• Unit of floppy disk volume. Information carrier floppy disk. Information capacity of a floppy disk. Chronology of the emergence of floppy disk formats

    And the controller of such a device is usually denoted by the abbreviation KMD.

    Floppy disks typically have a write-protect feature that allows read-only access to the data. Floppy disks were widely used from the 1970s until the end of the 1990s, giving way to more capacious and convenient DVDs and flash drives.

    An intermediate option between them and traditional floppy disks are more modern floppy disk drives using cartridges - Iomega Zip, Iomega Jaz; as well as magneto-optical media (MO), LS-120 and others, which combined a laser (used to heat a section of the disk surface) and a magnetic head (for writing and reading information from the disk surface).

    Story

    • - Alan Shugart led the team that developed disk drives in the IBM laboratory where floppy disk drives were created. David Noble (ur. David Noble), one of the senior engineers working under his direction proposed a floppy disk (prototype of an 8″ floppy disk) and a protective casing with a fabric lining.
    • - IBM presented the first floppy disk with a diameter of 8″ (200 mm) with a corresponding disk drive.
    • - Alan Shugart founds his own firm, Shugart Associates.
    • - Finn Conner Finis Conner) invited Alan Shugart to take part in the development and production of disk drives with 5¼″ diameter disks, as a result of which Shugart Associates, having developed the controller and the original Shugart Associates SA-400 interface, released a disk drive for mini-floppy 5¼″ floppy disks, which, quickly replacing 8″ disk drives, became popular in personal computers. Shugart Associates also created the Shugart Associates System Interface (SASI), which was renamed the Small Computer System Interface (SCSI) after formal approval by the ANSI committee in 1986.
    • - Sony introduces a 3½″ (90 mm) floppy disk to the market. In the first version (DD) the volume is 720 kilobytes (9 sectors). In 1984, Hewlett-Packard first used this drive in its HP-150 computer. The later version (HD) has a volume of 1440 kilobytes or 1.44 megabytes (18 sectors).
    • 1984 - Apple began using 3½″ drives in Macintosh computers
    • 1987 - 3½″ HD drive appeared in IBM PS/2 computer systems and became the standard for mass-market PCs.
    • 1987 - Ultra-high-density disk drives developed in the 1980s by Toshiba Corporation are officially introduced. Extra High Density, ED) the carrier for which was a floppy disk with a capacity of 2880 kilobytes or 2.88 megabytes (36 sectors).
    • 2011 - Sony in March 2011 put an end to the history of floppy disks by officially ceasing the production and sale of 3½″ floppy disks.

    Formats, depending on disc diameter

    8″

    Structurally, an 8″ floppy disk is a disk made of polymer materials with a magnetic coating, enclosed in a flexible plastic case. The case had holes: a large round one in the center for the spindle, a small round one for the index hole window that allows you to determine the beginning of the sector, and a rectangular one with rounded ends for the magnetic heads of the drive. There was also a recess at the bottom; by removing the sticker from it, you could protect the disc from writing.

    Floppy disk formats differed in the number of sectors per track. Depending on the format, 8″ floppy disks contained the following amounts of information: 80, 256 and 800 KB.

    5¼″

    5¼″ floppy disk

    The design of a five-inch floppy disk differed little from an eight-inch one: the index hole window was located on the right and not on the top, and the write protection slot was also on the right side of the floppy disk. To better preserve the disc, its case was made more rigid and reinforced around the perimeter. To prevent premature wear, an anti-friction pad was placed between the case and the disk, and the edges of the drive hole were reinforced with a plastic or metal ring (this ring was usually absent in high-density floppy disks, since errors in its location on the diskette can lead to problems arising when positioning the heads).

    There were floppy disks with a rigid breakdown into sectors: they were distinguished by the presence of several index holes according to the number of sectors. This scheme was later abandoned.

    Both floppy disks and five-inch disk drives came in single- and double-sided versions. When using a single-sided drive, it was not possible to read the second side simply by turning the floppy disk over due to the location of the index hole window - this would require the presence of a similar window located symmetrically to the existing one. The data protection mechanism was also revised - the window was located on the right, and a sealed hole meant a protected disk. This was done to protect against incorrect installation.

    Recording formats on five-inch floppy disks made it possible to store 110, 360, 720 or 1200 kilobytes of data on it.

    3½″

    The fundamental difference between a 3½″ floppy disk is its hard plastic casing. Instead of an index hole, 3½" floppy disks use a metal sleeve with an index hole that is located in the center of the diskette. The drive mechanism grips a metal sleeve, and the hole in it allows the floppy disk to be positioned correctly, so there is no need to make a hole directly in the magnetic disk for this. Unlike 8″ and 5¼″ floppy disks, the window for the heads of a 3½″ floppy disk is closed by a sliding metal flap, which opens when it is inserted into the drive. Write protection is provided by a sliding curtain in the lower left corner. At the bottom right there are windows that allow the drive circuit to determine the recording density of the floppy disk based on the number of holes:

    • no - 720 KB,
    • one - 1.44 MB,
    • two - 2.88 MB.

