Abstract: Method and apparatus for managing data in a memory, such as a flash memory. In accordance with some embodiments, a memory module has a non-volatile memory (NVM) and a memory module electronics (MME) circuit. A controller circuit communicates a first command to the MME circuit to perform a selected action upon a selected address of the NVM. After a variable delay time interval, a second command is communicated by the controller circuit to the MME circuit as a status request regarding the first command. The variable delay time interval is determined based on an accumulated count of status requests that were issued, prior to the first command, for the selected address.

Abstract: Systems and methods are disclosed for performing segment-based outer code recovery at a data storage device. An apparatus may comprise a circuit configured to disable outer code error recovery, and perform a read operation spanning a plurality of segments of a data storage medium, a segment including a plurality of sectors. The circuit may identify one or more segments from the plurality of segments that have one or more sectors with an error. For an identified segment of the one or more segments, the circuit may perform a re-read operation with outer code error recovery enabled, and perform outer code recovery on sectors with an error within the identified segment.

Abstract: A method of forming a near field transducer (NFT) layer, the method including depositing a film of a primary element, the film having a film thickness and a film expanse; and implanting at least one secondary element into the primary element, wherein the NFT layer includes the film of the primary element doped with the at least one secondary element.

Abstract: Aspects of this disclosure are directed to methods, apparatuses and approaches involving the use of a moisture absorbing material (e.g., desiccant) to control moisture. As may be implemented consistent with one or more embodiments, moisture is removed from an environmental control module that includes a desiccant material contained within a package. Liquid is deposited inside the package and sealed with the desiccant in the package.

Abstract: A data writer may be constructed and operated as part of a data storage device. The data writer can be positioned proximal a data storage medium. The data writer may have a write pole positioned adjacent a writer coil with the writer coil having a plurality of turns. A controller that is connected to each turn can be adapted to selectively activate less than all the coil turns in response to the data writer being positioned over a first portion of a data storage medium and selectively activate all of the coil turns in response to the data writer being positioned over a second portion of the data storage medium.

Abstract: An apparatus comprises a spindle to rotate a magnetic recording medium and a magnetic field generator to expose a track of the medium to a DC magnetic field. The magnetic field generator is configured to saturate the track during an erase mode and reverse the DC magnetic field impinging the track during a writing mode. A laser arrangement heats the track during the erase mode and, during the writing mode, heats the track while the track is exposed to the reversed DC magnetic field so as to write a magnetic pattern thereon. A reader reads the magnetic pattern and generates a read signal. A processor is coupled to the reader and configured to determine an anisotropy parameter using the read signal. The apparatus can further comprise a Kerr sensor that generates a Kerr signal using the magnetic pattern.

Abstract: Data compression techniques are provided that remove redundancy across the boundary of compression search engines. An illustrative method comprises splitting the data frame into a plurality of sub-chunks; comparing at least two of the plurality of sub-chunks to one another to remove at least one sub-chunk from the plurality of sub-chunks that substantially matches at least one other sub-chunk to generate a remaining plurality of sub-chunks; generating matching sub-chunk information for data reconstruction identifying the at least one removed sub-chunk and the corresponding substantially matched at least one other sub-chunk; grouping the remaining plurality of sub-chunks into sub-units; removing substantially repeated patterns within the sub-units to generate corresponding compressed sub-units; and combining the compressed sub-units with the matching sub-chunk information to generate a compressed data frame.

Abstract: Apparatus and method for managing map data in a data storage device. A programmable processor issues a find command to locate and place a requested map page of a map structure into a first cache to service a received host command. A non-programmable hardware circuit searches a forward table to determine whether the requested map page is in a second cache, and if so, loads the map page to the first cache. If not, the hardware circuit requests the requested map page from a back end processor which retrieves the requested map page from a non-volatile memory (NVM), such as a flash memory array. The hardware circuit searches a reverse table and the first cache to select a candidate location in the second cache for the retrieved requested map page from the NVM, and directs the storage of a copy of the requested map page at the candidate location.

Abstract: An apparatus includes a slider configured for heat-assisted magnetic recording. An input coupler of the slider is configured to-receive light produced by a light source. A waveguide of the slider comprises a waveguide core tapering from a first portion having a first cross sectional width to a second portion having a second cross sectional width along the light propagation direction. The second cross sectional width being smaller than the first cross sectional width, and the second portion having an output end. The waveguide includes at least one cladding layer comprising a metallic material. The at least one cladding layer surrounds at least the core. The at least one cladding layer is configured to sink heat away from the waveguide core. The waveguide is configured to provide a surface plasmon-enhanced near-field radiation pattern proximate the output end in response to the light received at the transducer region.

