The limits to magnetic recording

Magnetic recording has been used for high-capacity data storage because it possesses three key attributes: (1) no processing required between writing and reading, (2) infinite reversibility, and (3) the storage density could always be increased as needed. The author examines evidence that the latter is approaching limits to the technology. He shows that the two components of storage density, bits/inch (bpi) measured along the track and tracks/inch (tpi) measured along a radius in the case of disks (or perpendicular to the tracks in a general medium) are entering a period of diminishing improvement over time.<>