(MO), which were a hard polymer disk, reading from which was performed by a laser, and writing - using the combined action of a laser (to heat a surface area) and a stationary magnet (to reverse the magnetization of the information layer). They are not completely magnetic, although they use cartridges that are shaped like floppy disks.

History

Floppy disk device 3½ ″

Iomega Zip

By the mid-90s, even a 2.88 MB floppy disk capacity was no longer enough. Several formats pretended to replace the 3.5 ″ floppy disk, among which the Iomega Zip floppy disks were the most popular. Just like the 3.5 ″ floppy disk, the Iomega Zip media was a soft polymer disk covered with a ferromagnetic layer and enclosed in a hard case with a protective shutter. Unlike the 3.5 ″ diskette, 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 for 100, 250, and by the end of the format's existence - and 750 MB. In addition to the larger capacity, Zip drives provided more reliable data storage and faster read and write speeds than 3.5 ″. However, they were never able to displace three-inch floppy disks due to the high price of both floppy drives and floppy disks, as well as because of the unpleasant feature of the drives, when a diskette with mechanical damage to the disk would disable the drive, which, in turn, could spoil the inserted one. into it after that a floppy disk.

Formats

Chronology 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 ″ expanded density		2880

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

Diskette formats in IBM hardware

The "standard" formats of IBM PC floppy disks 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 (recording density) of the drive - the type of drive was marked:

• SD (English Single Density, single density, first appeared in the IBM System 3740),
• DD (English Double Density, double density, first appeared in IBM System 34),
• QD (English Quadruple Density, quadruple density, was used in domestic clones of Robotron-1910 - 5¼ "floppy disk 720 K, Amstrad PC, Neuron I9.66 - 5¼" floppy disk 640 K),
• HD (English High Density, high density, differed from QD by an increased number of sectors),
• ED (Extra High Density, extra high density).

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

Working density of drives and capacity of floppy disks in kilobytes

Magnetic coating parameter	5¼ ″			3½ ″
	Double Density (DD)	Quadruple Density (QD)	High density (HD)	Double Density (DD)	High density (HD)	Extra 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 per inch	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 the IBM PC and compatible PCs

Disc diameter, ″	5¼ ″					3½ ″
Disk capacity, KB	1200	360	320	180	160	2 880	1 440	720
MS-DOS Media Description Byte	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)	7	2	1	2	1	9	9	3
FAT quantity	2	2	2	2	2	2	2	2
Root directory length in sectors	14	7	7	4	4	15	14	7
Maximum number of items in the root directory	224	112	112	64	64	240	224	112
Total number of sectors on 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

The first (more precisely, the 0th) is the lower head. In single-sided drives, only the bottom head is actually used, and the top head is replaced with a felt pad. At the same time, it was possible to use double-sided floppy disks on single-sided drives, formatting each side separately and turning it over if necessary, but in order to take advantage of this opportunity, a second index window had to be cut in a plastic envelope of an 8-inch floppy disk, symmetrically to the first.

All floppy drives have a spindle speed of 300 rpm, with the exception of a 5¼ "high density floppy disk drive that spins at 360 min −1.

Floppy disk formats in other foreign equipment

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

A fairly common modification of the 3½ ″ floppy format is to format them at 1.2 MB (with a reduced number of sectors). This feature can usually be enabled in the BIOS modern computers... This use of 3½ ″ is typical for Japan and South Africa. As a side effect, activating this BIOS setting will usually read floppies formatted with drivers like 800.com.

