Abstract: A victim feedforward signal is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator, where the victim feedforward signal is configured to compensate for disturbances to a victim head caused by assertion of the aggressor VCM control signal. Each aggressor VCM control signal is asserted at a specific time by the aggressor actuator, for example in response to the aggressor head passing over a first servo wedge. A feedforward signal that compensates for the effect of the aggressor VCM control signal is then determined based on the aggressor VCM control signal, stored, and asserted via the victim microactuator at a predetermined time relative to when the aggressor VCM control signal is asserted.

Abstract: According to one embodiment, a magnetic disk device includes a disk including a normal recording region written in a normal recording and a shingled recording region written in a shingled recording, a head including a write head and a plurality of read heads, the head moving on the disk by rotation about a rotation axis, and a controller which selects and executes the normal recording and the shingled recording, wherein a first minimum value of a cross track interval in the radial direction of the disk between two read heads in the plurality of read heads in the normal recording region is smaller than a first maximum value of the cross track interval in the shingled recording region.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a head and a controller. The head writes data to the magnetic disk and reads data from the magnetic disk. The controller once reads the data written to a predetermined recording area according to the number of writes of data to the predetermined recording area of the magnetic disk and rewrites the read data to the predetermined recording area. The controller adjusts an additive value to the number of writes based on the presence or absence of a defect on the recording surface of the magnetic disk.

Abstract: A haptic engine includes a linear resonant actuator having a double-wound driving coil which is used for sensing a back electromotive force (EMF) voltage independently of the coil resistance, thus minimizing the back EMF voltage's sensitivity to temperature.

Abstract: Two or more different recording currents are applied to a write coil of a recording head. A first of the two or more currents is a positive current and a second of the two or more currents is a negative current. In response to the application of the two or more different recording currents, a data stream is recorded to regions of a moving continuous magnetic recording medium such that each region has three or more magnetic states. The three or more magnetic states can be read from the continuous magnetic recording medium via a magnetic read transducer to recover the data stream.

Abstract: A remote operation system of a surveying instrument includes a surveying instrument including a survey unit, a control unit, a management server capable of communicating with the surveying instrument through the communication network, a remote terminal configured to command the management server to add a function of the surveying instrument through the communication network, and a billing system connected to the communication network, wherein the remote terminal commands the management server MS to consume a quantity of virtual currency corresponding to addition of the function, the management server adds the function of the surveying instrument when the quantity of virtual currency corresponding to addition of the function is consumed based on the command from the remote terminal, and the billing system executes a billing process based on billing data corresponding to the quantity of virtual currency.

Abstract: According to one embodiment, when an inspection of a defect of a recording surface of the magnetic disk is carried out by using the first processing section and the second processing section on the basis of the output of the gap sensor, a magnetic disk device is configured to compare a threshold defined on the basis of outputs of the first processing section at a plurality of tracks excluding a track which is an inspection object and an output of the first processing section at the track which is the inspection object with each other and, when the output of the first processing section at the track which is the inspection object exceeds the threshold, detect that there is a defect on the track concerned of the magnetic disk.

Abstract: According to one embodiment, a magnetic disk device includes a disk having first servo data including a first preamble, a first servo mark, a first gray code, first burst data, and second burst data written after the first burst data, a head including a write head that writes data to the disk and a first read head and a second read head that read data from the disk, and a controller that reads the second burst data using the first read head and the second read head and calculates a servo demodulation position when the first servo data is servo-read without reading the first burst data in a short servo mode in which the first preamble, the first servo mark, and the first gray code are not read.

Abstract: A method includes determining at least one of an areal density margin or a reliability margin for a combination of a head and a data storage surface in a data storage drive. The method also includes employing the determined at least one of the AD margin or the reliability margin to adjust an on-cylinder limit value associated with the combination of the head and the data storage surface.

Abstract: An apparatus comprises a write pole for writing data to a magnetic recording medium and a near-field transducer (NFT) optically coupled to a laser source and configured to produce a thermal spot on the medium. A laser driver applies laser operation power (Iop) to the laser source. A channel circuit generates symbols having a length of nT, where T is a channel clock rate and n is an integer. The laser driver applies Iop to the laser source and a write driver applies bi-directional write currents to the write pole to record the symbols at a location of the thermal spot on the medium, wherein a duration of applying Iop to the laser source by the laser driver is dependent on a length of the symbols and the effective thermal spot size.

