List of floppy disk formats

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8-inch, 5+1⁄4-inch, and 3+1⁄2-inch floppy disks

This is a list of different floppy disk formats.

Physical formats

SizeDensitySidesTrackstpibpiSectoring Coercivity Unformatted capacity per side
2 inch Video Floppy 52256>800 kB or 50 fields of analog video [1]
2 inch LT-1 Double80245
21⁄2 inchSingle16 [2] [3] 48 [2] 64 kB
3 inch QuickDisk
3.25 inchSingle180 [4] 1404,625250 kB
Double9,250500 kB
31⁄2 inchSingle240 [5] 67.58,650Soft665 Oe250 kB[ citation needed ]
Double801358,717665 Oe [6] 500 kB[ citation needed ]
High8013517,434720-750 Oe1 MB
Extended8013534,868900 Oe2 MB
Triple [7] 240 [8] 406.5 [8] 36,700 [8] 6.5 MB
4 inch DemiDiskette 1 [9]
51⁄4 inchSingle/Double240485,876Soft or hard300 Oe250 kB
Quad77100300 Oe500 kB (Micropolis-compatible)
Quad80965,922300 Oe500 kB
High80969,646Soft600 Oe833 kB
EH [10] 10412529,5606.5  MB [11]
51⁄4 inch

Apple FileWare

Double28062.5Soft851 kiB [12]
8 inchSingle77483,268-3,408Soft or hard (inner edge)300 Oe1 MB
Double6,8161 MB
HD [13] 1549620,560600 Oe9.6 MB [14]
8 inch Memorex FD6501 [15] 50 [15] 2,400Hard (outer edge)1.5 Mb [15]
65164 [16] 3,1002.5 Mb [16] [17]
8 inch BurroughsDouble21391507,1002 [18]

Logical formats

Throughout the 1970s and 1980s, many different logical disk formats were used, depending on the hardware platform.

Contents

Common floppy disk formats, logical characteristics by platform
PlatformSizeDensitySidesTracks/ sideSectors/ trackBytes/ sectorSectoringCapacityrpmEncodingNote
Acorn 51⁄4 inchSingle14010256Soft100 kB300FM
80200 kB
Double14016256160 kBMFM
80320 kB
2640 kB
31⁄2 inchDouble28016256640 kB300MFMFormat L: MOS (Electron, Master Compact)
51024800 kB
  • Format D: Arthur, RISC iX
  • Format E: RISC OS
High101,600 kBFormat F: RISC OS 3 and later. Archimedes models before the A5000 require an upgraded floppy drive.
Agat 51⁄4 inchDouble28021256840 kB300MFM [NB 1]
Amstrad CPC/PCW 3 inchDouble1409512180 kB300MFMSingle head drive, but double-sided floppy discs (total of 360 kB per floppy)
Amstrad PCW8512/9512 3 inchDouble2809512720 kB300MFM720 kB mode uses both sides - ensure disc inserted correct way up.
Apple II 51⁄4 inchDouble13513256Soft113.75 kB300 GCR [NB 2]
116140 kB
31⁄2 inchDouble180Variable (8-12)512400 kB394 - 590GCR [NB 3]
2800 kB
High280185121,440 kB300MFM [NB 4]
Apple Lisa 51⁄4 inch FileWare Double246Variable (15-22)512Soft851 kB218 - 320 [19] GCR
Apple Lisa 2/Macintosh XL,