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 diskette formats in circulation exceeded ten. The most famous are MX, MY used in DVK;
• also known are 320/360-kilobyte Iskra-1030 / Iskra-1031 floppy disks - in fact, they were SS / QD diskettes, but their boot sector was marked as DS / DD. As a result, a standard IBM PC drive could not read them without using special drivers (such as 800.com), and the Iskra-1030 / Iskra-1031 drive, respectively, could not read standard DS / DD diskettes from IBM PC;
• in computers of the ZX-Spectrum platform, 5.25 ″ and 3.5 ″ floppy disks were used, but their own unique TR-DOS format was used - 16 sectors per track, each sector of 256 bytes (instead of 512 bytes standard for the IBM PC). Both double-sided and single-sided floppy disks and floppy drives were supported. As a result, the data volume was 640 and 320 KB, respectively. The format only supports the root directory, which occupies only the first 8 sectors of the 0th track, the 9th sector contains system information about the floppy disk - type (TR-DOS or not), one or two-sided disk, the total number of files and the number of free sectors ( not bytes, namely sectors). Sectors 10 to 16 on track 0 are not used. All files are located only sequentially - the TR-DOS format has no idea about fragmentation, and the maximum file size is 64 KB. After deleting a file inside the occupied space, free sectors appear, which can no longer be occupied until the ″ Move ″ disk compacting command is executed. On IBM PC compatible computers, such floppy disks can be read and written only with the help of special programs, for example, ZX Spectrum Navigator v.1.14 or ZXDStudio.

In addition to the TR-DOS format, arbitrary disk formats were often used in ZX-Spectrum compatible computers. Some ezines and games on the whole floppy disk used their own format, which is not compatible with anything at all. They could use sectors of 512 bytes, and even 1024 bytes, and often combined different sizes of sectors on one track, for example, 256 and 1024 bytes, and just different formats were used for different tracks. For example, this was done in the electronic magazine ZX-Format. Moreover, from issue number to issue, this magazine constantly changed the format of floppy disk tracks. This was done for two purposes: First, to increase the amount of data on a floppy disk, and secondly, to protect floppy disks from pirated copying. Such floppy disks on ZX-Spectrum compatible computers of users could only be read, run a magazine or a game from them, but nothing could be copied. To copy such floppy disks, for each individual issue of the ZX-Format magazine or game, you had to write your own individual formatter and copier in assembler, having previously hacked the rest of the protection steps. Of course, such floppy disks cannot be read and copied on IBM PC compatible computers. Once I came across a generally unique format - except for the non-standard size of sectors on the track (5 sectors of 1024 bytes), the numbers of all 5 sectors were the same. To run the software from such a floppy disk, a special bootloader was used, located on the first track after the directory with the standard TR-DOS format for the ZX-Spectrum. In ZX-Spectrum compatible computers, both 5.25 ″ and 3.5 ″ floppy disks were used in the same way, the format does not depend on the size of the floppy disk, nor on the density supported by it. But to use 3.5 ″ high density HD floppy disks, you had to tape the side density window with tape. 5.25 ″ HD floppy disks can be used in the ZX-Spectrum only if you use a drive that also supports HD density, but the drive must be jumpered to SD format (720 KB).

The pu_1700 driver also made it possible to provide shift and sector interleaving formatting - this accelerated sequential read-write operations, since the head was in front of the first sector when moving to the next cylinder. When using normal formatting, when the first sector is always located behind the index hole (5¼ ″) or behind the zone of passage above the reed switch or Hall sensor of the magnet attached to the motor (3½ ″), during the head step, the beginning of the first sector has time to slip through, so the drive has to make extra turnover.

Special BIOS extender drivers (800, pu_1700, vformat, and others) allowed formatting floppy disks with an arbitrary number of tracks and sectors. Since floppy drives usually supported from one to four additional tracks, and also allowed, depending on design features, formatting 1-4 sectors per track more than 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 with this method on 3½ ″ HD drives was 1700 KB. This technique was subsequently used in DMF floppy formats

The other one uses (used) special external media (floppy disks and disks). Naturally, technologies do not stand still and more and more new devices are invented, or the old ones are being improved in terms of data transfer speed and memory capacity.

In this article, we will look at how and when the first disks, floppy disks appeared, as well as their main characteristics and features.

Floppy disk 8 "(inches) - In 1971, the 8-inch floppy disk and disk drive for it was first introduced. This diskette was released by IBM. The disc itself consists of a magnetically coated polymer material in a plastic package. Depending on the number of sectors, such floppy disks had different sizes and were subdivided into 80 kb, 256 kb and 800 kb.

5.25 "floppy disk - In 1976, Shugart Associates designed and manufactured the 5.25" floppy disk drive and floppy disks. 5-inch floppy disks quickly gained popularity and superseded their predecessors. This floppy disk was not much different from the 8-inch parents, except that it was smaller in size, the plastic cover was stiffer, and the edges of the drive hole were reinforced with a plastic ring. Such disks (depending on the format) contained 110, 360, 720 or 1200 kilobytes of data.

