Patent ID: 7457072

Claim:
A magnetic recording disk drive comprising: a magnetic recording disk having a plurality of generally concentric data tracks arranged in a plurality of radially-spaced bands, each of the data tracks having a plurality of angularly spaced data sectors and a plurality of angularly spaced servo sectors containing servo information; an air-bearing slider maintained near the surface of the disk when the disk is rotating; a read/write head on the slider for reading and writing data in the data sectors and reading servo information in the servo sectors; a data controller coupled to the head for selecting a data track and data sector where data is to be read or written; a head-positioning actuator for moving the slider and attached head to a selected data track in response to servo information read by the head; a thermal fly-height actuator comprising a heater located on the slider near the head for moving the head relative to the slider to change the head-disk spacing; and a fly-height controller coupled to the data controller and the fly-height actuator for sending a control signal representing a value of heater power to the fly-height actuator to change the head-disk spacing in response to the selected data track and data sector, the head-disk spacing being a function of heater power; memory coupled to the fly-height controller for storing a set of band control signal (BCS) values, each of said BCS values being associated with a unique one of said bands and representing an optimal head-disk spacing for said associated band, and a plurality of sector control signal (SCS) values, each of said SCS values being associated with a unique angular position of the disk and representing an optimal head-disk spacing for said associated angular position, the number of stored SCS values being less than the number of angularly spaced servo sectors; and a program of instructions stored in said memory and readable by the fly-height controller for undertaking the method acts of: receiving from the data controller a selected data track and data sector where data is to be read or written; selecting the BCS value associated with the band containing the selected data track; selecting the SCS value associated with the disk angular position nearest the selected data sector; summing the selected BCS value with the selected SCS value to generate a fly-height control signal; and applying the fly-height control signal to the fly-height actuator to change the head-disk spacing at the selected data sector prior to reading or writing to the selected data sector.