Abstract: According to one embodiment, a magnetic disk device includes a disk including a recording region including a servo sector, a head configured to write data to the disk and read data from the disk, and a controller configured to acquire a plurality of correction data for a repeatable runout of the recording region, the correction data respectively corresponding to a plurality of measurement positions set based on a first linearity error acquired by reading the servo sector, and to correct a position of the head based on the correction data.

Abstract: HDDs including multiple heads driven by separate actuator spindles can read from or write to one or more platters simultaneously. Simultaneous active heads can be used to increase data rate or for other purposes. The multiple independently-actuated heads can access the same platter or different platters and may be moved across an associated platter surface in a number of different ways. However, multiple independently operating actuators may lead to mechanical coupling between the actuators. For example, as certain resonant frequencies, the movement of one actuator arm may cause unacceptable movement of another actuator arm within the HDD. This mechanical coupling can have detrimental effects on the HDD. The disclosed coupling observer and disable systems detect and mitigate detrimental effects of mechanical coupling between the independently operated actuators.

Abstract: A tape drive, according to one embodiment, includes: a processor, and logic which is integrated with the processor, executable by the processor, or integrated with and executable by the processor. The logic is configured to: determine whether a difference between information and corresponding design values is in a range. The information corresponds to how an array of writers write and/or are expected to write to a magnetic medium during shingled recording. Moreover, the logic is configured to: compute, using the information, data describing a lateral writing position to use during writing such that shingled track edges are aligned according to a format in response to determining that the difference between the information and corresponding design values is not in the range.

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: A magnetic recording cartridge is provided and including a magnetic recording medium, wherein an average thickness of the magnetic recording medium tT is 3.5 ?m?tT?5.6 ?m, a dimensional change amount ?w in a width direction of the magnetic recording medium with respect to a tension change in a longitudinal direction of the magnetic recording medium is 700 ppm/N??w?20000 ppm, and the magnetic recording medium is accommodated in a state of being wound around the reel in the cartridge case and (a servo track width on an inner side of winding of the magnetic recording medium)?(a servo track width on an outer side of winding of the magnetic recording medium)>0 is satisfied.

Abstract: A method includes writing first data to a first track of a magnetic recording medium of a storage device. First parity sectors corresponding to the first data are written. The first parity sectors have a first size. Second parity sectors corresponding to the first data are written. The second parity sectors have a second size. Second data is written to a second track of the magnetic recording medium. The second track is adjacent to the first track. It is determined whether an unrecoverable data error has occurred on the second track. After writing to the second track and determining that no unrecoverable data error has occurred, the first and second parity sectors corresponding to the first data are released.

Abstract: A data storage device is disclosed comprising a first actuator configured to actuate a head over a disk, a second actuator configured to rotate the disk, a first control circuit configured to generate a servo command, and a second control circuit configured to receive the servo command from the first control circuit, control the first actuator or the second actuator using the servo command, and override the servo command to avoid an overcurrent condition.

Abstract: A recording head includes a waveguide core layer that delivers light from a light source to a region proximate a magnetic write pole. A near-field transducer that is formed of a thin metal film is deposited over the waveguide core layer. The near-field transducer includes an enlarged part with two straight edges facing a media-facing surface and at obtuse angles relative to the media-facing surface. A peg extends from the enlarged part towards the media-facing surface. The near-field transducer includes a metal aperture plate at the media-facing surface. The metal aperture plate surrounds at least three sides of the end of the peg.

Abstract: A first time period is determined during which a first head driven by a first actuator will be performing a track-following operation. A second time period is also determined during which a second head driven by a second actuator will be performing a low-priority disk access operation that includes a seek. The first and second actuators are independently movable such that the first and second disk access operations are capable of being performed in parallel. If it is determined that the seek of the second head will impact servo control of the track-following operation of the first head, a start time of the seek of the second head is changed to correspond to a time that mitigates impacts to the track-following operation of the first head.

Abstract: An apparatus includes a substrate. A laser is formed on a non-self supporting structure and bonded to the substrate. A waveguide is deposited proximate the laser. The waveguide is configured to communicate light from the laser to a near-field transducer that directs energy resulting from plasmonic excitation to a recording medium. A light detector is configured to detect an amount of light. At least one laser heater is disposed proximate the laser. A controller is configured to control current supplied to the at least one heater based on the detected amount of light.

