Western Digital Technologies, Inc.

Sanghoon Chu

Yuriy Pavlenko

Scott Jinn

Kum-Jung Song

Guoxiao Guo

Jie Yu

Wei Xi

Abhishek Dhanda

Min Chen

Jianguo Zhou

Richard Koonwai Wong

Jifang Tian

Wei Guo

Jack M Chue

Young-Hoon Kim

Michael A Chang

Jun Xu

Carl E Barlow

Hien T Chu

Grant C Mackey

Teddy T Chen

Zhongjie Li

Eugene C Wu

The subject technology provides for managing a data storage system. A data operation error for a data operation initiated in a first non-volatile memory die of a plurality of non-volatile memory die in the data storage system is detected. An error count for an error type of the data operation error for the first non-volatile memory die is incremented. The incremented error count satisfies a first threshold value for the error type of the data operation error is determined. The first non-volatile memory die is marked for exclusion from subsequent data operations.

Method and system for managing memory device

The subject technology provides implementations, which may be included as part of firmware of the flash memory device, that will not solely rely on a flash controller interpreted status but includes additional checks to the returned flash status byte. Each flash read, write, and erase command requires a status read command to determine the state of operation. Depending on the particular command issued, each bit of the returned status has a different meaning. The flash memory device firmware can check whether an illogical or inconsistent status is present. For example, if an overall pass/fail bit indicates a 'pass' but a plane pass/fail bit indicates a 'fail' then there could be an erroneous detection. Also, for every operation, the firmware can read status twice when the flash memory is ready. If the second status byte fails to match the first status byte then a die may be flagged as failing.

Run-time memory device failure detection enhancement

Method and system for managing non-volatile memory

Run-time flash die failure detection enhancement

An apparatus includes: an adaptive declustered RAID array configured of data storage devices (DSDs), the DSDs comprise data chunks allocated as data, a local parity, or a global parity; and a controller configured to generate a reliability indicator reflective of a reliability status of at least a portion of the adaptive declustered RAID array for reallocating the data chunks by dynamically increasing or decreasing the data chunks allocated as the local parity, the global parity, or a combination thereof.

Electronic system with declustered data protection by parity based on reliability and method of operation thereof

For a disk drive involving a disk; a head; and control circuitry having a servo control system operable to actuate the head, the control circuitry may be configured to determine a magnitude of acceleration readings, the acceleration readings involving at least three degrees of freedom, wherein when a magnitude of the acceleration readings is less than a first threshold, the control circuitry confirms a free fall, wherein when the magnitude is between the first and second threshold, the control circuitry confirms a tilt drop. During the tilt drop and the free fall, the control circuitry is further configured to actuate the head to park and monitor the shock impact.

Fall detection scheme using FFS

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by full sectors and intervening short servo sectors, where each full servo sector comprises a preamble, a sync mark, and servo bursts, and each short servo sector comprises a reference pattern and servo bursts. A first phase error is generated based on the sync mark in a first full servo sector, and a disk locked clock is adjusted in response to the first phase error. A second phase error is generated based on the reference pattern in a first short servo sector, and the second phase error is processed to determine whether the disk locked clock slipped a cycle before the head reaching the first short servo sector.

Disk drive compensating for cycle slip of disk locked clock when reading mini-wedge

A disk drive is disclosed comprising a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors. A position of the head is measured based on the servo sectors, and a compensated position of the head is generated based on the measured position of the head and a fly height of the head. The head is actuated over the disk based on the compensated position of the head.

Disk drive compensating for non-linearity of a head based on a fly height of the head

A disk drive is disclosed comprising a head actuated over a disk. A position y of the head is measured based on servo sectors, and the measured position y of the head is adjusted based on:11()where z1 represents a first adjusted position and c1(y) represents first correction values. The first adjusted position z1 is adjusted based on:2=1+2(1)where z2 represents a second adjusted position and c2(z1) represents second correction values. The first and second correction values are combined based on:3()=1()+2(1()).The measured position y of the head is adjusted based on:3=3()where z3 represents a third adjusted position comprising the adjustment based on c1(y) and the adjustment based on c2(y), and c3(y) represents third correction values.

Disk drive iteratively adapting correction value that compensates for non-linearity of head

A disk drive is disclosed comprising a disk having a plurality of servo tracks defined by servo sectors, and a head actuated over the disk. The disk drive further comprises control circuitry comprising a servo control system operable to position the head over the disk. A disturbance is induced in the servo control system, and while positioning the head over the disk, a data track is accessed. The disturbance induced in the servo control system causes the data track to be non-circular relative to a rotation axis of the disk such that the non-circular data track crosses multiple of the servo tracks over a revolution of the disk.

Disk drive defining non-circular data tracks relative to a rotation axis of the disk

A disk drive is disclosed comprising a disk, a head actuated over the disk, and a controller. The disk comprises a plurality of data tracks and a plurality of servo wedges, wherein each servo wedge comprises a plurality of wedge repeatable runout (WRRO) fields in a circumferential direction, each of the plurality of WRRO fields including an WRRO compensation value for a different one of the data tracks and having a width that is wider than a width of the respective data track in a radial direction. The controller is configured to read the WRRO compensation value in at least one of the WRRO fields from the disk using the head, and to adjust a position of the head based on the read WRRO compensation value.

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San Jose, CA, United States of America

Sanghoon Chu