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.

Abstract: A disk drive with a write condition detector generates a write condition signal from a reference signal to warn of a high fly write or a low fly write. The reference signal is generated by the disk drive read/write head by reading a reference segment. The write condition detector processes fly-height varying components from the reference signal. The write condition detector generates a write condition signal, responsive to the fly-height varying components and the threshold, that indicates that the writing of data in a user data segment during the write operation is unsafe when the head deviates from its operating flying-height. The threshold is computed using zone coefficients determined during an intelligent burn in of the disk drive, and is based on a nominal fly height. The write condition signal is processed by a microprocessor that instructs a disk controller to deactivate a write gate controlling the write operation.

Abstract: The present invention provides a method of operating a disk drive having data sites on a disk for recording data thereon. The disk drive is connectable to a host computer and maintains a defect table comprising defective sites reportable to the host computer. The method includes the step of discovering a defective data site on the disk. The defective data site is bounded with a first tier of marginal data sites which are selected based on their proximity to the defective data site. The first tier of marginal data sites is bounded with a second tier of reserved data sites which are selected based on their proximity to the first tier of marginal data sites. The locations of the defective data site, the first tier of marginal data sites and the second tier of reserved data sites are stored in a defect table. The defective data sites and the first tier of marginal data sites are marked as defective sites reportable to the host.