Western Digital Technologies, Inc.

Jinghuan Chen

Kroum Stanimirov Stoev

Lisha Wang

Anthony E Pione

Kameron K Jung

Jinyoung Kim

Andrew Yu-Jen Wang

Yee Ching Liew

Kevin S Curran

Kian Wai Ng

Aspects of a storage device including a memory and a controller are provided. The controller may determine to perform garbage collection on a superblock. During the garbage collection process, the controller will typically move the superblock into an erase pool for erasing the superblock. However, aspects of the disclosure are directed to a method of measuring a raw bit error rate (RBER) of the superblock prior to erasure. The measured RBER may be used to estimate a data retention time of the storage device and provide the customer with an early warning notification if a health metric of the storage devices reaches a threshold retention time.

Data retention (DR) warning system

A disk drive is disclosed comprising a disk comprising a plurality of servo tracks defined by servo sectors, a head actuated over the disk, and control circuitry comprising a read channel. A plurality of data tracks are defined relative to the servo tracks, wherein each data track comprises a plurality of segments. The read channel is configured into a read mode in order to first read a first segment of a first data track. During the first read, a quality metric is generated at periodic points along the first segment. After the first read, the read channel is configured into a non-read mode for a predetermined interval. After the predetermined interval, the read channel is configured into the read mode in order to second read the first segment of the first data track and generate the quality metric at the periodic points along the first segment.

Disk drive generating quality metric map for a data track while in different configurations

Track placement on a disk of a Data Storage Device (DSD) including writing test data in a plurality of sectors in a test track on the disk. An adjacent track on the disk is written offset from the test track by an offset distance. Data is read from the test track from an Off-Track Read Capability (OTRC) position outside of the test track. An OTRC value is determined for each sector of the plurality of sectors by varying the OTRC position and determining whether the sector meets a criterion for correctly reading data from the sector. An average OTRC value and a standard deviation are calculated for the plurality of sectors. If it is determined that the average OTRC value is greater than or equal to the predetermined multiple of the standard deviation of the OTRC values, the adjacent track is rewritten at a decreased offset distance.

Track measurement for data storage device

In various embodiments, systems and methods to detect signal irregularity caused by defects in the read/write head element are disclosed. In some embodiments, an exemplary system comprises a memory and a processor. The processor is coupled to the memory and is configured to implement a filter module and a detector module. The filter module is configured to generate a test waveform based on data read from a medium by a storage device head to be tested. The detector module is configured to generate a signal quality value based on a property of at least a portion of the test waveform, compare the signal quality value to an event threshold, and generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

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Irvine, CA, United States of America

Jinghuan Chen