Abstract: A method for starting hard disks, applied in an electronic device, the method includes: starting a storage in the electronic device, and the storage comprising hard disks and a backplane extension chip; sending preset request signals by the hard disks to the backplane extension chip; verifying a number of the hard disks by the backplane expansion chip according to the request signals; when the number of the hard disks is verified successfully, performing type verification on the hard disks by the backplane expansion chip; and sending a start signal by the backplane expansion chip to the target hard disks having a successful type verification according to a preset start sequence and a preset number of the hard disks, to start the target hard disks.

Abstract: In accordance with an embodiment, a hard disk drive includes voice coil motors (VCMs) coupled to respective control units configured to drive retract an operation of the VCMs in the hard disk drive. The retract operation of the VCMs includes a sequence of retract steps. The control units are allotted respective time slots for communication over a communication line with the respective time slots synchronized via the common clock line, and are configured to drive sequences of retract steps of the VCMs in the hard disk drive in a timed relationship.

Abstract: A method of determining radial position of a magnetic head that includes a first read sensor and a second read sensor includes: with the first read sensor, detecting a servo spiral formed on a disk; with the second read sensor, detecting the servo spiral; measuring a time interval between when the servo spiral is detected by the first read sensor and when the servo spiral is detected by the second read sensor; and based on the time interval, determining a radial position of the magnetic head relative to the disk.

Abstract: The present disclosure is generally related to a tape drive comprising a tape head and a controller coupled to the tape head. The tape head comprises one or more modules, each module comprising a plurality of write heads aligned in a first row, a plurality of read heads aligned in a second row parallel to the first row, and at least four first servo heads aligned in the second row. Two or more first servo heads of the at least four first servo heads are configured to concurrently read first servo data from a first servo track. The controller is configured to concurrently process the first servo data, to compute the position of the tape head based on a known spacing between the at least two servo heads, and to dynamically adjust a position of the tape head based on the processed first servo data.

Abstract: A tape drive (226) for use in a tape library (10) that retains at least one tape cartridge (220) that retains magnetic tape (250) includes a drive housing (226A) and a media conditioner (255). The drive housing (226A) is configured to receive the tape cartridge (220). The media conditioner (255) is coupled to the drive housing (226A). The media conditioner (255) is configured to condition the magnetic tape (250) when the tape cartridge (220) is received within the drive housing (226A). The media conditioner (255) can be configured to remove at least one of abrasives, contaminants and lubricants that are on the magnetic tape (250) when the tape cartridge (220) is received within the drive housing (226A). The magnetic tape (250) is configured to move along a predefined path (251) within the drive housing (226A), which is defined by one or more rollers (254).

Abstract: The present disclosure generally relates to a tape drive including a tape head. The tape head comprises two modules, where each module comprises 64 writers, 64 readers, and three pairs of servo readers aligned with the 64 readers in a first row. The three pairs of servo readers comprise a first pair disposed at a first end of the first row, a second pair disposed between two groups of 32 readers, and a third pair disposed at a second end of the first row. The writers are disposed in a second row parallel to the first row, and are each aligned with an adjacent reader. The spacing between each reader and each writer is about 150 ?m to about 200 ?m. Each module is configured to write data to a tape using the 64 writers and to read verify the newly written data using the 64 readers.

Abstract: According to one embodiment, a magnetic disk device comprising a magnetic disk, a magnetic head, and a controller that registers an address and a positioning error, determines whether or not a positioning error of a second sector that is two tracks ahead in a radial direction of a first sector to which a data is written is registered, and when the positioning error of the second sector is registered, sets a first threshold that allows a write operation for a positioning error of the first sector based on the positioning error of the second sector, and determines whether or not the positioning error of the first sector exceeds the first threshold, and stops the write operation when the positioning error of the first sector exceeds the first threshold.

