Abstract: An automated test equipment (ATE) apparatus comprises a computer system comprising a system controller, wherein the system controller is communicatively coupled to a tester processor and an FPGA. The tester processor is operable to generate commands and data from instructions received from the system controller for coordinating testing of a device under test (DUT), wherein the DUT supports a plurality of non-standard sector sizes and a plurality of protection modes. The FPGA is communicatively coupled to the tester processor, wherein the FPGA comprises at least one hardware accelerator circuit operable to internally generate commands and data transparently from the tester processor for testing the DUT, and wherein the at least one hardware accelerator circuit is able to perform computations to calculate protection information associated with the plurality of protection modes and to generate repeatable test patterns sized to fit each of the plurality of non-standard sector sizes.

Abstract: A 3D printer is provided herein. In some embodiments, a 3D printer includes an ink tank for storing ink comprising a magnetic body, an injection nozzle which is linked to the ink tank and is adapted to inject ink, a substrate on which the injected ink is deposited, a heating unit so as to heat the ink coated onto the substrate by means of induction heating, and which is positioned behind the injection nozzle such that injection of ink occurs prior to induction heating of the ink; a carriage unit for changing the positions of the injection nozzle and the heating unit relative to the substrate: and a control unit for controlling the heating unit and the carriage unit.

Abstract: A storage system can include a first tape storage drive (TSD), a second TSD, and a printed circuit board assembly (PCBA) where the first and second TSD are coupled back-to-back, with the PCBA between the two. The first TSD can include a first enclosure, a first head assembly, a first actuator, and a first connector. The second TSD can include a second enclosure, a second head assembly, a second actuator, and a second connector. The PCBA can include a first side having a first mating connector configured to connect to the first connector for the first TSD, a second side opposite the first side, the second side having a second mating connector configured to connect to the second connector for the second TSD, and a controller configured to control activation of the first actuator of the first TSD and the second actuator of the second TSD.

Abstract: Provided is a servo controller that can prevent an unnecessary cut from being generated in a workpiece during oscillation machining. A servo controller 20 includes: an oscillation command generating unit 23 that generates an oscillation command for causing a workpiece W and a tool 11 to relatively oscillate; a position deviation estimating unit 31 that estimates an estimated position deviation from a moving command for causing the workpiece W and the tool 11 to relatively move; an adder that applies the oscillation command to a position deviation based on the moving command; a subtractor that deducts the estimated position deviation from a position deviation to which the oscillation command is applied; and a learning control unit that calculates a compensation amount from a position deviation based on the moving command after deducting the estimated position deviation.

Abstract: Implementation of a non-interfering micro-positioning device, for a tape drive write/read head module assembly utilizing piezoelectric elements, by generating at least two flexure brackets. The at least two flexure brackets may include the piezoelectric elements. Affixing at least one flexure bracket to a first side of the write/read head module assembly. Affixing at least one other flexure bracket to a second side of the write/read head module assembly.

Abstract: A system is provided to receive a first request to write data to an HDD which comprises a plurality of platters with corresponding heads, wherein a respective platter includes a plurality of tracks. The system aligns the heads at a same first position on a first track of each platter, and distributes the data as a plurality of data sectors to track sectors located at the same first position on the first track of each platter. The system then receives a second request to read the data from the HDD, and aligns the heads at a same random position on the first track of each platter. Subsequently, the system reads, during a single rotation of the platters, all data stored on the first track of each platter, stores the read data in a data buffer, and reshuffles the read data in the data buffer to obtain the requested data.

Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA) configured to adjust a fly height of the head over the disk. A temperature of the data storage device is measured, and the FHA is controlled as a function of the measured temperature. A first quality metric of the data storage device is measured, and when the first quality metric falls below a threshold, the FHA control as a function of the measured temperature is disabled and the FHA is controlled to decrease the fly height of the head.

Abstract: A method including obtaining a target actuation efficiency slope that is a linear function of temperature when a fixed active clearance is maintained between a transducing head and an adjacent storage surface in a sealed storage device. The target efficiency slope is obtained at least in part by a temperature dependence calibration of actuation efficiency. An operating temperature of the storage device is measure. Power to a clearance adjustment mechanism is adjusted to achieve the target actuation efficiency slope at the measured operating temperature.

