Abstract: Apparatus and method for managing namespaces in a Non-Volatile Memory Express (NVMe) controller environment. A non-volatile memory (NVM) is arranged to store map units (MUs) as addressable data blocks in one or more namespaces. A forward map has a sequence of map unit address (MUA) entries that correlate each of the MUs with the physical locations in the NVM. The MUA entries are grouped into immediately adjacent, contiguous ranges for each of the namespaces. A base MUA array identifies the address, within the forward map, of the beginning MUA entry for each namespace. A new namespace may be added by appending a new range of the MUA entries to the forward map immediate following the last MUA entry, and by adding a new entry to the base MUA array to identify the address, within the forward map, of the beginning MUA entry for the new namespace.

Abstract: Adaptive read reference voltage tracking techniques are provided that employ charge leakage mitigation. An exemplary device comprises a controller configured to: determine at least one reference voltage offset for a plurality of read reference voltages, wherein the at least one reference voltage offset is determined based on a shift in one or more of the read reference voltages over time; shift the plurality of read reference voltages using the at least one reference voltage offset; and employ the plurality of read reference voltages shifted by the at least one reference voltage offset to read data from the multi-level memory cells. The shifting step is optionally performed after a predefined time interval that approximates a settling time after a programming of the multi-level memory cells until a charge leakage of the multi-level memory cells has settled.

Abstract: An apparatus may include a first and second servo channels configured to output first and second position information to first and second writers, respectively, via a shared write path such that the first and second writers write first and second position information to first and second magnetic recording medium surfaces, respectively. In addition, the apparatus may include a controller configured to control the shared write path such that write access is changed between the first servo channel and second servo channel a plurality of times during a revolution of the first magnetic recording medium surface and second magnetic recording medium surface.

Abstract: Methods and apparatus are provided for read retry operations that estimate written data based on syndrome weights. One method comprises reading a codeword from a memory multiple times using multiple read reference voltages; obtaining a syndrome weight for each of the readings of the codeword; identifying a given reading of the codeword having a substantially minimum syndrome weight; and estimating a written value of the codeword based on the given reading. Two cell voltage probability distributions of cell voltages are optionally calculated for each possible cell state of the memory, based on the estimated written value and plurality of readings of the codeword. The cell voltage probability distributions are used to (i) dynamically select log likelihood ratio values for a failing page, (ii) determine a read reference voltage that gives a desired log likelihood ratio value, or (iii) dynamically select log likelihood ratio values for the page populations associated with the distributions.

Abstract: Systems and methods are disclosed for detection and mitigation of defects within a preamble portion of a signal, such as a data sector preamble recorded to a data storage medium. In certain embodiments, an apparatus may comprise a circuit configured to synchronize a sampling phase for sampling a signal pattern. The circuit may sample a preamble field of the signal pattern to obtain sample values, split the sample values into a plurality of groups, determine defect groups having samples corresponding to defects in the preamble field, remove the defect groups from the plurality of groups, and synchronize the sampling phase based on the plurality of groups.

Abstract: A data storage device fastener seal system can have at least a base, a cover, and a fastener seal. The base may have at least one fastener aperture and a first contact surface while the cover can have a second contact and a fastener hole. The second contact surface may physically contact the first contact surface to enclose a data storage region. The fastener seal can be positioned between the base and cover proximal the fastener aperture with the fastener seal extending less than an inch from the fastener aperture in every direction along a plane parallel to the first and second contact surfaces.

Abstract: Techniques are provided for adaptive read threshold voltage tracking with gap estimation between default read threshold voltages. A read threshold voltage for a memory is adjusted by estimating a gap between two adjacent default read threshold voltages using binary data from the memory, wherein the gap is estimated using statistical characteristics of at least one of two adjacent memory levels of the memory; computing an adjusted read threshold voltage associated with the two adjacent memory levels by using the statistical characteristics of the two adjacent memory levels and the gap; and updating the read threshold voltage with the adjusted read threshold voltage. Pages of the memory are optionally read at multiple read threshold offset locations to obtain disparity statistics, which can be used to estimate mean and/or standard deviation values for a given memory level. The gap is optionally estimated using the mean and/or standard deviation values.

Abstract: Systems and methods presented herein provide for open block handling of an SSD. In one embodiment, an SSD includes a buffer, and an MLC flash device. The SSD also includes a controller operable to write data in the buffer based on an Input/Output (I/O) request (e.g., from a host), to begin copying the data from the buffer to a block of the MLC flash device, to copy a portion of the data associated with open word lines of the block to another location in the buffer after a power cycle, and to update a lookup table for the copied portion of the data with the other location so that the copied portion of the data can be accessed via a subsequent I/O request.

Abstract: A recording head has a waveguide core with an input facet at an input surface. The waveguide core extends to a near-field transducer at a media-facing surface of the recording head. First and second cladding regions are co-planar with and on either cross-track side of the waveguide core. First and second pseudo-slab regions are co-planar with and on outer cross-track sides of the respective first and second cladding regions. The first and second pseudo-slab regions have an index of refraction higher than that of the first and second cladding regions. The first and second pseudo-slab regions confine and channel stray light away from the near-field transducer.

