Western Digital Technologies, Inc.

Andrew Larson

David Robison Hall

Zarko Popov

Wayne Howard Vinson

Abigail Cheng

Stephen Cauterucio

Shad Thorstenson

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

Data is written in tracks in a first sub-region of a region of a disk using Shingled Magnetic Recording (SMR). It is determined whether a predetermined data storage capacity for the region can be reached by adding a sub-region guard band and shingle writing throughout a remaining portion of the region using a lower limit of track overlap. The sub-region guard band does not store data and separates the first sub-region from a second sub-region in the region. In response to determining that the predetermined data storage capacity for the region can be reached by adding the sub-region guard band and shingle writing with the lower limit of track overlap throughout the remaining portion of the region, the sub-region guard band is added, and the second sub-region is shingle written with at least as much track overlap as the lower limit of track overlap.

Adjustable sub-regions for shingled magnetic recording

A data storage device executes access commands received from a host by a recording head actuated over a magnetic storage medium. A target command is selected from queued host access commands. A free command is selected that can be executed during a time required for a seek from the recording head location to a target command location. A seek energy difference between the energy required to seek from the recording head location to a free command location to the target command location, and to seek from the recording head location directly to the target command location is determined. The device seeks to and executes the free and target commands if the seek energy difference is less than a threshold, and seeks directly to the target command if the seek energy difference is greater than the threshold.

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Rochester, MN, United States of America

Andrew Larson