Samsung Electronics Co., Ltd.

Soo Il Choi

Sang Hoon Chu

Jun Seok Shim

Tung Thanh Nguyen

Kang Seok Lee

Seong Hwan Yu

Seong Hwon Yu

The present invention is a method and apparatus for positioning a read/write head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, where each of the tracks has a servo field with servo bits. The servo bits are read to provide a position signal for positioning a read/write head. The method determines a difference in position between an initial and a subsequent position of the read/write head on a track, where the subsequent location occurs after the read/write head has moved one revolution from the initial position on the track. The initial and subsequent positions are offset laterally. The method generates a compensation signal based on the initial position, the subsequent position and the difference. The position signal and the compensation signal are combined to provide a compensated position signal for positioning the read/write head. Various embodiments are described.

Method and apparatus for providing positional information on a disk

The present disclosure relates to a system for detecting a plurality of defect types on the surface of a disk in a hard disk drive. In particular, the disclosure relates to utilizing information obtained from a plurality of servo bits to determine if a sector contains a physical defect. Where such a defect is found, the sector's write gate is disabled and its burst signal data is ignored for track following purposes. In addition, large changes in PES are used to identify closure spike defects. Such defects are managed by providing a compensation signal to the read value of the PES to improve track following. Finally, high PES values are used to signal a third defect type where no other signs of defect are present. In such case, the sector is mapped as defective, but the burst signals continue to be used for track following purposes.

Servo defect management scheme in hard disk drives

An apparatus, method and computer program product for a hard disk drive defect detection system. In one embodiment, a method of detecting defects on the surface of a disk having a plurality of tracks is recited. The method comprises reading, one or more times, the servo bits for a plurality of sectors and determining a burst measure for at least one sector, where the burst measure is a function of the burst signals for the sector. This method further comprises determining a reference value, where the reference value is a function of the burst signals of the plurality of sectors, and comparing the burst measure of at least one sector to the reference value to identify a potential defect. In one embodiment, a sector is mapped as defective where its burst measure differs from the reference value by at least 5 percent.

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Santa Clara, CA, United States of America

Soo Il Choi