Abstract: A controller provides a plurality of first sections with numerical information on a first scale. The plurality of first sections are obtained by dividing a recording surface of a magnetic disk in units of first memory areas in each of which a first volume of data can be written by an SMR method. The first scale corresponds to a sequence of the first sections. The controller provides a plurality of second sections with numerical information on a second scale. The plurality of second sections are obtained by dividing the recording surface of the magnetic disk in units of second memory areas in each of which the first volume of data can be written by a CMR method. The second scale corresponds to a sequence of the second sections. The controller executes a plurality of commands in order based on a numerical information on the first scale or the second scale.

Abstract: Various illustrative aspects are directed to a data storage device comprising a slider with a resistive temperature detector (RTD) having a first resistance electrically connected to a first amplifier and a plurality of controlled current sources and switches, and one or more processing devices configured to: control the switches to generate an alternating-bias signal having a first clock frequency for biasing the first resistance, modulate an input signal of the first amplifier using the first clock frequency to generate a modulated signal, demodulate an amplified modulated signal at an output of a second amplifier using the first clock frequency to generate a resistance detection signal, the second amplifier coupled to the first amplifier, and process the resistance detection signal to determine the first resistance and/or a change in value of the first resistance.

Abstract: Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head having read and write portions configured to read data from and write data to the disk; read and write heaters configured to thermally adjust read and write spacings of the read and write portions from the disk surface; and a controller configured to control power applied to the read and write heaters based on a dual heater power ratio (DHR) of the respective power applied to each heater. The DHR is set based on a point during touchdown at which a reader shield and a writer shield have maximum contact with the surface of the disk (DHRmax).

Abstract: According to one embodiment, a magnetic disk device comprises a disk, a head that writes data to the disk and reads data from the disk, and a controller that controls a position of the head so as to write a first spiral servo pattern to the disk, and overwrite a second spiral servo pattern different from the first spiral servo pattern by shifting in a radial direction of the disk from the first spiral servo pattern.

Abstract: Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuating mechanism comprising one or more heads, and configured to position the one or more heads proximate to disk surfaces of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: determine a first burst value based on an averaged value of a first set of one or more bursts; determine a second burst value based on an averaged value of a second set of one or more bursts; generate a position error signal (PES) based on the determined first burst value and the determined second burst value; and control a position of at least one head among the one or more heads based on the PES.

Abstract: The present disclosure generally relates to a tape drive including a tape head. The tape head comprises one or more modules, each module comprising a plurality of writers disposed in a first row, a plurality of readers disposed in a second row parallel to the first row, a first servo reader aligned with either the first row or the second row, and a second servo reader aligned in a third row parallel to the first and second rows. The first servo reader and the second servo reader are offset from one another in a first direction and in a second direction perpendicular to the first direction, the first direction being a cross-track direction. The first servo reader and the second servo reader are spaced apart in the first direction about 1 ?m to about 20 ?m.

Abstract: Systems, apparatuses, methods, and computer program products are disclosed for facilitating contactless and socially distant payments. Specifically, certain embodiments are configured for generating and utilizing a user expression map for associating user expressions to control events. The methods further correspond to receiving, in real-time, image data representative of at least a portion of a user body, the user body tracked by a contactless human to device interface system. The methods further include causing a retrieval of a user expression map from a first computing device for provision to a second computing device, determining using the user expression map, that the image data is associated with a control event indicative of a directive to perform a particular transaction, and triggering the control event to cause performance of the particular transaction based, at least in part on the determination that the image data is associated with the control event.

Abstract: A noncontact communication medium includes a processor, and a memory incorporated in or connected to the processor, and performs noncontact communication with an external communication device. The memory has a storage block where information regarding an attribute of the noncontact communication medium is stored and that includes a plurality of storage fields. The plurality of storage fields include a specification-independent storage field where information independent of a specification of a magnetic tape cartridge, in which the noncontact communication medium is mounted, is stored. The processor is configured to write accompanying information regarding the magnetic tape cartridge in the specification-independent storage field in response to an instruction given from the external communication device to the noncontact communication medium by the noncontact communication.

