Rotational latency is reduced in a standard conventional form factor HDD system by replacing, for example, the prior art rotary arm actuator of a conventional HDD, with one or more belts and pulleys and one or more read/write heads mounted on, or otherwise associated with the belts. Multiple scaled iterations facilitate energy savings and power optimized systems, without compromise to data access performance.

A motor driver circuit includes: a current detection circuit configured to generate a current detection signal according to a drive current of a motor as an object to be driven; a first amplifier configured to amplify the current detection signal; a second amplifier configured to multiply a voltage across the motor by a gain smaller than 1 and output the multiplied voltage; and a third amplifier configured to generate a back electromotive force detection signal according to a difference between an output of the first amplifier and an output of the second amplifier.

A voice coil motor (VCM) includes a coil, and on a first side a first yoke having a coil-side facing the coil, a first low-coercivity permanent magnet positioned between the coil and the coil-side of the first yoke and having a yoke-side facing the first yoke and a coil-side opposing the yoke-side, and a first high-coercivity permanent magnet adjoining the coil-side of the first low-coercivity magnet. A second side of the VCM on the opposing side of the coil is similarly configured. The permeance coefficient of such a VCM enables magnetic stability of low-coercivity magnetic materials. Additional high-coercivity permanent magnets may be bonded to the coil-sides of each of the first and second yokes and adjoining the yoke-sides of each of the low-coercivity permanent magnets, if the relative thicknesses of the magnet materials so dictate by design.

A voice coil motor (VCM) includes a coil, and on a first side a first yoke having a coil-side facing the coil, a first low-coercivity permanent magnet positioned between the coil and the coil-side of the first yoke and having a yoke-side facing the first yoke and a coil-side opposing the yoke-side, and a first high-coercivity permanent magnet adjoining the coil-side of the first low-coercivity magnet. A second side of the VCM on the opposing side of the coil is similarly configured. The permeance coefficient of such a VCM enables magnetic stability of low-coercivity magnetic materials. Additional high-coercivity permanent magnets may be bonded to the coil-sides of each of the first and second yokes and adjoining the yoke-sides of each of the low-coercivity permanent magnets, if the relative thicknesses of the magnet materials so dictate by design.

Methods and apparatuses for modulating a position error signal detection gate signal responsive to a track crossing velocity are discussed. The position error signal can be used to detect position information. A track crossing velocity can be estimated and then used via the modulating. Phase errors due to the track crossing velocity can be minimized.

An actuator rotational limiter mechanism for a multiple disk-stack, shared actuator hard disk drive includes an actuator comb with a cam-lock feature and an actuator limiter with a rotatable cam-roller that is engagable with the cam-lock feature to temporarily hold in place the actuator comb. The cam-lock feature may be positioned at or near a middle location of a back arm of the actuator armature, where the actuator comb being held in place by the cam-roller corresponds to the head slider being positioned on a load/unload ramp between adjacent disk stacks.

A hard disk drive includes multiple disk media mounted on a spindle, where the outer diameter of each disk medium is offset from the inner diameter of the disk medium in a same direction along an axis of rotation of the spindle, and a load/unload ramp positioned, based on the offset, to align in correspondence with the outer diameters of the disk media. Thus, the curvature of irregular disk media, such as that associated with thinner and thinner disks, is mitigated by grouping similarly-characterized irregular disks together on a given spindle and compensating the ramp accordingly.

A hard disk drive includes multiple disk media mounted on a spindle, where the outer diameter of each disk medium is offset from the inner diameter of the disk medium in a same direction along an axis of rotation of the spindle, and a load/unload ramp positioned, based on the offset, to align in correspondence with the outer diameters of the disk media. Thus, the curvature of irregular disk media, such as that associated with thinner and thinner disks, is mitigated by grouping similarly-characterized irregular disks together on a given spindle and compensating the ramp accordingly.

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.

A data storage device includes a stack of data storage disks, a head stack assembly, and a piezoelectric motor. The head stack assembly includes an arm, a load beam, a head and a tail. The arm is configured for pivotal motion about a longitudinal axis of an actuator shaft. The load beam is attached to the arm. The head is attached to the load beam and is configured to interact with a surface of one of the disks, the surface defining an x-y plane. The tail is disposed on an opposite side of the actuator shaft from the arm and has a first engagement surface that is parallel to the x-y plane. The piezoelectric motor includes a piezoelectric element and a contact tip. The piezoelectric element comprises a first mounting surface. The contact tip is disposed at the first mounting surface and frictionally contacts the engagement surface.