Abstract: Magnetic sensors with effectively shaped side shields and their fabrication processes are provided. One such process includes depositing sensor materials on a substrate, shaping the sensor materials to form a stripe height of the magnetic sensor, shaping the sensor materials to form a track width of the magnetic sensor, depositing side shield materials on the shaped sensor materials, shaping the side shield materials such that a resulting side shield extends further than the stripe height, depositing an insulator layer on the shaped side shield materials, and shaping the insulator layer.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a recording head and a controller. The recording head includes a high-frequency oscillator disposed in a write gap between a main magnetic pole and a return magnetic pole and configured to oscillate in accordance with a bias voltage, and a bias voltage supply circuit configured to supply the bias voltage to the high-frequency oscillator. The controller includes a bias voltage controller configured to control the bias voltage to be applied to the high-frequency oscillator in accordance with a sampling frequency of data when the data is recorded on the magnetic disk by the recording head.

Abstract: A data storage device is disclosed comprising a head actuated over a disk surface, wherein the head comprises a plurality of elements including a write assist element. A bias signal applied to the write assist element is controlled such that the write assist element is substantially unprotruded, and while the write element is substantially unprotruded, an air bearing resonant frequency (ABRF) of the head and disk surface is measured. The bias signal applied to the write assist element is controlled such that the write assist element protrudes toward the disk surface, and while the write assist element protrudes toward the disk surface, the head is excited at the measured ABRF and the head touching down onto the disk surface is detected.

Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a trailing shield, a main pole, an STO disposed between the trailing shield and the main pole, and a non-magnetic conductive structure adjacent to the main pole and in contact with the STO. The STO includes an FGL and an SPL, and the FGL is disposed between the main pole and the SPL. The FGL includes a side extending over the main pole and at least a portion of the non-magnetic conductive structure. With the FGL disposed proximate to the main pole and over at least a portion of the non-magnetic conductive structure, current crowding and disturbance from the trailing shield are minimized.

Abstract: A switching circuit includes a switching circuit stage configured to supply a load via filter networks. Control circuitry is provided to control alternate switching sequences of transistors in the half-bridges of the switching circuit stage. A current flow line is provided between the output nodes of the half-bridges including an inductance between two switches. First and second capacitances are coupled with the output nodes of the half-bridges. The control circuitry switches first and second switches to the conductive state at intervals in the alternate switching sequences of the transistors in the half-bridges between switching the first pair of transistors to a non-conductive state and switching the second pair of transistors to a conductive state.

Abstract: A data-storage system comprises a head receiver configured to variably receive up to a number M of write heads. The data-storage system also includes an installed number N of write heads arranged in the head receiver, a substrate receiver configured to receive one or more data-storage substrates, and a positioner machine configured to adjust a relative placement of each of the M write heads with respect to at least one of the one or more data-storage substrates.

Abstract: A method includes processing, via an integrated circuit, data read from a first servo wedge; processing, via the integrated circuit, data from a second servo wedge; and skipping processing data from a third servo wedge positioned between the first servo wedge and the second servo wedge.

Abstract: A magnetic disk device includes a case including a magnetic disk, a magnetic head configured to read or write data from or to the magnetic disk, an actuator configured to move the magnetic head, and a humidity sensor positioned within the case to measure a humidity in the case and output a measurement value; a control circuit configured to calculate a value of a voltage to be applied to the actuator based on a displacement amount of the magnetic head and the measurement value output from the sensor, and output the calculated value; and a servo controller configured to control the actuator by applying the voltage to the actuator according to the value output by the control circuit.

Abstract: A dual-stage servo system of a disk drive includes a first fine positioning servo system with a first microactuator that independently controls the position of a first read/write head over a first recording surface and a second fine positioning servo system with a second microactuator that independently controls the position of a second read/write head over a second recording surface. The first microactuator accesses a first data stripe while the second fine positioning servo system simultaneously accesses a second data stripe. Data can be transferred to or from the first and second data stripes simultaneously.

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 includes a first system-on-a-chip (SOC) associated with a first read transducer that accesses one or more magnetic disks of the data storage drive. The first SOC has a first read channel operable to receive data from the first read transducer. A second SOC is associated with a second read transducer that accesses the one or more magnetic disks of the data storage drive independently of the first read transducer. The second SOC has a second read channel operable to receive second data from the second read transducer. The first and second SOCs are coupled via a data bus that facilitates communicating the first and second data to a host via a first host interface.

