G11B5/5565

HEAD SUSPENSION ASSEMBLY FOR DISK DEVICE AND INCLUDING DAMPER
20200294539 · 2020-09-17 ·

According to one embodiment, a head suspension assembly includes a support plate having a proximal end and a distal end, a wiring member on the support plate and including a metal plate and a wiring board laid on the metal plate, the metal plate including a first joined portion joined to the support plate close to the distal end and a second joined portion joined to the support plate and located on a proximal end side of the support plate, a head mounted on the wiring member, an extendable piezoelectric element mounted on the wiring member, and a damper including a viscoelastic layer and a constraint layer stacked on the viscoelastic layer and attached to the support plate to cover the first joined portion and the second joined portion.

MINIMIZATION OF THERMAL MAGNETORESISTIVE OFFSET CHANGE
20200135232 · 2020-04-30 · ·

Provided herein is an apparatus including a disk drive base, wherein the disk drive base includes a first metal composition with a first CTE (coefficient of thermal expansion). A disk drive cover is attached to the disk drive base, wherein the disk drive cover includes a second metal composition with a second CTE that are different from the first metal composition and the first CTE. An arm is connected to a reader and a writer, wherein the arm is coupled to the disk drive base, the reader and the writer are separated by a distance, and the distance affects an MR (magnetoresistive) offset. In response to temperature changes between 0 C. and 60 C., the first material and the second material expand and contract comparably and proportionally. In further response to the temperature changes between 0 C. and 60 C., a change in the MR offset is less than 10% or a preferably defined range of a track pitch on a recording medium attached to the disk drive base.

Data storage device computing notch filters for multiple temperatures

A data storage device is disclosed comprising a head actuated over the disk. A first notch filter is calibrated at a first temperature, and a second notch filter is computed for a second temperature based on the first notch filter and a first delta temperature between the first temperature and the second temperature. The second notch filter is computed by transforming a continuous-time transfer function of the first notch filter adjusted by the first delta temperature into a discrete-time transfer function of the second notch filter.

Magnetic disk apparatus and method

According to embodiments, a magnetic disk apparatus includes a magnetic disk, a magnetic head, a temperature sensor, and a controller. The magnetic disk has formed therein a servo sector in which servo data including a first post code and a second post code is recorded. In the positioning of the magnetic head, the controller performs a correction using a third post code that is based on the first and second post codes and a first temperature detected by the temperature sensor.

Magnetic media decommission management in a computer system

A computer program product, device, system, and method are provided for decommissioning a tape cartridge internally within a tape library. In one embodiment, a decommission canister is configured to be accepted within a tape library canister bay. The decommission canister has a fusing element configured to fuse together at least a portion of layers of magnetic tape of a tape cartridge within the tape library, to decommission the tape cartridge within the tape library. In one embodiment, the fusing element is a heating element adapted to emit heat directed at layers of magnetic tape of a tape cartridge to melt together at least a portion of layers of magnetic tape of a tape cartridge within the tape library. As a result, unwinding and reading of the magnetic tape is inhibited.

Magnetic disk apparatus
10008227 · 2018-06-26 · ·

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.

Data storage device employing smart braking to unload multiple voice coil motors

A data storage device is disclosed comprising a first voice coil motor (VCM) comprising a first voice coil, and a second VCM comprising a second voice coil. The first VCM and the second VCM are unloaded during a power failure by measuring a first velocity and a first position of the first VCM and measuring a second velocity and a second position of the second VCM. A BEMF voltage generated by a spindle motor is used to generate a first brake voltage based on the first velocity and the first position, and the BEMF voltage is used to generate a second brake voltage based on the second velocity and the second position. The first brake voltage is applied to the first voice coil, and the second brake voltage is applied to the second voice coil.

Magnetic recording system employing passive thermal asperity avoidance

An apparatus comprises magnetic recording disk surfaces and magnetic recording heads comprising a leading and a following head. A controller moves the heads so that the leading head, at a passive fly height, follows a first track of a first disk surface containing a passive thermal asperity (PTA), and the following head, at a passive fly height, follows a first track of a second disk surface. The PTAs on tracks of the second disk surface define virtual PTAs on corresponding tracks of the first disk surface. The controller moves the heads away from the respective first tracks and to neighboring tracks to avoid the PTA and virtual PTAs. The controller is configured to move the heads back to the respective first tracks so that a write or read operation can be performed by the leading head.

Method of detecting back electromotive force in electro-mechanical actuators, corresponding device and apparatus

A driver device coupled to a winding of an electro-mechanical actuator includes: a power stage driving the winding in a discontinuous mode by alternating conduction on-phases to off-phases, and a sensor circuit sensing a voltage across the winding in an off-phase, wherein, during such an off-phase the voltage across the winding includes a residual voltage which decays to zero. The power stage drives the winding from an on-phase to an off-phase by applying to the winding a reverse current pulse to invert the direction of flow of the current through the winding and produce an oscillation of the residual voltage, whereby the residual voltage includes a zero-crossing point after the current through the winding is exhausted. The sensor circuit senses the voltage across the winding at this zero-crossing point, whereby the voltage sensed across the winding at the zero-crossing point is indicative of the back electromotive force of the winding.

Feedforward compensation for multi-actuator hard drives

An apparatus includes a first controller, a second controller, and a coupling compensator. The first controller is configured to generate a first voice coil motor (VCM) control signal in response to a first position error signal. The second controller is configured to generate a second VCM control signal in response to a second position error signal. The coupling compensator is configured to generate a first feedforward correction signal in response to the first VCM control signal. The first feedforward correction signal modifies the second VCM control signal to generate a modified second VCM control signal.