Definitions for "Bit density"
Keywords:  bpi, tape, bpmm, magnetic, centimetre
Bit density is a measure of the number of bits encoded on magnetic tape per unit of distance (millimeter or inch). On banking and financial cards encoded to ISO standards, track 2 is encoded at 2.95 bits per millimeter (75 bits per inch); tracks 1 and 3 are 8.27 bits per millimeter (210 bits per inch). character- A character is one alphabetic or numeric symbol that is formed by joining individual bits to form intelligible data.
The number of bits per unit length recorded on a magnetic medium. On ISO standard identification cards track 1 and track 3 are recorded at 8.3 bpmm and track 2 at 3 bpmm
Number of bits that can be placed, per unit area or volume, on a storage medium (eg bits per inch of magnetic tape).