Abstract: A method according to one embodiment includes generating a y-position estimate based on a servo readback signal, and determining a nonlinearity-correction value corresponding to the y-position estimate. The method further includes adjusting the y-position estimate using the nonlinearity-correction value. A computer program product for compensating for nonlinearity in a timing based servo pattern according to another embodiment includes a computer readable storage medium having program instructions embodied therewith. The program instructions are readable and/or executable by a controller to cause the controller to perform the foregoing method. An apparatus according to another embodiment includes a controller configured to perform the foregoing method.

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: A media device may comprise a controller, a tape head, a tape comprising tape-position indicia, an indicia detection device, and an adjusting device. The indicia detection device may be configured to detect the tape-position indicia and provide an output corresponding to a tape position. The controller may be configured to send an adjustment command based on the output. The adjusting device may be configured to adjust the media device between a first configuration and a second configuration, based on the adjustment command. The tape may physically contact the tape head in the first configuration and not physically contact the tape head in the second configuration.

Abstract: In a position detector for converting, into position information, two signals shifted in phase by 90 degrees from each other, a phase correction value calculator for calculating a phase correction value for correcting a phase difference between the two signals calculates a phase change value representing a change in the phase correction value, to find a next phase correction value based on the phase change value and a present phase correction value. A virtual change value calculator calculates, based on second-order components obtained by Fourier analysis of a radius value, a virtual phase change value representing another change in the phase correction value obtained when changes in offset and amplitude ratio are ignored, and a virtual amplitude change value representing a change rate in an amplitude ratio correction value obtained when a change in the phase difference is ignored.

Abstract: An apparatus configured to characterize a magnetic recording tape of a tape cartridge, according to one embodiment, includes a magnetic head having servo readers of known pitch, a drive mechanism for passing a magnetic recording tape over the magnetic head, and a controller electrically coupled to the magnetic head. The controller is configured to measure, using signals from the magnetic head, a servo band difference at various locations along a length of the magnetic recording tape of a tape cartridge. The controller is also configured to store the servo band difference measurements and/or derivatives thereof in association with the tape cartridge.

Abstract: A system accesses metadata on a file system of the magnetic tape, where the metadata comprising one or more fields enabling to determine a longitudinal position (LPOS) of one or more files located on the magnetic tape. The system determines the LPOS of the one or more files located on the magnetic tape. The system determines an optimal location of the head on the magnetic tape based on computing an average value to the determined LPOS of the one or more files located on the magnetic tape and moves the head on the magnetic tape to the optimal location.

Abstract: Disclosed are mixtures containing: mono- and bi-functional polymers [polymers (P-A) and (P—B)] comprising a plurality of (per)fluoropolyether segments [segments (SRF)] joined together by hydrogenated (poly)ether segments [segments (SH)], said polymers having two ends, wherein one or both ends comprises a hydroxy or a leaving group; a non-functional polymer comprising a plurality of (per)fluoropolyether segments (SRF) joined together by hydrogenated (poly)ether segments (SH), with the proviso that the hydrogenated (poly)ether segments (SH) are not segments of formula —CH2OCH2OCH2—. Disclosed are also monofunctional polymers (P-A) that can be isolated from such mixtures. Methods for the obtainment of the mixtures and for separating the polymers therein contained are also provided, as well as methods of using the mixtures or each polymer therein contained as intermediates or building blocks for the synthesis of other polymers or as ingredients of compositions.

Abstract: In some embodiments, apparatuses and methods are provided herein useful to a test card for use in automated testing of a POS terminal. In some embodiments, the test card comprises a substrate including at least one track, wherein the substrate is configured to interact with a magnetic card reader, an electrical contact configured to receive magnetic stripe data from a database, and an electrical trace, wherein the electrical trace is programmable with respect to the received magnetic stripe data, wherein the electrical trace forms a continuous conductive pathway, wherein the electrical trace forms a stair step configuration comprising a plurality of linear segments including a first set of linear segments and a second set of linear segments, wherein the second set of linear segments includes at least one segment, and wherein the at least one segment connects ones of the first set of linear segments.

Abstract: The magnetic tape device includes a magnetic tape including a magnetic layer, in which an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %.

Abstract: The magnetic tape device includes a TMR head (servo head); and a magnetic tape, in which a magnetic layer of the magnetic tape includes fatty acid ester, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 7.0 nm, a difference between spacings before and after the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm, and ?SFD (=SFD25° C.?SFD?#° C.) in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head, and a controller that estimates a first frequency component resulting from a disturbance in a first range of a frequency corresponding to the disturbance in a signal with the disturbance, estimates a second frequency component corresponding to a second frequency of a positive integral multiple of 2 or larger of a first frequency of the first frequency component in a second range different from the first range, and suppresses a first harmonic component corresponding to the positive integral multiple of the first frequency in a position error of a target position of the head on the disk.

