Abstract: A system reads data from a magnetic storage media. A read head reads data from the magnetic storage media and produce an analog signal. A variable gain amplifier amplifies the analog signal. An offset adjust module substantially centers the amplified analog signal to a midscale. A Magneto Resistive Asymmetry (MRA) correction module MRA corrects the amplified analog signal. A Continuous Time Filter (CTF) compensation module processes the amplified analog signal. An Analog to Digital Converter (ADC) samples the amplified analog signal based upon a control signal to produce a digital signal. A Disk Lock Clock (DLC) system produces the control signal to the ADC. The control signal is representative of a frequency offset caused by at least one servo wedge rate error. A Finite Impulse Response (FIR) filter module filters the digital signal. A sequence detector processes the digital signal and detects a bit sequence from the digital signal.

Abstract: According to one embodiment, a head slider, includes: a slider body; an insulating nonmagnetic film configured to be laminated on an air outflow side end face of the slider body; a magnetoresistive effect film configured to be buried in the nonmagnetic film; first and second wiring patterns configured to be buried in the nonmagnetic film and connected to the magnetoresistive effect film; a third wiring pattern configured to be buried in the nonmagnetic film and connected to the first and second wiring pattern in parallel to the magnetoresistive effect film; and a switch element configured to be buried in the nonmagnetic film and change conductivity of the third wiring pattern between conduction and non-conduction.

Abstract: According to one embodiment, a magnetic disk apparatus includes a patterned disk, a slider, two read heads, a write head, and a drive circuit. The patterned disk has a magnetic recording surface on which bit patterns are arranged concentrically. The slider is located near the magnetic recording surface, and moves relatively to the magnetic recording surface. The read heads are arranged along a medium running direction at an end of the slider, and read magnetic data from the magnetic recording surface. The write head is located between the read heads, and records magnetic data to the bit patterns. The drive circuit drives the write head at a timing based on a period from when one of the read heads located upstream in the medium running direction reads magnetic data until the other located downstream reads the magnetic data at the same position on the magnetic recording surface.

Abstract: According to one embodiment, a control method for a magnetic disk device includes writing data by varying a phase of the array period of the plurality of magnetic elements or a phase of the time period of the recording signal in one section of the track from a corresponding phase in another section of the track, reading a reproduction signal from the track, and determining a phase shift between the array period of the plurality of magnetic elements and the time period of the recording signal, based on a reproduction signal read from the one section and a reproduction signal read from the other section. In another embodiment, a magnetic disk includes a track in which magnetic elements are magnetically separated and arranged in an array period, and a phase of the array period in one section is different from a phase in another section of the track.

Abstract: A storage device controlling device includes: a head sector generation section that creates predetermined information different from control information to be read out first from plural storage media; an input/output section that writes the control information into a head sector on the storage media; a reception section that receives an access request from outside; and a conversion section that converts a first sector number as a sector number on the plural storage media into a second sector number as a sector number other than that of the head sector on the plurality of storage media, based on a predetermined conversion method, the first sector number being designated by the access request, and the input/output section further accesses the plural storage media at the second sector number.

Abstract: An information storage device includes a magnetic track and a pinning element for pinning the magnetic domain wall. The magnetic track includes a plurality of magnetic domains and a magnetic domain wall arranged between each pair of adjacent magnetic domains. The pinning element is configured to apply a magnetic field to pin the magnetic domain wall to the magnetic track. The magnetic field may have the same magnetization direction as the magnetic domain wall.

Abstract: According to one embodiment, in a controller of a servo system that performs positioning control of a head by feedback control includes a generating module and a notch filter. The generating module compares a target position and position information decoded from data read by the head from a recording medium to generate a position error signal. The notch filter performs notch filter processing to remove machine vibration of a head driving module on the position error signal. The transfer function H(s) of the notch filter is set to H(s)=[{s2+2k??s+?2}/{s2+2??s+?2}]·[(?1s+1)] where s is a Laplace operator, k is a constant, ?1 and ?2 are time constants, ? is a damping constant, and ? is a notch frequency.

