List of floppy disk formats explained

This is a list of different floppy disk formats.

Physical formats

!Size !! Density !Sides!! Tracks !! tpi !! bpi !Sectoring!! Coercivity !! Unformatted capacity per side
2 inch Video Floppy52256>800 kB[1]
2 inch LT-1double80245
2 inchSingle 16[2] [3] 48 64 kB
3 inch QuickDisk
3.25 inchsingle180[4] 1404,625250 kB
double9,250500 kB
3 inch Single 240[5] 67.5 8,650 soft665 Oe 250 kB
Double80 135 8,717 665 Oe[6] 500 kB
High 80 135 17,434 720-750 Oe 1 MB
Extended 80 135 34,868 900 Oe 2 MB
Triple[7] 240[8] 406.5 36,700 6.5 MB
4 inch DemiDiskette1[9]
5 inch Single/Double 240 48 5,876 soft or hard300 Oe 250 kB
Quad 77 100 300 Oe 500 kB (Micropolis-compatible)
Quad 80 96 5,922 300 Oe 500 kB
High 80 96 9,646 soft600 Oe 833 kB
EH[10] 10412529,5606.5 MB[11]
5 inch Apple FileWareDouble28062.5soft851 kiB[12]
8 inch Single 77 48 3,268-3,408soft or hard (inner edge)300 Oe 1 MB
Double6,8161 MB
HD[13] 1549620,560600 Oe9.6 MB[14]
8 inch Memorex FD6501[15] 502,400hard (outer edge)1.5 Mb
65164[16] 3,1002.5 Mb[17]
8 inch BurroughsDouble21391507,1002

Logical formats

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

Common floppy disk formats, logical characteristics by platform!Platform !! Size !! Density !! Sides !! Tracks/ side !! Sectors/ track !! Bytes/ sector !Sectoring!! Capacity !! rpm !! Encoding !! Note
Acorn5 inchSingle14010256soft100 kB300FM
80200 kB
Double14016256160 kBMFM
80320 kB
2640 kB
3 inchDouble28016256640 kB300MFMFormat L: MOS (Electron, Master Compact)
51024800 kB
High101,600 kBFormat F: RISC OS 3 and later. Archimedes models before the A5000 require an upgraded floppy drive.
Agat5 inchDouble28021256840 kB300MFM[18]
Amstrad CPC/PCW3 inchDouble1409512180 kB300MFMSingle head drive, but double-sided floppy discs (total of 360 kB per floppy)
Amstrad PCW8512/95123 inchDouble2809512720 kB300MFM720 kB mode uses both sides - ensure disc inserted correct way up.
Apple II5 inchDouble13513256soft113.75 kB300GCR[19]
116140 kB
3 inchDouble180Variable (8-12)512400 kB394 - 590GCR[20]
2800 kB
High280185121,440 kB300MFM[21]
Apple Lisa5 inch FileWareDouble246Variable (15-22)512soft851 kB218 - 320[22] GCR
Apple Lisa 2/Macintosh XL,Macintosh3 inchDouble180Variable (8-12)512soft400 kB394 - 590GCR
Apple Macintosh2800 kB
High280185121,440 kB300MFM
Atari 8-bit5 inchSingle14018128soft90 kB288FM[23]
Double26128130 kBMFM
Double18256180 kB
Double218256360 kB300
Atari ST/TT/Falcon3 inchDouble1809512soft360 kB300MFM
2720 kB
High181,440 kB
Coleco ADAM5 inchDouble1408512soft160 kB300MFM
Commodore 64 (8-bit)5 inchDouble135Variable (17-21) ZCAV256soft170 kB300GCR[24]
2340 kB
Quad177Variable (23-29) ZCAV521 kB
21,042 kB
3 inchDouble28010512800 kBMFM 
Commodore Amiga5 inchDouble24011512soft440 kB[25] 300MFM[26]
Quad80880 kB[27]
3 inchDouble880 kB
High191,520 kBGCR[28]
221,760 kB150MFM
