Abstract: Systems and methods are disclosed for applying multi-stage multiple input single output (MISO) circuits for fast adaptation. An apparatus may comprise a first reader and a second reader configured to simultaneously read from a single track of a data storage medium, a MISO circuit. The MISO circuit may include a first stage filter having a first number of taps and configured to filter signal samples received from the first reader and the second reader and produce first filtered samples. The MISO circuit may also include a second stage filter having a second number of taps greater than the first number, and be configured to receive the first filtered samples corresponding to the first reader and the second reader from the first filter stage, filter the first filtered samples to produce second filtered samples, and combine the second filtered samples to produce a combined sample output.

Abstract: System and method are disclosed for managing storage space of a magnetic storage device. The system may read data from a first sector of the storage space and determine whether the data are successfully read from the first sector. The system may write updated data to the first sector and a second sector when it is determined that the data are not successfully read from the first sector.

Abstract: A precompensation circuit can include: a rising edge interpolator circuit configured to generate a phase shifted rising edge data signal; a falling edge interpolator circuit configured to generate a phase shifted falling edge data signal; a multiplexer circuit coupled with the rising edge interpolator circuit and with the falling edge interpolator circuit to multiplex the phase shifted rising edge data signal and the phase shifted falling edge data signal into an output data signal responsive to a select signal; and a control circuit coupled with the select input of the multiplexer circuit to control production of the output data signal, wherein the control circuit is further coupled with both the rising edge interpolator circuit and the falling edge interpolator circuit to change the select signal to the multiplexer circuit at times determined by both the phase shifted rising edge data signal and the phase shifted falling edge data signal.

Abstract: A first waveguide portion receives light from an energy source in a fundamental transverse electric (TE00) mode. A mode converter converts a portion of the light to higher-order transverse electric (TE10) mode. A second waveguide portion receives the light at the TE10 mode and delivers the light to a near-field transducer that heats a recording medium in response thereto. An optical spatial mode filter prevents remnant light in the TE00 mode from affecting the recording medium while passing the light at the TE10 mode.

Abstract: In one embodiment, a system includes a controller and logic integrated with and/or executable by the controller. The logic is configured to cause data to be written to a first write section of a magnetic medium as a plurality of first codeword sets, and cause at least some of the data to be written to a rewrite section of the magnetic medium as one or more rewritten codeword sets. A length of at least one rewritten row stored to the rewrite section of the magnetic medium is greater than either a length of another rewritten row in the same rewritten codeword set and/or a length of at least one row in a codeword set stored to the first write section of the magnetic medium.

Abstract: An optical pickup device includes a semiconductor laser that emits a laser beam, and an object lens that concentrates the laser beam emitted from the semiconductor laser on an optical disc. In this optical pickup device, an optical axis of the object lens is inclined with respect to an optical axis of the laser beam that is incident on the object lens so as to generate flares caused by coma aberration on an entrance side in a forward direction of pits of the optical disc.

Abstract: In a disk drive apparatus, a first time period is determined, during which a first head driven by a first actuator will be performing a first disk access operation. A second time period is determined, during which a second head driven by a second actuator will be performing a second disk access operation. The first and second actuators are independently movable such that the first and second disk access operations are capable of being performed in parallel. If it is determined that the second disk access operation will impact servo control of the first disk access operation, at least one of the first and second disk access operations is changed to reduce the impact to the servo control of the first disk access operation.

Abstract: In a device with first and second heads, the second head is held at a radial location over one or more disks via a second actuator that moves the second head. A position error of the second head is read while performing a seek with a first actuator, the first actuator moving the first head over the one or more disks. A mechanical transfer function is determined between the first actuator and the second actuator based on the position error of the second head. The mechanical transfer function is used to provide compensation for the second head via the second actuator in response to subsequent seek of the first actuator.

Abstract: One or more magnetic recording disks are coupled to a spindle motor, each of the disks having opposing recording surfaces. Two or more actuators are moveable independently over at least a first recording surface of the one or more disks. A first actuator of the two or more actuators comprises a first write head and a first read head. A second actuator of the two or more actuators comprises at least a second read head and may include a second write head. A controller is coupled to the two or more actuators and configured to write data to a track on the first recording surface using the first write head, and perform a read operation on the data written to the track using the second read head. The controller is also configured to verify that the data was successfully written to the track in response to the read operation. The read operation can be performed within less than one revolution of the first recording surface after the write operation.

Abstract: Devices having air bearing surfaces (ABS), the devices include a near field transducer (NFT) that includes a disc configured to convert photons incident thereon into plasmons; and a peg configured to couple plasmons coupled from the disc into an adjacent magnetic storage medium, wherein the disc includes a disc material and the peg includes a peg material, wherein the disc material is different from the peg material and wherein the disc material has a first real part of the permittivity and a peg material has a second real part of the permittivity and the second real part of the permittivity is not greater than the first real part of the permittivity.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head including a main pole configured to apply a recording magnetic field to the disk, and side shields provided in a first direction with respect to the main pole and possessing a magnetic field in the magnetization direction of the first direction, and a controller configured to output a recording current in which a magnitude of a first electric current and a magnitude of a second electric current opposite to the first electric current in direction of the current are different from each other to the head according to the magnetic field of the side shields.