Abstract: Methods and apparatus for determining and transmitting speed and/or direction information for a rotating target by a magnetic field sensor. A reference channel signal is generated for a target from at least one magnetic field sensing element and a virtual channel signal in quadrature with the reference channel signal is generated. A tangent signal is generated. A slope of an arctangent of the tangent signal is determined, wherein the slope corresponds to rotational speed of the target. The speed and/or direction of the target can be transmitted by a sensor IC.

Abstract: Various illustrative aspects are directed to a data storage device comprising data tracks N and N?1, and one or more processing devices, configured to measure signal to noise ratio (SNR) metrics for corresponding sectors of at least one of the data tracks N?1 and N, where the measuring is based at least in part on reading one or more of the data tracks N and N?1 using one or more read offsets, estimate a position of at least one of the data tracks based on measuring the one or more SNR metrics, and reconstruct one or more of risk values for at least a portion of the data track N?1 based on the one or more SNR metrics for the data track N?1, and a position error signal (PES) for at least one of the data tracks N?1 and N based on the corresponding estimated positions.

Abstract: Systems and methods are disclosed for phase locking of a clock. In some embodiments, a phase locked clock (PLC) module can phase-lock a write clock to a media written with multiple servo zones of different frequencies. In some implementations, this can be utilized to perform a self-servo write (SSW) of a disc surface within a hard disc drive (HDD). A PLC module can perform a method of writing with a single frequency phase coherently while a read element passes over servo zones with different frequencies. While the PLC module can perform such methods for a SSW process, the methods can also be utilized for other applications that can benefit from writing with a single frequency phase coherently based on servo zones with different frequencies.

Abstract: A data storage device includes at least one data storage disc having at least one data storage surface, and at least one read head configured to communicate with the at least one data storage surface. The data storage device also includes a controller communicatively coupled to the at least one read head. The controller is configured to determine a fly height for the at least one read head over the at least one data storage surface as a function of a read workload associated with the at least one data storage surface or as a function of an ability to satisfy a read request to the at least one data storage surface on a first read attempt.

Abstract: Example systems, data storage devices, and methods to provide long-term spacing compensation for heat assisted magnetic recording are described. The data storage device includes a storage medium with data tracks and a head that can be positioned for reading and writing those tracks. The head includes a laser for heat assisted magnetic recording and a fly height actuator. Based on the operation of the laser, both a short-term fly height compensation parameter and a long-term fly height compensation parameter are determined based on different temperature state models. The operating power of the fly height actuator is determined, at least in part, based on the short-term and long-term height compensation parameters.

Abstract: A magnetic tape cartridge includes a case in which a magnetic tape is housed, and an NVM of a cartridge memory provided in the case. The NVM stores cartridge information including an identification ID regarding an allowable range of temperature/humidity in using the magnetic tape, an upper limit of a preservation period of the magnetic tape, and an upper limit of a use frequency of the magnetic tape.

Abstract: The controller comprises a displacement controller and a rotating speed controller. The displacement controller includes a vibration force compensation control module and a dead-time vibration compensation module. The vibration force compensation control module receives actual displacements and a rotor mechanical angle and outputs corresponding vibration compensation forces. The vibration force compensation control module comprises a first neural network band-pass filter, a second neural network band-pass filter, a third PID controller, and a fourth PID controller. The dead-time vibration compensation module receives a rotor electrical angle and an actual quadrature-direct axis currents and an actual direct axis current and outputs a quadrature-direct axis compensation voltages and a direct axis compensation voltage.

Abstract: According to an embodiment, a manufacturing method includes: estimating a distribution of an initial value of a clearance of a magnetic head on a first recording surface; and recording first spiral signals on the first recording surface while controlling a clearance using the distribution of the initial value of the estimated clearance. The manufacturing method includes measuring a distribution of an initial value of a clearance of a magnetic head on a second recording surface under positioning control using the first spiral signals recorded on the first recording surface. The manufacturing method includes recording the first spiral signals on the second recording surface while controlling a clearance using the distribution of the initial value of the measured clearance of the magnetic head on the second recording surface.

