Abstract: Methods and apparatus are provided for multi-tier detection and decoding in flash memory devices. Data from a flash memory device is processed by obtaining one or more quantized estimates of a voltage stored on at least one bit of a cell of the flash memory device from the flash memory device; converting the one or more quantized estimates for the at least one bit to a reliability value; and decoding the at least one bit using the reliability value to obtain a value written for the at least one bit.

Abstract: Determining a Curie temperature (Tc) distribution of a sample comprising magnetic material involves subjecting the sample to an electromagnetic field, heating the sample over a range of temperatures, generating a signal representative of a parameter of the sample that changes as a function of changing sample temperature while the sample is subjected to the electromagnetic field, and determining the Tc distribution of the sample using the generated signal and a multiplicity of predetermined parameters of the sample.

Abstract: A read sensor having a bearing surface and an antiferromagnetic (AFM) layer recessed from the bearing surface. The read sensor includes a synthetic antiferromagnetic (SAF) structure over the AFM layer. The SAF structure includes a recessed lower pinned layer, an upper pinned layer, a reference layer and a stabilization feature. The stabilization feature may include deliberate reduction of the antiferromagnetic coupling energy density between the upper pinned layer and the reference layer, so that it becomes lower than the first energy density of antiferromagnetic coupling between the upper pinned layer and the lower pinned layer. The stabilization feature may alternatively include an intermediate pinned layer between the lower pinned layer and the upper pinned layer. The intermediate pinned layer is antiferromagnetically coupled to both the lower pinned layer and the upper pinned layer, and at least a portion of the intermediate pinned layer is recessed behind the bearing surface.

Abstract: An SSD controller maintains a zero count and a one count, and/or in some embodiments a zero/one disparity count, for each read unit read from an SLC NVM (or the lower pages of an MLC). In an event that the read unit is uncorrectable in part due to a shift in the threshold voltage distributions away from their nominal distributions, the maintained counts enable a determination of a direction and/or a magnitude to adjust a read threshold to track the threshold voltage shift and restore the read data zero/one balance. In various embodiments, the adjusted read threshold is determined in a variety of described ways (counts, percentages) that are based on a number of described factors (determined threshold voltage distributions, known stored values, past NVM operating events). Extensions of the forgoing techniques are described for MLC memories.

Abstract: A perpendicular recording medium with enhanced magnetic stability. In accordance with some embodiments, a multi-layer recording structure is formed on a base substrate and adapted to magnetically store a magnetic bit sequence in domains substantially perpendicular to said layers. A thin magnetic stabilization layer is formed on the multi-layer recording substrate to magnetically stabilize an upper portion of the recording structure.

Abstract: An apparatus comprising a slider and a detector coupled to the slider. The slider is configured for writing data to and reading data from a magnetic recording medium. The slider comprises a heater configured to receive a modulated signal and cause oscillation in a spacing between the slider and the medium. At least one heat generating component of the slider is configured to receive a modulated signal. A contact sensor is situated on the slider to receive heat generated by the at least one heat generating component. The detector is configured to measure a response signal of the heated contact sensor as the slider approaches the medium. The detector is further configured to detect contact between the slider and the medium in response to the response signal reaching a predetermined threshold.

Abstract: A waveguide core extends from an input coupler towards a media-facing surface of a read/write head. A cap is located between a terminating end of the waveguide core and the media-facing surface. The cap is formed of a high index of refraction, high-corrosion resistant material that is different than a material used to form the waveguide core. A near-field transducer is proximate the cap in a down-track direction. A head overcoat on the media-facing surface covers the cap.

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.

Abstract: Measuring surface features of a plurality of sliders including capturing an image of a surface of a slider bar using a large aperture interferometer, where the slider bar includes at least one slider of the plurality of sliders, and where the image includes surface height data for the slider bar surface and the included at least one slider. A bar height map is created of the slider bar based upon the surface height data of the captured image. Individual slider surfaces having individual slider height maps are identified, based at least in part of the number of sliders included on the slider bar.

Abstract: A system includes a data storage medium and a shockwave generator. The data storage medium includes cells and a plurality of layers. Each cell is configured to store information therein. At least two cells are arranged in a horizontal plane within a same layer of the plurality of layers of the data storage medium and at least two cells are arranged in a vertical plane in different layers of the plurality of layers of the data storage medium. The shockwave generator is configured to generate a shockwave signal that travels through a layer of the plurality of layers of the data storage medium. A target cell within the layer stores information responsive to a beam emitted from an emitter targeting the target cell as the shockwave signal is passing through the target cell. The target cell maintains the information after the shockwave signal exits through the target cell.

Abstract: Various aspects of the present disclosure are directed toward a disc drive actuator assembly including an e-block, a plurality of bearings, and one or more heat transfer components. The heat transfer component(s) operates to conductively draw heat from the plurality of bearings through the e-block, and convectively dissipate the heat into an atmosphere in contact therewith. The heat transfer component(s) mitigates temperature rise of the bearings during operation of a disc drive, thereby mitigating bearing lubricant outgassing from within the bearings.