Macintosh

31⁄2 inchDouble180Variable (8-12)512Soft400 kB394 - 590GCR
Apple Macintosh2800 kB
High280185121,440 kB300MFM
Atari 8-bit 51⁄4 inchSingle14018128Soft90 kB288FM [NB 5]
Dual26128130 kBMFM
Double18256180 kB
Double218256360 kB300
Atari ST/TT/Falcon31⁄2 inchDouble1809512Soft360 kB300MFM
2720 kB
High181,440 kB
Coleco ADAM 51⁄4 inchDouble1408512soft160 kB300MFM
Commodore 64 (8-bit)51⁄4 inchDouble135Variable (17-21) ZCAV 256Soft170 kB300GCR [NB 6]
2340 kB
Quad177Variable (23-29) ZCAV521 kB
21,042 kB
31⁄2 inchDouble28010512800 kBMFM 
Commodore Amiga 51⁄4 inchDouble24011512Soft440 kB [NB 7] 300MFM [NB 8]
Quad80880 kB [NB 9]
31⁄2 inchDouble880 kB
High191,520 kBGCR [NB 10]
221,760 kB150MFM [NB 8]
Commodore 900 51⁄4 inchHigh28013-16512Soft1,200kB?GCR https://vintagecomputer.ca/files/Commodore/C900/C900%20Floppy%20Specification.pdf
IBM 33FD8 inchSingle17726128240.5 kiB360FMDiskette 1 [20]
15256277.5 kiB
8512296 kiB
IBM 43FD226128481 kiBDiskette 2 [20]
15256555 kiB
IBM 53FDDouble26256962 kiBMFMDiskette 2D [20]
155121.08 MiB
81,0241.16 MiB
DEC RX018 inchSingle17726128250 kB360FM
DEC RX028 inchDouble17726256500 kB360FM/MFM
DEC RX50 51⁄4 inchQuad18010512400 kB300MFM
IBM PC compatibles [21] 8 inchSingle17726128Soft250.25 kB [NB 11] [21] [22] [23] 360FM [NB 12]
2500.5 kB [NB 11] [21] [22] [23]
Double181,024616 kB [NB 11] [22] [23] MFM
21,232 kB [NB 11] [21] [22] [23]
51⁄4 inchDouble1408512160 kB [NB 11] 300MFM 
2320 kB [NB 11]
19180 kB [NB 11]
2360 kB [NB 11]
Quad [NB 13] 1808320 kB [NB 11] 300
2640 kB [NB 11]
High280151,200 kB [NB 11] 360
31⁄2 inchDouble1808512320 kB [NB 11] 300MFM
9360 kB [NB 11]
28640 kB [NB 11]
9720 kB [NB 11]
High181,440 kB [NB 11]
211,680 kB [NB 11] DMF [NB 14]
821,720 kB [NB 11]
Extended80362,880 kB [NB 11]
MGT SAM Coupé 31⁄2 inchDouble28010512800 kB300MFM 
NEC PC98 8 inchSingle17726128250.25 kB [NB 11] 360FM 
Double27781,0241,232 kB [NB 11] MFM
51⁄4 inchDouble2808512640 kB [NB 11] 360MFM
9720 kB [NB 11]
High151,200 kB [NB 11]
77 (80) [NB 15] 81,0241,232 (1,280) kB [NB 11] [NB 15] [NB 15]
31⁄2 inchDouble2808512640 kB [NB 11] 360MFM
9720 kB [NB 11]
High151,200 kB [NB 11] 3-mode [NB 16] [NB 15]
77 (80) [NB 15] 81,0241,232 (1,280) kB [NB 11] [NB 15]
80185121.44 MB [NB 11] 300
Triple240385129,120 kB360 NEC PC-88 VA3 2TD drive only [8] [7]
Osborne 1 [24] 51⁄4 inchSingle14010256Soft100 kB300FM
Double51,024200 kBMFM
Sega SF-70003 inchSingle24016256160 kB ? ?Expansion unit for SC-3000 home computer. Capacity is per side.

