Abstract: In an optical data transfer system, a beam modulator is configured to embed a set of data in an input beam. A multimode optical waveguide network has an in-coupling region for receiving the input beam. The multimode optical waveguide network is configured to guide the input beam to an out-coupling region of the multimode optical waveguide network. A spatial coherent detector is configured to measure a phase and an amplitude of an output optical field at multiple locations. The output optical field is at least partially defined by the input beam and thus exhibiting distortion effects caused by the passage of the beam through the multimode waveguide network. Signal processing is applied to an output of the spatial coherent detector, in order to compensate for the distortion effects, and thereby recover, from the output of the spatial coherent detector, the set of data embedded in the input beam.

Abstract: The present disclosure generally relates to data storage devices, comprising: a magnetic tape; a tape head configured to write data to and read data from the magnetic tape; a first reel having a first interior surface; a second reel, wherein the first reel and the second reel are configured to wind and unwind the magnetic tape; one or more motors configured to actuate the first reel and the second reel; a first magnetic recording surface disposed on the first interior surface of the first reel; an actuating arm disposed between the first reel and the second reel; an actuator coupled to a distal end of the actuating arm; and a magnetic recording head disposed on the actuating arm. The magnetic recording head being situated a distance away from the actuator, wherein the actuating arm is configured to move about the actuator such that the magnetic recording head is able to contact the first magnetic recording surface to write data to and read data from the first magnetic recording surface.

Abstract: The present disclosure is generally related to a tape drive comprising a tape head assembly. The tape head assembly comprises a spring adaptor, the spring adaptor comprising a first hole, a second hole, and a spring member disposed between the first hole and the second hole, a beam disposed within the first hole of the spring adaptor, a first module disposed on the beam, the first module comprising a first plurality of write transducers and a first plurality of read transducers, a second module disposed on the beam adjacent to the first module, the second module comprising a second plurality of write transducers and a second plurality of read transducers, and an actuator disposed in the first hole. The actuator is controllable to move the beam in a direction transverse to a media movement direction. The spring adaptor stabilizes the beam while the beam is being actuated.

Abstract: According to one embodiment, a magnetic disk drive includes a notch filter, a parameter storage unit and a computation unit, when the sampling period changes from a first sampling period to a second sampling period, the computation unit computes a damping ratio parameter related to the damping ratio in a second set of parameters at the second sampling period, based on a first absolute value at a first angular frequency of a first transfer function computed from a first set of parameters at the first sampling period and a second absolute value at the first angular frequency of a second transfer function computed from the first set of parameters at the second sampling period, and the notch filter is set with the second set of parameters at the second sampling period is computed.

Abstract: According to one embodiment, a magnetic disk apparatus includes a magnetic disk, a magnetic head, and a controller. The magnetic disk is provided with a track including a plurality of first sectors. The controller accesses the magnetic disk by using the magnetic head. The plurality of first sectors includes a plurality of second sectors where data segments are written and a third sector where parity and first information indicating effectiveness or ineffectiveness of protection by the parity are written.

Abstract: According to one embodiment, a disk device includes a magnetic head, a piezoelectric element and a flexure. The piezoelectric element includes two electrodes. The flexure includes a first part and a second part that swings. The first part has a first surface to which a first electrode is joined. The second part has a second surface to which the magnetic head is joined. The magnetic head has a third surface facing the first surface and the second surface. The first electrode is spaced apart from a second electrode in a first direction. The first surface and an end of the third surface face each other. The second surface and another end of the third surface face each other. A distance between the first surface and the one end of the third surface is longer than a distance between the second surface and the other end of the third surface.

Abstract: A data storage device has a closed loop extended park mode during spin down operation. A data storage device comprises a spindle motor configured to rotate one or more disks, and one or more processing devices. The one or more processing devices are configured to determine a value of current that is discharged from the spindle motor over time during a spin down of the spindle motor, and control a braking duty cycle for braking the spindle motor during the spin down such that the value of current discharged from the spindle motor over time does not exceed a selected current limit.

Abstract: 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.

Abstract: A computer program product, system, and method are provided for direct resistance measurement of a magnetoresistive (MR) head of a storage drive in a storage system. In one embodiment, a voltage difference across the MR reader head is measured directly by applying an AC current to the MR head to generate an AC voltage across the MR head that can propagate through filter capacitors and be measured. In one embodiment, the voltage difference is amplified and the peak-to-peak voltage at the output of the amplifier is captured. Similarly, a reference voltage difference across a reference resistance is measured directly by applying a reference AC current to a reference resistance. The resistance of an MR reader head may be calculated directly as a function of the respective voltage differences without including the resistance of any bias resistors biasing the MR head.

Abstract: In one general embodiment, a data storage product includes a magnetic recording tape having written thereon at least two servo tracks extending along a longitudinal axis of the tape. Each servo track has a timing-based servo (TBS) pattern comprising a series of servo frames arranged to enable lateral positioning of a magnetic head relative to the servo tracks as well as tape dimensional stability (TDS) compensation via head skew. Each frame comprises a sequence of pairs of leading and trailing servo stripes. Midpoints between the servo stripes in each pair, at all points having a same relative lateral height on the tape, are located along a virtual median line oriented at an angle ? from perpendicular to the longitudinal axis of the tape, the angle ? being greater than 1 degree.

