Western Digital Technologies, Inc.

Chirag C Patel

Chun Sei Tsai

Carl E Barlow

Donald Joseph Brunnett

Thomas Anthony O'Dell

David E Fowler

Dean V Dang

David E Wachenschwanz

Thao Hieu Banh

Ammar A Zayed

Andrew W Fok

Boon Sien Chew

Dody Suratman

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. First data is written to a first data track, and the first data is read from the first data track to measure a first quality metric representing a recording quality of the first data. Second data is written to a second data track, and the second data is read from the second data track to measure a second quality metric representing a recording quality of the second data. The first and second quality metrics are processed to generate a first statistical quality metric. A first defect threshold is generated based on the first statistical quality metric, and at least part of the disk is scanned for defects based on the first defect threshold.

Disk drive calibrating defect threshold based on statistical quality metric measured for reference tracks

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks. A defect scan of at least one of the tracks is executed, and a log entry is generated when a defect is detected. After the defect scan, a verify operation is executed for at least two of the detected defects. A number of times the verify operation detects a false defect is counted, and whether the head is defective is determined based at least partly on the count.

Data storage device screening heads by verifying defects after defect scan

A disk drive is disclosed comprising a disk comprising a plurality of data tracks, and a head actuated over the disk, the head comprising an asperity sensor operable to generate a sensor signal having a magnitude based on a bias setting of the asperity sensor. The asperity sensor is configured with a first bias setting and a first asperity on the disk is detected based on the sensor signal generated at the first bias setting. The asperity sensor is configured with a second bias setting different from the first bias setting and a second asperity on the disk is detected based on the sensor signal generated at the second bias setting.

Disk drive detecting different asperities on a disk using different sensor bias settings

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. A first defect shape is detected during a manufacturing defect scan of the disk. A second defect shape is detected while the disk drive is deployed in-the-field. Whether the first defect shape is connectable to the second defect shape is determined, and when the first defect shape is connectable to the second defect shape, data sectors along a trajectory between the first defect shape and the second defect shape are relocated.

Disk drive connecting defect shapes to preempt data loss

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Rancho Santa Margarita, CA, United States of America

Chirag C Patel