Abstract: A data storage medium includes a substrate, and a plurality of spaced-apart discrete data storage tracks supported by the substrate. The data storage medium also includes magnetic flux sinking material between the discrete data storage tracks and over the substrate. As an alternative to the magnetic flux sinking material, plasmonic material may be included between the discrete data storage tracks and over the substrate.

Abstract: According to one embodiment, a first storage area and a second storage area in which a plurality of tracks are set are provided in a radial direction of a magnetic disk. A plurality of post codes corresponding to the second storage area is stored in the first storage area. A controller controls first processing of reading a plurality of post codes from the first storage area and writing the plurality of read post codes in servo area of the second storage area. In the first processing, the controller controls both second processing and third processing in a state where a write head is located on a first track. The second processing is processing of writing a post code among the plurality of read post codes in a servo area. The third processing is processing of writing user data in a data area or reading user data from a data area.

Abstract: A recording head has a near-field transducer that extends a first distance away from a media-facing surface. Two subwavelength focusing mirrors are at an end of a waveguide proximate the media-facing surface and extend a second distance away from the media-facing surface that is less than the first distance. The subwavelength mirrors are on opposite crosstrack sides of the near-field transducer and separated from each other by a crosstrack gap. The subwavelength focusing mirrors each include a first material at the media-facing surface and a plasmonic material that covers an edge of the subwavelength focusing mirror that faces the near-field transducer. The first material is more mechanically robust than the plasmonic material.

Abstract: A recording head has a near-field transducer proximate a media-facing surface of the recording head. A waveguide overlaps and delivers light to the near-field transducer. Two subwavelength focusing mirrors are at an end of the waveguide proximate the media-facing surface. The subwavelength mirrors are on opposite crosstrack sides of the near-field transducer and separated from each other by a crosstrack gap. The subwavelength focusing mirrors each include a core having a first edge exposed at the media-facing surface. The core formed of a core material that is resistant to mechanical wear and corrosion, such as a dielectric or robust metal. A liner covers a second edge of the core facing the near-field transducer. The liner includes a plasmonic metal that is different than the core material, such as Au or Al.

Abstract: A media library (10) for evaluating a health of a head (256) of a media drive (26) includes a library control system (30) that is configured to control oversight functionality of the media library (10). The library control system (30) receives media drive information generated during at least one of a read procedure and a write procedure being performed by the media drive (26) and analyzes the media drive information to determine the health of the head (256) of the media drive (26). The media drive information includes drive performance metrics generated by the media drive (26) during a read verify procedure performed by the media drive (26) upon request of the library control system (30) of the media library (10).

Abstract: A Data Storage Device (DSD) includes one or more magnetic disks with each magnetic disk including at least one recording surface. A segment mapping is generated having a predetermined number of segment entries per recording surface with each segment entry corresponding to a data segment of the recording surface. One or more segment entries include a first logical address corresponding to a first logical data block that begins in the corresponding data segment and at least one of the data segments is configured to store multiple logical data blocks. A target segment entry is located in the segment mapping corresponding to a highest logical address less than or equal to a requested logical address of a read command and a head of the DSD is moved to a beginning portion of a target data segment corresponding to the target segment entry to perform the read command.

Abstract: According to one embodiment, a magnetic disk device includes a disk including a first region with a first format efficiency and a second region with a second format efficiency lower than the first format efficiency, a head that writes data to the disk and reads data from the disk, and a controller that selects a first postcode to be written to the first region from a plurality of postcodes with different lengths and writes the first postcode to the first region, and selects a second postcode to be written to the second region from a plurality of postcodes with different lengths and writes the second postcode to the second region.

Abstract: A heat-assisted magnetic recording head includes a near-field transducer and a heat sink. The near-field transducer includes a middle disk and a near-field emitter. The near-field emitter includes a peg and an anchor disk. The peg is configured to produce a hot spot on a proximal magnetic disk. The peg is disposed proximal to a media-facing surface of the heat-assisted magnetic recording head. The anchor disk is disposed behind the peg relative to the media-facing surface. The heat sink includes a core and a liner. The core includes a primary metal, and the liner includes a primary metal. The liner is coupled to the core and is disposed along an outer surface of the core. The middle disk is disposed between and coupled to the liner and the anchor disk. The primary metal of the liner comprises at least one of iridium, rhodium, tantalum, tungsten, or ruthenium.

Abstract: A write command is received to write data in a target zone including one or more tracks and it is determined whether a data structure is stored in a memory for counting writes performed in a track of the target zone. If such a data structure is not stored in the memory, at least one Low Repeat Write (LRW) data structure is created for the target zone to count writes in sectors of respective tracks of the target zone since creation of the at least one LRW data structure. In another aspect, a write count for a segment is incremented in a data structure for a track to account for a write in the segment. A current overall Track Interference (TI) write count for the target zone is incremented if the incremented segment write count is the highest write count among respective segment write counts in the data structure.