3.5 ”Floppy Disk - In 1981, Sony introduced the 3.5” floppy disk for the first time. This diskette was already specifically different from the previous ones. The floppy disk was covered by a hard case, in the center of the floppy disk there was a metal sleeve, which allowed it to be correctly positioned in the disk drive. Floppy disks were mostly 1.44 MB, but there were 720 kb, as well as 2.88 MB. This type of floppy disk has survived the most on the market and is even still used in many structures and institutions.

Iomega ZIP - In the mid-90s, 3.5-inch floppy disks were replaced by ZIP disks. Outwardly, they resembled 3.5 ”floppy disks, but were slightly thicker. They were supposed to replace the previous generation, as 1.44 MB was no longer enough to store data. ZIP disks were produced in sizes of 100 MB and 250 MB (At sunset, even 750 MB were met). But the disks did not gain popularity, since the drives and the disks themselves were very expensive, so people remained faithful to their 3.5 ”comrades.

COMPACT DISCS (CD-ROM / CD-RW / DVD-ROM / DVD + R / DWD-R / DVDRWBlueRay)

For the first time a CD was developed by Sony already in 1979, and in 1982 mass production of these discs began. Initially, they wanted to use CDs only for audio recordings, but later they began to store all digital data on them. The vice-president of Sony insisted that Beethoven's Ninth Symphony, which took 74 minutes (under the direction of Wilhelm Furtwängler), could fully fit on the disc, then any classical work would fit on such a disc. If we take the amount of data, then such a floppy disk contained 650 MB. Starting somewhere in 2000, 700 MB (80 minutes) discs began to be produced.

The disc itself consists of polycarbonate coated with a thin layer of metal (aluminum, silver), which in turn is covered with a thin layer of varnish.

In 1988, the format appears CD-R (Recordable - Recordable). This is the same CD, but empty, in other words "Blank". Any information could be recorded on it, but then it was impossible to delete it from the disk.

In 1997, the format appears CD-RW (ReWritable - Rewritable). This is the same CD-R, only now the data from it could be erased and others written.

DVD (Digital Video Disk - Digital Video Disk) - the disk had the same dimensions as a regular CD and externally was no different, but had a more dense structure. The first discs appeared in Japan in 1996, and their volume was 1.46 GB (DVD-1), which was twice as much as regular CDs. The most popular are the 4.7 GB DVD (DVD-5). The maximum DVD capacity is 17.08 GB (DVD-18).

DVD-R - The first DVD-R was released in 1997 and was priced at $ 50 and a volume of 3.95 GB. Many people ask the question: how is DVD-R different from DVD + R? Everything is very simple. You cannot erase information from both of them, but you can write to "+" before, and you cannot write to "-".

DVD-RAM - Rewritable discs, but unlike DVD-RW, they can be rewritten at least 100,000 times (the usual ones are designed for 1000). Also, information is read much faster and writing to it occurs as on a removable hard disk, i.e. without additional software. Of course, such a disc is more expensive, and even not all players can read it.

BD (BlueRay Disc) - a disc with a higher density than DVD. Mainly designed to record high definition movies there. The disc was first introduced to the general public in 2006. Its volume is 25 GB (single layer) and 50 GB (dual layer). Mini BD 7.8 GB are also available.

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 the users are sure that this recording, including the medium, is flexible. magnetic disk, has sunk into oblivion. However, if you delve into this issue, you can find that manufacturers continue to produce magnetic disks and tapes. For what? Where is obsolete technology used? The focus of this article is magnetic recording on various media, technologies of the 20th century.

Historical reference

Many media sources indicate that magnetic disks have replaced magnetic tapes as more compact media. It is not true. In fact, floppy disks are substitutes for punched cards. And they cannot compete with magnetic tapes for one simple reason - their capacities are incommensurable.

The release of the very first magnetic disk was produced by IBM, which in 1971 showed the world an eight-inch floppy disk 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 medium 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 was 720 kilobytes. But later, thanks to an increase in the recording density, media with a capacity of 1.44 MB and 2.88 MB appeared.

