Floppy disk

A floppy disk is a data storage medium that is collected of a disk of thin, flexible ("floppy") magnetic storage medium covered in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be perplexed with "fixed disk drive", which is one more term for a hard disk drive.

Floppies come in three essential sizes:

8-inch: The first floppy disk design, imaginary by IBM in the late 1960s and used in the early 1970s as first a read-only format and then as a read-write format. The typical desktop/laptop computer does not employ the 8-inch floppy disk.

5¼-inch: The ordinary size for PCs made before 1987 and the precursor to the 8-inch floppy disk. This type of floppy is usually capable of storing between 100K and 1.2MB (megabytes) of data. The most ordinary sizes are 360K and 1.2MB.

3½-inch: Floppy is something of a misnomer for these disks, as they are covered in an unbending envelope. In spite of their small size, microfloppies contain a larger storage capacity than their cousins -- from 400K to 1.4MB of data. The most common sizes for PCs are 720K (double-density) and 1.44MB (high-density). Macintoshes hold up disks of 400K, 800K, and 1.2MB.