Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Theofilos George Fkiaras

Bernd Lamberts

Kris Victor Schouterden

David H Jen

Xiaoyu Sui

Douglas Michael Zuercher

Hoan Andrew Au

James M Dervin

Au Hoan Andrew

Dennis R Chan

Data recovery information characterizes data recovery procedure (DRP) steps to be performed within a hard disk drive (HDD) in response to a miss. Particular data recovery information corresponds to a radial position of the actuator and, therefore, the position of the magnetic recording read/write head relative to the associated storage media at the location at which the miss occurred. The data recovery information is based on the physical shape of a write pole and on how the physical shape of the pole inherently affects operational data error associated with the head. Because of the foregoing characteristics of such data recovery information, a more efficient and performant data recovery procedure is performed based thereon.

Adaptive data recovery procedure based on radial positioning

A method and system for adaptively limiting an off-track recovery displacement of a recording head during an off-track data recovery operation. A head disk assembly (HDA) includes an actuator that positions the recording head in accordance with an actuator control signal. First, an off-track recover displacement threshold is determined utilizing an off-track data field which overlays an on-track data field. The recording head is displaced with respect to the track center until the on-track data field is read. The relative displacement required to retrieve the on-track data is utilized as the threshold. In response to a failed read attempt, a data recovery procedure commences whereby the recording head is incrementally displaced from the track center while attempting to recover the data. During the DRP, the predetermined off-track recovery threshold is utilized to limit the head displacement such that the input/output (I/O) data integrity of the off-track recovery is ensured.

Adaptive off-track recovery

In summary, preferred embodiments disclose a system, method, and program for generating and displaying disk drive performance data. A center stripe of one sector of one track on a recordable surface is read. An indication is made indicating whether the read operation to the center of the sector succeeded. Each offset stripe from the center of the track in the sector within the track is read and indication is made as to whether each read operation to each offset stripe succeeded. Output in human observable format is generated indicating whether each offset stripe and the center stripe for the sector and track were read successfully or could not be read.

System, method, and program for analyzing offset track errors in a storage system

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San Jose, CA, United States of America

Theofilos George Fkiaras