Abstract: The present disclosure generally relates to a tape drive comprising a tape head assembly. The tape head assembly comprises a head block having a first end and a second end, the second end being opposite the first end, one or more tape head modules disposed on the head block, the one or more tape head modules each comprising a plurality of data elements, a first spring disposed at the first end of the head block, a piezoelectric element disposed in contact with the second end of the head block, a counterweight disposed adjacent to the second end of the head block, and a second spring disposed adjacent to the second end of the head block. The counterweight has a first weight. The head block and the one or more tape head modules have a collective second weight. The first weight is equal to or greater than the second weight.

Abstract: An external data storage device, without a battery, provides a user-selectable low power mode. The external data storage device includes storage media for storing data and a data port for receiving power and transmitting data to a host device. The external storage data device includes control circuitry configured to negotiate delivery of a first amount of power from the host device in response to connecting the external data storage device to the host device, receive the first amount of power from the host device, receive a selection, via an input device, of a reduced power mode from a user, and reduce power consumption from the host device to a second amount of power lower than the first amount of power in response to receiving the selection of the reduced power mode.

Abstract: The present disclosure is generally related to a tape drive comprising a tape and a tape head. The tape drive comprises a processor configured to perform a disturbance profile identification detecting one or more disturbances along a length of a tape. The disturbance profile identification is used to create a peak filter array, which is used to instruct the piezoelectric and/or voice coil motor actuators to move the tape head to adjust a frequency of the disturbances. The peak filter array is further used to partition the tape into a plurality of zones based on a size of the peak filter array. Servo parameters of a servo head are then updated based on the peak filter array within each zone to adjust the control strategy specific to each zone. Utilizing the disturbance profile identification prevents track following capability loss against the dynamic lateral tape motion of the tape drive.

Abstract: A hard disk drive enclosure base includes a groove extending from an internal sidewall surface into the sidewall and a gasket seal embedded in the groove. In the context of progressively larger recording disk diameters, corresponding expanding disk shrouds, and corresponding narrower baseplate sidewalls, such a baseplate is configured to enable a first cover to physically engage with a portion of the embedded gasket seal that extends inward away from the sidewall surface, thereby providing a suitable drive sealing mechanism.

Abstract: The present disclosure generally relates to spin-orbit torque (SOT) devices comprising a bismuth antimony (BiSb) layer. The SOT devices further comprises a nonmagnetic buffer layer, a nonmagnetic interlayer, a ferromagnetic layer, and a nonmagnetic barrier layer. One or more of the barrier layer, interlayer, and buffer layer comprise a polycrystalline non-Heusler alloy material, or a Heusler alloy and a material selected from the group consisting of: Cu, Ag, Ge, Mn, Ni, Co, Mo, W, Sn, B, and In. The Heusler alloy is a full Heusler alloy comprising X2YZ or a half Heusler alloy comprising XYZ, where X is one of: Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, Y is one of: Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Nb, Mo, Hf, and W, and Z is one of: B, Al, Si, Ga, Ge, As, In, Sn, Sb, and Bi.

Abstract: A data storage device stores a set of pre-trained machine learning (ML) models along with corresponding customer digital certificates and other information. Techniques are provided herein for allowing customers to access selected ML models using a digital certificate and a public key so that the selected ML models may then be loaded into a data storage controller of the data storage device for use, for example, by firmware of the controller to intelligently control data pre-fetch, data relocation, or other data processing functions. Techniques are also provided to allow customers to selectively update or replace ML models with customer-supplied models, subject to authentication of the customer and verification of the compatibility of the ML model within the data storage controller. Still other techniques are provided for allowing ML models from the data storage device to be loaded into a secure enclave within the host to execute within the secure enclave.

Abstract: Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: apply a first set of settings to the assistive energy emitter in association with writing a first spiral to the disk surface; and apply a second set of settings to the assistive energy emitter in association with writing a second spiral to the disk surface, wherein the second set of settings is different than the first set of settings.