[25]

SHARP X68000 51⁄4 inchHigh27781,0241,232 kB [NB 11] 360MFM 
31⁄2 inch
SHARP CE-1600F, CE-140F 21⁄2 inch [2] [3] Singledrive: 1, diskette: 2 (flippable)1685122× 64 kB270 GCR (4/5) Internally based on FDU-250 Micro Floppy Disk Drive Unit [2]
Thomson 51⁄4 inchSingle1401612880 kB300FMThomson UD90.070
Double2256320 kBMFMThomson DD90-320 [NB 17]
31⁄2 inchDouble18016256320 kB300MFMThomson TO9, Thomson DD09-350
Double2640 kBThomson TO8D, TO9+, Thomson DD90-352 [NB 18]
Victor 9000 / ACT Sirius 1 [26] 51⁄4 inchSingle18011-19 (variable)512612 kB [27] 252-417 (variable)GCRDisks varied sectors/track and disk speed to keep consistent bit density across tracks [26]
Double25121,196 kB [27]
Tandy TRS-8051⁄4 inchSingle13510256Soft88 kB300FMModel 1/3/4
51⁄4 inchDouble14018256180 kBMFMModel 1/3/4P
51⁄4 inchDouble24018256360 kBMFMModel 4D
8 inchDouble17726256500 kBMFMModel 2
31⁄2 inchSingle14021,280100 kB [28] FMTandy Portable Disk Drive (aka Brother FB-100, knitking FD-19)
31⁄2 inchSingle18021,280200 kB [29] FMUsed only in Tandy Portable Disk Drive 2
51⁄4 inchDouble13518256157 kB [30] MFMColor Computer
HP 9114A31⁄2 inchDouble28016256128-710kB [31] 600MFMUsed with HP 110 and Portable Series 40 & 70
HP 9895A8 inchDouble277292561.18 MB [32] 360MFM
HP 9130K51⁄4 inchDouble23516256286 kB [33] 300MFM
Burroughs MD1228 inchDouble213944256Soft6.26 MB [18] 524MFM
Memorex 6508 inchSingle15083,500 b Hard1.4 Mb [15] 375FM
Memorex 651Single64321.056 b 2.2 Mb [17]
PlatformSizeDensitySideTrackSectorByteSectoringCapacityRPMEncodingNote
Commodore 128 (CP/M)5 1/4Double24026128Soft260K300MFMCommodore 1571
16256320K
9512360K
51,024400K

https://www.c64-wiki.com/wiki/Commodore_1571

https://vintagecomputer.ca/files/Commodore/C900/C900%20Floppy%20Specification.pdf

See also

Notes

  1. ↑ Custom controller with unique track layout.
  2. ↑ 16 sector filesystems require a compatible disk controller (PROM update) and Apple DOS 3.3 or later.
  3. ↑ Apple II double-density 31⁄2-inch (90 mm) drives use variable sectors sizes (tracks 00-15: 12 sectors, tracks 16-31: 11 sectors, tracks 32-47: 10 sectors, tracks 48-63: 9 sectors, tracks 64-79: 8 sectors), 394 rpm to 590 rpm.
  4. ↑ Apple II high-density 31⁄2-inch (90 mm) drives require a compatible disk controller and ProDOS 8.
  5. ↑ Third party drives offer up to 1440 KB.
  6. ↑ Commodore floppy drives used a fixed rotation speed with variable sector density (see: Zone bit recording).
  7. ↑ This format was used by the Amiga 1020 external floppy drive and some third-party drives connected to the normal Amiga floppy drive bus.
  8. 1 2 Though the Amiga used MFM, the format places sectors too close together for a standard IBM PC compatible floppy disk controller to read (appearing as one 5632-byte physical sector per track).
  9. ↑ Format used by rare third-party drives with quad density disks; such drives were usually switchable between 80-track and 40-track (A1520/PC-compatible) operation.
  10. ↑ Format used by third-party gcrdisk.device driver in order to use PC-standard HD floppy drives (which rotated at a fixed 300 rpm) via the Amiga floppy drive bus. The Amiga's floppy controller could not keep up with the data rate needed for MFM recording on HD floppies without reducing rotational speed, so the third party driver used an alternate GCR mode.
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 The calculated formatted capacity is based on FAT12 format.
  12. ↑ While IBM didn't include an 8-inch floppy drive option on any of their PCs and PC DOS, MS-DOS 1.25 supported 8-inch disks and added support for higher capacities in version 2.0. MS-DOS' predecessor 86-DOS used 8-inch diskettes as well.
  13. ↑ Rare format appearing on some early PC/XT clones using quad-density disks.
  14. ↑ These variations are known as DMF diskettes, used for a time to pack more data on to each disk for software distribution.
  15. 1 2 3 4 5 6 Inner 3 tracks of 8 sectors/track format are unused.
  16. ↑ The PC98 31⁄2-inch (90 mm) formats are also known as "3 Mode" floppy disks, usable on IBM PC compatibles with a 3-mode floppy drive.
  17. ↑ The two sides are managed as two independent 160 KB disks
  18. ↑ The two sides are managed as two independent 320 KB disks