Abstract: A data object has a lock and a condition indicator associated with it. Based at least partly on detecting a first setting of the condition indicator, a reader stores an indication that the reader has obtained read access to the data object in an element of a readers structure and reads the data object without acquiring the lock. A writer detects the first setting and replaces it with a second setting, indicating that the lock is to be acquired by readers before reading the data object. Prior to performing a write on the data object, the writer verifies that one or more elements of the readers structure have been cleared.

Abstract: According to one embodiment, a magnetic disk device comprises a disk, a first head, a second head, a controller. The disk includes a first surface and a second surface different from the first surface. The first head carries out read and write of data from and to the first surface. The second head carries out read and write of data from and to the second surface. The controller adjusts a spiral speed of at least one of the first head and the second head according to a cylinder offset amount corresponding to a positional difference between the first head and the second head. The spiral speed is a speed at which spiral servo patterns are to be written.

Abstract: A method for cancelling, from servo signals read in a read channel while a write channel is active, interference caused by write signals in the write channel, includes generating a predicted channel response signal from the write signals in a data clock domain, resampling the generated predicted channel response signal using a clock in the data clock domain having a rate corresponding to a servo clock from a servo clock domain, transferring the resampled predicted channel response signal from the data clock domain to the servo clock domain and aligning phase of the transferred resampled predicted channel response signal with phase of the servo clock, determining a domain-boundary-crossing delay incurred in the transferring, based on the domain-boundary-crossing delay, synchronizing the phase-aligned transferred resampled predicted channel response signal with the servo signals, and subtracting the synchronized phase-aligned transferred resampled predicted channel response signal from the servo signals.

Abstract: Example control circuitry, data storage devices, and methods to provide a spiral data track format that is different from the underlying servo track format are described. The data storage device may include a storage medium configured with a plurality of tracks in at least one continuous spiral pattern and a head actuated over the storage medium. The data tracks may be written to the storage medium with track lengths that are different than a single revolution of the storage medium.

Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator arm assembly comprising a voice coil motor (VCM), the VCM configured to operate in a first mode and a second, different mode, wherein the first mode corresponds to at least a first and a second setting, and a control circuitry configured to cause the VCM to seek towards a target track in the first mode using the first setting for a first duration, control transition of the VCM from the first to the second setting in the first mode, cause the VCM to seek towards the target track using the second setting for a second duration, and control transition of the VCM from the first to a second mode, wherein controlling the transitioning comprises seeking the VCM toward the target track in the second mode for a third duration.

Abstract: In accordance with an embodiment, a hard disk drive includes voice coil motors (VCMs) coupled to respective control units configured to drive retract an operation of the VCMs in the hard disk drive. The retract operation of the VCMs includes a sequence of retract steps. The control units are allotted respective time slots for communication over a communication line with the respective time slots synchronized via the common clock line, and are configured to drive sequences of retract steps of the VCMs in the hard disk drive in a timed relationship.

Abstract: A method for starting hard disks, applied in an electronic device, the method includes: starting a storage in the electronic device, and the storage comprising hard disks and a backplane extension chip; sending preset request signals by the hard disks to the backplane extension chip; verifying a number of the hard disks by the backplane expansion chip according to the request signals; when the number of the hard disks is verified successfully, performing type verification on the hard disks by the backplane expansion chip; and sending a start signal by the backplane expansion chip to the target hard disks having a successful type verification according to a preset start sequence and a preset number of the hard disks, to start the target hard disks.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head, a command queue, a command residence time calculation unit calculating a residence time of each of commands in the command queue, a command information calculation unit calculating the number of the commands and a ratio, a limit time determination unit obtaining a latency limit time corresponding to the number of commands and the ratio, from a latency limit time determination table, and a command selection processing unit selecting a command to be executed, by considering the latency limit time.

Abstract: According to one embodiment, an information processing device includes an acquisition part, and a processor. The acquisition part is configured to acquire a reproduction signal obtained from a recording part. The recording part includes a recording medium. The reproduction signal includes a first signal corresponding to information recorded in the recording medium. The processor is configured to derive a first output and a second output. The first output is obtained by first information being processed by a first processing model. The first information includes the first signal. The second output is obtained by the first information being processed by a second processing model. The processor is configured to output a result of processing the first information based on a third output. The third output is obtained based on the first output, the second output, and the first information.

Abstract: A method of reading servo wedge data from a rotating constant-density magnetic storage medium having a plurality of tracks, where each track is written at a track pattern frequency, the respective track pattern frequencies varying from a lowest frequency at an innermost one of the tracks to a highest frequency at an outermost one of the tracks, includes, for each respective track, determining, based on the pattern frequency of the respective track, a desired sampling position, sampling actual samples of servo wedge data based on a sampling clock used for all tracks, having a sampling frequency at least equal to the track pattern frequency of the outermost track, determining a phase relationship of the desired sampling position to the sampling clock, and, depending on the phase relationship between the sampling position and the sampling clock, interpolating a sample, or omitting interpolation of a sample and squelching the interpolation clock.