Abstract: Various apparatuses, devices, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that, in some examples, provide a HAMR medium with a platinum-doped CO—BN capping layer. In one example, the HAMR medium includes a CoPtBN capping layer on a magnetic recording layer with Pt in the range of 5-12 atomic percentage (at. %). An atomic ratio of Co to Pt within the CoPtBN may be, e.g., in the range of 5 to 13. The BN in the CoPtBN may be, e.g., 22-30 mole percentage of the CoPtBN. The CoPtBN may have a face-centered cubic (FCC) crystalline structure. The HAMR medium may have various other layers, such as a substrate, a heatsink layer on the substrate, and a seed layer on the heatsink layer, with the magnetic recording layer on the seed layer. The seed layer may include MgO or MgO—TiO. An amorphous soft underlayer (SUL) may be provided.

Abstract: A Data Storage Device (DSD) includes at least one disk and at least one memory storing an active Primary defect List (P-List) indicating defective sectors identified during formatting, a Grown defect List (G-List) indicating defective sectors identified after formatting, and an inactive P-List including entries for accepting entries from the G-List. Entries of the G-List are merged into the P-List by successively reassigning descending sets of logical addresses from respective sets of sectors to a temporary storage area and reserving at least a portion of the sectors for a set of shifting P-List entries. Entries of the shifting P-List entries are retained in the inactive P-List for grown defect sectors, and the set of shifting P-List entries is reduced by the number of retained entries before shifting toward a next set of sectors. The descending sets of logical addresses are reassigned from the temporary storage area back to non-defect sectors.

Abstract: Systems, methods, and storage adapters for managing queue limits by offloading storage adapter submission queues to the controller memory buffers of data storage devices are described. The storage adapter may receive host storage commands from host devices in one format and provide those host storage commands to the data storage devices in another format for processing. The storage adapter may use submission queues in the controller memory buffers to store the host storage commands until it can preprocess them between the two formats and then notify the data storage device that the host storage command is available for processing.

Abstract: A client device encodes at least two datasets using one or more encoding functions to generate encoded data portions that are encrypted using a first key according to an approximate Fully Homomorphic Encryption (FHE) scheme to generate encrypted data portions that are sent to a plurality of servers. Encrypted results are received from at least a subset of servers of the plurality of servers. Each encrypted result is calculated by a respective server using at least two encrypted data portions received by the server. The encrypted results are decrypted using a secret key according to the approximate FHE scheme to derive decrypted encoded results that are decoded using an approximate decoding function. In one aspect, an encrypted result is calculated by each server by evaluating a multivariate function using the at least two encrypted data portions received by the server.

Abstract: The present disclosure generally relate to a magnetic recording device comprising a write head and a resistor network coupled to the write head. The resistor network comprises a first path comprising a primary coil of the write head and a second path in parallel with the first current path, the second path comprising an assistive write element of the write head. A preamplifier coupled to the resistor network is configured to apply current to the first and second paths, where the current diverts into the first and second paths individually. The resistor network is coupled to the preamplifier by a single lead. The first path is configured to apply current to a primary coil of the write head. The second path is configured to apply current from a leading shield, via the assistive write element, to a trailing shield at a media facing surface.

Abstract: When servo heads in a head chip of a servo write head assembly record servo patterns onto a tape's servo tracks, the servo heads are continuously being rapidly worn away by the tape. This general wear affects the servo heads' ability to record the servo patterns, impairing accurate positioning of the tape heads in the drive. However, by implementing, on the leading edge of the head chip, a support block that has a wear resistant skiving edge and landing zone for the tape “crow bar,” which forms when the tape is running over the servo head, the general wear of the servo heads from the tape is mitigated. The skiving edge, which may be formed by thin film technology process steps, causes the tape to fly over the head chip in those regions. An additional support block may be implemented at the trailing edge of the head chip.