Abstract: A stack includes a heatsink layer, a magnetic recording layer disposed over the heatsink layer, and a Si-based overcoat layer disposed over the magnetic recording layer. The Si-based overcoat layer is substantially devoid of carbon.

Abstract: Method and apparatus for predicting data storage device failures using adaptive failure prediction modeling. In some embodiments, monitored parameters are used to predict a potential imminent failure of a first data storage device using a first copy of a first failure prediction model (FPM). Data associated with the predicted potential imminent failure are transferred by the device across a computer network to a host device. The host device generates an updated, second FPM responsive to the transferred data as well as from data from at least a second data storage device transmitted across the computer network having a second copy of the first FPM. A first copy of the updated, second FPM is transferred, via the network, for use by the second data storage device.

Abstract: Two or more read modes of a data storage system and device are defined. The data storage device is capable of concurrently reading from two or more tracks using two or more read transducers. The read modes utilize different numbers of the two or more read transducers while reading data. The read modes are selected based on an operating condition of the data storage system or device.

Abstract: Apparatus and method for defending against a side-channel information attack such as a differential power analysis (DPA) attack. In some embodiments, a cryptographic hardware pipeline circuit performs a selected cryptographic function upon a selected set of data over a processing time interval. The pipeline circuit has a sequence of stages connected in series. The stages are enabled responsive to application of an asserted enable signal. An enable interrupt circuit is configured to periodically interrupt the selected cryptographic function to provide a plurality of processing intervals interspersed with the interrupt intervals. At least a selected one of the processing intervals or the interrupt intervals have random durations selected responsive to a series of random numbers.

Abstract: An apparatus is provided including a shaft, wherein the shaft is stationary. A rotatable component is configured to rotate with respect to the shaft. A fluid is operable to flow between the shaft and the rotatable component. A limiter is at a first axial end of the shaft, and a cup is at a second axial end of the shaft. An axially extending grooved region is between the limiter and the rotatable component.

Abstract: A disk drive including multiple magnetic recording disks and at least one read/write head, wherein the disk drive includes a rotatable center block having a vertical axis and a mounting member, a first motor attached to the center block for rotating the center block about the vertical axis, a vertical threaded rod positioned in the mounting member, a second motor moveable along the vertical threaded rod, at least one head suspension arm extending outwardly from the second motor, and at least one read/write head mounted to a distal end of one of the arms. The disk drive further includes multiple disks in a stack, wherein at least one of the arms is vertically moveable along the vertical threaded rod by the second motor to position the at least one read/write head in a position to access data on one of the disk surfaces of the plurality of disks.

Abstract: An apparatus includes a first magnetic layer. A second magnetic layer overlies the first magnetic layer and is magnetically softer than the first magnetic layer. An exchange control layer is between the first magnetic layer and the second magnetic layer. The exchange control layer is magnetic and increases vertical coupling between the first magnetic layer and the second magnetic layer.

Abstract: Method and apparatus for decoding data. In some embodiments, an LDPC decoder has a variable node circuit (VNC) with a plurality of variable nodes configured to store bit reliability values of m-bit code bits. A check node circuit (CNC) has a plurality of check nodes configured to perform parity check operations upon n-bit messages from the VNC. Each n-bit message is formed from a combination of the bit reliability values and stored messages from the check nodes. A pre-saturation compensation circuit is configured to maintain a magnitude of each n-bit message received by the CNC below a saturation limit comprising the maximum value that can be expressed using p bits, with p less than n and each of the n-bit messages received by the CNC having a different magnitude. The pre-saturation compensation circuit may apply different scaling and/or bias factors to the n-bit messages over different decoding iterations.

Abstract: A waveguide includes a segment with a substantially uniform cure profile and related methods and systems for making and using the same. The waveguide is formed by modifying a laser beam used to write the waveguide to provide a substantially uniform cure profile in the waveguide. A marker characteristic of laser writing may be present in the waveguide. A method or system modifies an intensity profile or a shape profile of a laser beam to proactively compensate for exposure convolution based on the characteristics of the laser beam spot profile. A convolution compensator is positioned in the path of the laser beam to modify the beam spot profile during writing to form the one or more segments of the waveguide in a photo-curable layer.

Abstract: A storage device sled for mounting a storage device within a chassis is provided. The storage device sled includes a bezel, which includes a first portion that is stationary relative to a storage device, a second portion vertically captured within the first portion and configured to slide between unlatching and latching positions, and a spring configured to push the latch outwardly from the bezel. The second portion includes a finger-movable member, a latch, and a horizontal biasing feature adjacent to the latch and configured to move in concert with the latch. The storage device sled also includes first and second longitudinal members, each orthogonally coupled to opposite ends of the bezel first portion and each coupled to opposite sides of the storage device. When the storage device is installed in the chassis, the horizontal biasing feature exerts force against a first chassis interior side surface and biases the storage device sled against a second chassis interior side surface.

Abstract: An apparatus may include a circuit configured to generate a set of first ADC samples based on a first signal associated with a first read head position and a failed segment and to generate a set of second ADC samples based on a second signal associated with a second read head position and the failed segment. The circuit may then generate, by a MISO equalizer, a set of equalized ADC samples based on the set of first ADC samples and the set of second ADC samples.