Abstract: According to one embodiment, a magnetic disk device including a disk, a head, and a controller which sets a first track pitch based on fringing when a second track is written, sets a second track pitch based on fringing when a third track is written, calculates a difference between the first track pitch and the second track pitch, sets, when the difference is less than or equal to a reference value, an area to which the first track is written in a first recording area, and sets, when the difference is greater than the reference value, the area to which the first track is written in a second recording area.

Abstract: A data storage device is disclosed comprising a first head actuated over a first disk surface, wherein the first head comprises a write coil and a write-assist component. First data is written to the first disk surface using the write coil and the write-assist component of the first head. An electrical bias is applied to the write-assist component of the first head to physically damage the write-assist component, thereby rendering the first disk surface read-only.

Abstract: A data storage device is disclosed comprising a disk comprising servo data, a spindle motor configured to rotate the disk, and a head actuated over the disk. A position error signal (PES) is generated based on the servo data, and the head is actuated over the disk based on the PES. While swinging a speed of the spindle motor, the swinging is disabled based on the PES.

Abstract: A folded lasing cavity comprises at least one bend. The folded lasing cavity is disposed on and configured to emit light along a substrate-parallel plane. An etched facet is on an emitting end of the folded lasing cavity and an etched mirror is on another end of the folding lasing cavity. An etched shaping mirror redirects light received from the etched facet in a direction normal to the substrate-parallel plane.

Abstract: An apparatus comprises a slider having an air bearing surface (ABS), a leading edge, and a trailing edge opposing the leading edge. A writer having a write pole is situated at or near the ABS. A near-field transducer (NFT) is situated at or near the ABS and between the write pole and the leading edge of the slider. An optical waveguide is configured to couple light from a laser source to the NFT. A contact sensor is situated between the write pole and the trailing edge. The contact sensor comprises a first ABS section situated at or near the ABS, a second ABS section situated at or near the ABS and spaced apart from the first ABS in a cross-track direction by a gap, and a distal section extending away from the ABS and connecting the first ABS section with the second ABS section.

Abstract: A slider configured for heat-assisted magnetic recording comprises a magnetic writer, a near-field transducer, and an optical waveguide coupling the near-field transducer to a light source. The writer is situated proximate the near-field transducer at an air bearing surface of the slider and comprises a first return pole, a second return pole, and a write pole situated between and spaced apart from the first return pole and the second return pole. A structural element is situated at or near the air bearing surface between the write pole and one of the first and second return poles. The structural element comprises a cavity. A thermal sensor is disposed in the cavity. The thermal sensor is configured for sensing contact between the slider and a magnetic recording medium, asperities of the medium, and output optical power of the light source.

Abstract: A thermally assisted magnetic head including a slider and a light source-unit. The slider includes a slider substrate and a magnetic head part. The light source-unit includes a laser diode and a sub-mount. The magnetic head part includes a medium-opposing surface, a light source-opposing surface and a waveguide which guides laser light from the light source-opposing surface to the medium-opposing surface. The thermally assisted magnetic head includes an optimal-structure which the following optimizing conditional expression, concerning an inlet-optical path length L1 of an inlet-interval of the waveguide, and an outlet-optical path length L2 of an outlet-interval, is satisfied, m1×L1=L2 (m1 is a natural number).

Abstract: According to one embodiment, there is provided a disk device including a head, a disk, a first motor, and a first circuit. The disk has a recording surface. The first motor causes the head to seek along the recording surface. The first circuit can switch between a first state and a second state. The first state is a state where a current path of the first motor is electrically cut off from a first electricity storage unit. The second state is a state where the current path of the first motor is electrically connected to the first electricity storage unit.

Abstract: A magnetic disk device includes a magnetic disk and a control circuit. The magnetic disk includes a first area where writing is performed in a manner such that a newly written track partially overlaps a previously written adjacent track. The control circuit is configured to specify a range of a second track, which is to be overlapped as a result of writing first data to a first track, write second data written in the specified range of the second track to a saving area prior to writing the first data to the first track, write the first data to the first track, and verify the second data in the second track after writing the first data to the first track.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head for writing data to the disk and reading data from the disk, and a controller configured to detect a positioning error of the head as the head is writing the data in a first track of the disk, and change a first threshold value for interrupting the writing based on one or more evaluation values corresponding to a possibility of correcting error data in the first track of the disk. The controller interrupts the writing when detecting the positioning error of the head writing the first track that exceeds the first threshold value.