Performance data of two or more actuators of a storage device is determined. The actuators independently move respective two or more heads over one or more disks coupled to a spindle motor. The independent movement of the two or more heads causes coupling therebetween that affects tracking of the two or more heads. Based on the performance data, bit aspect ratios associated with each of the two or more heads are selected that minimize performance impacts due to the coupling.

According to one embodiment, a magnetic disk device includes a disk including a first recording area, a head includes a write head configured to write data to the disk, and a read head configured to read data from the disk, and a controller configured to set particular areas in same circumferential positions on tracks of the first recording area, and to write, to the respective particular areas, parity data based on data read from areas other than the particular areas.

Method and apparatus for data security in a data storage device. In some embodiments, a first version of firmware is installed in a memory of the device. The firmware is used by a programmable processor to control accesses to a rotatable data recording medium on which is written pre-recorded servo positioning data used to position a data transducer. A newer, second version of the firmwave is subsequently installed in the memory to replace the first version of firmware. The second version of the firmware includes an instruction to corrupt a selected portion of the servo positioning data on the medium in order to authenticate the second version of the firmware. During a subsequent initialization of the device, host access is granted based on detection of the corruption of the selected portion of the servo positioning data.

An operational laser power for a heat-assisted, magnetic recording head is selected based on a function of a write quality metric versus laser power. The write quality metric of data written to a magnetic recording medium is monitored at the operational laser power. Responsive to the write quality metric satisfying a threshold, a power difference between the operational laser power and an offset laser power is determined. The offset laser power corresponds to a point of the function where the write quality metric is approximately equal to the threshold. A maximum laser power is set for a calibration operation. The maximum laser power is based on the sum of the operational laser power and the power difference.

A storage device disclosed herein includes a transducer head with a proximity sensor that generates head-disc proximity signals, a digitizer configured to convert the analog proximity signals from the proximity sensor to digitized sample data, a discrete wavelet transformation (DWT) module configured to analyze the digitized sample data by performing an enhanced DWT on the digitized sample data to generate DWT coefficients, and a modal filter configured to determine dominant head-disc interference (HDI) modes for a transducer head by analyzing the DWT coefficients.

According to one embodiment, a controller of a magnetic disk apparatus operates in a first operation of writing to data regions on a magnetic disk of the magnetic disk apparatus while positioning a magnetic head. In the first operation, the controller demodulates burst patterns to obtain a first burst demodulated value set and corrects the first burst demodulated value set to obtain a second burst demodulated value set. The first burst demodulated value set is corrected on the basis of a correction algorithm using a first set value as an argument. The controller calculates, on the basis of the second burst demodulated value set, an offset amount of the magnetic head from one of servo tracks on the magnetic disk.

Embodiments disclosed herein generally relate to a method for monitoring optical power in a HAMR device. In one embodiment, the method includes enhancing a thermal sensor bandwidth through advanced electrical detection techniques. The advanced electrical detection techniques include obtaining calibration waveform data for a thermal sensor by calibrating the thermal sensor, obtaining real-time waveform data for the thermal sensor that may deviate from the calibration waveform data, updating the calibration waveform data to include the real-time waveform data, repeating obtaining real-time waveform data and updating the calibration waveform data during writing operations. By updating the calibration waveform data, the bandwidth of the thermal sensor is determined by a fixed sampling time interval, and the thermal sensor rise time to steady state would not be a limitation to its response time.

According to one embodiment, a magnetic disk device includes a disk including a first recording area, a head includes a write head configured to write data to the disk, and a read head configured to read data from the disk, and a controller configured to set particular areas in same circumferential positions on tracks of the first recording area, and to write, to the respective particular areas, parity data based on data read from areas other than the particular areas.

A heat-assisted magnetic recording (HAMR) head includes a reader, a writer, a writer heater, a laser, and a near-field transducer (NFT). A processor is coupled to the head and configured to perform laser writeability calibration of the head. The processor is also configured to concurrently while performing the laser writeability calibration, correct for laser induced writer protrusion (LIWP) at a writer/NFT region of the head using writer clearance calculations based on reader clearance measurements.

A method and apparatus for detecting tightness of a pick-up head, and a method and apparatus for controlling the moving of the pick-up head are disclosed. The method for detecting the tightness of the pick-up head includes moving the pick-up head to an inner area of the disc reading device when then disc reading device is powered on, moving the pick-up head to an outer area of the disc reading device within a predetermined time period, moving the pick-up head from the outer area of the disc reading device to the inner area at a constant speed by a first fixed force, and recording the moving duration for moving the pick-up head from the outer area of the disc reading device to the inner area at the constant speed.