Abstract: A device and method for testing a slider of a head-gimbal assembly during disc drive manufacturing. The device includes a test disc, an actuator arm and a control module. The test disc has a first circumferential area for detecting contact between the slider and the test disc and a second circumferential area for burnishing sliders that contact the first circumferential area as the test disc rotates at or above the predetermined velocity. The head-gimbal assembly is affixed to the actuator arm such that the slider is operable to move between an inner diameter and an outer diameter of the test disc. The control module controls the movement of the actuator arm, and thus the slider, relative to the test disc. The control module monitors the slider-disc interface for contact therebetween. If contact is detected, the slider is either burnished or the head-gimbal assembly is discarded altogether.

Abstract: A method for inspecting magnetic characteristics of a thin film magnetic head that is arranged in a row bar includes: a step of preparing a row bar having sliders including a thin film magnetic head formed therein and lapping guides having magnetoresistance effect; a step of preparing a magnetic field applying row bar having first and second magnetic field applying elements; a first positioning step in which said magnetic field applying row bar is arranged opposite to said row bar; a second positioning step in which a relative movement between said magnetic field applying row bar and said row bar is made so that at least one of said lapping guides exhibits a largest output voltage; and a measurement step in which a relationship between the intensity of the magnetic field and an output voltage of a magnetic field sensor is obtained.

Abstract: A magnetic head testing apparatus having the function of evaluating pin holes in a tunnel barrier layer of a TMR element by a non destructive inspection is disclosed. The testing apparatus comprises a temperature control unit which sets a circumferential temperature of a TMR element, a bias electric current control unit which applies an electric current for measuring a resistance value, an element resistance measuring unit and a CPU which calculates a temperature coefficient. The CPU determines a pin hole state in the tunnel barrier layer based on the temperature coefficient.

Abstract: According to an example embodiment, there is a magneto-resistive (MR) sensor having an operation mode and a test mode. The MR sensors comprise a first plurality of first MR elements and a second plurality of second MR elements. A first signal processing unit is connected to the first plurality of first MR elements for generating a first output signal; the first output signal has a first phase. As second signal processing unit is connected to the second plurality of second MR elements for generating a second output signal; the second output signal has a second phase. There is a third signal processing unit or processing the first and second output signals; the third signal processing unit is adapted to activate one of the operation mode and the test mode on the basis of the first and second output signals. When the first and second plurality of first and second MR elements are exposed to a homogeneous magnetic field, the third signal processing unit is adapted to activate the test mode.

Abstract: A magnetic head assembly having a mounting base in which a mounting hole having a protruded peripheral edge is formed is easily mounted on a head clamp table positioning the magnetic head assembly by fitting the mounting hole on a boss pin or a receiving hole of a tray, with a pin or a hole on a mounting table and with a positioning pin on a head clamp table and positioning a suction collet with using a boss pin or a receiving hole of a tray as references, and sucking the mounting base of the magnetic head assembly by a handling robot without requiring high positioning accuracy.

Abstract: A high-resolution magnetic encoder system includes a magnetic resistive sensor, a fixed suspension, and a mechanism. The magnetic resistive sensor is mounted to the fixed suspension above a magnetic medium having at least one magnetic track. The fixed suspension is attached to the mechanism, such as a housing, a substrate, and/or an electronic board. The sensor is adapted to perform a relative movement with respect to and in close contact to the surface of the magnetic medium. The magnetic medium may be protected by an overcoat layer. The magnetic resistive sensor may be Giant Magnetic-Resistive (GMR) sensor and/or a Tunneling Magnetic-Resistive Sensor (TMR).

Abstract: It is an object of the present invention to provide a method for investigating magnetic domains, the method capable of easily grasping behavior of the magnetic domains in a head manufacturing process, and further to provide a testing method of a magnetic head capable of evaluating whether the writing performance of the magnetic head is good or not. The method for investigating magnetic domains comprises supplying direct current (DC) to a coil of an electromagnetic transducer provided in a magnetic head for writing data onto a magnetic recording medium; measuring an inductance of the electromagnetic transducer at each current value while varying the current value of the direct current; and investigating behavior of magnetic domains in a magnetic core of the electromagnetic transducer based on a relationship between the current values and the inductances.

Abstract: The method for testing a characteristic of a magnetic head is performed in the form of a wafer, especially in a heating state and a cooling state. The method for testing a characteristic of a magnetic head, in which a wafer including a dummy read-element having a size equal to that of a completed read-element, a product read-element and a heat conductive section being provided in the vicinity of the dummy read-element is tested as a test sample, comprises the steps of: applying an external magnetic field to the test sample; bringing a heat conducting member into contact with the heat conductive section so as to heat or cool the dummy read-element via the heat conductive section; and testing an electromagnetic conversion characteristic of the dummy read-element in a heating state or a cooling state.