Abstract: A magnetic head-positioning servo system is provided to accurately test a magnetic disk with a track written in advance, by providing two fine actuators. The second fine actuator, to which a magnetic head is attached, is mounted on the first fine actuator. The second fine actuator has a larger generating displacement than a generating displacement of the first fine actuator, and lets the magnetic disk to follow the eccentricity of the track. In this way, the positioning accuracy can be increased.

Abstract: A magnetic storage apparatus includes a recording medium having a first area in which servo information for controlling a magnetic head is stored, and a second area in which correction information for correcting the servo information is stored, an amplifying part configured to amplify a reproduced signal obtained by reproducing information recorded in the storage medium by the magnetic head, and a control part configured to define a gain of the amplifying part on the basis of an amplitude of a first reference signal obtained by reproducing a first waveform for amplitude measurement stored in the first area and cause the amplifying part to amplify a first reproduced signal obtained by reproducing the servo information and being configured to define the gain of the amplifying part on the basis of an amplitude of a second reference signal obtained by reproducing a second waveform for amplitude measurement stored in the second area and cause the amplifying part to amplify a second reproduced signal obtained by re

Abstract: A storage apparatus includes a controller circuit controlling the operation of a head actuator for moving a head relative to a storage medium. The storage apparatus further includes an acceleration sensor detecting acceleration. A notch filter outputs the result of detection of the acceleration sensor to the controller circuit. A frequency setting circuit is configured to set the notch frequency of the notch filter in accordance with a resonance frequency of the acceleration sensor.

Abstract: A production method for a magnetic recording medium on which a stable lubricant layer can be formed even if unevenness remains on the surface, and the thickness of the lubricant layer is not reduced over time is provided. The method includes forming a lubricant layer (12) on a surface of a magnetic recording medium (30) by the steps of: applying, onto the surface of the magnetic recording medium (30), a first lubricant (12a) with high wettability of the surface of the magnetic recording medium (30) with respect to the lubricant; and applying a second lubricant (12b) onto the surface of the magnetic recording medium (30) onto which the first lubricant (12a) has been applied.

Abstract: According to one embodiment, a storage device includes a target track write module and a test pattern read module. The target track write module performs a write operation on a target track, which is a predetermined track intersecting a test pattern, on a storage medium to which the test pattern is written. The test pattern intersects a plurality of tracks arranged at regular intervals and is continuously arranged over the tracks. The test pattern read module reads the test pattern overwritten by the target track write module.

Abstract: A flying height control device controls a flying height of a magnetic head and reports the state of the flying height control of a magnetic disk device to a host, using self monitoring, analysis and reporting functions. A function to control a flying height by controlling the heat power of a heater element of a magnetic head is added to functions of the self monitoring, analysis and reporting. And self recovery of the read performance is performed by correcting the heater power, and the heater power correction state using this function is reported to the host. Before data is lost, processing to avoid data loss can be started, and this function can be implemented simply by adding the heater power correction function since data of the self monitoring, analysis and reporting functions is utilized, thereby enabling easy installation.

Abstract: A flying height control device controls a flying height of a magnetic head, while preventing unnecessary execution of flying height control when read performance drops. A control circuit, which controls the flying height by controlling the heat power of a heater element of a magnetic head, checks the read performance, detects a drop in read performance, then judges and discerns which the cause of the drop in read performance is in the magnetic head and the magnetic disk, and executes the flying height control by the heat power correction processing when judging that the cause of the drop in read performance is in the magnetic head. Thus unnecessary adjustment while the magnetic disk device is operating is prevented.

