Disk drive employing method of monitoring transducer flying height to retire defective data site on recording surface

Abstract

A disk drive employs a method of monitoring a transducer flying height to retire a defective data site on a disk. The transducer is designed to comply with a fly-height specification while flying above the disk. In one aspect, the method includes generating a warning signal representing a condition in which the transducer is flying outside the fly-height specification as a result of flying above a defect site within a physical sector having a physical sector address. The method includes associating the warning signal with a defect site address that points to the defect site and storing the defect site address in a defect discovery table. The method further includes using the defect discovery table to locate the physical sector address. The method includes storing the physical sector address in a defect management table to retire the physical sector. In another aspect, the method includes reading data stored in a data region on the disk to produce a read signal having a first fly-height varying component and a second fly-height varying component. The method further includes generating a warning signal responsive to the first and second fly-height varying components and a threshold value when the transducer means is flying outside the fly-height specification. The method includes retiring the defective data site on the disk in response to the warning signal.