And speaking of 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 operation of recording on a soft medium is known to everyone. Recording on magnetic media is carried out sequentially. Correspondingly, the reading should proceed in the opposite way. This is for and is a huge disadvantage. But there are also advantages, because, due to the high recording density, one medium can store a large amount of information. Streamers are an example of such devices. But writing to hard media allows you to access data much faster thanks to only two mechanisms - a rotating spindle that spins the surface of the data disk, and a moving head reading information.

At the height of glory

If the capacity of flexible magnetic disks is limited by the surface area of \u200b\u200bthe medium, then the soft film can be wound on a reel about half a kilometer long. What is actively being done by manufacturers. In the 21st century, interest in streamers has not only not faded away, but, on the contrary, has grown. Manufacturers develop and improve new technologies for these devices. One such small medium with magnetic tape can store from 0.5 to 4 terabytes of information. Streamers are widely used in large corporations to store database archives. Films sent to the archive are placed on media in film studios. Administrators of large Internet resources store backup copies of all important sites on tape drive 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 comparable high-capacity media.
3. High reliability and stability of work.

A triumph that never happened

As you know, a monopoly on the market makes it possible to set your own prices, but you should not 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 floppy drive and 3.5-inch floppy disk drives to it were presented, allowing you to write data of 100, 250 and 750 megabytes on one medium. The price of such a device was so overpriced that not only ordinary users, but also huge corporations chose to refrain from buying. Due to low demand, the manufacturer was not immediately able to find out that a damaged floppy disk destroys the drive. The development of technology was hampered by laser recording, information about which was not classified from other manufacturers.

The device and design of a flexible storage device

The word "diskette" is derived from the English word diskette, which, in turn, became an abbreviation for floppy disk. In translation, floppy means "flexible". As a result, literally - a flexible magnetic disk. What is the name - figured out. It remains to understand its construction. The principle of operation is reduced to the presence of a marked area on the surface of the carrier and a head capable of writing and reading, which is located in the drive. In addition, the drive contains a special shaft that rotates the flexible disk. The access to the surface of the magnetic medium is carried out through a special window of the floppy disk, 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 that opens mechanically when a floppy disk is inserted into the drive. The absence of a shutter does not affect the device's performance, but it can lead to surface contamination, since the structure of the magnetic disk is capable of attracting dust to itself.

The principle of operation and small oddities

The principle of recording a magnetic layer on a flexible medium is quite interesting. In addition to the recording, the device has two control heads, which are located behind the main one and are offset to the sides from each other. Their task is to protect the overwriting of information on tracks adjacent to the recorded one. If the magnetic recording head has a strong impulse to touch the information located nearby, then the monitoring head cancels this change. It looks rather 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 disk surface. The fact is that the writing head built into the floppy disk drive does not have high frequency bias due to the complexity of its design. Therefore, such a simple and inexpensive solution was found.

Driving technology out of the IT market

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

1. Small recording capacity. In fact, even one song cannot be recorded on a disc.
2. Unreliable storage of information. The diskette is demagnetized by strong magnetic fields. For example, a one-time trip on a trolleybus or subway can format a floppy disk.
3. Even the stupidity launched in the media by manufacturers of SSD-drives about the dangerous effects of a hard magnetic disk and all drives with this technology gave its result.

Safety first

It may seem strange, but the floppy disk is very popular in the US government, including the presidential administration. The magnetic disk is designed to authorize users when entering the management 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 seized a USB key, a fraudster gains access to classified information. Quite a few feature films reveal this problem in the plot.

It's different with magnetic disks. Both the advantages and disadvantages of floppy disks play an important role. In addition to low cost, small size, rewritability, fast reading, media detection by any operating system without drivers, the advantage is easy disabling of the media. Naturally, without the possibility of recovery. This is the main advantage of the floppy disk. In the event of an unforeseen situation, the carrier can be easily destroyed along with important information. It will not be difficult to get a new key, for this it is enough to contact the security service of your structure.

Education 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 disk drive on their balance sheets. And thanks to school computer science programs, which have not undergone any significant changes over several years, all students receive practical skills in using magnetic disks. After all, the volume of a floppy disk allows you to store two entry-level programming languages \u200b\u200bon one medium, along with the tasks completed for the entire year of study. And without basic knowledge of the BASIC and Turbo Pascal programming languages, no technical university will open its doors to the applicant.