    Despite many disadvantages - sensitivity to magnetic fields and insufficient capacity by the mid-90s, the 3½″ format lasted on the market for more than a quarter of a century, leaving only after the advent of affordable flash memory-based drives.

    3½″ floppy disk device

    1 - window that determines the recording density (on the other side there is a write protection switch); 2 - disk base with holes for the drive mechanism; 3 - protective curtain of the open area of ​​the body; 4 - plastic floppy body; 5 - anti-friction gasket; 6 - magnetic disk; 7 - recording area (one sector of one track is conventionally highlighted in red).


    Iomega Zip

    Floppy disk Zip-250

    By the mid-90s, even a 2.88 MB floppy disk capacity was no longer enough. Several formats claimed to replace the 3.5″ floppy disk, among which Iomega Zip floppy disks gained the most popularity. Like the 3.5″ floppy disk, the Iomega Zip media was a soft polymer disk coated with a ferromagnetic layer and enclosed in a hard case with a protective shutter. Unlike the 3.5″ floppy disk, the hole for the magnetic heads was located at the end of the case, and not on the side surface. There were Zip floppy disks of 100, 250, and by the end of the format's existence - 750 MB. In addition to their larger capacity, Zip drives provided more reliable data storage and higher read and write speeds than 3.5″. However, they were never able to supplant three-inch floppy disks due to the high price of both floppy drives and floppy disks, as well as due to the unpleasant feature of the drives, when a floppy disk with mechanical damage to the disk disables the disk drive, which in turn could damage the disk inserted into it. after that a floppy disk.

    Formats

    Chronology of the emergence of floppy disk formats
    Format Year of origin Volume in kilobytes
    8″ 80
    8″ 256
    8″ 800
    8″ double density 1000
    5¼″ 110
    5¼″ double density 360
    5¼″ quadruple density 720
    5¼″ high density 1200
    3″ 360
    3″ double density 720
    3½″ double density 720
    2″ 720
    3½″ high density 1440
    3½″ extended density 2880

    It should be noted that the actual capacity of floppy disks depended on how they were formatted. Since, except for the earliest models, virtually all floppy disks did not contain rigidly formed tracks, the way was open for system programmers to experiment in the field of more efficient use of the floppy disk. The result was the emergence of many incompatible floppy disk formats, even under the same operating systems.

    Floppy disk formats in IBM equipment

    "Standard" IBM PC floppy disk formats differed in disk size, number of sectors per track, number of sides used (SS stands for single-sided floppy, DS for double-sided), and the type (recording density) of the drive - the drive type was labeled:

    • SD (English) Single Density, single density, first appeared on the IBM System 3740),
    • DD (English) Double Density, double density, first appeared in IBM System 34),
    • QD (English) Quadruple Density, quadruple density, used in domestic clones Robotron-1910 - 5¼″ floppy disk 720 K, Amstrad PC, PC Neuron - 5¼″ floppy disk 640 K),
    • HD High Density, high density, differed from QD in the increased number of sectors),
    • ED (English) Extra High Density, ultra-high density).

    Additional (non-standard) tracks and sectors sometimes contained copy protection data for proprietary floppy disks. Standard programs such as diskcopy, these sectors were not transferred when copying.

    Operating densities of disk drives and floppy disk capacities in kilobytes
    Magnetic coating parameter 5¼″ 3½″
    Double Density (DD) Quadruple Density (QD) High Density (HD) Double Density (DD) High Density (HD) Ultra High Density (ED)
    Base of the magnetic layer Fe Co Co
    Coercive force, 300 300 600 600 720 750
    Magnetic layer thickness, microinch 100 100 50 70 40 100
    Track width, mm 0,300 0,155 0,115 0,115 0,115
    Track Density 48 96 96 135 135 135
    Linear density 5876 5876 9646 8717 17434 34868
    Capacity
    (after formatting)
    360 720 1200
    (1213952)
    720 1440
    (1457664)
    2880
    Summary table of floppy disk formats used in IBM PC and compatible PCs
    Disc diameter, ″ 5¼″ 3½″
    Disk capacity, KB 1200 360 320 180 160 2 880 1 440 720
    Media description byte in MS-DOS F9 16 FD 16 FF 16 FC 16 FE 16 F0 16 F0 16 F9 16
    Number of sides (heads) 2 2 2 1 1 2 2 2
    Number of tracks on each side 80 40 40 40 40 80 80 80
    Number of sectors per track 15 9 8 9 8 36 18 9
    Sector size, bytes 512
    Number of sectors in a cluster 1 2 2 1 1 2 1 2
    FAT length (in sectors) 2 2 1 2 1 9 9 3
    FAT quantity 2 2 2 2 2 2 2 2
    Length of the root directory in sectors 14 7 7 4 4 15 14 7
    Maximum number of elements in the root directory 224 112 112 64 64 240 224 112
    Total number of sectors on the disk 2400 720 640 360 320 5 760 2 880 1 440
    Number of available sectors 2371 708 630 351 313 5 726 2 847 1 426
    Number of available clusters 2371 354 315 351 313 2 863 2 847 713