Abstract: A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate including a polyester as a main component, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The kurtosis of the surface of the magnetic layer is 3.0 or more. The base layer and the magnetic layer each include a lubricant including a fatty acid and a fatty acid ester. In the lubricant, a ratio of the content of the fatty acid to the content of the fatty acid ester is less than 0.6.

Abstract: A method may include controlling commutation of a plurality of switches of an output stage comprising the plurality of switches in order to transfer charge between an energy storage device and a load to generate an output voltage across the load as an amplified version of an input signal, wherein the load comprises capacitive energy storage and controlling the power converter in order to regulate a cumulative electrical energy present in the system at an energy target, wherein the power converter is configured to transfer electrical energy from a source of electrical energy coupled to an input of the power converter to the energy storage device coupled to the output of the power converter and configured to store the electrical energy transferred from the source of electrical energy.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors and the head comprises a first read element and a second read element. When a first read command is received from a host to read a plurality of data sectors from the disk, the first read element is used to read a first data sector of the first read command, and when the first read element fails to recover the first data sector of the first read command, the second read element is used to read a second data sector of the first read command.

Abstract: A data storage device includes a ferromagnetic center pole, a drive coil for an actuator arm assembly, and a magnetic assembly surrounding the drive coil. The drive coil surrounds the center pole and has a top, a bottom, and first and second sides; the first side is attached to the actuator arm assembly. The magnetic assembly includes a top magnet disposed above and spaced from the center pole, a bottom magnet disposed below and spaced from the center pole, and a side magnet disposed proximate the second side of the coil and spaced from the center pole. In another embodiment, a linear actuator comprises a ferromagnetic center pole, a drive coil supported for linear motion on a rail, and a magnetic assembly. A method including linearly moving a drive coil along a center pole by a magnetic field is also described.

Abstract: A self-servo-write (SSW) method in a storage device includes detecting, with a first read head, SSW spiral signals from a first track on a first storage medium surface, processing the SSW spiral signals from the first track using a first read channel, to generate first control signals for positioning the first read head relative to the first track, detecting, with a second read head, SSW spiral signals from a second track on a second storage medium surface, processing the SSW spiral signals from the second track using a second read channel, to generate second control signals for positioning the second read head relative to the second track, positioning a first write head relative to the first track using the first control signals via a single write channel, and positioning a second write head relative to the second track using the second control signals via the single write channel.

Abstract: Provided are a lubricant that is highly resistant to contamination and highly thermally stable, a lubricant that is highly durable and highly heat resistant, and a magnetic disk. A fluoropolyether compound contains perfluoropolyether groups, end groups each containing at least one hydroxyl group, and a linking group that is comprised of a C4-C14 hydrocarbon group and that contains at least one hydroxyl group.

Abstract: The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer has a servo pattern, and an absolute value ?N of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40, a magnetic tape cartridge and a magnetic tape apparatus including this magnetic tape.

Abstract: A haptic engine includes a linear resonant actuator having a double-wound driving coil which is used for sensing a back electromotive force (EMF) voltage independently of the coil resistance, thus minimizing the back EMF voltage's sensitivity to temperature.

Abstract: A magnetic disk device includes a plurality of magnetic disks, a plurality of sliders each including one or more resistive elements, each of which is arranged to face a recording surface of one of the plurality of magnetic disks, and is provided corresponding to the plurality of magnetic disks, and a processor configured to detect a change in a resistance value of one or more of the plurality resistive elements.

Abstract: A data storage device configured to access a magnetic tape is disclosed comprising a plurality of data tracks. A first head is configured to access a first data track comprising a first sync mark, and a second head is configured to access a second data track comprising a second sync mark. The first head is used to read first data from the first data track, wherein the first data comprises a plurality of symbols, and the second head is used to read the second sync mark from the second data track. The first data is symbol synchronized based on the second head reading the second sync mark from the second data track.

Abstract: According to one embodiment, a magnetic disk apparatus includes a magnetic disk, a magnetic head, and a controller. The magnetic disk includes a plurality of tracks. The magnetic head performs read/write from/to the plurality of tracks. The controller controls, in a first case in which, during execution of write to a first track among the plurality of tracks, a position of the magnetic head is displaced from a target position corresponding to the first track toward a second track, and a first distance exceeds a first threshold, write to the second track under a condition different from a condition in a second case in which the first distance is less than the first threshold. The second track is a track different from the first track among the plurality of tracks. The first distance is the distance between the target position and the position of the magnetic head.

