When a disk is formatted it is organized into tracks of concentric
rings, each containing some number of sectors. The sectors are usually
of a constant angular size, meaning that the sectors toward the
outside edge of the disk have a greater area than the sectors closer
to the center(the early Macintosh disk format is a notable
exception). Nevertheless, all sectors on the disk contain the same
number of bytes. In this scheme, the disk is always spun at a constant
angular velocity(CAV).

Sometimes floppy disks are advertised with an unformatted capacity
that is larger than that of a formatted disk. Formatted disks have a
smaller capacticy because they require sector and track control/header
information to be stored on the disk as well as the data to be stored.

Disks can also be either single or double-sided. Disk drives with only
one read/write head require that double-sided disks be flipped in
order to read the other side. Newer floppy drives are capable of
reading either side of the disk.

Most common formats:

5.25 inch
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(Bytes/sector, Sectors/track, Tracks/side, Sides, Formatted Capacity, RPM, Encoding)
IBM PC DSDD (512, 9, 40, 2, 360KB, 300, MFM)
IBM PC HD (512, 15, 80, 2, 1200KB, 360, MFM)


3.5 inch
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(Bytes/sector, Sectors/track, Tracks/side, Sides, Formatted Capacity, RPM, Encoding)
IBM PC DSDD (512, 9, 80, 2, 720KB, 300, MFM)
IBM PC HD (512, 18, 80, 2, 1440KB, 300, MFM)
Commodore Amiga DD (512, 11, 80, 2, 880KB, 300, MFM)
Macintosh SSDD (512, 8-12, 80, 1, 400KB, 394-590, GCR)
Macintosh DSDD (512, 8-12, 80, 2, 800KB, 394-590, GCR)
Macintosh HD (512, 18, 80, 2, 1440KB, 300, MFM)