System Administrator Tool

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

1. To read data from the medium, the drive built into the device is used, which does not need drivers for operation. No detections or tweaks.
2. There has been nothing cheaper than a floppy drive and media with the same fault tolerance on the market for a decade.
3. No need for large amounts of information - 1.44 MB for Unix-based systems is enough to store 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 carrier. At the same time, who moves this head, creates a specific sound in the drive, which is very well heard in a large room. This is what programmers have been using for many years. Using one of the low-level programming languages \u200b\u200b(Turbo Pascal or C +), with the help of special commands, it is possible to achieve control of the stepper with the help of sequential and short-term computer calls to various data recorded throughout the disk. Many people manage to reproduce a very complex melody using multiple drives, each of which acts as one instrument. In the media, you can learn more about this type of entertainment.

Finally

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

A little more than forty years ago, the first computer floppy disks appeared, and thirty years ago the well-known 3.5-inch floppy disks appeared. And they are still being produced! Nowadays, flash drives and external hard drives are used to transfer information, and all previous developments are almost forgotten. IT. TUT.BY studied which removable media left a noticeable mark in computer history, and which could become the standard for many years to come.

Here we will only consider floppy disks and cartridges with magneto-optical disks that were inserted into readers, and we will not disassemble ordinary disks and tape drives with magnetic tape.

Floppy Disc 8 "

Developer: IBM

Year of issue: 1971

Dimensions: 200x200x1 mm

Size: from 80 Kb at the beginning of release up to 1.2 Mb

Distribution: ubiquitous

In 1967, IBM under the leadership of Alan Shugart organized a group to develop new floppy disks. In 1971, the first eight-inch floppy disk was launched on the market: a round flat floppy disk in a plastic sleeve measuring 20x20 cm. Due to its flexibility, the novelty was named Floppy Disc - "floppy disk". At first, the capacity was only 80 kilobytes, but over time, the recording density was increased, and after five years the floppy disks could already contain more than a megabyte of information.

5.25 "Mini Floppy Disk

Developer: Shugart Associates

Year of issue: 1976

Dimensions: 133x133x1 mm

Size: from 110 Kb at the beginning of release to 1.2 Mb

Data exchange rate: up to 63 Kb / s

Distribution: ubiquitous

Two years after the release of the first eight-inch floppy disks, Alan Shugart founds his own company Shugart Associates, which three years later presented a new development - a five-inch floppy disk and a floppy drive. The company also noted the development of the SASI standard, which was later renamed to SCSI. Floppy disks were single-sided and double-sided, and many computer designers used their own formatting and writing algorithms, which made discs written in one drive unreadable in another. Schoolchildren of the period of the decline of the USSR and the first years of independence of the union republics loaded computers from such floppy disks and played the simplest games. By the mid-eighties, the capacity of floppy disks had been increased tenfold. And Shugart Associates, by the way, later changed its name to the well-known Seagate.

Floppy disk 3,5 "(Micro Floppy Disk)

Developer: Sony

Year of issue: 1981

Dimensions: 93x89x3 mm

Size: from 720 KB at the beginning of the release to 1.44 MB (standard), up to 2.88 MB (Extended Density)

Data exchange rate: up to 63 Kb / s

Distribution: ubiquitous

In 1981, Sony offers a completely the new kind floppy disks: three-inch. They weren't really flexible anymore, but the name remained. Now the magnetic circle was enclosed in plastic three millimeters thick, and the hole for the heads was covered with a spring shutter. These shutters, especially metal ones, loosened and bent during operation, and often came off inside the drive and remained there. Floppy disks became very popular, and various computer manufacturers equipped their machines with them. Sony has produced several models of digital cameras that were recorded on floppy disks. By 1987, the standard capacity of floppy disks had grown to 1.44 MB, and a little later, thanks to an even higher recording density, it was possible to "squeeze" up to 2.88 MB. Savvy students in dormitories (including Belarusian ones) for money "overclocked" floppy drives up to 1.7-1.8 MB, while they could be read in ordinary floppy drives. In spite of everything, three-inch floppy disks are still produced. Floppy disks are almost obsolete, but many programs still use the "Save" icon in the form of a floppy disk.