Abstract: A method for inspecting magnetic characteristics of a thin film magnetic head that is arranged in a row bar includes: a step of preparing a row bar having sliders including a thin film magnetic head formed therein and lapping guides having magnetoresistance effect; a step of preparing a magnetic field applying row bar having first and second magnetic field applying elements; a first positioning step in which said magnetic field applying row bar is arranged opposite to said row bar; a second positioning step in which a relative movement between said magnetic field applying row bar and said row bar is made so that at least one of said lapping guides exhibits a largest output voltage; and a measurement step in which a relationship between the intensity of the magnetic field and an output voltage of a magnetic field sensor is obtained.

Abstract: An information storage device comprises a ferroelectric media and a cantilever including a tip extending from the cantilever toward the ferroelectric media, and a capacitive sensor formed over the cantilever. The tip applies a probe voltage to the ferroelectric media and the capacitive sensor vibrates according to a response of the ferroelectric media to the probe voltage. Circuitry determines a polarization of the ferroelectric media based on the vibration of the capacitive sensor.

Abstract: A multi-track sense magnet for use in a system for sensing the relative displacement of two elements, and including a magnetic structure that is moveable relative to detector devices for detecting movement of the magnetic structure. The magnetic structure includes at least a first track and a second track extending generally parallel to each other, each track including a plurality of sectors of alternating magnetic poles. A blocker track is located between the first and second tracks, wherein the blocker track includes a predetermined number of sectors corresponding to the number of sectors on the first track. Each sector of the blocker track is aligned with and defines an opposite magnetic pole to an adjacent sector of the first track to alter the magnetic field of the first track extending toward the second track.

Abstract: A method for testing magnetic heads formed on a wafer to detect the presence of thermal induced popcorn noise resulting from thermal fly height control. The method includes performing a quasi test on a magnetic head, the quasi test being performed over 400 or more cycles of magnetic field application. For additional test accuracy, the write head can be cycled while 400 or more cycles of magnetic field are generated.

Abstract: A method, computer-readable medium, and apparatus for measuring properties of a magnetic read head are provided. In one embodiment, the method includes providing a first and a second magnetic read head. A first dimension of the first magnetic read head is different from a corresponding first dimension of the second magnetic read head. The method further includes determining a first change in conductance of the first magnetic read head resulting from an applied magnetic field and a second change in conductance of the second magnetic read head resulting from the applied magnetic field. The first change in conductance and the second change in conductance are used to determine a change in the first dimension and the corresponding first dimension of the first and second magnetic read heads, respectively. The change in the first dimension and the corresponding first dimension results from a manufacturing process of the first and second magnetic read heads.

Abstract: A magnetic recording head tester uses closed loop control to accurately control the magnetic field that is generated to test the magnetic recording head. The closed loop control compares the value of the sensed magnetic field to the desired value of the magnetic field and adjusts the magnetic field accordingly. A magnetic field sensor used in the tester may be located in a position that has a substantially different magnetic field magnitude than is experienced by the magnetic recording head. The value of the output signal from the magnetic field sensor is correlated to the magnitude of the magnetic field at the location of the magnetic recording head through calibration. The correlation can then be used to accurately produce the desired magnitude magnetic field at the location of the magnetic recording head.

Abstract: A structure and method for performing magnetic inductance testing of write heads formed on a wafer. The structure and method allows for the effective inductive testing of magnetic write heads at wafer level even if the write heads have an inductance that is too low to be effectively measured directly. A test head is constructed having a structure similar to that of the write heads, but having a significantly higher magnetic inductance. The higher magnetic inductance of the write head can be provided by extending the shaping layer to or beyond the air bearing surface plane ABS. The inductance of the test head can be further increased by increasing the width of the portion of the shaping layer that extends to the ABS (ie. shaping layer throat) and by increasing the width of the write pole throat.

Abstract: A slider tester includes a driving unit that rotates a test medium, a set plate that detachably supports a slider as a single body, and an investigating apparatus that is electrically connected to the slider supported by the set plate and investigates the characteristics of the slider. A movable support part 30 that tiltably supports the slider is provided on the set plate. There is also provided a pressing mechanism that elastically presses the slider via the movable support part toward a surface of the medium to dispose the slider floating over the surface of the medium. The pressing mechanism includes an elastic body 56 composed of a plate spring that contacts the movable support part and elastically presses the movable support part.

Abstract: A slider tester includes a driving unit that rotates a test medium, a set plate that detachably supports a slider as a single body, and an investigating apparatus that is electrically connected to the slider supported by the set plate and investigates the characteristics of the slider. A movable support part 30 that tiltably supports the slider is provided on the set plate. There is also provided a pressing mechanism that elastically presses the slider via the movable support part toward a surface of the medium to dispose the slider floating over the surface of the medium. The pressing mechanism includes an elastic body 56 composed of a plate spring that contacts the movable support part and elastically presses the movable support part.

