A multi-actuator hard disk drive includes a lower actuator with a corresponding voice coil motor assembly (VCMA), a coaxial upper actuator with a corresponding VCMA, and a central extended stiffener plate positioned between the upper and lower VCMAs and extending beyond the pivot area at least to an area adjacent to the disk stack. Use of an extended stiffener plate enables some control over the direct and coupled plant transfer functions, while effectively providing a base support structure for the upper VCMA and cover support structure for the lower VCMA.

According to an embodiment, tracks on a magnetic disk each include a long-distance sector having a length in the circumferential direction covering two or more servo sectors. A controller executes an acquisition operation to acquire one or more evaluation amounts on the basis of a track pitch in each of the two or more servo sectors included in a portion adjacent to the long-distance sector. The controller executes a protection operation to protect data of an adjacent track in a case where a total value of the one or more evaluation amounts exceeds a first threshold value.

Disclosed herein is a magnetic storage device that includes magnetic storage discs and a first carriage arm rotatably movable in a radial direction along a first one of the magnetic storage discs and within a region radially outward from the first one of the magnetic discs. The magnetic storage device includes a first suspension arm co-movably fixed to the first carriage arm and having a first-suspension-arm length extending from a proximate first-suspension-arm end of the first suspension arm to a distal first-suspension-arm end of the first suspension arm. The magnetic storage device also includes a second suspension arm co-movably fixed to the first carriage arm and having a second-suspension arm length extending from a proximate second-suspension arm end to a distal second-suspension arm end of the second suspension arm that is different from the first-suspension arm length.

The present disclosure generally relates to a tape drive comprising one or more tape head modules. Each tape head module comprises 65 data elements disposed in a first row, each data element being a write element or a read element, and at least 5 servo element pairs disposed in a second row, the second row being disposed parallel to the first row. The second row is spaced a distance in a first direction from the first row. One or more data elements and one or more servo element pairs may be unwired and non-operable. The tape drive may comprise three tape head modules, where the second tape head module is disposed between the first and third tape head modules. Each data element of the first tape head module and the third tape head module are write elements, and each data element of the second module is a read element.

According to one embodiment, a controller of a magnetic disk apparatus operates in a first operation of writing to data regions on a magnetic disk of the magnetic disk apparatus while positioning a magnetic head. In the first operation, the controller demodulates burst patterns to obtain a first burst demodulated value set and corrects the first burst demodulated value set to obtain a second burst demodulated value set. The first burst demodulated value set is corrected on the basis of a correction algorithm using a first set value as an argument. The controller calculates, on the basis of the second burst demodulated value set, an offset amount of the magnetic head from one of servo tracks on the magnetic disk.

A system for recalling data from tape is disclosed. The system includes computer processing circuits and computer readable storage media having computer executable instructions. When executed, the instructions cause the computer-processing circuits to start, in response to a request to recall data from a tape, to read the tape at a read position. Additionally, the instructions cause the circuits to determine that the tape comprises a damaged region. Further, the instructions cause the circuits to determine a start position of the damaged region by skimming the tape. Additionally, the instructions cause the circuits to determine an end position of the damaged region by skimming the tape. Further, the instructions cause the circuits to read between the read position and the start position of the damaged region. Additionally, the instructions cause the circuits to read between the end position of the damaged region and an end of data indicator.

The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. Sci obtained by measuring a surface of the magnetic layer with an atomic force microscope and by Equation A is 1.40 or more and 1.60 or less, and standard deviation of the Sci in a width direction of the surface of the magnetic layer is 0.05 or less. In Equation A, Sq is a root-mean-square height Sq specified in ISO 25178, Vv(h.sub.0.05)-Vv(h.sub.0.8) is a void volume in a region where a load area ratio in a bearing curve is 5% or more and 80% or less, and A is a measurement region area.

[00001]$\begin{array}{cc}\mathrm{Sci}=\left(\frac{\mathrm{Vv}\left(h_{0.05}\right)-\mathrm{Vv}\left(h_{0.8}\right)}{A}\right)/\mathrm{Sq}& \mathrm{Equation}A\end{array}$

The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. A protruding peak height Spk specified in ISO 25178 on a surface of the magnetic layer is 1.5 nm or more and 3.0 nm or less, and standard deviation of the Spk in a width direction of the surface of the magnetic layer is 0.5 nm or less.

An apparatus includes a microactuator controller configured to generate a microactuator control signal, a feedforward microactuator compensator configured to generate a microactuator compensation signal, and a microactuator model filter configured to filter a modified microactuator control signal. The microactuator compensation signal is configured to be injected into the microactuator control signal to generate the modified microactuator control signal. The microactuator model filter generates a filtered modified microactuator control signal and injects the filtered modified microactuator control signal into a position error signal to generate a modified position error signal.

Systems and methods for compensating for hysteresis in a disc drive are described. In one embodiment, a method may use an inverse hysteresis model to linearize effects of hysteresis of a microactuator in the disc drive. The hysteresis model may be a Coleman-Hodgdon hysteresis model. The hysteresis of the microactuator may be characterized, and the inverse hysteresis model may be based at least in part on the characterization. The inverse hysteresis model may be used to implement a digital filter. The digital filter may be employed in series with the microactuator to linearize the effects of hysteresis.