Amstrad Disc 3 "(Compact Floppy Disc, CF2)

Developer: Hitachi, Maxell, Matsushita

Year of issue: 1982

Dimensions: 100x80x5 mm

Size: from 125 Kb at the beginning of the release to 720 Kb

Distribution: quite wide - mainly computers Amstrad CPC and Amstrad PCW, also Tatung Einstein, ZX Spectrum +3, Sega SF-7000, Gavilan SC

Amstrad, a renowned computer manufacturer, decided to go its own way and promoted a different 3-inch floppy disk from Hitachi. Even more surprising is the fact that the company was founded by the same Alan Shugart, who developed the first floppy disks. The magnetic disk itself inside the case took up less than half of the free space - the rest fell on the media protection mechanisms, which is why the cost of these disks was quite high. Although these floppy disks were more expensive than standard 3.5-inch floppy disks with less memory, the company had been promoting them for quite some time and succeeded: more than 3 million Amstrad CPC computers were produced alone.

Bernoulli box

Developer: Iomega

Year of issue: 1983

Dimensions: Bernoulli Box: 27.5x21 cm, Bernoulli Box II: 14x13.6x0.9 cm

Volume: from 5 MB at the beginning of release to 230 MB

Data transfer rate: up to 1.95 Mb / s

Distribution: small

Iomega, later one of the main "whales" of the removable media market, developed the original Bernoulli Box in 1983. In it, the floppy disk rotates at a high speed (3000 rpm), as a result of which the disk surface directly under the read head is bent and does not come into contact with it: read / write operations are performed through an air cushion. The equations for describing these air flows were proposed by the prominent Swiss scientist Daniel Bernoulli in the 18th century. Thanks to this development, the company gained fame, although the first products did not differ in either capacity or portability: the first cartridges were 27.5x21 cm in size and contained only 5 megabytes of information. The second generation decreased in size by about four times, and the amount of memory by 1994 had grown to 230 megabytes. But by that time, magneto-optical disks began to be actively promoted.

Magneto-optical drive (MO)

Developer: Sony

Year of issue: 1985

Dimensions: 133x133x6 mm, 93x89x6 mm, 72x68x5 mm for MiniDisc

Volume: 650 MB to 9.2 GB for 5-inch, 128 MB to 2.3 GB for 3.5-inch, 980 MB for mini-disks

Data exchange rate: up to 10 Mb / s

Distribution: significant

Magneto-optical discs look like regular standard and reduced-size CDs in a box. But at the same time they have an important difference: the recording is carried out in a magnetic way, that is, first the laser heats the surface to a high temperature, and then the magnetization of the sections changes with an electromagnetic pulse. The system is highly reliable and resistant to mechanical damage and magnetic radiation, but it provided a low recording speed and had a high power consumption. Both disks and drives were expensive, so magneto-optics did not receive very wide distribution like CDs. Distribution was also hindered by the fact that for a very long time such discs only allowed data to be recorded once. But in some industries (for example, medicine), where the preservation of a large amount of information is required for a long time (and MO disks "live" up to 50 years), the technology has gained acceptance. Sony still makes magneto-optical discs for both small and large size... MiniDisc music discs, presented by the same Sony company in 1992, are a special case of magneto-optical discs. If at first they allowed recording only music, then modifications MD Data (1993) and Hi-MD (2004) provide recording of any data with a volume of 650 MB and 980 MB, respectively. "Minidisks" are also still in production.

SyQuest wheels

Developer: SyQuest

Year of issue: around 1990

Dimensions: 5.25 "(approximately 13x13 cm) and 3.5" (approximately 9x9 cm)

Sizes: 5.25 ": 44, 88 and 200 MB; 3.5": 105 and 270 MB

Distribution: Medium (mainly with MacIntosh computers)

Founded in 1982 by former Seagate employee Syed Iftikar, QyQuest entered the market with removable hard drives for the IBM XT. The firm later developed several different cartridge disk systems. The most popular are the 5.25-inch SQ400 / SQ800 / SQ2000 cartridges (44, 88 and 200 MB), as well as the 3.5-inch SQ310 / SQ327 (105 and 270 MB). Their main drawback, besides size, was that later systems were not fully compatible with earlier ones. For example, drives for 200MB discs could only read 88MB discs, but could not write to them. The younger systems could neither read nor write to the older ones. In the year of release, 44MB drives cost about $ 100. A variety of incompatible standards and the absence of a normal trade name for a particular technology did not allow the disks to gain wide popularity. Magneto-optical disks provided more capacity, and Iomega's Zip disks soon followed.