Abstract: First and second tracks are read simultaneously via a first reader mounted in a head-gimbal assembly. The first reader provides a first signal based on detecting a total perpendicular field of the first and second tracks. The first and second tracks are read simultaneously via a second reader mounted in the head-gimbal assembly. The second reader provides a second signal based on detecting a total longitudinal field of the first and second tracks. At least one of a position error and a timing error of at least one of the first and second readers are determined based on user data read via the respective first and second signals.

Abstract: According to one embodiment, a semiconductor device includes a semiconductor element, and a first member. The first member includes a first nonmagnetic planar region separated from the semiconductor element in a first direction, a first magnetic planar region provided between the first nonmagnetic planar region and the semiconductor element in the first direction, and a second nonmagnetic planar region provided between the first magnetic planar region and the semiconductor element in the first direction. The first magnetic planar region includes a first end portion extending along a second direction crossing the first direction. A first magnetization direction of the first magnetic planar region is tilted with respect to the second direction.

Abstract: Systems and methods for servo zone transition optimization are described. In one embodiment, the storage system device includes a disk drive and a controller. In some embodiments, the controller may be configured to assess at least one operation of a read/write head of the disk drive; and format, based at least in part on the assessing of the read/write head, a disk surface of the disk drive with a first servo zone, a second servo zone, and an overlap region extending between a start point of the second servo zone and an end point of the first servo zone. In some cases, the overlap region starts towards a disk inner diameter (ID) and ends towards a disk outer diameter (OD).

Abstract: The present disclosure provides a feedback control system and method for a bidirectional VCM. The system employs an analog core that is common to both the PWM and linear modes of operation. The analog core includes a feedback mechanism that determines the error in the current flowing through the motor. The feedback mechanism produces an error voltage that corresponds to the current error, and applies the voltage to a control driver. The control driver then controls the motor, based on the error voltage, in either a PWM or linear mode. By sharing a common core, the switching time between modes is improved. Furthermore, the output current error between modes is reduced.

Abstract: An electronic device is installed in a machine where there is a possibility in occurrence of vibration or impact. The electronic device includes an acceleration detecting unit detecting acceleration in a predetermined time interval, and an impact determining unit. In a case where it is determined that an acceleration value exceeds a predetermined first threshold value, a second threshold value is calculated based on a maximum value among acceleration values of plural accelerations for a predetermined time interval after the determination. In a case where the number of accelerations where acceleration values exceeds the second threshold value among the plural accelerations is a predetermined number or less, the impact as a single-type impact is determined. In a case where the number exceeds the predetermined number, the impact as a multiple-type impact is determined. Also included is an output unit outputting a signal in a case where the impact is determined as the multiple-type impact.

Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.

Abstract: An error detection device includes a generation unit and a detection-correction unit. When writing data into a storage unit, the generation unit generates error detection information for each piece of division-data into which write-data are divided. The error detection information is information which is available in determining whether a bit error includes in the division-data, and by which a position where the bit error is caused can be detected based on plural pieces of the error detection information of the plural division-data composing the write-data. Using the error detection information, the detection-correction unit can determine whether the bit error is caused in the division-data. Using plural pieces of the error detection information of the data including the division-data in which it is detected that the bit error is caused, the detection-correction unit can detect the position where the error is caused, and can correct the bit error.

Abstract: The present disclosure provides a method and system for data persistence in stream computing, and the present disclosure belongs to the technical field of data storage. The method comprises: initiating, by a management module, a task; extracting a key corresponding to the task from a data source based on the task; acquiring a value corresponding to the key from the data source based on the key, performing data processing to generate intermediate data and a first signal, and storing the intermediate data and the first signal; detecting whether the first signal has been stored, and sending detection information to the management module. By using the present disclosure, the intermediate data persistence result may be effectively fed back, such that the intermediate data persistence may be ensured to be transactional.

Abstract: In some examples, a portable electronic device may monitor a plurality of device care metrics to detect and characterize a level of care provided to an electronic device by a user. Further, the user may receive a reward for providing a level of care as specified by one or more device care thresholds. For example, the device may monitor sensor information from one or more sensors for determining whether the device has experienced a physical event, such as a fall event, an excessive moisture event, or the like. Further, the device may also monitor for system events, such as whether to update a program, whether malicious code has been installed, or the like. The occurrence of a physical event and/or the user's actions in response to a system event may determine a user's eligibility to receive a reward based on the level of device care provided.

