WRITE CURRENT AND FLY HEIGHT ADJUSTMENT FOR COMPENSATING MEDIA COERCIVITY VARIATION

摘要

A data storage device with compensation for coercivity variations in a magnetic disk storage medium is disclosed. Two procedures are executed to perform the coercivity compensation. In a first procedure, typically performed prior to writing of data, the coercivity at a number of locations on the disk is measured and stored. A second procedure writes data to locations on a magnetic disk storage medium having varying coercivities. To maintain writing widths within predefined limits, a writing parameter is varied according to a predetermined relationship between the value of the writing parameter and the coercivity. Choices of writing parameter comprise the writing current and fly height. The method may be employed for both data writing and self-servo writing of servo patterns.

主权项

1. A method for adjusting a writing parameter of a disk drive to compensate for variations in coercivity from a nominal coercivity in a magnetic storage medium, comprising:
a first procedure, comprising:
defining a multiplicity of measurement locations on the magnetic storage medium;measuring the coercivity at each measurement location in the multiplicity of measurement locations; andstoring the measured coercivities and measurement locations; and a second procedure, comprising:
receiving a writing location at which data is to be written from a control system of the disk drive;calculating a writing coercivity at the writing location using the measured coercivity values and measurement locations stored in the first procedure;modifying the writing parameter to compensate for deviations of the writing coercivity from the nominal coercivity; andwriting data to the magnetic storage medium using the modified writing parameter.