A disk device includes first and second recording surfaces, a first head for the first recording surface, including a first heater which generates heat via a first electric power, a second head for the second recording surface, including a second heater which generates heat via a second electric power, and a control circuit configured to execute a first preheating operation in which the first electric power is supplied to the first heater for a first time interval prior to starting a first writing process to write data on the first recording surface by the first head, and to execute a second preheating operation in which the second electric power is supplied to the second heater for a second time interval prior to starting a second writing process to write data on the second recording surface by the second head. The first time interval is different from the second time interval.

A magnetic disk device includes a magnetic disk that includes a plurality of tracks, a magnetic head for reading data from the magnetic disk, and a controller. The controller begins controlling the magnetic head to move to a second track of the plurality of tracks from a first track of the plurality of tracks before decoding of a first track signal output from the magnetic head is completed, wherein the first track signal is output from the magnetic head while the magnetic head is positioned over the first track.

A method for minimizing head seek movement and improving I/O performance of a hard disk drive is disclosed. In one embodiment, such a method includes logically dividing storage space of a hard disk drive into storage areas of substantially equal size. The method monitors a temperature of each of the storage areas. The temperature indicates how frequently data in a corresponding storage area is accessed. The method swaps data in storage areas of the hard disk drive based on temperature. These swaps involve moving hotter data toward outer tracks of the disk drive and colder data toward inner tracks of the disk drive. A corresponding system and computer program product are also disclosed.

Example storage medium servo patterns, data storage devices, and methods to provide servo tracks with continuously varying frequency in a data storage device are described. The data storage device may include storage media, such as magnetic disks, having servo sectors that define servo tracks, where adjacent servo tracks have continuously varying frequency as the head moves from one servo track to the next. As the head is actuated over the storage medium, a target track frequency may be determined based on the radial position of a target servo track and the channel frequency may be set to the target track frequency to follow the target servo track.

A magnetic disk device includes a magnetic disk that includes a plurality of tracks, a magnetic head for reading data from the magnetic disk, and a controller. The controller begins controlling the magnetic head to move to a second track of the plurality of tracks from a first track of the plurality of tracks before decoding of a first track signal output from the magnetic head is completed, wherein the first track signal is output from the magnetic head while the magnetic head is positioned over the first track.

In a disk drive apparatus, a first time period is determined, during which a first head driven by a first actuator will be performing a first disk access operation. A second time period is determined, during which a second head driven by a second actuator will be performing a second disk access operation. The first and second actuators are independently movable such that the first and second disk access operations are capable of being performed in parallel. If it is determined that the second disk access operation will impact servo control of the first disk access operation, at least one of the first and second disk access operations is changed to reduce the impact to the servo control of the first disk access operation.

A method involves determining a threshold error rate that will result on data stored on a magnetic disk surface of a disk drive being unrecoverable. The method also involves determining a seek velocity that will overwrite sufficient portions of the data such the data will exhibit at least the threshold error rate. The disk drive performs at least one traversal of the magnetic disk surface with a head of the disk drive that emits an erase field during the at least one traversal at the seek velocity. The at least one traversal sanitizes the data.

A data storage device is disclosed comprising a first voice coil motor (VCM) configured to actuate a first head, and a second VCM configured to actuate a second head. A high priority is assigned to the first VCM and a low priority to the second VCM. A first access command is serviced using the first head by seeking the first VCM using a first high performance seek profile. When seeking the second VCM without seeking the first VCM, a second access command is serviced using the second head using a second high performance seek profile. When concurrently seeking the first VCM and the second VCM, the seeking of the second VCM is with a reduced performance seek profile, wherein the second high performance seek profile decreases a seek time of the second VCM compared to the reduced performance seek profile.

According to one embodiment, a magnetic disk apparatus includes a magnetic head, a voice coil motor, a driving circuit, and a VCM resistance estimation unit. The magnetic head accesses a magnetic disk. The voice coil motor drives the magnetic head over the magnetic disk. The driving circuit applies a VCM current to the voice coil motor. The VCM resistance estimation unit estimates a VCM resistance in the voice coil motor based on the saturated VCM current and a velocity of the magnetic head.

A data storage device comprising a head actuated over a disk comprising a plurality of tracks. The head is positioned over a target track, and a sampled position error signal (PES) is generated representing a position of the head relative to the target track. The sampled PES is filtered with a servo compensator to generate a sampled control signal, and the sampled control signal is upsampled to generate an upsampled control signal. The sampled PES is upsampled to generate an upsampled PES, and the upsampled PES is processed to generate compensation values. The upsampled control signal is combined with the compensation values to generate a compensated control signal, and the position of the head over the target track is adjusted based on the compensated control signal.