Abstract: A method and system for determining slider-disk contact in a hard-disk drive (HDD) that has dual independent heaters for thermal fly-height control, and dual embedded contact sensors, includes dithering power to the two heaters at different frequencies. The HDD has the two contact sensors electrically connected to provide a single combined output signal in response to the dithering. The single combined output signal is analyzed to detect two signals at the two different frequencies. When either detected signal exceeds a predetermined touchdown threshold value, the values of heater power for the two heaters are recorded, indicating that that combination of heater power values corresponds to slider-disk contact.

Abstract: A control device includes an interface for exchanging data with a servo driver. The servo driver is configured to execute a control arithmetic operation in which a manipulation amount for driving the servo motor is determined on the basis of a control parameter determined in accordance with a control target. The control device includes a creation unit that acquires the control parameter of the servo driver and creates an internal model representing a motion characteristic of the control target, and a target value calculation unit that calculates a corrected target value to be supplied to the servo driver on the basis of a target value corresponding to a target track and a feedback value from the control target.

Abstract: The magnetic tape device includes a magnetic tape including a magnetic layer, in which an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %.

Abstract: A positioning control device of an actuator provided with a strain wave gearing has a full-closed control system for feeding back a position of a load shaft, and driving and controlling a motor so as to position the load shaft at a target position. The full-closed control system has an H? compensator designed so that, when a generalized plant having angular transmission error in the strain wave gearing as a disturbance input is assumed, an H? norm of a transfer function from the disturbance input of the generalized plant to an evaluation output is a predetermined value or less. Mechanical vibration during positioning response caused by angular transmission error in the strain wave gearing can be reliably suppressed.

Abstract: A clearance heater of a write head is engaged with a boosted current that exceeds a steady-state current. The steady-state current causes the write head to maintain a desired clearance over a disk during writing, the boosted current being applied before a start of the writing. The boosted current is monotonically decreased before the start of the writing and the steady-state current is applied to the heater after the start of the writing.

Abstract: Embodiments of the present disclosure relate to a method and an apparatus for operating a hybrid storage device, the hybrid storage device including a storage device of a first type and a storage device of a second type that is different from the first type, the method comprising: synchronously writing data in the storage device of the first type and the storage device of the second type. By using the embodiments of the present disclosure, the actual storage space may be increased, and the service life of the storage device may be prolonged.

Abstract: A spin-orbit torque type magnetization reversal element including a ferromagnetic metal layer with a varying magnetization direction; and spin-orbit torque wiring that extends in a first direction intersecting with a stacking direction of the ferromagnetic metal layer and that is joined to the ferromagnetic metal layer; wherein when viewed from the first direction, the spin-orbit torque wiring is asymmetrical in a second direction that is orthogonal to the first direction and the stacking direction, with respect to an axis that passes through a center, in the second direction, of the ferromagnetic metal layer.

Abstract: Operations include compensating for a Tracking Error Signal (TES) offset in an optical tape drive. The tracking error offset compensation system detects a control signal for controlling movement of an optical head across a surface of a tape. The tracking error offset compensation system computes an estimated movement of the optical head, based on the initial control signal. The tracking error offset compensation system determines an estimated TES offset, based on the estimated movement of the optical head. The tracking error offset compensation system uses the estimated TES offset to correct a TES. The tracking error offset compensation system transmits the corrected TES, for controlling additional movement of the optical head.

Abstract: According to one embodiment, a servo write control apparatus is for a disk apparatus including a read element and a write element located in an outer side of a disk from the read element. The servo write control apparatus detects a plurality of first burst signals recorded in a circumferential direction of the disk by the read element. The servo write control apparatus calculates an offset in a radial direction when the write element writes a second burst signal, based on amplitude values of at least two of the first burst signals used for positioning the read element. The servo write control apparatus adjusts a write position of the second burst signal based on the offset.

Abstract: An apparatus may include a first and second servo channels configured to output first and second position information to first and second writers, respectively, via a shared write path such that the first and second writers write first and second position information to first and second magnetic recording medium surfaces, respectively. In addition, the apparatus may include a controller configured to control the shared write path such that write access is changed between the first servo channel and second servo channel a plurality of times during a revolution of the first magnetic recording medium surface and second magnetic recording medium surface.