Abstract: Described herein are embodiments related to defect detection in memory components of memory systems with time-varying bit error rate. A processing device determines that a bit error rate (BER) corresponding to a read operation to read a unit of data in a memory component satisfies a threshold criterion, determines a write-to-read (W2R) delay for the read operation, wherein the W2R delay comprises a difference between a time of the read operation and a write timestamp indicating when the unit of data was written to the memory component, and determines whether the W2R delay is within a W2R delay range corresponding to an initial read voltage level used by the read operation to read the unit of data. The processing device initiates a defect detection operation responsive to the W2R delay being within the W2R delay range, the defect detection operation to detect time-varying defects in the memory component.

Abstract: According to one embodiment, a magnetic disk device includes a plurality of magnetic disks, a plurality of magnetic heads provided correspondingly to the plurality of magnetic disks and configured to carry out read/write of data from/to the magnetic disks, and a control section configured to control read/write of the magnetic heads. Each of the plurality of magnetic disks includes a first storage section storing therein control information concerning read/write of the magnetic head. The control section switches the first storage section which is a storage destination of first information that is at least a part of the control information from the magnetic disk to another magnetic disk.

Abstract: A media library (10) for evaluating a health of a head (256) of a media drive (26) includes a library control system (30) that is configured to control oversight functionality of the media library (10). The library control system (30) receives media drive information generated during at least one of a read procedure and a write procedure being performed by the media drive (26) and analyzes the media drive information to determine the health of the head (256) of the media drive (26). The media drive information includes drive performance metrics generated by the media drive (26) during a read verify procedure performed by the media drive (26) upon request of the library control system (30) of the media library (10).

Abstract: Example systems, data storage devices, and methods to provide data protection during concurrent operations for multiple actuator data storage devices are described. The data storage device includes a plurality of actuators configured to actuate a plurality of heads over different subsets of a plurality of disk surfaces. Responsive to receiving a write command for one of the actuators, the coupling state with at least one other of the actuators is determined and execution of write commands is inhibited if the coupling state indicates a possible coupling event. The inhibit of the write commands in the presence of coupling events may prevent off-track writes and protect data.

Abstract: Two or more data values are received from one or more sensors of a hard disk drive. The two or more data values are indicative of a fly height of a recording head of the hard disk drive. The two or more data values are input into a machine-learning processor during operation of the hard disk drive. A fly height of the recording head during the operation of the hard drive head is adjusted based on an output of the machine learning processor.

Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head, one or more separate polarizer layers, or combinations thereof. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes a Mn or a Mn-alloy layer.

Abstract: A solid-state imaging device includes: a pixel unit that outputs a pixel signal corresponding to an amount of incident light; an A/D converter that performs A/D conversion on the pixel signal; and a D/A conversion circuit that generates a reference signal to be used by the A/D converter. The D/A conversion circuit includes a first buffer circuit that outputs a base voltage VTOP for generating the reference signal, and the first buffer circuit includes a differential pair circuit including a first transistor and a second transistor, and a suppression circuit that suppresses a variation in the base voltage by canceling out a characteristic difference between the first transistor and the second transistor.

Abstract: The technology disclosed herein provides a method including determining an acceptable parameter rate for a dual reader storage device having dual readers, identifying one of the dual readers as the preferable reader, comparing an actual parameter rate of the storage device to the acceptable parameter rate of the storage device, and in response to determining that the actual parameter rate is below the acceptable parameter rate, operating the storage device using only the preferable reader. In one implementation, the parameter rate is bit-error rate (BER) of the dual readers.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, an electric power supply section, a control section, and an address storage section. The control section reads data from the magnetic disk by means of the read head on the basis of the address stored in the address storage section at predetermined timing, and writes the read data to the magnetic disk by means of the write head without suppressing the magnetic field range.