    Floppy disk formats in other foreign equipment

    Additional confusion was caused by the fact that Apple used disk drives in its Macintosh computers that used a different principle of magnetic recording encoding than on the IBM PC - as a result, despite the use of identical floppy disks, transferring information between platforms on floppy disks was not possible until that time , when Apple introduced high-density SuperDrive drives that operated in both modes.

    A fairly common modification of the format of 3½″ floppy disks is their formatting to 1.2 MB (with a reduced number of sectors). This feature can usually be enabled in the BIOS of modern computers. This use of 3½″ is typical for Japan and South Africa. As a side effect, activating this BIOS setting usually makes it possible to read floppies formatted with 800-type drivers.

    Features of using floppy disks in domestic technology

    In addition to the above format variations, there were a number of improvements and deviations from the standard floppy disk format:

    • for example, for RT-11 and its versions adapted in the USSR, the number of incompatible floppy disk formats in circulation exceeded a dozen. The most famous are those used in DVK MX, MY;
    • 320/360 KB floppy disks Iskra-1030/Iskra-1031 are also known - they were actually SS/QD floppy disks, but their boot sector was marked as DS/DD. As a result, the standard IBM PC disk drive could not read them without using special drivers (such as 800.com), and the Iskra-1030/Iskra-1031 disk drive, accordingly, could not read standard DS/DD floppy disks from the IBM PC.

    The pu_1700 driver also made it possible to provide formatting with shifting and interleaving of sectors - this accelerated sequential read-write operations, since the head, when moving to the next cylinder, ended up in front of the first sector. When using conventional formatting, when the first sector is always located behind the index hole (5¼″) or behind the area where the magnet attached to the motor (3½″) passes over the reed switch or Hall sensor, during the head step the beginning of the first sector manages to slip through, so the drive has to be extra turnover.

    Special BIOS expander drivers (800, pu_1700, vformat and a number of others) made it possible to format floppy disks with an arbitrary number of tracks and sectors. Since disk drives usually supported from one to 4 additional tracks, and also allowed, depending on design features, to format 1-4 sectors per track more than required by the standard, these drivers provided the appearance of such non-standard formats as 800 KB (80 tracks, 10 sectors) 840 KB (84 tracks, 10 sectors), etc. The maximum capacity consistently achieved by this method on 3½″ HD drives was 1700 KB. This technique was subsequently used in Microsoft's DMF floppy disk formats, which expanded the capacity of floppy disks to 1.68 MB by formatting floppy disks into 21 sectors (for example, in Windows 95 distributions), similar to IBM's XDF format, which was used in OS/2 distributions.

    Security of information

    One of the main problems associated with the use of floppy disks was their fragility. A magnetic disk could relatively easily become demagnetized from exposure to magnetized metal surfaces, natural magnets, or electromagnetic fields near high-frequency devices, which made storing information on floppy disks quite unreliable.

    The most vulnerable element of the floppy disk design was the tin or plastic casing that covered the floppy disk itself: its edges could bend, which led to the floppy disk getting stuck in the drive; the spring that returned the casing to its original position could move, as a result the floppy casing was separated from the case and never returned to starting position. The plastic case of the floppy disk itself did not provide sufficient protection for the floppy disk from mechanical damage (for example, when the floppy disk was dropped on the floor), which rendered the magnetic medium inoperable. Dust could get into the cracks between the floppy disk body and the casing.

    The massive displacement of floppy disks from everyday use began with the advent of rewritable CDs, and especially flash memory-based media, which have orders of magnitude greater capacity, higher exchange speeds, and a greater actual number of rewrite cycles and durability.

    Current situation

    External drive with USB interface

    Currently, the use of floppy disks has practically ceased. Since 2010, a large number of motherboards for desktop personal computers have been produced that do not contain a connector for connecting a disk drive at all. Built-in disk drives completely disappeared from laptops a few years earlier.

    Electronic keys when working with Bank-Client systems, providing an electronic digital signature of a document, previously distributed on floppy disks, are increasingly being produced in the form of a flash drive with a biometric protection function.

    When installing drivers for equipment (for example, a RAID array) during the installation of modern operating systems of the MS Windows family (Windows Vista, Windows Server 2008 R2, Windows 7), a flash drive can also be used.