Abstract: Systems and methods are disclosed for magnetoresistive asymmetry (MRA) compensation using a digital compensation scheme. In certain embodiments, a method may comprise receiving an analog signal at a continuous-time front end (CTFE) circuit, and performing analog offset compensation to constrain an extremum of the analog signal to adjust a dynamic range based on an input range of an analog-to-digital converter (ADC), rather than to modify the analog signal to have a zero mean. The method may further comprise converting the analog signal to a digital sample sequence via the ADC; performing, via a digital MRA compensation circuit, digital MRA compensation on the digital sample sequence; receiving, via a digital backend (DBE) subsystem, the digital sample sequence prior to digital MRA compensation; and generating, via a DBE, a bit sequence corresponding to the analog signal based on an output of the DBE subsystem and an output of the digital MRA compensation circuit.

Abstract: The present disclosure generally relates to a magnetic recording head for a magnetic media drive. The magnetic recording head comprises a near field transducer (NFT), a vertical cavity surface emitting laser (VCSEL) device, and a waveguide structure coupled between the NFT and the VCSEL device. The waveguide structure comprises a plurality of waveguide channels and a multimodal interference (MMI) combiner coupled to the waveguide channels. One or more of a curvature, a path length, and a propagation length of each of the waveguide channels is optimized such that each waveguide channel is controllable, or otherwise phase coherent with adjacent waveguide channels. The VCSEL device is capable of emitting a plurality of lasers through the plurality of waveguide channels, and the plurality of lasers are phase coherent when input into the MMI combiner. The MMI combiner combines a power of the plurality of lasers, which is output to the NFT.

Abstract: A magnetic tape device; a magnetic tape; and a magnetic tape cartridge, in which the magnetic tape is caused to run between a winding reel and a cartridge reel in a state where a tension is applied in a longitudinal direction and a maximum value of the tension is 0.50 N or more, and the magnetic tape after running in a state where the tension is applied is wound around the cartridge reel by applying a tension of 0.40 N or less in the longitudinal direction of the magnetic tape, and the number of recesses having an equivalent circle diameter of 0.20 ?m to 0.50 ?m existing on a surface of the magnetic layer of the magnetic tape is 10 to 500 per 40 ?m×40 ?m area.

Abstract: Example systems, data storage devices, and methods to provide data protection during concurrent operations for multiple actuator data storage devices are described. The data storage device includes a plurality of actuators configured to actuate a plurality of heads over different subsets of a plurality of disk surfaces. Responsive to receiving a write command for one of the actuators, the coupling state with at least one other of the actuators is determined and execution of write commands is inhibited if the coupling state indicates a possible coupling event. The inhibit of the write commands in the presence of coupling events may prevent off-track writes and protect data.

Abstract: According to one embodiment, a magnetic disk device includes a disk that includes a first track, a head that includes a heater, writes data to the disk, and reads data from the disk, and a controller configured to set a variation of a parameter related to a write process for the disk within one round of the first track to suppress a variation of an evaluation index corresponding to a write/read processing characteristic within one round of the first track.

Abstract: Data can be transmitted and represented by signal gaps in a transmission, the gaps having various attributes. In various examples, data points are encoded and represented by the attributes of said signal gaps. Various attributes of such gaps, including duration, pattern, quantity, time, and/or coordination with a gap in another signal can represent data.

Abstract: The technology disclosed herein provides a method including determining an acceptable parameter rate for a dual reader storage device having dual readers, identifying one of the dual readers as the preferable reader, comparing an actual parameter rate of the storage device to the acceptable parameter rate of the storage device, and in response to determining that the actual parameter rate is below the acceptable parameter rate, operating the storage device using only the preferable reader. In one implementation, the parameter rate is bit-error rate (BER) of the dual readers.

Abstract: According to one embodiment, a magnetic recording device includes a magnetic head and a controller. The magnetic head includes a first magnetic pole, a magnetic element including a first magnetic layer, and a coil. The controller is electrically connected to the magnetic element and the coil. The controller is configured to supply a recording current to the coil and supply an element current to the magnetic element. The recording current includes a first period of a first polarity, a second period of a second polarity, a third period that shifts from the first to second period, and a fourth period that shifts from the second to first period. The element current includes DC and AC components. The AC component in the first period is the same as the AC component in the second period, the AC component in the third period, and the AC component in the fourth period.

Abstract: A heat assisted magnetic recording (HAMR) write head includes a main pole, a waveguide, at least one dielectric matrix layer, and a near-field transducer disposed between the waveguide and the main pole. The near-field transducer is embedded in at least one dielectric matrix layer. The near-field transducer includes an antenna and a thermal shunt. The thermal shunt includes a thermal shunt body portion in direct contact with the antenna, and a metallic shunt diffusion barrier laterally surrounding the thermal shunt body portion and disposed between the thermal shunt body portion and the at least one dielectric matrix layer.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a control unit, and a setting unit. The magnetic head includes a write element which writes data to the magnetic disk and heater elements which adjust a levitation amount relative to the magnetic disk. The setting unit sets a heater value to be set on the basis of a measurement result of measuring the recording quality of the data written to the magnetic disk. The control unit controls electric power to be supplied to the heater elements on the basis of the heater value to be set to the setting unit.

Abstract: A heat-assisted magnetic recording (HAMR) device is configured to write regions of neutral polarity on a magnetic media during a same pass of the recording head in which other regions are written of positive polarity and negative polarity. The various disclosed write techniques may facilitate creation of “zero state” (substantially net zero polarity) transition zones between each pair of data bits of opposite polarity and/or may facilitate the encoding of three different logical states (e.g., 1, 0, and ?1) on the media.