This is a list of different floppy disk formats.
Physical formats +Size Density Sides Tracks tpi bpi Sectoring Coercivity Unformatted capacity per side2 inch Video Floppy52256>800 kB or 50 fields of analog video2 inch LT-1Double80245 2 inch Single 16 48 64 kB 3 inch QuickDisk 3.25 inchSingle1801404,625250 kBDouble9,250500 kB 3 inch Single 2 40 67.5 8,650 Soft 665 Oe 250 kBDouble 80 135 8,717 665 Oe 500 kB High 80 135 17,434 720-750 Oe 1 MB Extended 80 135 34,868 900 Oe 2 MBTriple 240 406.5 36,700 6.5 MB4 inch DemiDiskette1 5 inch Single/Double 2 40 48 5,876 Soft or hard 300 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 Soft 600 Oe 833 kBEH10412529,5606.5 MB5 inch Apple FileWareDouble28062.5Soft851 kiB 8 inch Single 77 48 3,268-3,408Soft or hard (inner edge) 300 Oe 1 MBDouble6,8161 MBHD1549620,560600 Oe9.6 MB8 inch Memorex FD6501502,400Hard (outer edge)1.5 Mb651643,1002.5 Mb8 inch BurroughsDouble21391507,1001.57MB
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 platformPlatform Size Density Sides Tracks/ side Sectors/ track Bytes/ sector Sectoring Capacity rpm Encoding Note Acorn 5 inch Single 1 40 10 256Soft 100 kB 300 FM 80 200 kB Double 1 40 16 256 160 kB MFM 80 320 kB 2 640 kB 3 inch Double 2 80 16 256 640 kB 300 MFM Format L: MOS (Electron, Master Compact) 5 1024 800 kB High 10 1,600 kB Format F: RISC OS 3 and later. Archimedes models before the A5000 require an upgraded floppy drive. Agat 5 inch Double 2 80 21 256 840 kB 300 MFM Custom controller with unique track layout. Amiga 5 inch Double 2 40 11 512 Soft 440 kBThis format was used by the Amiga 1020 external floppy drive and some third-party drives connected to the normal Amiga floppy drive bus. 300 MFM 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). Quad 80 880 kBFormat 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. 3 inch Double 880 kB High 19 1,520 kB GCR 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. 22 1,760 kB 150 MFM Amstrad CPC/PCW 3 inch Double 1 40 9 512 180 kB 300 MFM Single head drive, but double-sided floppy discs (total of 360 kB per floppy) Amstrad PCW8512/9512 3 inch Double 2 80 9 512 720 kB 300 MFM 720 kB mode uses both sides - ensure disc inserted correct way up. Apple II 5 inch Double 1 35 13 256 Soft 113.75 kB 300 GCR 16 sector filesystems require a compatible disk controller (PROM update) and Apple DOS 3.3 or later. 1 16 140 kB 3 inch Double 1 80 Variable (8-12) 512 400 kB 394 - 590 GCR 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. 2 800 kB High 2 80 18 512 1,440 kB 300 MFM Apple II high-density 3-inch (90 mm) drives require a compatible disk controller and ProDOS 8. Apple Lisa 5 inch FileWare Double 2 46 Variable (15-22) 512Soft 851 kB 218 - 320 GCR Apple Lisa 2/Macintosh XL, Macintosh 3 inch Double 1 80 Variable (8-12) 512 Soft 400 kB 394 - 590 GCR Macintosh 2 800 kB High 2 80 18 512 1,440 kB 300 MFM Atari 8-bit 5 inch Single 1 40 18 128 Soft 90 kB 288 FM Third party drives offer up to 1440 KB. Dual 26 128 130 kB MFM Double 18 256 180 kBDouble218256360 kB300 Atari ST/TT/Falcon 3 inch Double 1 80 9 512 Soft 360 kB 300 MFM 2 720 kB High 18 1,440 kBBurroughs MD1228 inchDouble213944256Soft6.26 MB524MFM Coleco ADAM 5 inch Double 1 40 8 512soft 160 kB 300 MFM Commodore 64 (8-bit) 5 inch Double 1 35 Variable (17-21) ZCAV 256 Soft 170 kB 300 GCR Commodore floppy drives used a fixed rotation speed with variable sector density (see: Zone bit recording). 