floppy disk drives and diskettes were designed by Apple Computer as a higher-performance alternative to the Disk II and Disk III floppy systems used on the Apple II and Apple /// personal computers...
. While basically similar to a standard 5¼-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 3½-inch floppy disk from Sony. The drives were notoriously unreliable and Apple was criticized for needlessly diverging from industry standards.
The 3-inch compact floppy disk
Throughout the early 1980s the limitations of the 5¼-inch format were starting to become clear. Originally designed to be smaller and more practical than the 8-inch format, the 5¼-inch system was itself too large, and as the quality of the recording media grew, the same amount of data could be placed on a smaller surface. Another problem was that the 5¼-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
Video Floppy
A Video Floppy is a analog recording storage medium in the form of a 2" magnetic floppy disk used to store still frames of composite analog video. A video floppy, also known as a VF disk, could store up to 25 frames either in the NTSC or PAL video standards, with each frame containing 2 fields of...
, 2½-inch, 3-inch and 3½-inch (50, 60, 75 and 90 mm) all being offered by various companies. They all shared a number of advantages over the older format, including a small form factor
Form factor
Form factor may refer to:*Form factor or emissivity, the proportion of energy transmitted by that object which can be transferred to another object...
and a rigid case with a slideable write protect
Write protection
Write protection is any physical mechanism that prevents modification or erasure of valuable data on a device. Most commercial software, audio and video is sold pre-protected.-Examples:...
catch. The almost-universal use of the 5¼-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 3¼-inch floppy disk, the later ubiquitous Sony 3.5" disk and the 3-inch format:
- the 3-inch BRG MCD-1 developed in 1973 by Marcell Jánosi, a Hungarian inventor of Budapest Radiotechnic Company (Budapesti Rádiótechnikai Gyár - BRG).
- the AmDisk-3 Micro-Floppy-disk cartridge system in December 1982., which was originally designed for use with the Apple IIApple IIThe Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
Disk IIDisk IIThe Disk II Floppy Disk Subsystem was a 5¼-inch floppy disk drive designed by Steve Wozniak and manufactured by Apple Computer. It was first introduced in 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the controller card and cable...
interface card - the Mitsumi's Quick Disk 3-inch floppies.
The 3-inch floppy drive itself was manufactured by Hitachi
Hitachi, Ltd.
is a Japanese multinational conglomerate headquartered in Marunouchi 1-chome, Chiyoda, Tokyo, Japan. The company is the parent of the Hitachi Group as part of the larger DKB Group companies...
, Matsushita and Maxell
Maxell
, commonly known as Maxell, is a Japanese company which manufactures consumer electronics. The company's notable products are batteries -- the company's name is a contraction of "maximum capacity dry cell" -- and recording media, including audio cassettes and blank VHS tapes, and recordable optical...
. Only Teac
Teac
TEAC Corporation is an electronics company based in Japan. TEAC was founded in 1953 as the Tokyo Electro Acoustic Company. TEAC has four divisions:*TASCAM - consumer to professional audio products, mostly recording...
outside this "network" is known to have produced drives. Similarly, only three manufacturers of media (Maxell
Maxell
, commonly known as Maxell, is a Japanese company which manufactures consumer electronics. The company's notable products are batteries -- the company's name is a contraction of "maximum capacity dry cell" -- and recording media, including audio cassettes and blank VHS tapes, and recordable optical...
, Matsushita and Tatung
Tatung Company
Tatung Company , also known as Tatung, is a multinational corporation established in 1918 and headquartered in Zhongshan, Taipei, Taiwan. Tatung also maintains a regional headquarters in Long Beach, California for the U.S...
) are known (sometimes also branded Yamaha, Amsoft
Amsoft
Amsoft was a wholly owned subsidiary of Amstrad, PLC, founded in 1984 and re-integrated with its parent company in 1989. Its purpose was to provide an initial infrastructure of software and services for users of Amstrad's range of home computers, the Amstrad CPC and, from 1986, the Sinclair ZX...
, Panasonic
Panasonic
Panasonic is an international brand name for Japanese electric products manufacturer Panasonic Corporation, which was formerly known as Matsushita Electric Industrial Co., Ltd...
, Tandy
Tandy
Tandy is the title of a short story by Sherwood Anderson.Tandy is also a name which can refer to:-Tandy Corporation:* Tandy Corporation - a leather supply company which subsequently became the RadioShack Corporation...