Floptical

Developer: Insite Peripherals

Year of issue: 1991 (Insite Floptical), 1998 (Caleb UHD144, Sony HiFD)

Dimensions: 93x89x3 mm

Size: 21 MB (Insite Floptical), 144 MB (Caleb UHD144), 150-200 MB (Sony HiFD)

Data exchange rate: up to 125 Kb / s

Distribution: very small

Another magneto-optical technology, but of a different kind. The information is read by the magnetic heads, and the optical subsystem (infrared LEDs) ensures the accuracy of the head positioning. Thus, instead of the usual 135 tracks per inch, like floppy disks, they achieved a recording density of 1250 tracks per inch. Floptical drives were compatible with regular 3.5-inch floppy disks, and Floptical drives were initially marketed as the successor to floppy disks, but this did not happen. Seven years later, Caleb Technology developed a similar system, the Caleb UHD144, and Sony released Sony HiFD discs. Both of these systems were also compatible with regular floppy disks and both were also named as floppy disks, but they faced a loud failure in the market, because by that time the market for removable media of 100-250 MB was captured by Iomega Zip disks.

Zip Drive (Iomega Zip)

Developer: Iomega

Year of issue: 1994

Dimensions: 98x98x6 mm

Volume: from 100 MB at the beginning of release to 750 MB

Data exchange rate: about 1 Mb / s

Spread: very wide

Compact discs were still expensive and did not allow erasing records (CD-RWs appeared only in 1997), magneto-optical discs were expensive and gluttonous, and the capacity of ordinary floppy disks was no longer enough. Iomega has refined the magnetic recording technology and introduced Zip disks: slightly larger than floppy disks, and with a capacity of as much as 100 megabytes. The head to the disk was approached not from the top, but from the side, and the data exchange rate was about 15 times faster than that of conventional floppy disks. Disk drives were produced in several formats - both external and internal, graceful in shape and blue, which could be placed flat on the table or vertically. The technology quickly gained popularity. Despite the clicks of death, which were a sign of disk failure, the zips were selling well. In the year of release, floppy drives cost $ 100 and discs $ 20 each; later, 250 MB drives (round in shape, but the same dimensions) and 750 MB (of the usual shape) appeared. Since the early 2000s, the popularity of Zip drives has declined, but Iomega still sells 100-megabyte drives for $ 9 apiece, and "seven hundred and fifty" - for $ 12.5. Many ancient technology enthusiasts are still using epoch-making devices.

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3.4. COMPUTER MEMORY

FLEXIBLE MAGNETIC DRIVES

Diskette - a portable magnetic storage medium used for multiple recording and storage of relatively small data. This type of media was especially common in the 1970s and late 1990s. The abbreviation is sometimes used instead of the term "diskette" GMD - "floppy disk" (respectively, the device for working with floppy disks is called NGMD - "floppy disk drive").

Typically, a floppy disk is a flexible plastic plate covered with a ferromagnetic layer, hence the English name "floppy disk". This plate is housed in a plastic housing that protects the magnetic layer from physical damage. The shell is flexible or rigid. Floppy disks are written and read using a special device - a floppy disk drive (floppy drive).

Floppy disks usually have a write protection feature, through which you can provide read-only access to data.

Floppy disks (8 ″; 5,25 ″ ; 3.5 ″ respectively)

History

· 1971 - The first 200 mm (8 ″) floppy disk with a suitable floppy disk drive was introduced by IBM. Usually the invention itself is attributed to Alan Sugart, who worked at IBM in the late 1960s.

· 1973 - Alan Shugert founds his own firm, Shugart Associates.

· 1976 - Alan Schugert develops the 5.25 ″ floppy disk.

· 1981 - Sony introduces a 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 volume 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 appeared (from the English. Extended Density - "extended density"), which had a volume of 2880 kilobytes (36 sectors), which did not become widespread.

