Floppy Disk Format
Floppy disk format and density refer to the physical and logical layout of data stored on a floppy disk. Since their introduction, there have been many floppy disk types, densities, and formats, popular and rare, used in computing, leading to much confusion over their differences. In the early 2000s, most floppy disk types and formats became obsolete, leaving the -inch disk, using an IBM PC compatible format of 1440 KiB, as the only remaining popular format. Different floppy disk types have different recording characteristics, with varying magnetic coercivity (measured in oersteds, or in modern SI units in amperes per meter), ferrite grain size, and tracks per inch (TPI). TPI was not a part of the physical manufacturing process; it was a certification of how closely tracks of data could be spaced on the medium safely. The term density has a double meaning for floppy disks. Originally, single density and double density indicated a difference in logical encoding on the ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Disk Density
Disk density is a capacity designation on magnetic storage, usually floppy disks. Each designation describes a set of characteristics that can affect the areal density of a disk or the efficiency of the encoded data. Such characteristics include modulation method, track width, coercivity, and magnetic field direction. 8-inch media ''Single density'' (SD or 1D) describes the first generation of floppy disks that use an iron oxide coating. Floppy drives utilize 300-oersted write heads, FM encoding, and a track width of for a density of 48 tracks-per-inch (tpi) and 5,876 bits-per-inch (bpi). ''Double density'' (DD or 2D) doubles capacity over SD by replacing FM encoding with an improved line code, such as modified frequency modulation (MFM), modified modified frequency modulation (M²FM), FM/MFM or group coded recording (GCR). 5¼-inch media ''SD'' (''1D'') and ''DD'' (''2D'') designations were generally identical to those of 8-inch disks. ''Quad density'' (QD or 4D) dou ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Commodore 8050
The Commodore 8050, Commodore 8250, and Commodore SFD-1001 are 5¼-inch floppy disk drives manufactured by Commodore International, primarily for its 8-bit CBM and PET series of computers. The drives offered improved storage capacities over previous Commodore drive models. They are notable for the disk drive having twice the processing power than the connected computer in having two 1MHz 6502 processors sharing operation of communication and disk operation, though only supporting 4k of main memory. The disk operating system is actually contained within the disk drive unit with commands being sent via the 8 bit GPIB interface where the system decodes the message and carries out the requested operation such as formatting a disk without further involvement from the connected computer. Specifications All three models utilize 5¼-inch double-density floppy disks with a track spacing of 100 tracks-per-inch, for a total of 77 logical tracks per side. Data is encoded using Commodore' ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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FAT12
File Allocation Table (FAT) is a file system developed for personal computers and was the default file system for the MS-DOS and Windows 9x operating systems. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. The increase in disk drive capacity over time drove modifications to the design that resulted in versions: FAT12, FAT16, FAT32, and exFAT. FAT was replaced with NTFS as the default file system on Microsoft operating systems starting with Windows XP. Nevertheless, FAT continues to be commonly used on relatively small capacity solid-state storage technologies such as SD card, MultiMediaCard (MMC) and eMMC because of its compatibility and ease of implementation. Uses Historical FAT was used on hard disks throughout the DOS and Windows 9x eras. Microsoft introduced NTFS with the Windows NT platform in 1993, but FAT remained the standard for the home user until the introduction of Windows XP in 2001. W ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Superformatting
Superformatting is the process of formatting a floppy disk at a capacity that the disk is not designed for. It can ruin a floppy disk, but it is used in some floppy-based Linux distros to increase the room for applications and utilities. muLinux is a notable example of this technique. Another common use (which is not as popular nowadays) was to format low-density 3.5-inch or 5.25-inch floppies as high-density, or in the case of 3.5-inch disks, even extra-high density (HD-36). "Notched" disks will usually turn up a lot of bad sectors, especially if the formatted capacity is a considerable (1.5 to 3) number of times higher than intended. Superformatting is usually done with a low-level format (such as "FORMAT /U" in DOS DOS (, ) is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-DOS, both of which were introduced in 1981. Later compatible syste ... and " fdfor ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Amiga
Amiga is a family of personal computers produced by Commodore International, Commodore from 1985 until the company's bankruptcy in 1994, with production by others afterward. The original model is one of a number of mid-1980s computers with 16-bit or 16/32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphics and audio compared to previous 8-bit systems. These include the Atari ST as well as the Macintosh 128K, Macintosh and Acorn Archimedes. The Amiga differs from its contemporaries through custom hardware to accelerate graphics and sound, including sprite (computer graphics), sprites, a blitter, and four channels of sample-based audio. It runs a pre-emptive multitasking operating system called AmigaOS, with a desktop environment called Workbench (AmigaOS), Workbench. The Amiga 1000, based on the Motorola 68000 microprocessor, was released in July 1985. Production problems kept it from becoming widely available until early 1986. While ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Disk Controller