Commodore 9005 1/4 inchHigh28013-16512Soft1,200kB?GCRhttps://vintagecomputer.ca/files/Commodore/C900/C900%20Floppy%20Specification.pdf
IBM 33FD8 inchSingle17726128240.5 kiB360FMDiskette 1[29]
15256277.5 kiB
8512296 kiB
IBM 43FD226128481 kiBDiskette 2
15256555 kiB
IBM 53FDDouble26256962 kiBMFMDiskette 2D
155121.08 MiB
81,0241.16 MiB
DEC RX018 inchSingle17726128250 kB360FM
DEC RX028 inchDouble17726256500 kB360FM/MFM
DEC RX505 inchQuad18010512400 kB300MFM
IBM PC compatibles8 inchSingle17726128soft250.25 kB[30] [31] [32] 360FM[33]
2500.5 kB
Double181,024616 kBMFM
21,232 kB
5 inchDouble1408512160 kB300MFM 
2320 kB
19180 kB
2360 kB
Quad[34] 1808320 kB300
2640 kB
High280151,200 kB360
3 inchDouble1808512320 kB300MFM
9360 kB
28640 kB
9720 kB
High181,440 kB
211,680 kBDMF[35]
821,720 kB
Extended80362,880 kB
MGT SAM Coupé3 inchDouble28010512800 kB300MFM 
NEC PC988 inchSingle17726128250.25 kB360FM 
Double27781,0241,232 kBMFM
5 inchDouble2808512640 kB360MFM
9720 kB
High151,200 kB
77 (80)81,0241,232 (1,280) kB[36]
3 inchDouble2808512640 kB360MFM
9720 kB
High151,200 kB3-mode[37]
77 (80)81,0241,232 (1280) kB
80185121.44 MB300
Triple240385129,120 kB360NEC PC-88 VA3 2TD drive only
Osborne 1[38] 5 inchSingle14010256soft100 kB300FM
Double51,024200 kBMFM
Sega SF-70003 inchSingle24016256160 kB??Expansion unit for SC-3000 home computer. Capacity is per side.[39]
SHARP X680005 inchHigh27781,0241,232 kB360MFM 
3 inch
SHARP CE-1600F, CE-140F2 inchSingledrive: 1, diskette: 2 (flippable)1685122× 64 kB270GCR (4/5)Internally based on FDU-250 Micro Floppy Disk Drive Unit
Thomson5 inchSingle1401612880 kB300FMThomson UD90.070
Double2256320 kBMFMThomson DD90-320[40]
3 inchDouble18016256320 kB300MFMThomson TO9, Thomson DD09-350
Double2640 kBThomson TO8D, TO9+, Thomson DD90-352[41]
Victor 9000 / ACT Sirius 1[42] 5 inchSingle18011-19 (variable)512612 kB[43] 252-417 (variable)GCRDisks varied sectors / track and disk speed to keep consistent bit density across tracks
Double25121,196 kB
Tandy TRS-805 inchSingle13510256soft88 kB300FMModel 1/3/4
5 inchDouble14018256180 kBMFMModel 1/3/4P
5 inchDouble24018256360 kBMFMModel 4D
8 inchDouble17726256500 kBMFMModel 2
3 inchSingle14021,280100 kB[44] FMTandy Portable Disk Drive (aka Brother FB-100, knitking FD-19)
3 inchSingle18021,280200 kB[45] FMUsed only in Tandy Portable Disk Drive 2
5 inchDouble13518256157 kB[46] MFMColor Computer
HP 9114A3 inchDouble28016256128-710kB[47] 600MFMUsed with HP 110 and Portable Series 40 & 70
HP 9895A8 inchDouble277292561.18 MB[48] 360MFM
HP 9130K5 inchDouble23516256286 kB[49] 300MFM
Burroughs MD1228 inchDouble213944256soft6.26 MB[50] 524MFM
Memorex 6508 inchsingle15083,500 bhard1.4 Mb375FM
Memorex 651single64321.056 b2.2 Mb
!Platform!Size!Density!Side!Track!Sector!Byte!Sectoring!Capactiy!RPM!Encoding!Note
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