Abstract: Aspects of the present disclosure provide various magnetic recording slider structures and fabrication methods that can reduce head overcoat (HOC) thickness without significantly reducing the lifetime and reliability of a slider by using a protective cap placed on preselected locations on the outermost surface or HOC of the slider. A slider includes a writer comprising an energy-assisted recording element. The writer is configured to store information on a magnetic medium using the energy-assisted recording element. The slider includes a head overcoat (HOC) layer providing an outermost media facing surface. The slider further includes a protective cap positioned on the HOC layer to at least partially cover the energy-assisted recording element, the protective cap including a preselected shape configured to protect the energy-assisted recording element.

Abstract: According to one embodiment, a magnetic disk device comprises a magnetic disk, a magnetic head, a monitoring unit, and a control unit. When carrying out write of data to a first track, if an absolute difference between a light output monitored by the monitoring unit at the time of write and a light output monitored last time by the monitoring unit exceeds a predetermined value, the control unit controls a position of a write head and writes data again to the first track or a second track one track before the first track.

Abstract: According to one embodiment, a disk device includes a plurality of recording media, a plurality of magnetic heads, a plurality of blades, and a housing. The recording medium has a recording surface, is rotatable around a rotation axis extending in an axial direction intersecting the recording surface, and is aligned in the axial direction. The magnetic head is configured to read and write information from and to the plurality of recording media. The plurality of first blades forms a spoiler, and the first blades of the plurality are located in a plurality of gaps provided between the plurality of recording media. The housing is provided with an inner chamber in which the plurality of recording media, the plurality of magnetic heads, and the plurality of first blades are accommodated. The number of first blades is smaller than the number of gaps.

Abstract: A motor driving system includes motor driving circuitry configured to operate an electric motor. The system further includes a controller that is configured to send a signal to energize the electric motor and to measure a back electromotive force voltage of the electric motor. The controller is further configured to determine a temperature value based on the measured back electromotive force voltage using a back electromotive force voltage mapping that maps back electromotive force voltages to temperature values. The controller is further configured to determine an expected winding resistance value based on the determined temperature value using a resistance mapping that maps winding resistance values to temperature values. The controller is further configured to measure a winding resistance of the electric motor, to compare the measured winding resistance of the electric motor to the expected winding resistance value, and to output a match result indication based on the comparison.

Abstract: A method for writing servo information in a disk drive that includes a write head and one or more recording surfaces includes: writing a first portion of a first spiral with the write head on a first recording surface of the one or more recording surfaces while controlling a radial position of the write head with a controller that is configured with a first set of controller parameter values; after the read head crosses a second spiral formed on a second recording surface of the one or more recording surfaces, determining a radial position error for the write head based on information associated with the second spiral; and in response to the radial position error exceeding a disturbance threshold value, writing a second portion of the first spiral with the write head while controlling the radial position of the write head with the controller while the controller is configured with a second set of controller parameter values.

Abstract: A fall detection and identification system includes a tag worn by a user and a server. The tag collects acceleration data from one or more sensors embedded within the tag and transmits the data to the server. The server receives the data from the tag and performs an analysis on the data to detect and identify a fall. The analysis includes determining a change in acceleration of the user over the time window based on the acceleration data; comparing the change in acceleration of the user against one or more thresholds; and determining a status of the user based on the comparison of the change in acceleration of the user against the one or more thresholds.

Abstract: A system includes a substrate, a first and a second magnetic field sensor, and a computing device communicatively coupled to the first and second magnetic field sensors. The substrate has a surface encoded with a magnetic pattern sequenced along a direction of movement of the substrate. The magnetic pattern includes a data pattern that indicates a position of the substrate along the direction of movement and a clock pattern interleaved and substantially colinear with the data pattern that indicates a plurality of clock transitions. The computing device is configured to receive, from the first and second magnetic field sensors positioned above the magnetic pattern, a plurality of magnetic field signals detected from the magnetic pattern. The computing device is configured to determine, based on the plurality of magnetic field signals, the position of the substrate and output the position of the substrate.