A disk controller is a controller circuit that enables a CPU to communicate with a hard disk, floppy disk or other kind of disk drive. It also provides an interface between the disk drive and the bus connecting it to the rest of the system.{{Cite book , url=https://ieeexplore.ieee.org/document/955038 , access-date=2023-10-18 , date=2001 , doi=10.1109/ICCD.2001.955038 , s2cid=3084914 , language=en-US , last1=Jeppesen , first1=J. , last2=Allen , first2=W. , last3=Anderson , first3=S. , last4=Pilsl , first4=M. , title=Proceedings 2001 IEEE International Conference on Computer Design: VLSI in Computers and Processors. ICCD 2001 , chapter=Hard disk controller: The disk drive's brain and body , pages=262–267 , isbn=0-7695-1200-3 Early disk controllers were identified by their storage methods and data encoding. They were typically implemented on a separate controller card. Modified frequency modulation (MFM) controllers were the most common type in small computers, used for bot ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Floptical
Floptical refers to a type of floppy disk drive that combines magnetic and optical technologies to store data on media similar to standard -inch floppy disks. The name is a portmanteau of the words "floppy" and "optical". It refers specifically to one brand of drive and disk system, but is also used more generically to refer to any system using similar techniques. The original Floptical technology was announced in 1988 and introduced late in 1991 by Insite Peripherals, a venture funded company set up by Jim Adkisson, one of the key engineers behind the original -inch floppy disk drive development at Shugart Associates in 1976. The main shareholders were Maxell, Iomega and 3M. This original format normally held 21 MB of data, compared to the contemporary 3.5" floppy capacity of 720 kB or 1.44 MB. Over the next several years, similar products were introduced by other companies with ever increasing capacity, eventually reaching 240 MB in some systems. All of ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Optical Disc
An optical disc is a flat, usuallyNon-circular optical discs exist for fashion purposes; see shaped compact disc. disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to be detected on the other side. Optical discs can store analog information (e.g. LaserDisc), digital information (e.g. DVD), or store on the same disc (e.g. CD Video). Their main uses are the distribution of media and data, and long-term archival. Design and technology The encoding material sits atop a thicker substrate (usually polycarbonate) that makes up the bulk of the disc and forms a dust defocusing layer. The encoding pattern follows a continuous, spiral path covering the entire disc surface and extending from the innermost track to the outermost track ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Flippy Disk
The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the Floppy disk#8-inch floppy disk, 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and encoding methods for the data held on the disk. Non-standard media and devices IBM DemiDiskette In the early 1980s, IBM Rochester developed a 4-inch floppy disk drive, the Model 341 and an associated diskette, the DemiDiskette. At about half the size of the original 8-inch floppy disk the name derived from the prefix ''demi (metric prefix), demi'' for "half". This program was driven by aggressive cost goals, but missed the pulse of the industry. The prospective users, both inside and outside IBM, preferred standardization to what by release time were small cost reductions, and were unwilling to retool p ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Double-sided Disk
In computer science, a double-sided disk is a disk of which both sides are used to store data. Early floppy disks only used one surface for recording. The term ''single-sided disk'' was not common until the introduction of the double-sided disk, which offered double the capacity in the same physical size. Initially, double-sided disks had to be removed and flipped over to access data on the other side, but eventually, devices were made that could read both sides without the need to eject the disk. Manufacturers sold both single-sided and double-sided disks with the double-sided disks being typically 50% more expensive than single-sided disks. While the magnetic-coated medium was coated on both sides, the single-sided floppies had a read-write notch on only one side, thus allowing only one side of the disk to be used. When users discovered this, they began buying the less-expensive single-sided disks and "notching" them using scissors, a hole punch, or a specially designed "notc ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Hard Sectoring
Hard sectoring in a magnetic or optical data storage device is a form of sectoring which uses a physical mark or hole in the recording medium to reference sector locations. In older 8- and 5-inch floppy disks, hard sectoring was implemented by punching sector holes in the disk to mark the start of each sector. These were equally spaced holes, at a common radius. This was in addition to the index hole, situated between two sector holes, to mark the start of the entire track of sectors. When the index or sector hole was recognized by an optical sensor, a sector signal was generated. Timing electronics or software would use the faster timing of the index hole between sector holes, to generate an index signal. Data read and write is faster in this technique than soft sectoring as no operations are to be performed regarding the starting and ending points of tracks. Storage formats using hard sectoring *32 sector 8-inch floppy disks *10 sector and 16 sector 5-inch floppy disks *Numer ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Floppy Disk
A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a fabric that removes dust particles from the spinning disk. The three most popular (and commercially available) floppy disks are the 8-inch, 5¼-inch, and 3½-inch floppy disks. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device. The first floppy disks, invented and made by IBM in 1971, had a disk diameter of . Subsequently, the 5¼-inch (133.35 mm) and then the 3½-inch (88.9 mm) became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |