A measure of the amount of information in a given dimension of a storage
medium. For magnetic tape it is the amount of information recorded per unit
length of tape, usually in bits per inch or bits per millimeter. In general the
number of flux reversals per inch (or per mm) is greater because of redundancy
in the coding. The density is stated for a single track. A tape transport can
often read tapes with different densities under program control.
The density of information on a disk is almost always a fixed number of bits per
sector, sectors per track, and tracks per disk. The standard density for paper
tape is usually 10 holes per inch on a single track.