Abstract: Systems and methods are disclosed to abort a command at a data storage controller, in accordance with certain embodiments of the present disclosure. In some embodiments, an apparatus may comprise a data storage controller configured to receive an abort indicator from a host device, generate an abort tracking indicator at a receiving unit configured to receive commands from the host device, monitor to determine when the selected command is received at the receiving unit based on the abort tracking indicator, and abort the selected command when the selected command is received at the receiving unit. In some embodiments, the data storage controller may generate an abort tracking indicator at a completion unit configured to notify the host device of completed commands, and monitor for the selected command at the completion unit based on the abort tracking indicator.

Abstract: Embodiments described herein provide an apparatus that is operable with a disk drive. The apparatus includes a memory device operable to store a plurality of bit sets. Each bit set identifies a track and a sector of the disk drive and a number of times that the track of the disk drive has been written. A controller of the disk drive is operable to increment the number when the track is written. Each bit set comprises a number of bits that is established according to track location of the disk drive.

Abstract: An apparatus includes a circuit, a code modulator, and an actuator. The circuit is operable to detect displacements of a rotating object while in motion. The circuit is operable to detect a position of the displacements and to generate a signal associated therewith. The code modulator is operable to generate a modulated signal based on the position and the displacements. The actuator is operable to apply a force to the rotating object, wherein the force is based on the modulated signal.

Abstract: An apparatus may include a circuit configured to generate, by an analog to digital converter (ADC), one or more ADC samples based on an input signal. The circuit may be further configured to generate a first estimated signal using a first channel pulse response estimation with a gain constraint based on the one or more ADC samples and generate a second estimated signal using a second channel pulse response estimation with a phase constraint based on the one or more ADC samples.

Abstract: A circuit may be configured to adjust a correction signal for each phase of an electric motor based on a rotational position of a spindle of the electric motor, generate a distorted waveform based on the correction signal, and drive the electric motor in response to the distorted waveform. In some examples, back electromotive force (BEMF) may be determined in order to adjust a motor drive waveform, which may reduce or eliminate motor vibrations. A motor drive signal may be pre-warped (i.e. distorted) such that when the correctional signal and drive signals are combined, there is a reduction in acoustic emissions or motor vibrations. Other parameters, such as cogging torque, may be measured to reduce motor vibration and acoustic emissions.

Abstract: Apparatus and method for managing data in a hybrid data storage device. In some embodiments, a hybrid device has a hard disc drive (HDD) controller circuit coupled to non-volatile rotatable media and a solid state drive (SSD) controller circuit coupled to non-volatile solid state memory. A top level controller circuit directs a selected access command one of the HDD controller circuit or the SSD controller circuit responsive to a selected parameter associated with the selected access command. In a normal mode, the top level controller circuit directs a transfer of data between the host and the HDD controller circuit and handles host interface communications. In a tunneling mode, the top level controller circuit directly connects the HDD controller circuit to the host device. In this way, tunnel mode bypasses processing operations required by the top level controller circuit. Tunnel mode and normal mode may be selected on a command-by-command basis.

Abstract: An apparatus comprises a slider configured for heat-assisted magnetic coupled to a controller. The slider comprises a writer, a heater, a near-field transducer, and an optical waveguide for communicating light from a laser diode to the near-field transducer. The controller is configured to set a target pre-write clearance of the slider prior to performing a write operation, set a target write clearance of the slider for performing the write operation, and determine a difference between the target pre-write and write clearances to define a target pre-write clearance offset. The controller is also configured to measure, for a plurality of different target pre-write clearance offsets, a writability metric for the slider while sweeping a laser diode current, and adjust the target pre-write clearance offset so that the writability metric reaches a predetermined threshold. The controller is further configured to perform subsequent write operations using the adjusted target pre-write clearance offset.

Abstract: Provided herein is an apparatus including a top continuous layer and a bottom continuous layer under the top continuous layer. The top continuous layer and the bottom continuous layer are antiferromagnetically coupled. A number of granular columns are under the bottom continuous layer. The number of granular columns include at least a first granular layer under the bottom continuous layer and a second granular layer also under the first granular layer. The first granular layer and the second granular layer are separated by a non-magnetic spacer. The first granular layer and the second granular layer are ferromagnetically coupled. The first granular layer is antiferromagnetically coupled to the bottom continuous layer.

Abstract: A slider of a heat-assisted recording head comprises electrical bond pads coupled to bias sources and a ground pad, an air bearing surface, and a waveguide configured to receive light from a laser source. A contact sensor proximate the air bearing surface is coupled between a first bond pad and a second bond pad. A bolometer is coupled to a reference thermal sensor. The bolometer is situated at a slider location that receives at least some of the light communicated along the waveguide. The reference thermal sensor is situated at a slider location unexposed to the light communicated along the waveguide. The bolometer and reference thermal sensor are coupled between the first and second bond pads and in parallel with the contact sensor. A ground connection is coupled to the ground pad and at a connection between the bolometer and the reference thermal sensor.