According one embodiment, a magnetic disk device includes a disk including a first region and a second region to which data before written to the first region is temporarily written, a head which writes data to the disk and reads data from the disk, and a controller which selectively performs conventional magnetic recording for writing a track at an interval in a radial direction of the disk and shingled magnetic recording for writing a track so as to overlap in the radial direction, and changes a cache data capacity of data which can be written to the second region in accordance with a first write capacity of data which can be written to the first region by the shingled magnetic recording.

A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer.

A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer.

An approach to a reduced-head hard disk drive (HDD) involves a load/unload (LUL) ramp subsystem that includes a ramp assembly that includes a rotatable latch link configured for mechanical interaction with a head-stack assembly (HSA) and a LUL ramp coupled with the latch link, configured such that in response to a force applied to the latch link by the HSA, the latch link rotates which disengages a magnetic latch and drives the LUL ramp to rotate into an operational state disengaged from any recording disk of a multiple-disk stack. The subsystem may further include a motor configured to drive rotation of a lead screw to which the ramp assembly is attached, to drive vertical translation of the ramp assembly, thereby providing for loading the vertically-translatable HSA onto and off of each of the disks of the disk stack.

An approach to a reduced-head hard disk drive (HDD) involves a load/unload (LUL) ramp subsystem that includes a ramp assembly that includes a rotatable latch link configured for mechanical interaction with a head-stack assembly (HSA) and a LUL ramp coupled with the latch link, configured such that in response to a force applied to the latch link by the HSA, the latch link rotates which disengages a magnetic latch and drives the LUL ramp to rotate into an operational state disengaged from any recording disk of a multiple-disk stack. The subsystem may further include a motor configured to drive rotation of a lead screw to which the ramp assembly is attached, to drive vertical translation of the ramp assembly, thereby providing for loading the vertically-translatable HSA onto and off of each of the disks of the disk stack.

According to one embodiment, there is provided a hard disk drive including a first recording surface, a second recording surface, a first magnetic head, a first actuator and a second actuator that move the first magnetic head, a second magnetic head, a third actuator and a fourth actuator that move the second magnetic head, a fifth actuator that moves the second actuator and the fourth actuator, a drive circuit that implements at least one of a first mode in which the second actuator and the fourth actuator operate differently from each other or a second mode in which the first and third actuators operate differently from each other, and a controller that controls the drive circuit.

According to one embodiment, a magnetic disk device includes a disk, a head including a write head that writes data to the disk, and a first read head and a second read head that read data from the disk, and a controller that, in reading a first track of a first region of the disk, positions a middle portion of the first read head and the second read head at a first track center of the first track, and in reading a second track of a second region of the disk different from the first region, positions any one of the first read head and the second read head at a second track center of the second track.

A data storage device includes a first data storage surface and a second data storage below the first data storage surface. The data storage device also includes a first micro-actuator coupled to a first arm that supports a first head over the first data storage surface, and a second micro-actuator coupled to a second arm that supports a second head over the second data storage surface. The data storage device further includes a coarse actuator, to which the first and second arms are coupled, that positions the first head and the second head between corresponding first and second tracks on the respective first and second data storage surfaces. Micro-actuator drive circuitry finely positions the first head over the first track and the second head over the second track by concurrently driving the first micro-actuator and the second micro-actuator in opposite directions.

According to one embodiment, there is provided a hard disk drive including a first recording surface, a second recording surface, a first magnetic head, a first actuator and a second actuator that move the first magnetic head, a second magnetic head, a third actuator and a fourth actuator that move the second magnetic head, a fifth actuator that moves the second actuator and the fourth actuator, a drive circuit that implements at least one of a first mode in which the second actuator and the fourth actuator operate differently from each other or a second mode in which the first and third actuators operate differently from each other, and a controller that controls the drive circuit.

Systems and methods are disclosed for reducing adjacent track erasure from write retry operations. In certain embodiments, an apparatus may comprise a circuit configured to abort a write operation while writing to a selected sector of a disc storage medium during a first revolution of the disc storage medium, and mark the selected sector as a temporary bad sector in a mapping table. The circuit may perform a write retry to continue the write operation starting at a next sector contiguously following the selected sector, without attempting to write the selected sector again, during a second revolution of the magnetic disc.