Per disk
the upper part of a magnetic disk, called {sector}
a disk coated with cellulose acetate
the usable capacity of a disk drive
a device of a computer that drives a floppy disc, called disc drive
the disk space that is set aside for virtual memory
the part of a floppy disk or hard disk where information is stored about the location of each piece of information on the disk (and about the location of unusable areas of the disk)
a disk on which digital data is minutely recorded by a laser beam and then read