Patent ID: 9064526
Filing Date: 2015-06-23
Classification: G11B

Abstract:
1. A disk drive apparatus, comprising: a disk having a disk surface; a head movable over the disk surface to write data on the disk; a head positioning mechanism configured to control a position of the head over the disk surface; and a controller configured to determine a demodulated positioning error from a demodulated position and a target position to control the head positioning mechanism, the demodulated position being obtained by demodulating a servo signal readout from the disk, wherein the controller is configured to: estimate a demodulation noise amount included in the demodulated position on the basis of a signal quality of the servo signal; correct a predetermined off-track threshold with a correction value which is obtained from the estimated demodulation noise amount; and inhibit a write operation of writing data on the disk, if the demodulated positioning error exceeds the corrected off-track threshold.