    If there are no drives connected to the corresponding “classic” interface connector on the motherboard, you can use an external device that has a USB or SCSI interface.

    Floppinet

    The English name of the floppy disk “floppy disk” owes its appearance to the informal term “Floppinet”, which denotes the use of removable storage media (primarily floppy disks) for transferring files between computers. The prefix “-no” ironically compares this method of transmitting information with the semblance of a computer network at a time when the use of a “real” computer network is impossible for some reason. The term "floppy disk networks" is also sometimes used.

    Symbolism

    The image of a three-inch floppy disk is still used in GUI applications as an icon for buttons and menu items. Save.

    Notes

    Literature

    • Voroisky F. S. Informatics. New systematic explanatory dictionary-reference book. - 3rd ed. - M.: FIZMATLIT, 2003. - 760 p. - (Introduction to modern information and telecommunication technologies in terms and facts). - ISBN 5-9221-0426-8

    Links

    Half of the owners of personal computers do not even suspect that there is such a technology as magnetic recording, and the remaining half of users are sure that this recording, including the flexible magnetic disk media, has sunk into oblivion. However, if you delve deeper into this issue, you will find that manufacturing plants continue to produce magnetic disks and tapes. For what? Where is obsolete technology used? The focus of this article is magnetic recording on various storage media, technologies of the 20th century.

    Historical background

    Many media sources indicate that magnetic disks have replaced magnetic tapes as more compact media. This is not true. In fact, floppy disks are substitutes for punched cards. But they cannot be competitors of magnetic tapes for one simple reason - their capacities are incommensurable.

    The very first magnetic disk was released by IBM, which in 1971 showed the world a floppy disk with an eight-inch diameter and a disk drive capable of writing and reading data from a storage medium. The floppy disk capacity was one hundred kilobytes, which was quite enough for storage at that time. A few years later, a five-and-a-quarter-inch media appeared on the market, and in 1981, the world-famous Sony concern introduced a 3.5-inch floppy disk to the market. At first, the floppy disk capacity was 720 kilobytes. But later, thanks to an increase in recording density, media with capacities of 1.44 MB and 2.88 MB appeared.

    And if we talk about magnetic recording in general

    Information can be transferred not only to a flexible magnetic disk, but also to film and hard media. The principle of recording on soft media is known to everyone. Recording on magnetic media is carried out sequentially. Accordingly, reading should occur in the reverse way. This is a huge disadvantage. But there are also advantages, because, thanks to the high recording density, one medium can store a large amount of information. An example of such devices are streamers. But writing to a hard drive allows you to access data much faster thanks to only two mechanisms - a rotating spindle, which spins the surface of the disk with data, and a moving head that reads information.

    At the pinnacle of glory

    If the capacity of flexible magnetic disks is limited by the surface area of ​​the media, then the soft film can be wound on a reel half a kilometer long. What is actively being done by manufacturing plants. In the 21st century, interest in streamers not only has not faded, but, on the contrary, has grown. Manufacturers are developing and improving new technologies for these devices. One such small medium with magnetic tape can record from 0.5 to 4 terabytes of information. Tape drives are widely used in large corporations to store database archives. In film studios, films sent to the archive are placed on media. Administrators of large Internet resources store backup copies of all important sites on streamer cartridges. And all this thanks to several devices that have not yet been surpassed by any technology.

    1. Huge recording density with small media sizes.
    2. Low power consumption compared to similar high-capacity media.
    3. High reliability and stability.

    A triumph that never came

    As you know, a monopoly on the market makes it possible to set your own prices, but you shouldn’t expect any grandiose development from products that have no analogues. It turned out that the little-known company Iomega Zip entered the IT technology market at the end of the 20th century with an innovation that had no analogues in the world. A disk drive and 3.5-inch floppy disk drives for it were introduced, allowing you to record data of 100, 250 and 750 megabytes in size on one medium. The price of such a device was so high that not only ordinary users, but also huge corporations chose to refrain from purchasing it. Due to low demand, the manufacturer was not immediately aware that a damaged floppy disk was damaging the drive. The development of technology was prevented by laser recording, information about which was not classified from other manufacturers.

    Device and design of a flexible information storage device

    The word “floppy disk” was derived from the English word diskette, which in turn became an abbreviation for floppy disk. Translated, floppy means “flexible”. The result is literally a flexible magnetic disk. What is it called - we figured it out. It remains to understand its design. The principle of operation comes down to the presence of a marked area on the surface of the media and a head capable of recording and reading, which is located in the drive. In addition, the drive contains a special shaft that rotates the flexible disk. Access to the surface of the magnetic medium is carried out through a special floppy disk window, the length of which allows the head to move along the entire radius of the disk surface. To protect the magnetic surface, the window is protected by a special shutter, which opens mechanically when a floppy disk is inserted into the drive. The absence of a curtain does not affect the performance of the device, but may lead to surface contamination, since the structure of the magnetic disk is capable of attracting dust.

