The recording density , also known as storage , data or data recording density , is a measure of the number of data per unit area , length or weight that can be stored on a data carrier . For magnetic tapes , BPI (bits per inch = bits per inch ) or FCI (flux changes per inch = flux changes per inch ) is usually used as the unit of measurement , and bits per square inch for hard drives .
The terms single density , double density , quadruple density , high density and extended density or their English counterparts single density (SD) , double density (DD) , quadruple density (QD) , high are used mainly in connection with floppy disks , but also magnetic tapes Density (HD) and extra-high density (ED) used. These indicate the ratio of the recording density to a standard density.
In the case of magnetic data carriers, the recording density depends, among other things, on the material with which the storage medium is coated. The higher the recording density, the larger the storage capacity .
- Hermann Strass: Technology Trends for hard drives & Co . TEC CHANNEL, March 15, 2001, updated April 7, 2003, accessed October 18, 2007.