, Godexco and Dixons
Dixons
Dixons is an online retailer in the United Kingdom and Ireland. It is owned by Dixons Retail plc.With its origins in a photographic shop opened by Charles Kalms, the chain had a store in most towns and cities across the UK and Ireland...
), but "no-name" disks with questionable quality have been seen in circulation.
Amstrad
Amstrad
Amstrad is a British electronics company, now wholly owned by BSkyB. As of 2006, Amstrad's main business is manufacturing Sky Digital interactive boxes....
included a 3-inch single-sided, double-density (180 KB) drive in their CPC
Amstrad CPC
The Amstrad CPC is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom,...
and some models of PCW
Amstrad PCW
The Amstrad PCW series was a range of personal computers produced by British company Amstrad from 1985 to 1998, and also sold under licence in Europe as the "Joyce" by the German electronics company Schneider in the early years of the series' life. When it was launched, the cost of a PCW system was...
. The PCW-8512 included a double-sided, quad density (720 KB) 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
ZX Spectrum
The ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd...
computer after Amstrad bought the rights from Sinclair
Sinclair Research Ltd
Sinclair Research Ltd is a British consumer electronics company founded by Sir Clive Sinclair in Cambridge. Originally incorporated in 1973 as Ablesdeal Ltd., it remained dormant until 1976, and did not adopt the name Sinclair Research until 1981....
. The Oric-1 & 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 the upper side at one time.
The disk format itself had no more capacity than the more popular (and cheaper) 5¼-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 5¼-inch or 3½-inch disks, the 3-inch disks were designed to be reversible and sported two independent write-protect switches. It was also more reliable thanks to its hard casing.
3-inch drives were also used on a number of exotic and obscure CP/M systems such as the Tatung Einstein
Tatung Einstein
The Tatung Einstein was an eight-bit home/personal computer produced by Taiwanese corporation Tatung, designed in Bradford, England at Tatung's research laboratories and assembled in Bridgnorth and Telford, England. It was aimed primarily at small businesses....
and occasionally on MSX
MSX
MSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...
systems in some regions. Other computers to have used this format are the more unknown Gavilan
Gavilan SC
The Gavilan SC was an early laptop computer, and was the first ever to be marketed as a "laptop".The brainchild of Gavilan Computer Corp. founder Manuel Fernandez, the Gavilan was introduced in May, 1983, at approximately the same time as the similar Sharp PC-5000...
Mobile Computer and Matsushita's National Mybrain 3000. The Yamaha MDR-1
Yamaha MDR-1
The Yamaha Music Disc Recorder MDR-1 was a floppy disk unit which could be attached to the FX/FS organs and digitally record and play back Electone and Clavinova performances.Two models were produced:* MDR-1A for the FX-1, and...
also used 3-inch drives.
The main problems with this format were the high price, due to the quite elaborate and complex case mechanisms. However, the tip on the weight was when Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
in 1984 convinced Apple Computer to use the 3½-inch drives
Macintosh External Disk Drive
The Macintosh External Disk Drive was the original of a series of external 3.5" floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January, 1984. Later, Apple would unify their external drives to work cross-platform between the...
in the Macintosh 128K
Macintosh 128K
The Macintosh 128K machine, released as the "Apple Macintosh", was the original Apple Macintosh personal computer. Its beige case contained a monitor and came with a keyboard and mouse. An indentation in the top of the case made it easier for the computer to be lifted and carried. It had a selling...
model, effectively making the 3½-inch drive a de-facto standard.
Mitsumi's "Quick Disk" 3-inch floppies
Mitsumi
is a Japanese manufacturer of consumer electronic components, founded in 1954.-Products:One of the company's most noticeable product lines are video game console controllers...
's Quick Disk format. The Quick Disk format is referred to in various size references: 2.8-inch, 3-inch×3-inch and 3-inch×4-inch. Mitsumi offered this as OEM
Original Equipment Manufacturer
An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...
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 a see-through hole near 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 sq housing.
The Quick Disk's most successful use was in Nintendo's Famicom Disk System
Famicom Disk System
The was released on February 21, 1986 by Nintendo as a peripheral for the Family Computer console in Japan. It was a unit that used proprietary floppy disks for data storage. It was announced, but never released, for the North American Nintendo Entertainment System...