Abstract: A temperature compensation equation is generated during manufacture of a heat-assisted magnetic recording (HAMR) disk drive using initial total currents supplied to a laser diode of the disk drive at different initial operating temperatures. The total currents represent currents for recording data to or erasing data from the medium. The temperature compensation equation is stored in the disk drive, and updated, during field operation, using a subsequent total current associated with an operating temperature differing from the initial operating temperatures. The total current supplied to the laser diode for a subsequent write operation is adjusted using the updated temperature compensation equation in response to the operating temperature at the time of the subsequent write operation.

Abstract: A slider having an air bearing surface is configured for heat-assisted magnetic recording (HAMR). The slider comprises a write pole, a near-field transducer (NFT) proximate the write pole, a return pole magnetically coupled to the write pole, and an optical waveguide configured to receive light from a light source and couple the light to the NFT. The optical waveguide comprises first and second opposing major surfaces and opposing first and second edges connected to the first and second major surfaces. An optically opaque overlay is disposed on one or both of the first and second major surfaces of the optical waveguide. The optically opaque overlay can be light reflective or light absorbing.

Abstract: A slider configured for heat-assisted magnetic recording comprises an optical sensor coupled to first and second bond pads. The optical sensor comprises a bolometer and a reference sensor. The bolometer is situated at a location of the slider that receives at least some of the light and exposed to an ambient temperature at the slider. The bolometer produces a signal in response to a change in the ambient temperature and the change in output optical power. The reference sensor is situated at a location of the slider unexposed to the light and exposed to the ambient temperature. The reference sensor is coupled to the bolometer and configured to produce a signal in response to the change in the ambient temperature. The optical sensor is configured to generate a sensor signal indicative of changes in output optical power of a laser source without contribution due to ambient temperature changes.

Abstract: A data storage device may be configured with a transducing head separated from a data storage medium by an air bearing. The transducing head and data storage medium are each contained within a housing. The transducing head can consist of a variable resistance sensor that is connected to a temperature module positioned within the housing. One or more operational variables can be measured by the variable resistance sensor to allow an ambient temperature within the housing to be calculated based on a measured operational variable.

Abstract: An apparatus includes an input coupler configured to receive light excited by a light source. A near-field transducer (NFT) is positioned at a media-facing surface of a write head. A layered waveguide is positioned between the input coupler and the NFT and configured to receive the light output from the input coupler in a transverse electric (TE) mode and deliver the light to the NFT in a transverse magnetic (TM) mode. The layered waveguide comprises a first layer extending along a light-propagation direction. The first layer is configured to receive light from the input coupler. The first layer tapers from a first cross track width to a second cross track width where the second cross track width is narrower than the first cross track width. The layered waveguide includes a second layer that is disposed on the first layer. The second layer has a cross sectional area in a plane perpendicular to the light propagation direction that increases along the light propagation direction.

Abstract: Technologies are described herein for power management in a peripheral device. A bridge is coupled to a communication link that provides power. The bridge determines an available power from the communication link. The bridge informs a peripheral device coupled to the bridge of the available power.

Abstract: A write head includes a waveguide, a magnetic pole, and a near-field transducer. The near-field transducer includes an enlarged portion and a peg. The peg is separated from the magnetic pole in a downtrack direction by a dielectric gap. A peg coupler covers a bottom surface of the magnetic pole and is separated from the peg. The peg coupler is formed of a first plasmonic material. A pad extends from the peg coupler into part of the gap in the downtrack direction towards the peg. The pad is formed of a second plasmonic material and extends into the write head away from the media-facing surface a distance L that is less than a corresponding distance of the peg coupler.

Abstract: A read sensor that includes a free layer having a magnetization that changes according to an external magnetic field. The read sensor also includes an additional magnetic layer and a non-magnetic layer. The non-magnetic layer may include a corrugated surface facing the additional magnetic layer. The corrugated surface is configured to enhance uniaxial anisotropy in the read sensor.

Abstract: NAND flash storage devices and methods are provided that use a non-NAND cache to store write data until a substantially complete storage unit is available. An exemplary solid state storage device comprises a NAND flash memory device; a non-NAND cache; and a controller configured to obtain write data from a remote host for storage in the NAND flash memory device; store the write data in the non-NAND cache; and transfer the write data from the non-NAND cache to the NAND flash memory device when a predefined storage criterion is satisfied. The predefined storage criterion comprises, for example, a storage unit of the write data stored in the non-NAND cache, where the storage unit comprises a block of data erased in a single garbage collection cycle. The predefined storage criterion is optionally established to reduce open block degradation in NAND flash memory devices.

Abstract: Described are filters useful in a hard disk drive of a comparable electronic device that requires a highly contaminant-free environment for operation, particularly to these devices in combination with the filter, wherein the filter contains graphene.

Abstract: Random numbers are generated using entropic properties associated with circuit hardware. Consistent with one method, a switching voltage regulator circuit is used to generate a random number. Data that is responsive to switching states of the switching voltage regulator circuit is generated. A multi-bit random number is then generated from the generated data.