Embodiments provide a method of operating a voice coil motor via a transconductance loop. The method includes detecting an actual value of a supply voltage of the transconductance loop. An offset compensation signal of the transconductance loop is produced as a function of the detected actual value of the supply voltage based on a relationship between offset values and the supply voltage of the transconductance loop. The offset compensation signal is applied to a loop control signal of the transconductance loop. A drive current is applied to the voice coil motor. The drive current is related to a target drive current that is based on the loop control signal.

A magnetic head includes a first servo reading element pair, a second servo reading element pair, and a plurality of magnetic elements. The first servo reading element pair consists of a first servo reading element and a second servo reading element, the second servo reading element pair consists of a third servo reading element and a fourth servo reading element, the first servo reading element and the third servo reading element are disposed on one end side of the plurality of magnetic elements and read one servo band of the pair of servo bands, and the second servo reading element and the fourth servo reading element are disposed on the other end side of the plurality of magnetic elements and read the other servo band of the pair of servo bands.

Example control circuitry, data storage devices, and methods for parallel self-servo writing of interleaved servo patterns in a data storage device are described. The data storage device may include multiple heads actuated over different surfaces of a data storage device and receive read signals from two different heads over two different surfaces in parallel. The servo wedges of the two surfaces may be offset to enable independent determination of phase while writing servo patterns in parallel to the two surfaces using their respective heads.

A data storage device may include an outer fine actuator group, an inner fine actuator group, and control circuitry comprising: a slew control voltage generator, a first switch, and a second switch. The control circuitry is configured to: generate a control signal; control the first switch to apply the control signal to a first fine actuator group for a first duration; control the first switch to apply the control signal to a second fine actuator group for a second duration, wherein each of the first and the second fine actuator groups comprises one of the inner or the outer fine actuator groups, and wherein the first and second fine actuator group are different; concurrently discharge the first fine actuator group during the second duration, based at least in part on controlling the second switch to couple the first fine actuator group to the slew control voltage generator.

According to an embodiment, in a magnetic disk device, a current detection circuit detects an amount of a first current that is generated by a drive circuit and drives a motor. In a seek operation, a controller acquires a commanded value based on a deviation amount of the amount of the first current detected by the current detection circuit from the commanded value. Then, the controller inputs the acquired commanded value to the drive circuit.

According to one embodiment, a magnetic disk drive includes rotatable disks, heads, microactuators, a voice coil motor (VCM), and a control system, wherein the control system determines a final set of heads of target for simultaneously positioned on their respective target tracks from among the heads, by using at least a displacement amount of the microactuators, determines a target position of the VCM when the heads in the final set are simultaneously positioned on their respective target tracks, switches a controller of the VCM when the heads in the final set are simultaneously positioned on their respective target tracks, and switches controller of the microactuators included in each of the heads in the final set.

A controller of a magnetic disk device executes an integration operation each time a magnetic head passes through a servo sector during a write operation for a write target section of a first track among a plurality of tracks, so long as a positioning error amount in a servo sector that was most recently passed through by the magnetic head is within a range of an error threshold. The integration operation includes calculating an integrated offset amount by adding up positioning error amounts in two or more servo sectors including at least the servo sector that was most recently passed through by the magnetic head among all servo sectors that were passed through by the magnetic head during the write operation. The controller executes a protection operation for protecting data of a second track adjacent to the first track among the plurality of tracks based on the integrated offset amount.

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: determine an initial track pitch based on a performance metric determined for the head; determine a track pitch adjustment based on a measure of servo pattern distortion associated with a region of the disk; and set a final track pitch for the region of the disk based on the track pitch adjustment and the initial track pitch.

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: determine an initial track pitch based on a performance metric determined for the head; determine a track pitch adjustment based on a measure of servo pattern distortion associated with a region of the disk; and set a final track pitch for the region of the disk based on the track pitch adjustment and the initial track pitch.

According to one embodiment, a magnetic disk drive includes rotatable disks, heads, microactuators, a voice coil motor (VCM), and a control system, wherein the control system determines a final set of heads of target for simultaneously positioned on their respective target tracks from among the heads, by using at least a displacement amount of the microactuators, determines a target position of the VCM when the heads in the final set are simultaneously positioned on their respective target tracks, switches a controller of the VCM when the heads in the final set are simultaneously positioned on their respective target tracks, and switches controller of the microactuators included in each of the heads in the final set.