    References

    1. ↑ US4609949A, Kutaragi, Ken,"Magnetic disc reproducing apparatus",issued 1986-09-02, assigned to Sony Corporation
    2. 1 2 3 4 "Model CE-1600F". Sharp PC-1600 Service Manual (PDF). Yamatokoriyama, Japan: Sharp Corporation, Information Systems Group, Quality & Reliability Control Center. July 1986. pp. 98–104. Archived (PDF) from the original on March 23, 2017. Retrieved March 23, 2017.
    3. 1 2 Sharp Service Manual Model CE-140F Pocket Disk Drive (PDF). Sharp Corporation. 00ZCE140F/SME. Archived (PDF) from the original on March 11, 2017. Retrieved March 11, 2017.
    4. ↑ Tabor TC-500 Specifications. USA: Tabor Corp. Archived from the original on January 12, 2022.
    5. ↑ "PF-10" (PDF). Epson. 1984. Archived from the original (PDF) on June 21, 2020. Retrieved November 30, 2022.
    6. ↑ "Floppy Drive Tech Info". www.retrotechnology.com. Retrieved July 6, 2023.
    7. 1 2 NEC μPD72070 - Floppy Disk Controller Specification Version 2.0 (PDF). 2.0 preliminary. NEC Corporation. October 1991. Archived from the original (PDF) on March 20, 2017. Retrieved March 20, 2017.
    8. 1 2 3 4 "ハードウエア" [Hardware]. NEC PC-88VA (in Japanese). Archived from the original on June 18, 2017.
    9. ↑ US4482929A,Beck, John L.; Bornhorst, Randy J.& Smith, Donald J.et al.,"Magnetic recording disk cartridge",issued 1984-11-13
    10. ↑ "Fujitsu Sales Prospector 1986". Archive.org. 1986. p. 238. Retrieved November 7, 2023.
    11. ↑ "コンピュータ・情報システム・パソコン・周辺機器" [Hitachi Computer Peripherals](PDF). hitachihyoron.com. January 6, 1985. p. 9. Retrieved November 7, 2023.
    12. ↑ Berry, D (September 7, 1982). Lisa Hardware Manual (PDF). Apple Computer Inc. pp. 9–1.
    13. ↑ "Fujitsu Sales Prospector 1986". 1986. pp. 238, 239 – via Archive.org.
    14. ↑ "FDD-441大容量フロッピーディスク駆動装置の開発" [Development of FDD-441 Large-Capacity Floppy Disk Drive](PDF). hitachihyoron.com. August 3, 1984. p. 3. Retrieved November 7, 2023.
    15. 1 2 3 4 650 Flexible Disc File OEM Manual 2944.010. Memorex Corp. 1972. p. 9.
    16. 1 2 Memorex Markette Flexible Discs (PDF). USA: Memorex Corp. 1978. pp. 1–2.
    17. 1 2 Memorex 651 Flexible Disc File OEM Manual. USA: Memorex Corp. 1977. p. 4.
    18. 1 2 Burroughs MD 122 Brochure. USA: Burroughs Marketing. 1979. p. 2.
    19. ↑ "Apple's Twiggy Disks". www.brouhaha.com. Retrieved October 11, 2023.
    20. 1 2 3 The IBM Diskette General Information Manual (PDF) (Reference Manual). USA: IBM. 1979. pp. 18–19.
    21. 1 2 3 4 "Standard Floppy Disk Formats Supported by MS-DOS". 2.0. Microsoft. December 17, 2000. Retrieved February 5, 2020.