Abstract: The present invention provides a magnetic recording medium that has sufficient recording/reproducing characteristics and good write characteristics and can correspond to high recording density, and a method of manufacturing the same. A magnetic recording medium 1 includes a plurality of magnetic recording patterns 2 that is magnetically separated from each other. Each of the magnetic recording patterns 2 includes a low-coercivity region 2a and a high-coercivity region 2b having a coercivity higher than the low-coercivity region, and the high-coercivity region 2b is arranged at the center of the low-coercivity region 2a in a plan view.

Abstract: One embodiment of the invention includes a voice coil motor (VCM) drive system. The system includes a VCM configured to move a read/write head across a magnetic disk in response to a current flow through the VCM. The system also includes a VCM output stage configured to direct the current through the VCM in one of a first direction corresponding to retraction of the read/write head and a second direction corresponding to extension of the read/write head in response to switching control signals. The system further includes a retract controller configured to control a retraction velocity of the read/write head by generating the switching control signals to provide the current in the first direction to increase the retraction velocity of the read/write head and to provide the current in the second direction to decrease the retraction velocity of the read/write head during a retraction mode of the VCM drive system.

Abstract: A magnetic disk device includes a magnetic storage medium including a surface coated with a first coating layer material having an elementary composition, and a magnetic head including a surface coated with a second coating layer material having the elementary composition.

Abstract: A disk drive including a delay circuit to provide a delayed reset signal is disclosed. The disk drive includes a head to perform write and read operations to and from a disk and a disk controller that is coupled to the head to control the write and read operations performed by the head. The disk drive further includes: a power loss detection circuit to detect a power loss and to generate a reset signal in response to the power loss; a reset power line coupled to the disk controller and the power loss detection circuit to provide a non-delayed reset signal to the disk controller; and a delay circuit coupled to the reset power line wherein the delay circuit delays the reset signal to provide a delayed reset signal.

Abstract: A method for manufacturing a magnetic recording medium includes the steps of depositing a magnetic layer on at least one of surfaces of a nonmagnetic substrate and injecting atoms partially in the magnetic layer, thereby demagnetizing parts having admitted the injected atoms or imparting amorphousness thereto, to form a magnetically separated magnetic recording pattern. The step of injecting includes the steps of applying resist to the at least one surface subsequent to the step of depositing, partially decreasing a thickness of the resist and irradiating a surface of the resist with atoms, thereby inducing partial injection of the atoms to the magnetic layer through portions of the resist decreased in thickness.

Abstract: According to one embodiment, a storage device that reads data from and writes data to a recording medium, which is rotationally driven by a motor, by a head, includes a ground disconnector, a motor voltage application module, and a Coulomb force detector. The ground disconnector disconnects a connection between the motor and ground. The motor voltage application module applies voltage to be supplied to the motor. The Coulomb force detector detects read output while the motor voltage application module applies voltage to the motor. The Coulomb force detector then calculates, based on the read output, an amount of change in floating height of the head to read data from or write data to the recording medium to detect the magnitude of Coulomb force generated by electrical charging of the recording medium based on the applied voltage and the amount of change in floating height of the head.

Abstract: An information recording and reproducing apparatus 1 having a high efficiency of information transfer includes one or more recording media forming a plurality of recording surfaces, a plurality of heads respectively disposed on the recording surfaces, a first actuator for supporting the heads and moving the heads uniformly, a plurality of second actuators provided one for an associated one of the heads, the second actuators moving the heads independently relative to the first actuator, recording processing circuits for simultaneously outputting recording signals, and reproducing processing circuits simultaneously supplied with reproduced signals read out by the heads to reproduce information from the reproduced signals.