    Operating principle and small oddities

    The principle of recording a magnetic layer on a flexible medium is quite interesting. In addition to the recording head, the device has two monitoring heads, which are located behind the main one and offset to the sides from each other. Their task is to protect the overwriting of information on tracks located next to the one being recorded. If the writing magnetic head has affected nearby information with a strong impulse, the control head cancels this change. It looks quite strange from the outside. After all, if you take a hard magnetic disk for comparison, you can see that it has only one head for each surface of the disk. The fact is that the write head built into the floppy disk drive does not have high-frequency bias due to the complexity of its design. That's why such a simple and inexpensive solution was found.

    Displacement of technology from the IT market

    Just a few years ago, when purchasing a personal computer, floppy disk drives were a mandatory attribute in the system unit. But interest in the device among users quickly faded. And now the presence of a 3.5-inch disk drive indicates that the PC owner has a weak computer. There are many reasons for the disappearance of flexible drives from the market. Here are a few of them.

    1. Small recording capacity. In fact, you can't even record one song on a disc.
    2. Unreliability of information storage. A floppy disk becomes demagnetized when exposed to large magnetic fields. For example, a one-time trip on a trolleybus or metro can format a floppy disk.
    3. Even the nonsense launched in the media by SSD drive manufacturers about the dangerous effects of a hard magnetic drive and all drives with this technology has yielded results.

    Safety first

    This may seem strange, but the floppy disk is very popular in US government agencies, including the presidential administration. The magnetic disk is designed to authorize users when logging into the control system. While the whole world has switched to using USB dongles, America is using technology from the last century. This approach is explained by the fact that very often, having taken possession of a USB key, a fraudster gains access to sensitive information. Many feature films reveal this problem in the plot.

    With magnetic disks everything is different. The advantages and disadvantages of floppy disks play a big role at the same time. In addition to low cost, small size, the ability to rewrite, quickly read, and detect the media by any operating system without drivers, the advantages include easy removal of the media. Naturally, without the possibility of recovery. This is the main advantage of a floppy disk. In case of an unforeseen situation, the media can be easily destroyed along with important information. Obtaining a new key will not be difficult; to do this, just contact the security service of your structure.

    Educational system

    But Russian children know more about floppy disks than their parents. After all, most Russian schools still have personal computers with a built-in floppy drive. And thanks to school computer science programs, which have not undergone any significant changes over several years, all students also receive practical skills in using magnetic disks. After all, the volume of a floppy disk allows you to store two entry-level programming languages ​​on one medium, along with completed assignments for the entire year of study. And without basic knowledge of the programming languages ​​BASIC and Turbo Pascal, not a single technical university will open its doors to an applicant.

    System Administrator Tool

    It is a floppy magnetic disk, and not a USB drive, that a system administrator uses to update the firmware of system devices, servers and control systems. In addition, the floppy disk is used to transfer authorization keys, system equipment settings, and configure controllers and arrays. Not to mention the fact that banal damage to the BIOS of any personal computer can be corrected either using a floppy disk or a programmer. There are several reasons for the active use of a floppy magnetic disk.

    1. To read data from the media, a disk drive built into the device is used, which does not require drivers to operate. No detection or configuration.
    2. There has been nothing on the market cheaper than a disk drive and media with the same fault tolerance for a decade now.
    3. There is no need for large amounts of information - 1.44 MB for Unix-based systems is enough to save the necessary data.

    About entertainment for programmers

    Due to the fact that the structure of the magnetic disk is a spiral, the read head has to constantly move along the surface of the media. At the same time, which moves this head, creates a specific sound in the drive, which is very clearly audible in a large room. This is exactly what programmers have been using for many years. Using one of the low-level programming languages ​​(Turbo Pascal or C+), with the help of special commands, you can achieve stepper control using sequential and short-term computer access to different data recorded throughout the disk. Many people manage to reproduce a very complex melody using several disk drives, each of which acts as one instrument. You can learn more about this type of entertainment in the media.

    In conclusion

    There is only one conclusion: a flexible magnetic disk, like a hard disk, is too early to be written off. Having worked in the IT field for about 25 years, floppy disks and hard drives remain in demand in many areas of human activity. Along with the disadvantages that are attributed to these storage media, they also have many advantages that can be seen when trying to get to know the technology better. Naturally, you should not pay attention to the nonsense of narrow-minded people who talk about the dangerous effects of a hard magnetic disk, and of magnetic recording in general. All equipment massively presented on the market undergoes more than one certification before hitting the counter.