    22. 1 2 3 4 Zbikowski, Mark; Allen, Paul; Ballmer, Steve; Borman, Reuben; Borman, Rob; Butler, John; Carroll, Chuck; Chamberlain, Mark; Chell, David; Colee, Mike; Courtney, Mike; Dryfoos, Mike; Duncan, Rachel; Eckhardt, Kurt; Evans, Eric; Farmer, Rick; Gates, Bill; Geary, Michael; Griffin, Bob; Hogarth, Doug; Johnson, James W.; Kermaani, Kaamel; King, Adrian; Koch, Reed; Landowski, James; Larson, Chris; Lennon, Thomas; Lipkie, Dan; McDonald, Marc; McKinney, Bruce; Martin, Pascal; Mathers, Estelle; Matthews, Bob; Melin, David; Mergentime, Charles; Nevin, Randy; Newell, Dan; Newell, Tani; Norris, David; O'Leary, Mike; O'Rear, Bob; Olsson, Mike; Osterman, Larry; Ostling, Ridge; Pai, Sunil; Paterson, Tim; Perez, Gary; Peters, Chris; Petzold, Charles; Pollock, John; Reynolds, Aaron; Rubin, Darryl; Ryan, Ralph; Schulmeisters, Karl; Shah, Rajen; Shaw, Barry; Short, Anthony; Slivka, Ben; Smirl, Jon; Stillmaker, Betty; Stoddard, John; Tillman, Dennis; Whitten, Greg; Yount, Natalie; Zeck, Steve (1988). "Technical advisors". The MS-DOS Encyclopedia: versions 1.0 through 3.2. By Duncan, Ray; Bostwick, Steve; Burgoyne, Keith; Byers, Robert A.; Hogan, Thom; Kyle, Jim; Letwin, Gordon; Petzold, Charles; Rabinowitz, Chip; Tomlin, Jim; Wilton, Richard; Wolverton, Van; Wong, William; Woodcock, JoAnne (Completely reworked ed.). Redmond, Washington, USA: Microsoft Press. ISBN   1-55615-049-0. LCCN   87-21452. OCLC   16581341. (xix+1570 pages; 26 cm) (NB. This edition was published in 1988 after extensive rework of the withdrawn 1986 first edition by a different team of authors. )
    23. 1 2 3 4 Xerox 16/8 Professional Computer – MS-DOS OS Handbook for 8" Floppy Disks (PDF). Xerox. November 1983.
    24. ↑ Hogan, Thom; Iannamico, Mike (1982). Osborne 1 Technical Manual (PDF). Osborne Computer Corporation. p. 39.
    25. ↑ "Sega SF-7000 Super Control Station User Guide". Sega Enterprises. Retrieved February 10, 2020.
    26. 1 2 "Victor 9000 Hardware Reference Manual" (PDF). Archived (PDF) from the original on January 29, 2022. Retrieved September 12, 2022.
    27. 1 2 Lemmons, Phil (November 1982). "Victor Victorious". BYTE . p. 216. Retrieved October 19, 2013.
    28. ↑ Tandy Portable Disk Drive Operation Manual 26-3808. Japan: Radio Shack. 1985. p. 25.
    29. ↑ Tandy Portable Disk Drive 2 Operation Manual 26-3814. Japan: Radio Shack. 1986. p. 33.
    30. ↑ Radio Shack Hardware Manual: Color Computer Disk System Owners Manual (1981)(Tandy). 1981.
    31. ↑ 9914A Disc Drive (PDF). Hewlett-Packard. June 1, 1984. p. 1-2.
    32. ↑ 9895A Flexible Disc Users Manual (PDF). Fort Collins, Colorado USA: Hewlett-Packard Desktop Computer Division. 1978. p. 6.
    33. ↑ HP 9130K Flexible Disc Drive Service Documentation (PDF). Fort Collins, Colorado USA: Hewlett-Packard Greeley Division. 1981.
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