Abstract: There is provided a recording head 2 including a slider 20, a recording element 21 fixed to a side surface of the slider 20 on the side of an outflow end and having a main magnetic pole 32 and an auxiliary magnetic pole 30 which generate a recording magnetic field; and a spot light generating element 22 including a core 40 having a reflecting surface 40a configured to reflect a luminous flux L introduced from one end side to the other end side in a direction different from the direction of introduction and a luminous flux condensing unit 40b configured to generate a spot light R by propagating the reflected luminous flux to the other end side while condensing the same, and a clad 41 configured to confine the core in the interior thereof, and fixed adjacently to the recording element in a state in which the other end side is faced toward a magnetic recording medium; and luminous flux introducing means 4 arranged in parallel with the slider and allows the luminous flux to be introduced from the one end side int

Abstract: A magnetic storage apparatus has a reproducing head to reproduce information from a perpendicular magnetic recording medium that is recorded with servo information, eccentricity correction data and read/write data. The apparatus further has a filter part to filter a reproduced output of the reproducing head by filtering the servo information which has a differentiated waveform by a non-differentiating characteristic and by filtering the eccentricity correction data and the read/write data which have rectangular waveforms by a differentiating characteristic, a demodulating part to demodulate the servo information, the eccentricity correction data and the read/write data that are filtered by the filter part, and a servo system to carry out a control process including an eccentricity control based on the servo information and the eccentricity correction data that are demodulated.

Abstract: A patterned media type magnetic storage medium has separated magnetic dots formed a data area having a first magnetic dots and a servo area. The micro position detection portion in the servo area is constructed with first and second dot arrays having a different number of second magnetic dots in the circumference direction and face with the center line that the first magnetic dots of the data area in the magnetic storage medium are disposed, as the axis. The area of the magnetic dot constituting the micro position detection portion of the servo area is small, so the coercive force of the servo area increases. The frequency is changed depending on the number of magnetic dots, and the phase is changed depending on the position of the magnetic dot array in the radius direction with the center line as an axis.

Abstract: A method for writing servo patterns onto a disk of a disk drive. The method includes providing a plurality of different drive currents for an actuator while pushing the actuator into a crash stop defining a swing range of the actuator. The method also includes performing a write operation for at least one of the plurality of different drive currents to write a plurality of servo pattern tracks including a plurality of separate servo pattern sectors. Furthermore, the method includes gradually changing a drive current of the plurality of different drive currents while pushing the actuator into the crash stop so as to gradually move a read element in searching for a servo pattern track to a radial position different from a radial position of the write element. Moreover, the method includes positioning the read element at one of the plurality of servo pattern tracks.

Abstract: Planar magnetic heads and methods of making the same using a built-up approach and thru-hole via technology to achieve a true planar head. A head may comprise a substrate having conductive thru-hole vias extending therethrough, a first magnetic layer deposited and patterned on the substrate, a first insulation layer deposited and patterned on the first magnetic layer, a conductive coil layer deposited and patterned on the first insulation layer and connected to the conductive thru-hole vias, a second insulation layer deposited and patterned on the conductive coil layer, vias patterned into the insulation layer extending to the first magnetic layer, a second magnetic layer deposited in the vias, and a third magnetic layer deposited and patterned on the second insulation layer and second magnetic layer. The third magnetic layer may be connected to the first magnetic layer through the second magnetic layer deposited in the vias of the insulation layers.

Abstract: According to an aspect of the embodiment, an MPU obtains, as a first gain value from a RDC, a gain value of a servo signal when data is read from a magnetic storage medium, and obtains, as a second gain value from the RDC, the gain value of the servo signal when data is written to the magnetic storage medium. The MPU controls supplied power for controlling flying height of the magnetic head when data is written to the magnetic storage medium based on a result of the comparing between the first gain value and the second gain value.

Abstract: A magnetic disk apparatus includes a magnetic disk, and a magnetic head facing the magnetic disk. The magnetic disk apparatus also includes a thermal deforming member and a thermal deformation controller. The thermal deforming member is provided in the magnetic head for thermally deforming the magnetic head to change the projecting amount of the magnetic head toward the magnetic disk. The thermal deformation controller controls the driving power supplied to the thermal deforming member, so that the falling characteristic of the driving power in transition from an on-state to an off-state is gentler in inclination than the rising characteristic of the driving power in transition from an off-state to an on-state.