Abstract: A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.

Abstract: According to one embodiment, a magnetic disk device includes a disk including two first servo sectors and at least a second servo sector, a head, and a controller, wherein the first servo sector includes burst data and a first data pattern written before the circumferential direction of the burst data, the second servo sector includes the burst data, the first data pattern, and a second data pattern written after the circumferential direction of the burst data, a first frequency of the first data pattern is different from a second frequency of the second data pattern, and a first length of the first data pattern is different from a second length of the second data pattern.

Abstract: According to one embodiment, a magnetic disk includes a disk, first and second heads which write data to the disk and read data from the disk, a first actuator includes the first head, a second actuator includes the second head, first and second controllers which control the first head, the second head, the first actuator and the second actuator, an auxiliary power supply which supplies power when power from a power supply is shut off, and a power supply detection unit which makes power supplied from the auxiliary power supply to the first controller higher than the power supplied from the auxiliary power supply to the second controller when shutoff of power from the power supply is detected.

Abstract: Devices and techniques for temperature informed memory refresh are described herein. A temperature counter can be updated in response to a memory device write performed under an extreme temperature. Here, the write is performed on a memory device element in the memory device. The memory device element can be sorted above other memory device elements in the memory device based on the temperature counter. Once sorted to the top of these memory device elements, a refresh can be performed the memory device element.

Abstract: According to one embodiment, a magnetic disk device includes a disk including a first sector arranged at a first radial position deviated from a target position in a radial direction by a first offset amount larger than a first threshold value, a head that writes data to the disk and reads data from the disk, and a controller that reads the first sector by arranging the head at a second radial position deviated from the target position by a second offset amount different from the first offset amount.

Abstract: A data storage device (DSD) includes a base-deck, a disc above the base-deck, and a shaft extending perpendicular from the base-deck. The DSD also includes a head stack assembly (HSA) including a head gimbal assembly having a load beam and a head at a first end of the HSA. The head interacts with a surface of the disc. The HSA also includes a second end movably mounted on the shaft. The DSD additionally includes an elevator that linearly moves the HSA along the shaft to adjust a distance between the load beam and the surface of the disc in response to receiving a feedback signal associated with the interaction of the head with the surface of the disc. The feedback signal is one of a plurality of feedback signals employed by the elevator to adjust the distance between the load beam and the surface of the disc.

Abstract: Systems and methods are disclosed for resource allocation for multi-actuator systems. In some examples, a data storage device can include two or more independently moveable voice coil motor (VCM) actuators where the resources of the system to operate the VCM actuators are divided. The disclosure here describes methods to allocate or re-allocate the divided resources, such as unused resources, to a VCM actuator that has a need for more resources. The methods and systems herein can also be applied to other actuator systems.

Abstract: A data processing method including: searching for a smallest data unit of a buffer with regard to appending data in an append write request; sequentially writing at least some of the appending data into the smallest data unit of the buffer to obtain a first smallest data unit to be stored, and writing data not yet written in the appending data into at least one smallest data unit to obtain at least one second smallest data unit to be stored; writing the first smallest data unit to be stored into a storage device in an overwriting manner, and sequentially writing the at least one second smallest data unit to be stored into the storage device; and buffering a smallest data unit not fully written that corresponds to the appending data. The present disclosure ensures data integrity, increase operation convenience, and write operation efficiency.

Abstract: A data storage device is disclosed comprising a first plurality of heads actuated over a first subset of disk surfaces by a first actuator, and a second plurality of heads actuated over a second subset of disk surfaces by a second actuator. A plurality of access commands is received, wherein each access command is associated with one of the heads. A scalar is configured for each access command based on at least one of a current radial location of the corresponding head or a target radial location of the corresponding head associated with executing the access command. The access commands are sorted based on the scalars, and one of the access commands is selected for execution based on the sort.

Abstract: Systems and methods are disclosed for calibrating actuators in a multi-stage servo system. In certain embodiments, a method may comprise performing a calibration process on a multi-stage actuated servo system, including simultaneously injecting voltage injections into multiple microactuators of the servo system, measuring a resulting position error signal (PES), and determining gain settings for each of the multiple microactuators based on the PES. Multiple microactuators can therefore be calibrated during a single-injection calibration operation.

