Optical Method for Compensating Disk Diameter Variations in Flexible Disk Devices
Original Publication Date: 1985-Jun-01
Included in the Prior Art Database: 2005-Feb-18
Present track densities in flexible disk files without servo control are limited to approximately 100 tracks per inch (tpi). Greater densities for floppy disk drives can only be achieved if variables, such as temperature, humidity, disk runout, and head positioning inaccuracies, can be compensated for. This disclosure demonstrates how the use of an optical sensor, when placed at the edge of a floppy disk, can detect changes due to temperature, humidity, and disk runout. When this arrangement is used in conjunction with an accurate head- positioning mechanism, much greater track densities can be achieved. Manufacturers that compensate for these environmental and mechanical variations to achieve high track densities are currently using disks that have been encoded with magnetic or optical servo information.