Abstract: A magnetic disk device includes a VCM coil that controls the movement of a head for recording or reproducing information onto and from a rotating magnetic disk, and an airflow guiding unit that guides an airflow occurring by the rotation of the magnetic disk toward the VCM coil when the temperature of the VCM coil exceeds a limit temperature defined in advance.

Abstract: A floating amount of the magnetic head is controlled. The disk device has a temperature or humidity sensor and a controller. The controller monitors the detected temperature or humidity and retracts the magnetic head to an area where the circumferential speed is fastest, such as at the outermost side of the flying guarantee area of the magnetic disk, if the temperature or humidity is a predetermined value or more. The lubricant transferred from the magnetic disk to the magnetic head can be removed, and the increase of the flying height of the magnetic head can be suppressed.

Abstract: A magnetic disk apparatus includes a magnetic disk, a magnetic head, a reverse-pulse detector, and a re-magnetizer. The magnetic disk includes a data recording area and a servo-pattern area. The magnetic regions of the servo-pattern area have been pre-magnetized in the same direction or pre-magnetizing direction. The magnetic head is arranged to reciprocate radially of the magnetic disk. The reverse-pulse detector is provided for reading the servo-pattern area with the magnetic head before data recording or reproducing with respect to the data recording area is performed. The reverse-pulse detector detects, from servo reproduction signal pulses, reverse pulses corresponding to the reversal of magnetization direction relative to the pre-magnetizing direction. The re-magnetizer causes the magnetic head to perform the re-magnetizing of the magnetic regions in the servo-pattern area when the count of reverse pulses is not smaller than a threshold number.

Abstract: A method for the production of a magnetic recording medium includes the steps of forming a magnetic layer on a nonmagnetic substrate, injecting atoms into portions of the magnetic layer to cause the portions to be demagnetized or allowed to acquire amorphousness, thereby forming a magnetically separated magnetic recording pattern, the step of injecting atoms including the steps of applying to a surface of the formed magnetic layer an SOG film as a resist, partly removing or thinning the resist, and irradiating the surface with atoms, thereby partly injecting atoms into the magnetic layer through the portions of the magnetic layer from which the resist is removed or in which the resist is thinned.

Abstract: According to one embodiment, a position control apparatus includes: a digital control module that performs position control including disturbance adaptive control with a predetermined sampling period with the use of a control constant, in accordance with a position error between a target position and a current position of the object; and a table that stores the control constant corresponding to a value of sin(?T/2), wherein the digital control module determines a control value of the actuator in accordance with the position error, calculates the value of sin(?T/2) according to an adaptive law from a signal based on the position error, reads the corresponding control constant from the table in accordance with the calculated value of sin(?T/2), and updates the control constant.

Abstract: A magnetic storage medium is formed of magnetic nanoparticles that are encapsulated within carbon nanotubes, which are arranged in a substrate to facilitate the reading and writing of information by a read/write head. The substrate may be flexible or rigid. Information is stored on the magnetic nanoparticles via the read/write head of a storage device. These magnetic nanoparticles are arranged into data tracks to store information through encapsulation within the carbon nanotubes. As carbon nanotubes are bendable, the carbon nanotubes may be arranged on flexible or rigid substrates, such as a polymer tape or disk for flexible media, or a glass substrate for rigid disk. A polymer may assist holding the nano-particle filled carbon-tubes to the substrate. Magnetic fields may be applied to draw the carbon nanotubes into data tracks and orient the carbon nanotubes within the data tracks. Read/write devices and methods create servo sectors and rotational markers on the magnetic storage medium as well as data.

Abstract: A disk storage device is disclosed including at least one disk unit, a first processor to control the disk unit making possible access of its data and a second processor communicating with the first while operating a file system for disk access and at least one network interface. The network interface is operated to receive an access request. The file system is operated based upon the access request to organize access of the data to create an access response. The disk units are disclosed as a hard disk unit and/or a solid state data unit. The disk storage unit may further include at least one multi-media interface and/or at least one serial interface and/or a Bluetooth interface. An integrated circuit and an assembled circuit board are disclosed including both processors.