Abstract: An apparatus-implemented method according to one embodiment includes detecting an error while writing data to a tape volume on a tape and repositioning the tape in response to detecting the error. A determination whether a rewrite of data associated with the error to the tape volume is allowed is made based on a current position of the tape after the repositioning. The data is rewritten to the tape volume in response to determining that the rewrite of data associated with the error to the tape volume is allowed. A computer program product for protecting overwrite of a tape volume according to another embodiment includes a computer readable storage medium having program instructions embodied therewith, the program instructions readable and/or executable by a controller to cause the controller to perform the foregoing method.

Abstract: The present disclosure relates to a method and apparatus for processing of multi-dimensional readback signal from magnetic recording or optical, physical data recording so as to reduce/control Inter Symbol Interference (ISI) and noise within acceptable limits. The method is based on Partial Response Maximum Likelihood (PRML) detection and takes care of time varying channel conditions. In an embodiment, the filter coefficients of both the equalizer and the partial response (PR) target are jointly adapted to account for the channel condition for both separable and non-separable targets thus reducing signal detection complexity. In an aspect, the disclosure provides an apparatus that incorporates an adaptation engine along with the equalizer and the PR target that updates filter coefficients of both the equalizer and the PR target following the formulated mathematical equations.

Abstract: Implementations disclosed herein include a method comprising receiving a TRIM request for a media cache in a storage media from a host, determining whether a TRIM range in the TRIM request overlaps with an active operation, invalidating the TRIM range responsive to determining that the TRIM range does not overlap with an active operation, and inserting at least one null node in the media cache. The method may comprise receiving a host read request, performing a media cache search for a read LBA range, and determining where data is located. If all the data is located in the media cache, the system reads from the media cache. If the data is located in a null node, patterning for the null node occurs. If the data is located partially in the main store, the media cache, or a null node, the data may be read, combined, and returned to the host.

Abstract: First and second servo control processors are coupled to respective first and second actuators that independently position first and second heads over one or more disks of a data storage drive. The first and second servo control processors are further coupled to first and second low-latency ports. First and second unidirectional buses couple the first and second low-latency ports. The first and second unidirectional busses are operable to isochronously exchange servo positioning data between the first and second servo control processors. The first and second servo control processors each use the servo positioning data to compensate for movement caused by another of the first and second servo control processors.

Abstract: A tape layout module for determining a tape layout allocation strategy for laying out data on tape, the data being organized into a plurality of fixed-size subdata sets with each of the plurality of subdata sets including a plurality of codeword interleaves, the tape including a plurality of media defect characteristics, includes a tape layout optimization system including a processor that receives information on the plurality of media defect characteristics. The tape layout optimization system determines the tape layout allocation strategy based at least in part on at least one of the plurality of media defect characteristics. Additionally, the tape layout optimization system can determine the tape layout allocation strategy further based on distance spectra between pairs of the plurality of codeword interleaves. Further, the tape layout optimization system can determine the tape layout allocation strategy by selectively utilizing at least one tape layout parameter.

Abstract: A method for writing data from a table to a tape includes setting a number of partitions on the tape, where the number of partitions is greater than or equal to a number of columns of the table to be written to the tape, and writing data from each column of the table to at least one partition of the tape, the at least one partition including two or more wraps, the data is written from a top of the two or more wraps towards a bottom of the two or more wraps in a direction of a width of the at least one partition. The written data is reciprocated from a beginning of the tape to an end of the tape in a longitudinal direction of the tape such that writing of a last data entry of one column ends at a beginning of the two or more wraps.

Abstract: A method and system for adjusting a servo head in a tape drive is disclosed. Position information for the servo head can be obtained and used to determine if an adjustment of one of the servo heads is necessary. By comparing the position of the tape against two servo heads, erroneous adjustments to the servo head can be obviated.

Abstract: In a storage device, data is written to tracks on a storage medium. Data for each track includes a preamble. The preamble in any current track is orthogonal to the preamble in any track adjacent to the current track. A first read head is positioned over the current track and off-center toward a first adjacent track on a first side of the current track to detect first signals from among the current track, the first adjacent track, and a second adjacent track on a second side of the current track. A second read head is positioned over the current track and off-center relative to the current track toward the second adjacent track to detect second signals from among the current track, the first adjacent track, and the second adjacent track. Analyzing the first and second signals determines an amount by which the read heads are off-track from the current track.

Abstract: An apparatus includes a frequency analyzer circuitry, filter circuitry, and voice coil motor (VCM) control circuitry. The frequency analyzer circuitry is configured to detect one or more dominant frequencies of a position error signal (PES). The filter circuitry is configured to identify one or more filters in response to detecting the one or more dominant frequencies, apply the one or more identified filters to at least one of a microactuator control signal and PES, and generate a VCM compensation signal in response to the filtered PES or the microactuator control signal. The VCM control circuitry is configured to generate a VCM control signal in response to the VCM compensation signal.