2 340 kB Quad 1 77 Variable (23-29) ZCAV 521 kB 2 1,042 kB 3 inch Double 2 80 10 512 800 kB MFM Commodore 128 (CP/M) 5 1/4Double24026128Soft260K300MFMCommodore 1571 16256320K9512360K51,024400KCommodore 9005 inchHigh28013-16512Soft1,200kB?GCR DEC RX018 inchSingle17726128250 kB360FMDEC RX028 inchDouble17726256500 kB360FM/MFM DEC RX50 5 inch Quad 1 80 10 512 400 kB 300 MFMHP 1103 inchDouble2769512710kB600MFMHP 9114AHP 80 9800 1000 and 30008 inchDouble277302561.18 MB360MFMHP 9895AHP 865 inchDouble23516256280 kB300MFMHP 9130KIBM 33FD8 inchSingle17726128240.5 kiB360FMDiskette 115256277.5 kiB8512296 kiBIBM 43FD226128481 kiBDiskette 215256555 kiBIBM 53FDDouble26256962 kiBMFMDiskette 2D155121.08 MiB81,0241.16 MiB IBM PC compatibles 8 inch Single 1 77 26 128 Soft 250.25 kBThe calculated formatted capacity is based on FAT12 format. 360 FM 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. 2 500.5 kB Double 1 8 1,024 616 kBMFM 2 1,232 kB 5 inch Double 1 40 8 512 160 kB 300 MFM 2 320 kB 1 9 180 kB 2 360 kB QuadRare format appearing on some early PC/XT clones using quad-density disks. 1 80 8 320 kB 300 2 640 kB High 2 80 15 1,200 kB 360 3 inch Double 1 80 8 512 320 kB 300 MFM 9 360 kB 2 8 640 kB 9 720 kB High 18 1,440 kB 21 1,680 kB DMFThese variations are known as DMF diskettes, used for a time to pack more data on to each disk for software distribution. 82 1,720 kB Extended 80 36 2,880 kBMemorex 6508 inchSingle15083,500 bHard1.4 Mb375FMMemorex 651Single64321.056 b2.2 Mb MGT SAM Coupé 3 inch Double 2 80 10 512 800 kB 300 MFM NEC PC-98 8 inch Single 1 77 26 128 250.25 kB 360 FM Double 2 77 8 1,024 1,232 kB MFM 5 inch Double 2 80 8 512 640 kB 360 MFM 9 720 kB High 15 1,200 kB 77 (80) 8 1,0241,232 (1,280) kBInner 3 tracks of 8 sectors/track format are unused. 3 inch Double 2 80 8 512 640 kB 360 MFM 9 720 kB High 15 1,200 kB 3-modeThe 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. 77 (80) 8 1,024 1,232 (1,280) kB 80 18 512 1.44 MB 300 Triple 240 38 512 9,120 kB 360 NEC PC-88 VA3 2TD drive only Osborne 1 5 inch Single14010 256Soft 100 kB 300 FM Double5 1,024 200 kB MFM Sega SF-7000 3 inch Single 2 40 16 256 160 kB ? ? Expansion unit for SC-3000 home computer. Capacity is per side. SHARP X68000 5 inch High 2 77 8 1,024 1,232 kB 360 MFM 3 inch SHARP CE-1600F, CE-140F 2 inch Single drive: 1, diskette: 2 (flippable) 16 8 512 2× 64 kB 270 GCR (4/5) Internally based on FDU-250 Micro Floppy Disk Drive UnitTandy TRS-805 inchSingle13510256Soft88 kB300FMModel 1/3/45 inchDouble14018256180 kBMFMModel 1/3/4P5 inchDouble24018256360 kBMFMModel 4D8 inchDouble17726256500 kBMFMModel 23 inchSingle14021,280100 kBFMTandy Portable Disk Drive (aka Brother FB-100, knitking FD-19)3 inchSingle18021,280200 kBFMUsed only in Tandy Portable Disk Drive 25 inchDouble13518256157 kBMFMColor Computer Thomson 5 inch Single 1 40 16 128 80 kB 300 FM Thomson UD90.070 Double 2 256 320 kB MFM Thomson DD90-320The two sides are managed as two independent 160 KB disks 3 inch Double 1 80 16 256 320 kB 300 MFM Thomson TO9, Thomson DD09-350 Double 2 640 kB Thomson TO8D, TO9+, Thomson DD90-352The two sides are managed as two independent 320 KB disks Victor 9000 / ACT Sirius 15 inchSingle18011-19 (variable)512612 kB252-417 (variable)GCRDisks varied sectors/track and disk speed to keep consistent bit density across tracksDouble25121,196 kB Vtech Laser210/VZ200 5 inch Single ? 40 16 ? Soft 78 kB ? FM RPM: 75. +PlatformSizeDensitySideTrackSectorByteSectoringCapacityRPMEncodingNoteIBM PC Compatible5 1/4Quad28031512Soft2.5MB300MFMRana 2000 with Rana controller card
See also Zip drive (floppy-like, but incompatible medium using different technology) PocketZip (floppy-like, but incompatible medium using different technology) SuperDisk (floppy-like with drives also compatible with 3.5" floppy disks) Magneto-optical drive (floppy-like, but incompatible medium using different technology) List of Ecma standards (ECMA standards 54, 59, 66, 69, 70, 78, 99, 100, 125 and 147)
Notes
References (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. )
External links
Floppy Disk Formats at the Museum of Obsolete Media