Abstract: According to one embodiment, a position control apparatus includes: a digital control module that performs position control including disturbance adaptive control with a predetermined sampling period using a control constant, in accordance with a position error between a target position and a current position of the object; and a table that stores the control constant corresponding to a value of sin(?T) or cos(?T), wherein the digital control module is configured to determine a control value of the actuator in accordance with the position error, calculates the value of sin(?T) or cos(?T) according to an adaptive law from a signal based on the position error, reads the corresponding control constant from the table in accordance with the calculated value of sin(?T) or cos(?T), and updates the control constant, to perform the position control including the disturbance adaptive control.

Abstract: According to one embodiment, a position control apparatus includes: a digital control module that performs position control including disturbance adaptive control with a predetermined sampling period using a control constant, in accordance with a position error; and a table that stores the control constant corresponding to one of values sin(?T), cos(?T), and sin(?T/2), wherein the digital control module determines a control value of the actuator in accordance with the position error, calculates a value of one of estimated errors of sin(?T), cos(?T), and sin(?T/2) according to an adaptive law from a signal based on the position error, multiplies the calculated estimated error by an adaptive gain in accordance with a value of the angular frequency ?, updates one of the values, reads the corresponding control constant from the table based on the updated value, and updates the control constant.

Abstract: Provided is a recording medium onto which a plurality of tracks that constitute a unit as one unit of signal processing for reproducing data are recorded, each of the plurality of tracks being recorded with at least data and, as a preamble necessary for controlling the reproduction of the data, a separation pattern necessary for detecting a positional relationship between a reproducing head and the plurality of tracks in a track width direction and synchronization patterns for synchronization processing, the synchronization patterns being recorded in front and rear of the separation pattern in a running direction of the plurality of tracks.

Abstract: An information storage apparatus includes a housing; a recording medium in which information is recorded, disposed in the housing; a head that records/reproduces information onto/from the recording medium by making contact with or approaching to a surface of the recording medium; a head holding member for holding the head, being rotatable about a predetermined axis and moving the head along the recording medium; a driving section that drives the head holding member to rotate about the axis; a rotation restricting member disposed in a position where the head holding member collides, and that restricts a rotation area of the head holding member; a temperature change detecting section that detects temperature change in the housing; and a drive controlling section that causes the driving section to drive the head holding member to collide with the rotation restricting member, when a detection result by the temperature change detecting section indicates temperature change.

Abstract: According to an aspect of the embodiment, a magnetic recording apparatus has a sensor detecting a first signal including disk flutter and arm flexural vibration and a sensor for detecting a second signal only including the arm flexural vibration. The magnetic recording apparatus obtains the frequency component of disk flutter based on the first signal and second signal, and executes the control of positioning a head based on the obtained frequency component of the disk flutter.

Abstract: According to one embodiment, an adjusting element adjusts a dynamic flying height of a head lying over a disk in accordance with the power supplied to it. A calculation module calculates the power to supply to the adjusting element, from a barometric pressure detected by a barometric pressure sensor. A failure detection module detects failure of the barometric pressure sensor. An unload controller predicts an abnormal dynamic flying height of the head from the failure detected and then instructs the unloading of the head away from the disk.

Abstract: A disk drive power system is described. The system is operable such that during power interruption, the system taps electric power by rectifying the back-EMF generated across each winding of a DC motor and supplying power to a voice-coil motor to park a read/write head safely away from an associated magnetic disk surface.

Abstract: A storage apparatus includes: a magnetic recording disk having discrete magnetic dots forming circular tracks coaxial with a rotation axis; a rotary actuator supporting a head slider facing the magnetic recording disk, the rotary actuator coupled to a pivot bearing shaft parallel to the rotation axis; and read and write elements separately-located at a gap distance on a given straight line. A distance between two circular tracks depends on the gap distance and the angle between one circular track of the two circular tracks and the given straight line.

