Abstract: Data is written to data sectors of a heat-assisted magnetic recording (HAMR) medium using a laser of a HAMR head supplied with a sum of an operational current and a threshold current. A service current is supplied to the laser when the head is over servo sectors of the medium, such that a temperature of the medium at the servo sectors is greater than or equal to a temperature of the head when over the servo sectors.

Abstract: A tolerance ring including a sidewall and at least one projection from the sidewall that projects radially and axially to prevent axial displacement of the tolerance ring with respect to a component interior or exterior to the tolerance ring.

Abstract: A storage device includes a storage medium having a plurality of data tracks. At least one data track of the plurality of data tracks includes a number of super parity sectors. The number of super parity sectors selected for the at least one data tracks is selected based on a distance between an inner diameter of the storage medium and the data track. The number of super parity sectors provides error correction code for the at least one data track.

Abstract: An error is determined in a target track of a heat-assisted recording medium. The error triggers an error recovery procedure. The error recovery procedure involves storing data from at least part of an adjacent track that is immediately proximate the target track to another data storage location. The error recovery procedure also involves, for two or more iterations in which a laser power is incrementally changed from a lower power to a higher power, erasing at least part of the adjacent track at the laser power and attempting to recover the target track.

Abstract: Before writing to a heat-assisted magnetic recording medium, a DC signal modulated with an AC signal is applied to a laser of a read/write head. A modulation level of an optical power sensor is measured, the optical power sensor being coupled to detect optical output of the laser in response to the modulated current. A target value of the DC signal that causes the modulation levels to reach a predetermined value between zero and a maximum value is determined and used to set a bias current for subsequent activation of the laser based.

Abstract: Before writing to a heat-assisted magnetic recording medium, a DC signal modulated with an AC signal is applied to a laser of a read/write head. A modulation level of an optical power sensor is measured, the optical power sensor being coupled to detect optical output of the laser in response to the modulated current. A target value of the DC signal that causes the modulation levels to reach a predetermined value between zero and a maximum value is determined and used to set a bias current for subsequent activation of the laser based.

Abstract: An apparatus and method provide for performing, using a heat-assisted magnetic recording head, multiple sequential writes to a recording medium, and recording a metric of write performance for each of the writes. The apparatus and method further provide for calculating fluctuations in the metric, detecting whether the head has a laser mode hopping problem using the metric fluctuations, and categorizing a severity of the laser mode hopping problem.

Abstract: An apparatus and method provide for performing, using a heat-assisted magnetic recording head, multiple sequential writes to a recording medium, and recording a metric of write performance for each of the writes. The apparatus and method further provide for calculating fluctuations in the metric, detecting whether the head has a laser mode hopping problem using the metric fluctuations, and categorizing a severity of the laser mode hopping problem.

Abstract: Before writing to a heat-assisted magnetic recording medium, a current of a laser is modulated about a default threshold current level. A modulation level of an optical power sensor is measured, the optical power sensor being coupled to detect optical output of the laser in response to the modulated current. A bias current for subsequent activation of the laser is adjusted based on the modulation level of the optical power sensor.

Abstract: A storage device includes a storage medium having a plurality of data tracks. At least one data track of the plurality of data tracks includes a number of super parity sectors. The number of super parity sectors selected for the at least one data tracks is selected based on a distance between an inner diameter of the storage medium and the data track. The number of super parity sectors provides error correction code for the at least one data track.

Abstract: For each head in a collection of heat-assisted magnetic recording read/write heads, a reader width and a writer width is measured. A predicted life is determined for each head based on the respective reader width and writer width. In a first set of drives having relatively fewer heads per drive, a first subset of the heads having a higher value of the predicted life are used. In a second set of drives having relatively more heads per drive, a second subset of the heads having a lower value of the predicted life are used.

Abstract: A storage device includes a storage medium having a first set of non-adjacent data tracks having a number of super parity sectors and a second set of non-adjacent data tracks interlaced with the first set of non-adjacent data tracks. The number of super parity sectors on a data track of the first set of non-adjacent data tracks is selected based on a distance between the data track and an inner diameter of the storage medium.

Abstract: An apparatus and method provide for performing, using a heat-assisted magnetic recording head, multiple sequential writes to a recording medium, and recording a metric of write performance for each of the writes. The apparatus and method further provide for calculating fluctuations in the metric, detecting whether the head has a laser mode hopping problem using the metric fluctuations, and categorizing a severity of the laser mode hopping problem.

Abstract: A combination user data signal is read from two or more inner tracks of a recording medium via a first reader that encompasses the inner tracks. First and second data signals are read from respective first and second outer tracks that surround the inner tracks via second and third co-planar readers that are on a same head-gimbal assembly as the first reader. The first reader is centered between and downtrack from the first and second co-planar readers on the read head. User data is recovered based on the combination user data signal and the first and second data signals.

Abstract: A cross-track profile of a known good test track on a recording medium is read during operation of a data storage device. Two or more center locations of the test track are determined at two or more different amplitude levels via a read transducer. A health condition of the read transducer is determined by comparing the two or more center locations of the test track with one another.

Abstract: An apparatus includes a light source, a slider including a sensor having a resistance or voltage that varies with the temperature of the sensor, the sensor being mounted to be heated by a portion of light emitted by the light source, and a controller controlling the light source power in response to the resistance or voltage of the sensor.

Abstract: Method and apparatus for controlling the position of a control object in a closed loop control system, such as a servo control system used in a data storage device. In some embodiments, spaced apart first and second data tracks are written to a rotatable data recording medium without using repeated runout (RRO) compensation values to correct for RRO error in servo data written to the medium. A third data track is subsequently written so as to be interspersed between and partially overlap the first and second data tracks. The third data track is written using a set of RRO compensation values to correct for the RRO error in the servo data.

Abstract: A relatively larger nominal track spacing associated with a first write head is determined and a relatively smaller nominal track spacing associated with a second write head is determined. The first and second write heads simultaneously write to respective different first and second surfaces of a heat-assisted recording medium. A laser write power for a selected one of the first write head and the second write head is changed to enable the first write head and the second write head to operate at an equivalent nominal track spacing.

Abstract: An apparatus comprises a controller configured to apply a writing configuration (WC) to a heat-assisted magnetic recording head to write data to a recording medium. The recording medium includes a plurality of sectors. The controller is further configured to determine an optimized WC for each of the plurality of sectors and initiate a write operation to one of the plurality of sectors. The write operation is configured to be performed by the head utilizing the optimized WC for the respective sector.

Abstract: An apparatus comprises a controller configured to apply a writing configuration (WC) to a heat-assisted magnetic recording head to write data to a recording medium. The recording medium includes a plurality of sectors. The controller is further configured to determine an optimized WC for each of the plurality of sectors and initiate a write operation to one of the plurality of sectors. The write operation is configured to be performed by the head utilizing the optimized WC for the respective sector.