    A floppy disk is a portable magnetic storage medium used for repeated recording and storage of relatively small data. This type of media was especially common in the 1970s - late 1990s. Instead of the term “floppy disk”, the abbreviation FMD is sometimes used - “floppy magnetic disk” (accordingly, a device for working with floppy disks is called NGMD - “floppy magnetic disk drive”).
    Typically, a floppy disk is a flexible plastic plate coated with a ferromagnetic layer, hence the English name “floppy disk”. This plate is placed in a plastic case that protects the magnetic layer from physical damage. The shell can be flexible or rigid. Writing and reading floppy disks is carried out using a special device - a floppy disk drive (floppy drive).
    Floppy disks typically have a write-protect feature that allows read-only access to the data.

    Story
    • 1971 - The first floppy disk with a diameter of 200 mm (8″) and a corresponding floppy drive was introduced by IBM. The invention itself is usually credited to Alan Shugart, who worked for IBM in the late 1960s.
    • 1973 - Alan Shugert founded his own firm, Shugart Associates.
    • 1976 - Alan Shugert developed the 5.25″ floppy disk.
    • 1981 - Sony introduces the 3.5″ (90 mm) floppy disk to the market. In the first version, the volume is 720 kilobytes (9 sectors). The later version has a capacity of 1440 kilobytes or 1.40 megabytes (18 sectors). It is this type of floppy disk that becomes the standard (after IBM uses it in its IBM PC).
    • Later, the so-called ED floppy disks (from the English Extended Density - “extended density”) appeared, which had a volume of 2880 kilobytes (36 sectors), which never became widespread.
    Formats
    Chronology of the emergence of floppy disk formats
    Format Year of origin Volume in kilobytes
    8 1971 80
    8″ 1973 256
    8″ 1974 800
    8″ double density 1975 1000
    5.25″ 1976 110
    5.25″ double density 1978 360
    5.25″ quad density 1982 720
    5.25″ high density 1984 1200
    3″ 1982 360
    3″ double density 1984 720
    3.5″ dual density 1984 720
    2″ 1985 720?
    3.5″ high density 1987 1440
    3.5″ extended density 1991 2880

    It should be noted that the actual capacity of floppy disks depended on how they were formatted. Since, except for the earliest models, virtually all floppy disks did not contain rigidly formed tracks, the road was open for experiments in the field of more efficient use of the floppy disk for system programmers. The result was the emergence of many incompatible floppy disk formats, even under the same operating systems. For example, for RT-11 and its versions adapted in the USSR, the number of incompatible floppy disk formats in circulation exceeded a dozen. (The most famous are MX, MY used in DCK).
    Additional confusion was caused by the fact that Apple used disk drives in its Macintosh computers that used a different principle of magnetic recording encoding than on the IBM PC. As a result, despite the use of identical floppy disks, transferring information between platforms on floppy disks was not possible until Apple introduced high-density SuperDrive disk drives that operated in both modes.
    The "standard" IBM PC floppy disk formats differed in the size of the disk, the number of sectors per track, the number of sides used (SS stands for single-sided floppy, DS stands for double-sided), and the type (density) of the floppy drive. The drive type was marked as SD - single density, DD - double density, QD - quadruple density (used in clones such as Robotron-1910 - 5.25″ floppy disk 720 K, Amstrad PC, PC Neuron - 5.25″ floppy disk 640 K , HD - high density (differed from QD in the increased number of sectors), ED - extended density.

    8-inch drives have long been included in the BIOS and supported by MS-DOS, but there is no clear information on whether they were shipped to consumers (they may have been shipped to businesses and organizations and not sold to individuals). In addition to the above format variations, there were a number of improvements and deviations from the standard floppy disk format.
    The most famous - 320/360 KB floppy disks Iskra-1030/Iskra-1031 - were actually SS/QD floppy disks, but their boot sector was marked as DS/DD. As a result, the standard IBM PC disk drive could not read them without using special drivers (800.com), and the Iskra-1030/Iskra-1031 disk drive, accordingly, could not read standard DS/DD floppy disks from the IBM PC.
    Special driver-extenders BIOS 800, pu_1700 and a number of others made it possible to format floppy disks with an arbitrary number of tracks and sectors. Since disk drives usually supported from one to 4 additional tracks, and also allowed, depending on design features, to format 1-4 sectors per track more than required by the standard, these drivers provided the appearance of such non-standard formats as 800 KB (80 tracks, 10 sectors) 840 KB (84 tracks, 10 sectors), etc. The maximum capacity consistently achieved by this method on 3.5″ HD drives was 1700 KB.
    This technique was subsequently used in Windows 98, as well as Microsoft's DMF floppy disk format, which expanded the capacity of floppy disks to 1.68 MB by formatting floppy disks into 21 sectors in a similar IBM XDF format. XDF was used in OS/2 distributions, and DMF was used in distributions of various Microsoft software products.
    The pu_1700 driver also made it possible to provide formatting with shifting and interleaving of sectors - this accelerated sequential read-write operations, but did not allow compatibility even with the standard number of sectors, sides and tracks. Finally, a fairly common modification of the format of 3.5″ floppy disks is their formatting to 1.2 MB (with a reduced number of sectors). This feature can usually be enabled in the BIOS of modern computers. This use of 3.5″ is typical for Japan and South Africa. As a side effect, activating this BIOS setting usually makes it possible to read floppies formatted with 800-type drivers.
    Additional (non-standard) tracks and sectors sometimes contained copy protection data for proprietary floppy disks. Standard programs such as diskcopy did not transfer these sectors when copying. The unformatted capacity of a 3.5″ floppy disk, determined by the recording density and storage area, is 2 MB.
    The height of a 5.25″ floppy drive is 1 U. All CD drives, including Blu-ray drives, are the same width and height as a 5.25″ floppy drive (this does not apply to laptop drives). The width of the 5.25″ drive is almost equal to three times its height. This was sometimes used by computer case manufacturers, where three devices placed in a square “basket” could be reoriented with it from a horizontal to a vertical arrangement.