Abstract: An upward warp of a terminal pad of a flexible cable which is kept horizontal by a suction head is prevented by a pressing arm which contacts with an upper surface of a rear portion of the flexible cable.

Abstract: A magnetoresistive head is provided with high reliability and produced at a high yield rate. The magnetoresistive head includes a lower magnetic shield layer, an upper magnetic shield layer, a magnetoresistive effect film, and means for causing a current to flow in the direction of the thickness of the magnetoresistive effect film. The magnetoresistive effect film is provided between the lower magnetic shield layer and the upper magnetic shield layer. The magnetoresistive effect film is composed of a fixed layer, a non-magnetic layer, an insulating barrier layer and a free layer. The four layers of the magnetoresistive effect film are formed in this order. The insulating barrier layer is an oxide layer containing at least one of titanium and nickel.

Abstract: According to one embodiment, a head positioning control method comprises suppressing a first frequency component and increasing a second frequency component of a control signal for moving a head to a desired position over a magnetic disk, and moving the head to the desired position over the magnetic disk by an actuator based on the control signal.

Abstract: A posture adjustment method of magnetic heads includes a method in which a magnetic head initial position adjustment apparatus 11 measures an initial position of the magnetic head 1 which was moved and adjusted, and writes the initial position into an adjustment position information shared apparatus 10, a magnetic head posture adjustment apparatus 12 reads from the adjustment position information shared apparatus 10, and information of an adjustment amount given to the magnetic head 1 when the magnetic head 1 is moved and adjusted to a final position is written in the adjustment position information shared apparatus 10, and an adjustment position as a current position of the magnetic head 1 is calculated using the initial position information and the adjustment amount information, and a method in which it is detected that one of the magnetic heads 1 reached a moving limit at which movement and adjustment of the magnetic head 1 becomes impossible, and other magnetic heads 1 which do not reach the moving limit

Abstract: A method of controlling the position of a read/write head relative to a disk in a test apparatus is disclosed. The test apparatus has a positioner for positioning the head. The positioner has a sensor to measure the actual position achieved by the positioner. The method includes generating a sensor signal measuring the actual position achieved by the positioner; generating a position error signal of the head relative to the disk detected at the head; high pass filtering the head position error signal and low pass filtering the sensor signal so that there is substantially no overlap in frequency between them; and, deriving a low frequency head error signal from the head position error signal corresponding to any drift of the head.

Abstract: Provided is a thin-film magnetic head that can stably generate electromagnetic field with a desired frequency, even under the existence of significantly strong write field with frequently reversed direction. The head comprises an electromagnetic-field generating element between the first and second magnetic poles. The electromagnetic-field generating element comprises a spin-wave excitation layer provided adjacent to the first magnetic pole and having a magnetization with its direction varied according to external magnetic fields, for generating an high frequency electromagnetic field by an excitation of spin wave. And a magnetization of the spin-wave excitation layer is biased in a direction substantially perpendicular to its layer surface by a portion of magnetic field generated from the first magnetic pole, and pin-wave excitation current flows in the electromagnetic-field generating element in a direction from the second pole to the first pole.

Abstract: A head flying height control method includes the steps of: detecting contact of a head having a heater with a corresponding storage medium, and associating the amount of heat generated by the heater when the contact is detected with a situation where the flying height of the head is zero; measuring at least one type of characteristics that are the saturation characteristics of the read margin of data written on the storage medium with the head, and the saturation characteristics of the electromagnetic conversion characteristics of the head, the measuring step being carried out every time the flying height of the head is varied, with a reference being the situation where the flying height of the head is zero, the current used for writing the data being a parameter in the saturation characteristics; and adjusting the flying height of the head, based on the measurement result of the measuring step.