. The FDS package of Mitsumi's Quick Disk used a 3-inch×4-inch plastic housing called the "Disk System Card". Most FDS disks did not have cover protection to prevent media contamination, but a later special series of five games did include a protective shutter.
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 the mid 1980s. A non-inclusive list includes: the Roland S-10 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, the Roland S-220, 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 the cost in the 1980s to add 5.25-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 the DPQ-280 Quickdisk for the Daewoo/Dynadata MSX1 DPC-200, in a Dragon 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, 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 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.
3½-inch format
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
introduced their own small-format 90.0 mm × 94.0 mm disk, similar to the others but somewhat simpler in construction than the AmDisk 3-inch floppy. The first computer to use this format was Sony's SMC 70 of 1982. Other than Hewlett-Packard's HP-150
HP-150
The HP-150, a "compact, powerful and innovative" computer made by Hewlett-Packard in 1983 and based on the Intel 8088, was one of the world's earliest commercialized touch screen computers. The machine was not IBM PC compatible, although it was MS-DOS compatible. Customized MS-DOS versions 2.01,...
of 1983 and Sony's MSX computers that year, this format suffered from a similar fate as the other new formats; the 5¼-inch format simply had too much market share.
Things changed dramatically when in 1982 the Microfloppy Industry Committee, a consortium ultimately of 23 media companies, agreed upon a 3½-inch media specification based upon but differing from the original Sony design. The first drives compatible with this new media specification were shipped in early 1983. In 1984 Apple Computer selected the format for their new Macintosh computers. Then, in 1985 Atari
Atari
Atari is a corporate and brand name owned by several entities since its inception in 1972. It is currently owned by Atari Interactive, a wholly owned subsidiary of the French publisher Atari, SA . The original Atari, Inc. was founded in 1972 by Nolan Bushnell and Ted Dabney. It was a pioneer in...
adopted it for their new ST line
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
, and Commodore
Commodore International
Commodore is the commonly used name for Commodore Business Machines , the U.S.-based home computer manufacturer and electronics manufacturer headquartered in West Chester, Pennsylvania, which also housed Commodore's corporate parent company, Commodore International Limited...
for their new Amiga
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...
. By 1988 the 3½-inch was outselling the 5¼-inch.
The term "3½-inch" or "3.5 inch" disk was primarily targeted at the non-metric US market and was rounded from the actual metric size of 90 mm used internationally.
The 3½-inch disks had, by way of their rigid case's slide-in-place metal cover, the significant advantage of being much better protected against unintended physical contact with the disk surface than 5¼-inch disks when the disk was handled outside the disk drive. When the disk was inserted, a part inside the drive moved the metal cover aside, giving the drive's read/write heads the necessary access to the magnetic recording surfaces. Adding the slide mechanism resulted in a slight departure from the previous square outline. The irregular, rectangular shape had the additional merit that it made it impossible to insert the disk sideways by mistake as had indeed been possible with earlier formats.
The shutter mechanism was not without its problems, however. On old or roughly treated disks the shutter could bend away from the disk. This made it vulnerable to being ripped off completely (which does not damage the disk itself but does leave it much more vulnerable to dust), or worse, catching inside a drive and possibly either getting stuck inside or damaging the drive.
Evolution
Like the 5¼-inch, the 3½-inch disk underwent an evolution of its own. When Apple introduced the Macintosh in 1984, it used single-sided 3½-inch disk drivesMacintosh External Disk Drive
The Macintosh External Disk Drive was the original of a series of external 3.5" floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January, 1984. Later, Apple would unify their external drives to work cross-platform between the...
with an advertised capacity of 400 kB. The encoding technique used by these drives was known as GCR, or Group Code Recording
Group Code Recording
In computer science, group code recording refers to several distinct but related encoding methods for magnetic media. The first, used in 6250 cpi magnetic tape, is an error-correcting code combined with a run length limited encoding scheme...
(similar recording methods were used by Commodore on its 5¼ inch drives and Sirius Computer in its Victor 9000 non PC compatible MS-Dos machine). Somewhat later, PC-compatible machines began using single-sided 3½-inch disks with an advertised capacity of 360 kB (the same as a double-sided 5¼-inch disk), and a different, incompatible recording format called MFM (Modified Frequency Modulation
Modified Frequency Modulation
Modified Frequency Modulation, commonly MFM, is a line coding scheme used to encode the actual data-bits on most floppy disk formats, hardware examples include Amiga, most CP/M machines as well as IBM PC compatibles. Early hard disk drives also used this coding.MFM is a modification to the original...
