A flopy disk is a reusable magnetic storage medium.  It was invented by IBM and introduced in the early 1970s as an  8" square format, floppies have been the primary method for distributing personal computer software up until the mid 1990s when the CD-ROM became a competitive medium.CD-ROM's are cheaper and eser to produce and last longer.  Floppies are widely used for backup and to transfer data between users that are not attached to a network.
    Also called a diskette, the floppy is a flexible circle of magnetic material similar to magnetic tape, except that both surfaces are used for recording. The drive grabs the floppy's center and spins it inside its housing. The read/write head contacts the surface through the litle opening in the disks casing..
     Floppies spin at 300 rpm, at least one-tenth the speed of a hard disk. They are also at rest until a data transfer is requested. In order of last to first developed, the following chart shows the capacities of all the floppies that have been used since their inception. Today, the common 3.5" format holds 1.44MB.
 

External format Capacity Creator 3.5" rigid case	400KB - 2.8MB	Sony
5.25" flexible envelope	100KB - 1.2MB	Shugart
8" flexible envelope	100 - 500KB	IBM

    Although floppy disks look the same, what's recorded on them determines their capacity and compatibility. Every new floppy must be "formatted," which records the sectors on the disk that hold the data. See format program, magnetic disk and high-capacity floppy.
 

 

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This page was compiled from http://www.techweb.com/encyclopedia/defineterm?term=FLOPPYDISK