    – Igor (Administrator)

    A floppy disk or floppy magnetic disk (FMD) is a magnetic device for storing data, with the ability to repeatedly read and write information. It is a square structure, inside of which there is a plastic disk with a magnetic surface. The box itself, inside of which this disk is located, is made of either hard or soft plastic. Reading and writing data is performed using a special drive, which uses a magnetic head for these actions (in some ways a prototype of today's hard drives).

    Previously, you could find references to “floppy-disk” in various system errors. If you have seen this, then we are talking about floppy disks. The first floppy disks were as large as 8 inches, but gradually reached 3.5 inches (there are also 2-inch options). The first variations made it possible to save as much as 80 KB of data. The last common option allowed you to save 1.44 MB. At one time, each of these volumes represented quite a lot of space.

    Some of the notable features of this medium include:

    1. Floppy disks had to be periodically formatted in order to preserve the properties of the magnetic surface of the disk. They were repaired using the same method.

    2. Some floppy disks have write protection - a small hole in the box. If this hole is not closed, then recording cannot be performed. This point was often confused, as there was some illogicality.

    3. Despite the fact that the disk is called flexible, it cannot be bent. However, you can’t touch the disk itself or anything else with your hands.

    4. The floppy disk should not be removed while reading or writing, as in this case the data could easily be damaged. When reading and writing, it was clearly audible how the drive moved the head.

    5. Since information is stored on a magnetic disk, the floppy disk should not be stored near magnets or devices that create a magnetic field. In a sense, it is easy to quickly erase information from floppy disks, all you need is a strong magnet.

    6. Many floppy disks usually came with paper stickers or they were already pasted on, so you could write what was stored on a given floppy disk.

    7. Floppy disks were actively used for 40 years - quite a significant period.

    8. At one time, it was floppy disks that served as a hard drive, since computers did not have their own data storage device for permanent storage.

    9. Previously, a lot of programs and toys could fit on floppy disks (for example, in the era of 286 - 486 computers).

    Today, it is quite difficult to find a floppy disk, since it has practically gone out of industrial production. The problem was the volume of data. The fact is that the maximum size of data that can be saved on such a medium is 2.88 MB, which is very small given today's data volumes.

    Despite the end of the floppy disk era, 3.5 floppy disks are still used in everyday life.

    Let's take a closer look at where they can be found, what's special about them and why the floppy disk is still one of the most popular means of transmitting secret information.

    Contents:

    Basic concepts and history of use

    Floppy disk is a physical storage medium with which data can be moved, erased, or rewritten many times.

    In simple words, this is a simplified version of modern flash drives and disk drives.

    The floppy disk was the first to appear.

    Externally, the device has a rectangular shape and a plastic case. A ferrimagnetic layer is applied on top, with the help of which the floppy drive reads information. You can't read a floppy disk using . To do this, you will need a special floppy drive.

    Today it can only be found in older desktop computers. Typically the drive is located at the bottom of the case and has the following form:

    The first floppy disk was created in 1967 by Alan Shugart- at that time one of the leading specialists at IBM. Before 1076, Shugart created and developed his own company, which began supplying storage drives to computer system developers. This began the era of using floppy disks. The most popular floppy disk format was developed by Sony in 1981. A drive with a diameter of 3.5 inches can still be found in stores. Also, it is this type of floppy disk that is recognizable. In most programs, a key with a 3.5-inch floppy disk icon means saving actions.

    Floppy disks were common among users from the 70s to the 90s of the last century.

    With the invention of optical disks, the popularity of floppy disks gradually began to decline. As you know, optical discs are already being removed from use today.