). GCR and MFM drives (and their formatted disks) were incompatible, although the physical disks were the same. In 1986, Apple introduced double-sided, 800 kB disks, still using GCR, and soon after, IBM began using 720 kB double-sided double-density MFM disks in PCs like the IBM PC Convertible and IBM PC compatibles adopted it too, whilst the Amiga used MFM encoding on the same disks to give a capacity of 880 kB.
A newer and better, MFM-based, "high-density" format, displayed as "HD" on the disks themselves and storing 1440 kB of data, was introduced in 1987. These HD disks had an extra hole in the case on the opposite side of the write-protect notch. IBM used this format on their PS/2
IBM Personal System/2
The Personal System/2 or PS/2 was IBM's third generation of personal computers. The PS/2 line, released to the public in 1987, was created by IBM in an attempt to recapture control of the PC market by introducing an advanced proprietary architecture...
series introduced in 1987. Apple started using "HD" in 1988, on the Macintosh IIx
Macintosh IIx
The Macintosh IIx was introduced by Apple in 1988 as an incremental update of the original Macintosh II model. It replaced the 16 MHz Motorola 68020 CPU and 68881 FPU of the II with a 68030 CPU and 68882 FPU ; and the 800 KB floppy drive with the 1.44 MB SuperDrive...
, and the HD floppy drive soon became universal on virtually all Macintosh and PC hardware. Apple's FDHD (Floppy Disk High Density) drive was capable of reading and writing both GCR and MFM formatted disks, and thus made it relatively easy to exchange files with PC users. Apple later marketed this drive as the SuperDrive
SuperDrive
SuperDrive is a trademark used by Apple Inc. for two different storage drives: from 1988–99 to refer to a high-density floppy disk drive capable of reading all major 3.5" disk formats; and from 2001 onwards to refer to a combined CD/DVD reader/writer....
. Interestingly, Apple began using the SuperDrive brand name again in 2001 to denote their all-formats CD/DVD reader/writer.
Besides Sony, Apple was the first major manufacturer to start selling computers with 3½-inch disk drives
Macintosh External Disk Drive
The Macintosh External Disk Drive was the original of a series of external 3.5" floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January, 1984. Later, Apple would unify their external drives to work cross-platform between the...
as well as the first to stop shipping those in 1998 with introduction of iMac
IMac
The iMac is a range of all-in-one Macintosh desktop computers built by Apple. It has been the primary part of Apple's consumer desktop offerings since its introduction in 1998, and has evolved through five distinct forms....
.
Another advance in the oxide coatings allowed for a new "extended-density" ("ED") format at 2880 kB introduced on the NeXTcube
NeXTcube
The NeXTcube was a high-end workstation computer developed, manufactured and sold by NeXT from 1990 until 1993. It superseded the original NeXT Computer workstation and was housed in a similar cube-shaped magnesium enclosure. The workstation ran the NeXTSTEP operating system.- Hardware :The...
and NeXTstation
NeXTstation
NeXTstation was a high-end workstation computer developed, manufactured and sold by NeXT from 1990 until 1993. It ran the NeXTSTEP operating system. The NeXTstation was released as a more affordable alternative to the NeXTcube at about US $4,995 or about half the price...
in 1991, and on IBM PS/2 model 57 also in 1991, but by the time it was available it was already too small in capacity to be a useful advance over the HD format and never became widely used. The 3½-inch drives sold more than a decade later still use the same 1.44 MB HD format that was standardized in 1989, in ISO 9529
ISO 9529
ISO 9529 is a standard published by the International Organization for Standardization which defines the data format used on 3.5 inch floppy disks. This also known as .- External links :*...
-1,2.
Patents
- Flores, et al., "Magnetic Record Disk Cover", US Patent 3,668,658 applied for December 22, 1969 and granted June 6, 1972 assigned to IBM.
- Dalziel , et al., "Data Storage Apparatus Employing a Single Magnetic Disk", US Patent 3,678,481, applied for March 13, 1970, and granted July 18, 1972, assigned to IBM.