Formats

Chronology of floppy disk formats
Format	Year of origin	Volume in kilobytes
8 ″ double density
5.25 "double density
5.25 ″ Quad Density
5.25 "high density
3 ″ double density
3.5 "double density
3.5 "high density
3.5 ″ expanded density

It should be noted that the actual capacity of the floppy disks depended on how they were formatted. Since, apart from the earliest models, virtually all floppy disks did not contain hard-formed tracks, the path for experiments in the field of more efficient use of the floppy disk was open for system programmers. The result was the emergence of many incompatible diskette 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 ten. (The most famous are MX, MY used in DCK).

Added to the confusion was the fact that Apple used floppy drives in its Macintosh computers that use a different magnetic tape encoding principle than 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 SuperDrives that worked in both modes.

The "standard" formats of IBM PC floppy disks differed in disk size, number of sectors per track, number of sides used (SS stands for single-sided floppy, DS stands for double-sided), and the type (recording density) of the 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 ″ 720 K floppy disk, Amstrad PC, PK Neuron - 5.25 ″ 640 K floppy disk , HD - high density (differed from QD by an increased number of sectors), ED - extended density.

Working density of drives and capacity of floppy disks in kilobytes
Density	Inch

8-inch drives have long been included in the BIOS and were supported by MS-DOS, but there is no exact information about whether they were supplied to consumers (perhaps they were supplied to enterprises and organizations and were 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 diskettes Iskra-1030 / Iskra-1031 - actually were 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, respectively, could not read the standard DS / DD diskettes from the IBM PC.

Special drivers-extenders BIOS 800, pu_1700 and a number of others allowed formatting floppy disks with an arbitrary number of tracks and sectors. Since floppy 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 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 by 3.5″ HD drives was 1700 KB.

This technique was later used in Windows 98, as well as Microsoft's DMF floppy disk format, which expanded the floppy disk capacity to 1.68 MB by formatting the floppy disks into 21 sectors in the same IBM XDF format. XDF was used on OS / 2 distributions, and DMF was used on various distributions software products from Microsoft.

Finally, a fairly common modification of the 3.5 ″ floppy format is to format them at 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 R. As a side effect, the activation of this bIOS settings usually reads floppy disks 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 recording density and media area, is 2 MB.

The height of a 5.25 "floppy disk drive is 1 U. All CD drives, including Blu-ray, are the same width and height as a 5.25" drive (this does not apply to notebook drives).

The 5.25 ″ drive is nearly three times the height. This was sometimes used by the manufacturers of computer cases, where three devices placed in a square “basket” could be reoriented with it from horizontal to vertical arrangement.

Disappearing

One of the main problems with floppy disks was their fragility. The most vulnerable element of the floppy disk design was a tin or plastic casing that covered the floppy disk itself: its edges could bend, which led to the floppy disk getting stuck in the floppy drive, the spring that returned the casing to its original position could be displaced, as a result, the floppy disk 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 a floppy disk fell on the floor), which rendered the magnetic medium out of order. Dust could have entered the crevices between the disk case and the casing. And the floppy disk itself could be relatively easily demagnetized from the influence of magnetized metal surfaces, natural magnets, electromagnetic fields near high-frequency devices, which made the storage of information on floppy disks extremely unreliable.

The massive displacement of floppy disks from everyday life began with the advent of rewritable CDs, and especially, flash-based media, which have a much lower unit cost, orders of magnitude greater capacity, higher actual number of rewrite cycles and durability, and higher data exchange rate.

An intermediate option between them and traditional floppy disks are magneto-optical media, Iomega Zip, Iomega Jaz and others. These removable media are sometimes also called floppy disks.

However, even in 2009, a floppy disk (usually 3.5 ") and an appropriate disk drive are needed (if it is impossible to do this via the Internet directly from the operating system) to" flash "the BIOS flash memory of many motherboards, for example, Gigabyte. they are also used to work with small files (usually with text files), to transfer these files from one computer to another, so we can say with complete confidence that floppy disks will be used for several more years, at least until the moment when the price of the cheapest flash drives will not be comparable to the prices for floppy disks (now their difference is ~ 10 times, but it is steadily decreasing).