    Many manufacturers of laptops and personal computers have completely abandoned the use of disk drives.

    Despite this, floppy disks are still produced and sold.

    With the onset of the 2010s, all global IT corporations began to abandon the production of floppy disks.

    For example, in 2011 Sony announced that it would completely stop creating and selling 3.5-inch floppy disks.

    Now they can only be manufactured by order of the government.

    Other cases of failure of floppy disks:

    • 2014– Toshiba announced the closure of its disk manufacturing plant. That same year, the plant was converted into a huge organic vegetable farm;
    • 2015– developers from Microsoft decided not to create support for floppy disks in . This OS does not work with floppy disks and it will be impossible to connect an external drive. The system simply “will not see” the device;
    • 2016- The Pentagon drew up a modernization plan, one of the goals of which was to abandon the use of floppy disks. The plan is scheduled to be completed by the end of 2018.

    Floppy disk formats

    Types of floppy disks are divided depending on the diameter of the drive. Over the entire period of floppy disk distribution The following formats existed:

    • 8-inch;

    The first type of floppy disk that became widespread among PC users was the eight-inch drive.

    Externally, it has a rectangular shape and is made of polymer materials.

    The magnetic mechanism itself is located inside a plastic case. Inside there is a special recess with which the drive reads information from. After the drive starts up, the device reads the location of the first track. This is how the process of “decrypting” information from the floppy disk begins.

    An eight-inch floppy disk can have a capacity of 80 KB, 256 KB, or 800 KB. Over time, such a volume of information even became insufficient, so the development of floppy disks with a larger volume began.

    • 5.25 inches;

    This generation of floppy disks is practically no different in appearance from eight-inch drives.

    The only difference- improved index holes for data reading.

    Thanks to the use of new technology for creating material for the case, the disc was preserved for a longer time and was resistant to scratches and falls from low heights.

    These types of floppy disks were either single-sided or double-sided. To start using the additional side, you just had to turn the drive over. On single-sided models, this action could thin out the drive.

    5.25-inch floppy disks could store 110 KB, 360 KB, 720 KB, or 1200 KB of information.

    The production of such floppy disks ended in the early 2000s.

    • 3.5 inches;

    The 3.5-inch floppy disk is the most popular floppy drive option.

    Externally, it differs from previous generations with an even more durable body, as well as a completely solid surface.

    In this type of floppy disk, it became possible to install .

    it can be configured by the floppy disk user before the first recording of information to removable media.

    The capacity of a 3.5 floppy disk is determined by the square holes in the lower right corner of the device. One square - capacity 720 KB, two - 1.44 MB and three - 2.88 MB.

    Despite all the disadvantages of using floppy disks, namely low capacity and sensitivity to the influence of magnetic fields, the 3.5 floppy disk was popular even after the release of optical disks.

    All because of the convenience of data transfer and the cheap cost of floppy disks and disk drives.

    Iomega Zip.

    This type of drive became intermediate between the eras of floppy disks and optical disks.

    Externally, Iomega looks like a floppy disk, but the device's body is flexible.

    Due to its high cost and lack of manufacturer interest in such a floppy disk, Iomega never became more popular than standard 3.5-inch floppy disks.

    Iomega capacity reached 750 MB.

    Also, the device was distinguished by high speed of reading and processing data.

    Why is a floppy disk needed today?

    Despite the widespread belief that the era of floppy disks is over, you can still encounter floppy disks in many areas.

    In the CIS, floppy disks are still used in government agencies to record citizens' data.

    For example, tax departments store data about taxpayers in the form of floppy disks. The use of such an outdated drive is explained by the fact that they still store records from 10 or even 20 years ago. Information does not transfer to newer devices due to lack of funding or lack of new computers.

    Also, 3.5-inch floppy disks are used in schools.

    Floppy drives are still common in any computer science classroom.

    Students bring their homework and hand it in to the teacher. This property is not typical for all, but for most schools. This is explained by outdated equipment.

    Floppy disks 3.5 and Pentagon

    One of the most interesting uses of floppy disks in the modern world is the Pentagon.

    The most high-tech and popular state-level security center still works with ordinary floppy disks.

    Of course, Pentagon employees do not store absolutely all information on floppy disks.

    According to the organization's 2015 official report, floppy disks work as an additional method of protecting information.

    They store data on nuclear weapons and other secret information.

    To read and process data, the Pentagon uses old models of computers that do not have and operate without being connected to any networks.

    This approach eliminates the possibility of an “over-the-air” hacker attack, which the Pentagon has faced countless times.

    According to the US Department of Defense plan, floppy disks should be phased out at the Pentagon by the end of 2018. It is reported that to increase the level of security of secret data, it is planned to introduce ultra-resistant algorithms and constant monitoring without using the Internet.

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