Abstract: A method for collecting position information in a disk drive having a read head and a disk with a set of spirals formed thereon includes: while the read head crosses a first spiral included in the set of spirals, opening a first frame integration window; while the first frame integration window is open, generating first signals with the read head as the read head crosses over a first set of magnetic transitions; closing the first frame integration window; after closing the first frame integration window, generating second signals with the read head as the read head crosses over a second set of magnetic transitions; and determining a radial position of the read head by integrating amplitudes of the first signals, wherein the first set includes magnetic transitions having a first polarity, and the second set includes two or more magnetic transitions having a second polarity.

Abstract: An integrated circuit includes a read/write channel and a servo controller. The read/write channel is configured to: determine, in connection with a first path, respective read errors associated with N number of the data sectors; estimate respective offset positions of the N number of the data sectors; and generate a second path based, at least in part, on the respective estimated offset positions. The servo controller is configured to cause adjustment of a position of a read transducer based on the second path.

Abstract: According to one embodiment, a magnetic disk device includes a first disk including a first data sector, a second disk including a second data sector, a first head including a first read head, a second head including a second read head, a first controller that stops write operations of both the first head and the second head based on first data sector position error information obtained by reading and demodulating the first data sector by using the first read head, and a second controller that stops the write operations of both the first head and the second head based on second data sector position error information obtained by reading and demodulating the second data sector by using the second read head.

Abstract: A method for writing repeatable run-out (RRO) data, to surfaces of a rotating magnetic storage medium in a storage device having two read channels, includes detecting, with a first head, using a first read channel, a servo sync mark (SSM) on a first track on a first surface, establishing a recurring servo-gating signal at a successive fixed interval from the SSM, detecting, with the first head, servo signals from the first track on occurrence of the recurring servo-gating signal, processing the servo signals from the first track, to generate first positioning signals for positioning the first head relative to the first track, following a similar procedure with a second read channel having a second head to generate second positioning signals for the second read head, and writing first and second RRO data to servo wedges of the first and second tracks according to the respective positioning signals.

Abstract: According to one embodiment, a magnetic disk device includes a first disk, the second disk, and a first head which writes and reads to the first disk, a second head which writes and reads to the second disk, and a controller which calculates an estimated position at which the second head is estimated to be disposed on the second disk based on first relative position information related to a relative position in a radial direction between the first head and the second head when the first head is switched to the second head.

Abstract: A data storage device is disclosed comprising a head actuated over a disk. A spiral track is written on the disk, and a disk locked clock (DLC) is synchronized to the spiral track. The spiral track is read to generate a spiral track crossing signal, and the spiral track crossing signal is processed to generate a position error signal (PES) representing a position of the head over the disk. When the DLC indicates a first part of the spiral track crossing signal is corrupt, the corruption is compensated in order to generate a compensated PES. While servoing the head over the disk based on the PES, a plurality of concentric servo sectors are written on the disk based on the DLC.

Abstract: A storage device includes a controller that determines a degree of data degradation for a data track targeted by a pending read command and sets a head/media clearance parameter for execution of the read command based on the determined degree of data degradation for the data track, the head/media clearance parameter providing for a greater head-media separation when the determined level of degradation is lower than when the determined level of degradation is higher.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a heater a control section. When making the magnetic head carry out the seek operation from the first position to the second position, the control section starts application of a first voltage to the heater while the seek operation is carried out and, after application of the first voltage, makes the voltage to be applied to the heater a second voltage greater than the first voltage before the magnetic head is positioned to the second position and write of data is started by the magnetic head.

Abstract: According to one embodiment, there is provided a hard disk drive including a first recording surface, a second recording surface, a first magnetic head, a first actuator and a second actuator that move the first magnetic head, a second magnetic head, a third actuator and a fourth actuator that move the second magnetic head, a fifth actuator that moves the second actuator and the fourth actuator, a drive circuit that implements at least one of a first mode in which the second actuator and the fourth actuator operate differently from each other or a second mode in which the first and third actuators operate differently from each other, and a controller that controls the drive circuit.

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.