Abstract: The present disclosure generally relates to magnetoresistive device apparatus and methods. The magnetoresistive device includes a read head. The read head is a tunneling magnetoresistive reader that includes a multilayer free layer structure. The multilayer structure includes one or more layers of Co or FCC FeCo sandwiched between a BCC CoFe50 nanolayer and an amorphous CoFeB layer. The one or more layers of Co or FCC FeCo create nanocrystalline disorder that allows the thickness of the amorphous CoFeB layer to be reduced while retaining or even improving TMR and reducing the interlayer coupling field.

Abstract: According to one embodiment, a magnetic disk device includes a disk having a first area, and a second area to which data is temporary written, a head including a write head which writes data to the disk, and an assisting element which generates energy which improves write performance of the write head, and a controller which writes data to the first area by supplying energy having a first value to the assisting element, and writes data to the second area by supplying energy having a second value different from the first value to the assisting element.

Abstract: Described are magnetic recording heads that include a read transducer and a write transducer, with the two transducers being arranged in a side-by-side configuration.

Abstract: A method for mitigating intentional potential interruptions in data signal communication, the method comprising transmitting (S21) or receiving (S23) a data signal, determining when a portion of the data signal has been successfully transmitted (S22) or received (S24), when the portion of the data signal has been successfully transmitted or received, generating (S25) a transmission interruption signal, and in response to the transmission interruption signal, performing one or more maintenance operations, such as beamforming, that may potentially interrupt transmission or reception of the data signal.

Abstract: A servo writer includes a writing head that writes a servo signal on a long magnetic tape that is traveling and at least two first guide rollers that guide the travel of the magnetic tape, in which the at least two first guide rollers on which a spiral groove is provided have a circumferential surface that has contact with the traveling magnetic tape, tensile forces act on the magnetic tape from the at least two first guide rollers in a width direction of the traveling magnetic tape, and the tensile forces that act on the magnetic tape from the at least two first guide rollers cancel each other.

Abstract: A method, and associated computer program product and mobile computing device, for backing-up information stored in the mobile computing device. The mobile computing device detects one or more support computing devices located within a corresponding communication range and being available to support the mobile computing device for backing-up the information stored in the mobile computing device. The mobile computing device detects a dangerous condition indicative of a risk of inoperability of the mobile computing device. The mobile computing device sends back-up information corresponding to selected information stored in the mobile computing device to at least one of the support computing devices in response to the detection of the dangerous condition to cause the at least one support computing device to upload the back-up information to a back-up computing system.

Abstract: The present invention provides a method for positioning short circuit failure, used to position the short circuit point between a first metal wire and a second metal wire. The positioning method comprises: measuring the resistance between the first metal wire and the second metal wire, and positioning the first region where the short circuit point is located by a resistance ratio. In the first region, the short circuit point may be gradually approached by periodically cutting the first metal wire and the second metal wire, electrically isolating the cut portions, and performing a plurality of voltage contrast analysis on the first metal wire and the second metal wire based on the principle of the dichotomy, thereby accurately locating the short circuit point. With the positioning method provided by the present invention, the region where the short circuit defect of the nA (nano ampere) level is located may be accurately found from the first metal wire and the second metal wire that are extremely long.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media. A write boost is configured to a first setting, and a first pattern of magnetic transitions is written to a first servo field of a servo sector on the magnetic media using the first setting for the write boost. The write boost is configured to a second setting different from the first setting, and the first pattern of magnetic transitions is written to a second servo field of the servo sector on the magnetic media using the second setting for the write boost.

Abstract: A computer-implemented method includes, by one or more processors in electronic communication with a tunneling magnetoresistive sensor, wherein the tunneling magnetoresistive sensor is a component of a magnetic storage drive configured to read magnetic data from a magnetic storage medium, detecting a short across the tunneling magnetoresistive sensor, measuring a change in resistance of the tunneling magnetoresistive sensor, measuring a change in voltage amplitude for the tunneling magnetoresistive sensor, and dividing said change in voltage amplitude by said change in resistance to yield a ratio. The computer-implemented method further includes, responsive to the ratio being greater than a predetermined ratio threshold, determining that the short is caused by a magnetic shunt. A corresponding computer program product and computer system are also disclosed.

