Floppy disk

A floppy disk is a data storage device that is composed of a ring of thin, flexible (i.e.

"floppy") magnetic storage medium encased in a square or rectangular plastic wallet. Floppy disks

are read and written by a floppy disk drive or FDD, the latter initialism not to be confused with

"fixed disk drive", which is an old IBM term for a hard disk drive.

Floppy disk format Year introduced

Storage capacity

(binary kilobytes if not

stated)

Marketed

capacity¹

8-inch (read-only) 1969 80 ←

8-inch 1972 183.1 1.5 Megabit

8-inch 1973 256 256 KB

8-inch DD 1976 500 0.5 MB

5¼-inch (35 track) 1976 89.6 110 KB

8-inch double sided 1977 1200 1.2 MB

5¼-inch DD 1978 360 360 KB

3½-inch

HP single sided

1982 280 264 KB

3-inch 1982] 360 ←

3½-inch (DD at release) 1984 720 720 KB

5¼-inch QD 1984 1200 1.2 MB

3-inch DD 1984 720 ←

3-inch

Mitsumi Quick Disk

1985 128 to 256 ←

2-inch 1985 720 ←

5¼-inch Perpendicular 1986] 100 MiB ←

3½-inch HD 1987 1440 1.44 MB

3½-inch ED 1991 2880 2.88 MB

3½-inch LS-120 1996 120.375 MiB 120 MB

3½-inch LS-240 1997 240.75 MiB 240 MB

3½-inch HiFD 1998/99 150/200 MiB] 150/200 MB

Acronyms: DD = Double Density; QD = Quad Density; HD = High Density ED = Extended

Density; LS = Laser Servo; HiFD = High capacity Floppy Disk

¹The marketed capacities of floppy disks frequently corresponded only vaguely to their their actual

storage capacities; the 1.44 MB value for the 3½-inch HD floppies is the most widely known

example. See reported storage capacity.

Dates and capacities marked ? are of unclear origin and need source information; other listed

capacities refer to:

• For 8-inch: standard IBM formats as used by the System/370 mainframes and newer

systems

• For 5¼- and 3½-inch: standard PC formats, capacities quoted are the total size of all sectors

on the disk and include space used for the bootsector and filesystem

Other formats may get more or less capacity from the same drives and disks.