Abstract: A heater power of a heat-assisted magnetic recording head is set based on an initial head-medium clearance estimate in response to the heater power. For a plurality of iterations, an optimum laser power of the recording head is determined and a heater power is set for a next iteration that results in an optimum heater power for the optimum laser power. If differences in the heater and laser powers between two subsequent iterations are below thresholds, the iterations are stopped and the optimum heater power and the optimum laser power for one of the subsequent iterations are used as an operational heater power and an operational laser power.

Abstract: Systems and methods of laser bias calibration are presented. A preamplifier circuit may include a laser voltage monitor circuit and a laser bias control circuit configured to automatically adjust an output laser bias threshold voltage based on a monitored laser voltage. The laser bias control circuit may include a first differentiator circuit, a second differentiator circuit, and a threshold detection circuit. The preamplifier circuit may be utilized in a heat assisted magnetic recording device.

Abstract: An apparatus comprises a laser diode configured to generate modulated light during a write operation in response to receiving modulated current having a mean amplitude that varies or is constant. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A writer heater of the slider is configured to receive power during the write operation having a magnitude that varies or is constant. A sensor is situated on or within the slider. The sensor is configured to produce a sensor signal representative of output optical power of the laser diode. Measuring circuitry is coupled to the sensor and configured to measure a change in the sensor signal indicative of a laser mode hop during the write operation.

Abstract: Pseudorandom bit sequences are recorded to a heat-assisted recording medium at a laser power that is stepped while recording the pseudorandom bit sequences. The pseudorandom bit sequences are read from the heat-assisted recording medium to determine timing differences between bits written before and after the laser power is stepped. A thermal gradient of bits written to the heat-assisted recording medium is determined based on the timing differences.

Abstract: A method for performing a flaw scan test on a hard disk drive is disclosed. The hard disk drive includes a magnetic recording medium and spindle motor associated with a predetermined rated speed. The method includes writing a test pattern to the magnetic recording medium while operating the spindle motor at a speed greater than the predetermined rated speed. The method also includes reading the test pattern at the greater speed and detecting flaws in response to reading the test pattern.

Abstract: A method for scanning for flaws on a magnetic recording medium is disclosed. The magnetic recording medium has a first set of nonconsecutive data tracks and a second set of nonconsecutive data tracks. The method includes writing a test pattern to only the first set of nonconsecutive data tracks of the magnetic recording medium, reading of the test pattern written to the first set of nonconsecutive data tracks, and identifying flaws within the first set of nonconsecutive data tracks and the second set of nonconsecutive data tracks based on the reading the test pattern.

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 heater power of a heat-assisted magnetic recording head is set based on an initial head-medium clearance estimate in response to the heater power. For a plurality of iterations, an optimum laser power of the recording head is determined and a heater power is set for a next iteration that results in an optimum heater power for the optimum laser power. If differences in the heater and laser powers between two subsequent iterations are below thresholds, the iterations are stopped and the optimum heater power and the optimum laser power for one of the subsequent iterations are used as an operational heater power and an operational laser power.

Abstract: A storage device controller is configured to select one of multiple written track widths for a storage location based on a write attribute of data to be recorded at the storage location. According to one implementation, the storage device controller is further configured to select a power level for a heat-assisted magnetic recording (HAMR) device based on the write attribute.

Abstract: A heater power of a heat-assisted magnetic recording head is set to an initial power to induce an initial head-medium clearance. For a plurality of iterations, a heater power at an optimum laser power is determined that achieve a target clearance. If differences in the heater power and optimum laser power between the two subsequent iterations are below a threshold, the iterations are stopped and the heater power and the optimum laser power for one of the two subsequent iterations is used as an operational heater power and laser power for the heat-assisted magnetic recording head.

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: In a data storage device where a data writer is predicted to fail, cold data can be identified and subsequently moved to a data storage medium corresponding to the failing data writer. The data writer may be positioned proximal the data storage medium where data is stored. A controller can predict the failure in the data writer and transition all the data in the data storage medium to a read only status.

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: A read/write head has a set of components that at least include: at least one clearance actuator; at least one read transducer configured to read from a magnetic recording medium; and at least one write transducer configured to write to the magnetic recording medium. A switch network is coupled to the set of components and configured to, in response to a control signal, couple a selected sub-combination of the components to a common set of signal lines. The coupling of the selected sub-combination facilitates operation in a selected mode of the read/write head.

Abstract: An optical power level applied via a laser when recording data to a track of a heat-assisted recording medium is determined. In response to the optical power level being too low or too high, remedial action is taken to prevent loss of data on one or more of the track and an adjacent track.

Abstract: An apparatus determines that phase errors have exceeded a threshold when reading data previously recorded to a heat-assisted recording medium. In response to the phase errors exceeding the threshold, remedial action is taken to prevent loss of data due changes in power applied to heat the heat-assisted recording medium when recording.

Abstract: A storage device controller addresses consecutively-addressed portions of incoming data to consecutive data tracks on a storage medium and writes the consecutively-addressed portions to the consecutive data tracks in a non-consecutive track order. In one implementation, the storage device controller reads the data back from the consecutive data tracks in a consecutive address order in a single sequential read operation.

Abstract: A set of consecutive user data wedges are each located between consecutive servo wedges of a heat-assisted recording medium. Test data is written at least every other one of the consecutive data wedges using different laser power values. Based on reading the test data, a nominal laser power is selected for use by the read/write head.

Abstract: Data is written to a magnetic recording medium of a drive using a read/write head. The read/write head has an energy source that applies a hotspot to the magnetic recording medium while recording. During the writing, a steady-state current applied to the energy source is changed by a step value. A timing error induced by the change in the steady-state current is measured based on reading back the data. A thermal gradient of the hotspot is determined based on the step value and the timing error.