References

External links

Notes and References

  1. US4609949A. Magnetic disc reproducing apparatus. 1986-09-02. Kutaragi. Ken.
  2. Book: Sharp PC-1600 Service Manual . July 1986 . Sharp Corporation, Information Systems Group, Quality & Reliability Control Center . Yamatokoriyama, Japan . 98–104 . Model CE-1600F . 2017-03-23 . https://web.archive.org/web/20170323132153/http://sharppocketcomputers.com/4HK7JnFJDuVm/Service/ce1600f_service_manual.pdf . 2017-03-23 . live.
  3. Book: Sharp Service Manual Model CE-140F Pocket Disk Drive . . 00ZCE140F/SME . 2017-03-11 . https://web.archive.org/web/20170311145818/http://pockemul.free.fr/Documents/ce-140f_Service_manual.pdf . 2017-03-11 . live.
  4. Book: Tabor TC-500 Specifications . Tabor Corp . USA . en . https://web.archive.org/web/20220112061305/https://twitter.com/Foone/status/1316017501621215233/photo/1 . 12 Jan 2022.
  5. Web site: PF-10 . . 1984 . Epson . November 30, 2022 . https://web.archive.org/web/20200621102808/http://electrickery.xs4all.nl/comp/px8/doc/PF-10Manual.pdf . June 21, 2020.
  6. Web site: Floppy Drive Tech Info . 2023-07-06 . www.retrotechnology.com.
  7. Book: NEC μPD72070 - Floppy Disk Controller Specification Version 2.0 . 2.0 preliminary . . October 1991 . 2017-03-20 . dead . https://web.archive.org/web/20170320235834/http://dec8.info/Apple/uPD72070.pdf . 2017-03-20 .
  8. Web site: ハードウエア. https://web.archive.org/web/20170618120229/http://www.pc88.gr.jp/va/va-hard.html . 2017-06-18 . live . ja . NEC PC-88VA . Hardware .
  9. US4482929A. Magnetic recording disk cartridge. 1984-11-13. Beck. Bornhorst. Smith. Zell. John L.. Randy J.. Donald J.. Michael N..
  10. Web site: 1986 . Fujitsu Sales Prospector 1986 . 2023-11-07 . Archive.org . 238.
  11. Web site: 1985-01-06 . コンピュータ・情報システム・パソコン・周辺機器 . Hitachi Computer Peripherals . 2023-11-07 . hitachihyoron.com . 9 .
  12. Book: Berry, D . Lisa Hardware Manual . 7 September 1982 . Apple Computer Inc. . 9–1.
  13. Web site: 1986 . Fujitsu Sales Prospector 1986 . Archive.org . 238,239.
  14. Web site: 1984-08-03 . 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 . 2023-11-07 . hitachihyoron.com . 3.
  15. Book: 650 Flexible Disc File OEM Manual 2944.010 . Memorex Corp . 1972 . 9 . en.
  16. Book: Memorex Markette Flexible Discs . Memorex Corp . 1978 . USA . 1–2 . en.
  17. Book: Memorex 651 Flexible Disc File OEM Manual . Memorex Corp . 1977 . USA . 4 . en.
  18. Custom controller with unique track layout.https://github.com/sintech/AGAT/blob/master/docs/agat-840k-format.txt
  19. 16 sector filesystems require a compatible disk controller (PROM update) and Apple DOS 3.3 or later.
  20. Apple II double-density 3-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. https://support.apple.com/kb/TA39910?locale=en_US&viewlocale=en_US
  21. Apple II high-density 3-inch (90 mm) drives require a compatible disk controller and ProDOS 8.
  22. Web site: Apple's Twiggy Disks . 2023-10-11 . www.brouhaha.com.
  23. Third party drives offer up to 1440 KB.
  24. Commodore floppy drives used a fixed rotation speed with variable sector density (see: Zone bit recording).
  25. This format was used by the Amiga 1020 external floppy drive and some third-party drives connected to the normal Amiga floppy drive bus.
  26. 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).
  27. 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.
  28. 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.
  29. Book: The IBM Diskette General Information Manual . IBM . 1979 . USA . 18–19 . Reference Manual.
  30. The calculated formatted capacity is based on FAT12 format.
  31. Web site: Standard Floppy Disk Formats Supported by MS-DOS . Microsoft . 2000-12-17 . 2020-02-05 . 2.0.
  32. Book: Xerox . November 1983 . Xerox 16/8 Professional Computer – MS-DOS OS Handbook for 8" Floppy Disks .
  33. 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.
  34. Rare format appearing on some early PC/XT clones using quad-density disks.
  35. These variations are known as DMF diskettes, used for a time to pack more data on to each disk for software distribution.
  36. Inner 3 tracks of 8 sectors/track format are unused.
  37. The PC98 3-inch (90 mm) formats are also known as "3 Mode" floppy disks, usable on IBM PC compatibles with a 3-mode floppy drive.
  38. Book: Hogan . Thom . Osborne 1 Technical Manual . Iannamico . Mike . 1982 . Osborne Computer Corporation . 39.
  39. Web site: Sega SF-7000 Super Control Station User Guide . Sega Enterprises . 2020-02-10.
  40. The two sides are managed as two independent 160 KB disks
  41. The two sides are managed as two independent 320 KB disks
  42. Web site: Victor 9000 Hardware Reference Manual . 2022-09-12 . https://web.archive.org/web/20220129140512/http://bitsavers.org/pdf/victor/victor9000/Victor_9000_Hardware_Reference_Manual_1983.pdf . 2022-01-29 . live.
  43. News: Victor Victorious . . November 1982 . 2013-10-19 . Lemmons . Phil . 216.
  44. Book: Tandy Portable Disk Drive Operation Manual 26-3808 . Radio Shack . 1985 . Japan . 25.
  45. Book: Tandy Portable Disk Drive 2 Operation Manual 26-3814 . Radio Shack . 1986 . Japan . 33.
  46. Book: Radio Shack Hardware Manual: Color Computer Disk System Owners Manual (1981)(Tandy) . 1981.
  47. Book: 9914A Disc Drive . Hewlett-Packard . 1 June 1984 . 1-2 . en.
  48. Book: 9895A Flexible Disc Users Manual . Hewlett-Packard Desktop Computer Division . 1978 . Fort Collins, Colorado USA . 6 . en.
  49. Book: HP 9130K Flexible Disc Drive Service Documentation . Hewlett-Packard Greeley Division . 1981 . Fort Collins, Colorado USA . en.
  50. Book: Burroughs MD 122 Brochure . Burroughs Marketing . 1979 . USA . 2 . en.

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