Western Digital Technologies, Inc.

Zarko Popov

Wayne Howard Vinson

Hitoshi Yoshida

Mao Nishiyama

David Robison Hall

Bernd Lamberts

Andrew Larson

Andrew E Larson

Weldon Mark Hanson

Niranjay Ravindran

Remmelt Pit

David Timothy Flynn

Gregory Michael Frees

Timothy G Lieber

Robert Lester

Shad Henry Thorstenson

Xing Huo

Stephanie Louise Aho

Hiroyasu Masuda

Ryoheita Hattori

Arundhathi R Kanchrakuntla

Victor Ramirez

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: maintain a refresh monitor for a refresh zone of one of the one or more disks, wherein the refresh zone comprises at least one data sector; update the refresh monitor in response to a write operation being performed in a track different than a track containing the refresh zone; update the refresh monitor at predefined time intervals based on a temperature of the one of the one or more disks or of the data storage device; and control a refresh operation of the refresh zone using the refresh monitor.

Data storage device with combined track interference and thermal decay refresh monitor

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: estimate access times of a plurality of access commands included in a command queue of a disk drive containing the one or more disks; adjust a respective one of the access times of a respective one of the access commands based on the respective one of the access commands satisfying one of one or more conditions that indicate an increased likelihood of performing a pre-heating operation to heat a laser diode associated with a head of the disk drive; and select one of the access commands as a next command for execution in the disk drive based on the access times.

Data storage device with command selection that minimizes frequency of pre-heating

Controlling a shingled magnetic recording (SMR) hard drive involves writing, to a first track of a zone pre-sized based on a nominal track width based on an expected mean track width across an entire zone, a portion of a write operation according to the nominal track width. Then, based on the positional accuracy of the first track writing, determining a second track position for an adjacent second track, and writing the second track another portion of the write operation according to the determined second track position. Thus, the determination and position of a given track is determined by the positional accuracy of a previously written track, considering for example the position error signal corresponding to the writing of the previously written track. Thus, the track pitch is effectively defined by the average positional error across a zone rather than by a worst-case scenario positional error across the zone.

Dynamic track pitch in shingled magnetic recording hard disk drive

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: maintain respective measures of write commands associated with respective ones of shingled magnetic recording (SMR) zones defined in a data storage device, wherein data associated with the write commands is stored in a write cache associated with the data storage device; select one of the SMR zones based on the respective measures; perform a pre-heat operation of a laser diode included in a head associated with the selected one of the SMR zones; and perform a continuous write operation in the selected one of the SMR zones following the pre-heat operation, wherein the continuous write operation writes at least a portion of data stored in the write cache associated with the selected one of the SMR zones.

Data storage device with write caching for maximizing disk access during laser diode steady state

Various illustrative aspects are directed to a data storage device comprising data tracks N and N−1, and one or more processing devices, configured to identify, during a track write on the data track N, a write abort event based upon an expected risk for the data track N−1 exceeding a risk threshold, read one or more sectors of the data track N−1 and collect one or more corresponding sector metrics, verify the one or more sectors based upon the collected sector metrics, wherein the verifying comprises assigning each of the one or more sectors as one of a readable or a non-readable sector, and continue the track write on the data track N upon determining each of the one or more sectors is a readable sector, or recovering and relocating the data track N−1 based on determining at least one of the sectors is a non-readable sector.

Sector metrics to estimate health of written data

Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator assembly comprising one or more disk heads; and one or more processing devices, configured to detect a plurality of areas with a coercivity lower than a threshold on the one or more disks; map out one or more sectors in each of the plurality of lower coercivity areas on the one or more disks; write data to, or read data from, the one or more disks, based at least in part on mapping out the one or more sectors in each of the plurality of lower coercivity areas. In some embodiments, the writing or reading data comprises writing data to, or reading data from, one or more sectors of the one or more disks that are not mapped out.

Sector mapout of low coercivity media for enhancing aerial density

The present disclosure is directed to a data storage device that includes a refresh monitor based on a learning based feedback control. The refresh monitor is used to control refresh operations to account for effects of writes to media, e.g., adjacent track interference (ATI). Read operations are analyzed to derive damage information usable to update one or more probability distributions, upon which the learning is updated or reinforced and carried forward. In one embodiments, the data storage device includes control circuitry configured to maintain a refresh monitor based on a learning system, analyze a read operation with the refresh monitor; adjust the refresh monitor by updating the one or more probability distributions based on the analyzed read operation; and execute a refresh operation to refresh data based on the adjusted refresh monitor.

Data storage device adjusting refresh monitor based on a learning based feedback control

Illustrative aspects are directed to a data storage device comprising one or more disks; an actuator mechanism comprising one or more heads, and configured to position a head proximate to a disk surface; and one or more processing devices. The one or more processing devices are configured to: measure a read quality of a location on the disk surface; modify a refresh frequency for performing refresh writes at the location, based on the read quality at the location; in response to the refresh frequency at the location becoming stabilized, determine an integrated track interference (xTI) per write metric at the location; and, in response to determining that the xTI per write metric at the location is below a threshold for the xTI per write metric, modify an operating parameter of the head at the location to improve a longevity metric.

Data storage device with adaptive write policy and enhanced longevity

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors and the head comprises a first read element and a second read element. When a first read command is received from a host to read a plurality of data sectors from the disk, the first read element is used to read a first data sector of the first read command, and when the first read element fails to recover the first data sector of the first read command, the second read element is used to read a second data sector of the first read command.

Data storage device adapting read element usage

A data storage device is disclosed comprising a head actuated over a magnetic media comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors. A plurality of access commands are stored in a command queue, and an access command is selected from the command queue. When the selected access command is a write command to a target data track and at least part of a first data track proximate the target data track needs to be refreshed, a refresh read command is executed to read data from at least part of the first data track prior to executing the write command to the target data track.

Data storage device executing just-in-time refresh

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, including a first data track and a second data track. In connection with writing to at least part of the first data track, a quality metric is measured for at least part of the first data track. In connection with writing to at least part of the second data track, a refresh metric is updated based on the write to at least part of second data track and the quality metric measured for the first data track, and at least the first data track is refreshed based on the refresh metric.

Data storage device updating refresh metric based on quality of victim data track during write operation

A dynamic scalable error correction coding (ECC) scheme for a data storage system involves a system controller predicting a type and/or amount of ECC needed to reconstruct data to be stored on a particular data storage device(s) based on operational data integrity information accessed from the array of data storage devices. Thus, redundancy does not need to be allocated unless required. The devices may be logically grouped into subsets according to common characteristics, whereby the prediction made for a device in a subset may be based on the data integrity information from that subset, as well as from other relevant subsets.

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Mission Viejo, CA, United States of America

Zarko Popov