Abstract: A memory system according to an embodiment includes a nonvolatile memory and a memory controller. The memory controller converts a received value read from the nonvolatile memory into first likelihood information by using a first conversion table, executes decoding on the first likelihood information and outputting a posterior value, outputs an estimated value of the received value obtained on the basis of the posterior value in a case where the decoding is successful. The memory controller generates a second conversion table on the basis of the posterior value in a case where the decoding fails. The memory controller converts the received value into second likelihood information by using the second conversion table in a case where the second conversion table has been generated, and executes decoding on the second likelihood information and outputs a posterior value.

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: According to one embodiment, a servo write method includes a head and a disk having a plurality of spiral servo patterns which are written radially in a first direction from a first area to a second area other than the first area at velocity that varies between the first area and the second area, the method including moving the head in a second direction opposite to the first direction to read each of the spiral servo patterns, measuring a plurality of time intervals at which each of the spiral servo patterns is read in the first area, and writing a plurality of servo patterns to the first area based on the time intervals.

Abstract: According to one embodiment, a magnetic disk includes a disk, first and second heads which write data to the disk and read data from the disk, a first actuator includes the first head, a second actuator includes the second head, first and second controllers which control the first head, the second head, the first actuator and the second actuator, an auxiliary power supply which supplies power when power from a power supply is shut off, and a power supply detection unit which makes power supplied from the auxiliary power supply to the first controller higher than the power supplied from the auxiliary power supply to the second controller when shutoff of power from the power supply is detected.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a read head to read data from the magnetic disk and a write head to write data to the magnetic disk, and a controller configured to control read/write from/to the magnetic disk by the magnetic head. The magnetic head includes a thermal actuator configured to project a head surface of the magnetic head to a recording surface of the magnetic disk, and a detector configured to detect a gap between the head surface and the recording surface of the magnetic disk. The controller controls a degree of projection of the magnetic head to the recording surface by the thermal actuator corresponding to the gap detected by the detector during the read/write.

Abstract: According to one embodiment, a method for evaluating a magnetic head is disclosed. The method can include measuring an electrical characteristic of a current path when an alternating-current magnetic field is applied to the magnetic head. The magnetic head includes the current path. The current path includes an oscillator. The method can include, based on the electrical characteristic, deriving a frequency value relating to an oscillation frequency of the oscillator.

Abstract: A power supply circuit comprises a power conversion circuit, a voltage selection circuit, and a voltage regulator. The voltage regulator coupled to the voltage selection circuit and a digital-to-analog converter (DAC), and the voltage regulator is configured to provide supply power to the DAC; the power conversion circuit is coupled to a first power supply and a power amplifier (PA), and the power conversion circuit is configured to convert, based on output power of the PA, a voltage of the first power supply into an output voltage that supply power to the PA; and the voltage selection circuit is coupled to a second power supply, the power conversion circuit and the voltage regulator, and the voltage selection circuit is configured to select the second power supply or the power conversion circuit to supply power to the voltage regulator based on an output voltage of the power conversion circuit.

Abstract: The present disclosure, in various aspects, describes technologies and techniques for use by a data storage device that includes a controller of a non-volatile memory (NVM). In one example, the controller applies a default storage format to a storage region of the NVM, the default storage format configuring the storage region as a number of distinct storage regions logically arranged along a horizontal dimension and a vertical dimension. The controller modifies the default storage format using a combination of horizontal dimension scaling and vertical dimension scaling based on a performance capability of the storage region to obtain a modified storage format. The controller applies the modified storage format to the storage region.

Abstract: A magnetic disk device includes a magnetic disk, a first read element, a second read element, and a controller. In the magnetic disk, first servo information is written. The controller controls the servo writing of second servo information on the magnetic disk, based on the first servo information. In addition, the controller controls acquisition of the first servo information by the first read element. The controller switches a read element to be used to control the servo writing from the first read element to the second read element based on quality of the first servo information acquired by the first read element.

Abstract: According to one embodiment, a recording medium controller includes a recording medium, an input module, a reading module, and a writing module. The recording medium includes a write area and an escape area. The write area includes track groups. Each of the track groups is a unit for writing data and includes tracks. The input module receives a write command for data. The reading module reads data stored in the escape area and data from a first track group of the track groups. The writing module writes data received for the write command to the escape area, and writes merged data obtained by merging the data read from the escape area and the data read from the first track group to each track of a second track group of the track groups by using a shingle recording technique in which adjacent tracks are partly overlapped with each other.