In illustrative aspects, a system comprises an actuator; a control object, controlled by the actuator; and one or more processing devices. The one or more processing devices are configured to perform positioning control of the control object via the actuator, wherein performing the positioning control comprises: generating a feedforward polydyne positioning control input; and outputting the feedforward polydyne positioning control input to the actuator.

According to one embodiment, a method for manufacturing a magnetic disk device includes: moving a magnetic head such that a read head is located on a first learning position among a plurality of learning positions set in a radial direction of a magnetic disk; and learning RRO correction information related to the first learning position using the read head. The method further includes: moving the magnetic head such that the read head is located on a second learning position among the plurality of learning positions; and executing writing of the RRO correction information related to the first learning position using the write head in parallel while learning RRO correction information related to the second learning position using the read head when the read head is located on the second learning position.

According to one embodiment, a first storage area and a second storage area in which a plurality of tracks are set are provided in a radial direction of a magnetic disk. A plurality of post codes corresponding to the second storage area is stored in the first storage area. A controller controls first processing of reading a plurality of post codes from the first storage area and writing the plurality of read post codes in servo area of the second storage area. In the first processing, the controller controls both second processing and third processing in a state where a write head is located on a first track. The second processing is processing of writing a post code among the plurality of read post codes in a servo area. The third processing is processing of writing user data in a data area or reading user data from a data area.

A data storage device may be destroyed by suspending a transducing head above a data storage medium prior to inducing contact of the transducing head with a first layer of the data storage medium in response to a signal from a controller. Deflection of the transducing head can then be increased to penetrate to a destroy depth in a second layer of the data storage medium that is maintained while the data storage medium spins. The controller may then issue at least one data read command to access data from the data storage medium and when a data read error is received, the data storage medium and transducing head can be verified as destroyed and incapable of accessing data previously written to the data storage medium.

A data storage device is disclosed comprising a head actuated over a disk, and a sensor configured to generate a sensor signal representing at least one of a shock and a thermal popping affecting the data storage device. The sensor signal is first filtered based on a first frequency range corresponding to the shock to generate a shock signal, and second filtered based on a second frequency range corresponding to the thermal popping to generate a pop signal, wherein the second frequency range is different from the first frequency range. The shock signal and the pop signal are individually processed, for example, to log a disturbance event, to abort a write operation, or to generate a feed-forward servo compensation signal.

A method is disclosed for positioning a transducer over a magnetic recording medium having a plurality of tracks. The method includes positioning the transducer over a first track using a voice coil motor (VCM) and a microactuator. The method further includes applying a feedforward voltage profile to the microactuator to position the transducer over a second track.

According to one embodiment, a magnetic disk device includes a disk including a first sector arranged at a first radial position deviated from a target position in a radial direction by a first offset amount larger than a first threshold value, a head that writes data to the disk and reads data from the disk, and a controller that reads the first sector by arranging the head at a second radial position deviated from the target position by a second offset amount different from the first offset amount.

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

A data storage device includes at least one data storage disc, at least one head supported by a rotatable actuator arm, an elevator configured to move the rotatable actuator arm in a z direction, a first vertical guide post, a ramp assembly configured to support the head on a movable ramp, and a bracket attached to the movable ramp. The at least one head is configured to communicate with the at least one data storage disc when positioned over the at least one data storage disc. The movable ramp is moveable in a z direction parallel to the first vertical guide post. The bracket is engageable to the rotatable actuator arm so that the bracket moves along the first vertical guide post in unison with z direction motion of the rotatable actuator arm via the elevator, and the bracket is disengageable from the rotatable actuator arm.

According to one embodiment, a magnetic disk device includes a disk including a first sector arranged at a first radial position deviated from a target position in a radial direction by a first offset amount larger than a first threshold value, a head that writes data to the disk and reads data from the disk, and a controller that reads the first sector by arranging the head at a second radial position deviated from the target position by a second offset amount different from the first offset amount.