Abstract: The present disclosure generally relates to a servo write bar comprising one or more servo write heads for writing servo patterns on a tape. Each servo write head comprises a first end pole, a second end pole, and a center pole disposed between the first and second end poles. The center pole is spaced from the first end pole by a first gap, and spaced from the second end pole by a second gap. A coil coupled to a current source is disposed around the center pole. A top surface is disposed over the center pole, and the first and second end poles. A servo pattern is disposed on the top surface over the coil. A first servo line of the servo pattern is disposed over the first gap, and a second servo line of the servo pattern is disposed over the second gap.

Abstract: Example systems and methods for embedding an oligo index in a series of reference marks along the oligo for DNA data storage are described. A data unit may be encoded in oligos that include reference marks at predetermined intervals along the length of each oligo that encode the oligo index, generally in multiple copies encoded with varying symmetries. During decoding, the reference marks may be analyzed through multiple correlation matrices to determine a most likely set of values for the oligo index. In some configurations, the same reference marks may be processed through another correlation matrix to determine and correct insertions and deletions based on multiple copies of the oligo, as identified by the decoded oligo indices in those copies.

Abstract: A data storage device comprises a recording head, a disk, a first fine actuator group configured to position the recording head over the disk, and control circuitry. The control circuitry is configured to apply a slew control voltage waveform to the first fine actuator group to transition the first fine actuator group from an active state to an inactive state, and apply a control signal initiating at a last-applied value of the slew control voltage waveform to the first fine actuator group to transition the first fine actuator group back to the active state before completion of the slew control voltage waveform.

Abstract: The present disclosure generally relate to a tape drive including a tape head assembly comprising a tape head. The tape head assembly further comprises a substrate having a leading edge (LE), a trailing edge (TE), and a first media facing surface (MFS) disposed between the leading and trailing edges, and a recession disposed in the substrate, the recession being recessed from the first MFS. The tape head is disposed in the recession. The tape head has a second MFS that extends above the first MFS by a distance of about 20 nm to about 200 nm. The LE comprising a first step and a second step. The first and second steps, the recession, and the extended tape head enable a tape of the tape drive to be spaced from the substrate and tape head as the tape moves over the tape head assembly during operation.

Abstract: A substrate for use in a magnetic recording medium, and methods and apparatus for identifying a substrate suitable for a magnetic medium of a data storage device are described. In an aspect, the substrate includes a surface comprising physical characteristics including composite waviness values determined for multiple locations on the surface, each of the composite waviness values being less than a composite waviness threshold. In an aspect, the composite waviness values are based on first waviness values and second waviness values, the first waviness values being representative of surface waviness of the surface within a first wavelength range, at the multiple locations, respectively, and the second waviness values being representative of surface waviness of the surface within a second wavelength range, at the multiple locations, respectively, the second wavelength range being different from the first wavelength range.

Abstract: A data storage device comprises a disk and a recording head. The recording head comprises a write thermal sensor, a read thermal sensor, and a laser configured for heat assisted magnetic recording (HAMR). Control circuitry shapes a bias signal applied to the read thermal sensor to mirror a thermal response of the write thermal sensor during laser operation, generates a differential signal based on a difference between the write thermal sensor response and the read thermal sensor response, and monitors the differential signal to detect laser mode hopping.

Abstract: The present disclosure generally relate to a tape drive including a tape head assembly comprising a tape head. The tape head assembly further comprises a substrate having a leading edge (LE), a trailing edge (TE), and a first media facing surface (MFS) disposed between the leading and trailing edges, and a recession disposed in the substrate, the recession being recessed from the first MFS. The tape head is disposed in the recession. The tape head has a second MFS that extends above the first MFS by a distance of about 20 nm to about 200 nm. The LE comprising a first step and a second step. The first and second steps, the recession, and the extended tape head enable a tape of the tape drive to be spaced from the substrate and tape head as the tape moves over the tape head assembly during operation.