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: 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 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: 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: Systems and methods for improving system debugging using finite state machines are described. In one embodiment, the systems and methods includes selecting, by a first multiplexor, a period of a timer tick for one or more blocks of a system on a chip (SoC), comparing, by a first comparator, a current state of the one or more blocks to a previous state of the one or more blocks, and receiving, by a finite state machine (FSM), the result from the first comparator as a first input, receiving a pulse based on the selected period of the timer tick from the first multiplexor as a second input, and based on the first and second inputs generating an output indicating whether the current and previous states remain unchanged after a time of at least two timer ticks. In one embodiment, a result from the first comparator indicates whether the current state equals the previous state of the one or more blocks.

Abstract: Apparatus and associated method that contemplates performing a first atomic force microscope (AFM) scan of a first region of a sample centered at a first position at a first angle to produce a first scan image, the first AFM scan including a first component scan at a first speed and a second component scan at a second speed; performing a second AFM scan of the first region of the sample at a second angle to produce a second scan image, the second AFM scan including performing a third component scan at the first speed and a fourth component scan at the second speed; and correcting a first error in the first scan image based on the second scan image to produce a corrected image output.

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: 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: 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: Systems and methods for forward corrupted track detection and by-pass are described. In one embodiment, a storage system comprising a storage controller performs a read operation for a target track of a shingled magnetic recording (SMR) disk drive and detects a read operation failure of the read operation for the target track. The storage controller also performs a boundary track read operation on one or more tracks including or adjacent to the target track and detect a forward corruption area based on the boundary track read operation. In another embodiment, a method is provided that includes detecting a read operation failure of a read operation for a track of a disk drive and performing a boundary track read operation on one or more tracks including or adjacent to the target track. The method also includes detecting a forward corruption area based on the boundary track read operation.

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: 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: A near-field transducer has an enlarged portion with a peg extending towards a media-facing surface. Two reflectors are located co-planar with near-field transducer and located on either side of the near-field transducer in a crosstrack direction. The two reflectors are separated by a gap proximate the peg of the near-field transducer. The two reflectors each include a first edge at the media facing surface and a second edge at an acute angle to the media-facing surface. The second edge faces the near-field transducer. The two reflectors concentrate the light on the peg of the near-field transducer.

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.

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: Waveguides that include a top cladding layer; a bottom cladding layer; and a core layer positioned between the top cladding layer and the bottom cladding layer, the core layer including a material having a refractive index of not less than 2.1, for example amorphous hydrogenated silicon carbide (SiC:H), or bismuth titanate. Methods of forming core layers of waveguides are also disclosed.

Abstract: Systems and methods for maximizing shingled magnetic recording (SMR) drive capacity are described. In one embodiment, the SMR drive may include a main store to store user-accessible data, a media cache and media scratchpad to store internal data temporarily for internal operations, and a storage controller to process read and write requests. In some cases, the main store comprises a shingled media partition and an unshingled media partition. The storage controller may designate one or more data tracks from the shingled media partition as temporary data track guard bands. In some embodiments, a track range is selected based at least in part on at least one of an amount of data in the media cache, a size of the new data in the media cache, and an association between the new data in the media cache and data currently stored within the selected track range.

Abstract: A device that includes a near field transducer (NFT); at least one cladding layer adjacent the NFT; and a carbon interlayer positioned between the NFT and the at least one cladding layer.

Abstract: Systems and methods are disclosed to perform early termination error recovery at a data storage device. A data storage device may be configured to perform error recovery operations in response to encountering an error while executing a host command, and terminate the error recovery operations prior to completion based on an error recovery time limit. Based on early termination of the error recovery operations, the storage device can add a storage location corresponding to the error to a scan list of storage locations on which to perform additional error recovery operations. In some embodiments, the host may set the error recovery time limit.

Abstract: An apparatus includes a spin torque oscillator, a sensor, and a processing unit. The spin torque oscillator is configured to receive a current and to generate a microwave output signal. The sensor is configured to detect the microwave output signal and to detect changes to frequency of the detected microwave output signal responsive to changes in an external magnetic field. The processing unit is configured to receive a sensed signal from the sensor. The processing unit is further configured to process the sensed signal and the changes to the frequency to determine magnitude and direction associated with the external magnetic field.