Abstract: A testing method of a thin-film magnetic head has an MR read head element with a multi-layered structure including a magnetization-fixed layer, a magnetization-free layer and a nonmagnetic intermediate layer or a tunnel barrier layer sandwiched between the magnetization-fixed layer and the magnetization-free layer. The method includes a step of feeding through the MR read head element a sense current, a step of measuring non-signal output versus frequency characteristics of the MR read head element over a frequency range that covers at least FMR of the magnetization-fixed layer, and a step of discriminating whether the thin-film magnetic head is a head providing high-temperature noises by comparing a frequency of a peak of the non-signal output resulting from FMR of the magnetization-fixed layer with a threshold.

Abstract: An electronic component tester characterizes electronic components such as magnetic head/media components measure performance parameters such as signal-to-noise ratio and overwrite evaluation. The electronic component tester has a tester process controller and a spectrum analyzer. The tester process controller generates calibration and control signals for the electronic component tester. The spectrum analyzer is in communication with electronic components such as magnetic head or media components to receive a response characterization signal resulting from a stimulus signal applied to the electronic components. The spectrum analyzer then determines a frequency spectrum of the response characterization signal. The spectrum analyzer is also in communication with the tester process controller for transferring the frequency spectrum to the tester process controller.

Abstract: A set of magnets, e.g., electromagnets, are used to produce an in-plane magnetic field with respect to an article under test or manufacture. The set of electromagnets includes electromagnets that are positioned above and below the plane of symmetry respectively. The bottom electromagnets may be positioned below the surface of the chuck for example. The plane of the article and/or set of electromagnets are positioned so that the plane of symmetry approximately coincides with the article. The set of electromagnets may include individual electromagnets or C-core electromagnets, which may produce magnetic fields with complementary polarities near the field of symmetry both above and below the field of symmetry. Magnetic fields with the same polarity are positioned near each other on opposite sides of the plane of symmetry to produce the in-plane magnetic field. A second set of electromagnets may be used to provide field rotation if desired.

Abstract: A quasi-static tester is disclosed. The quasi static tester comprises: a mount configured to fix a head gimbal assembly in a given position; a camera configured to observe the head gimbal assembly when the head gimbal assembly is fixed in the mount, wherein the camera is used to position the head gimbal assembly in an observation position; and a magnet for performing quasi-static testing of the head gimbal assembly when the head gimbal assembly is fixed in the mount, wherein the observation position and a testing position in a uniform area of the magnet are a predetermined distance apart.

Abstract: Embodiments of the present invention include a method and System for Hard Drive component testing, particularly for magnetic recording head testing. The method of testing magnetic recording heads includes: performing a magnetic write width test (on a plurality of disk drive heads), sorting the plurality of heads into a first group and a second group based on the magnetic write width test, testing the first group with signal to noise ratio tests with adjacent tracks present under a first set of parameters, wherein the first set of parameters are based on the magnetic write width test, testing the second group with signal to noise ratio tests with adjacent tracks present under a second set of parameters, wherein the second set of parameters are based on the magnetic write width test.

Abstract: Disclosed is a CCP-CPP-GMR head assembly which has: a CCP-CPP-GMR head that includes at least a current control layer having as a microstructure a plurality of truncated cone electric conductors with axes the same as a current direction and an insulator filling between the plurality of truncated cone electric conductors, and in which a surface on which a larger-area basal plane of the plurality of truncated cone electric conductors is greater in number is a first surface of the current control layer and a surface of an opposite side of the first surface is a second surface of the current control layer; and a sense current source providing the CCP-CPP-GMR head with a sense current that flows from the second surface to the first surface, a magnetic recording/reproducing apparatus having such a head, and a specification method of an appropriate sense current direction of the CCP-CPP-GMR head.

Abstract: An apparatus and methods for predicting and/or for calibrating memory yields due to process defects and/or device variations, including determining a model of a memory cell, identifying a subset of parameters associated with the model, determining and executing a refined model using the parameters, determining a predicted probability the simulated memory cell will be operational based on the simulated operation of the refined model, determining yield prediction information from the predicted probability, and determining the minimum number of repair elements to include in a memory array design to insure a desired yield percentage based on the yield prediction information.

Abstract: An embodiment is a circuit including 2n?1 first comparators to generate a first result by comparing data from at least two of 2n memory cells to which test pattern data are written. 2n?1 first switching circuits provide the first result or a disable signal responsive to a first switching signal. And 2n?2 second comparators generate a second result by comparing signals output from some of the 2n?1 first switching circuits. N may be a natural number greater than or equal to three.

Abstract: A method for testing the integrity of a memory with defective sections under a plurality of operating environments includes testing the memory with defective sections under a plurality of operating environments, recording results of each operating environment test, and comparing the results of the tests. If the results of are the same, the memory with defective sections is declared to have integrity. If not, the memory with defective sections is declared to not have integrity.

Abstract: A slider tester includes a driving unit that rotates a test medium, a set plate that detachably supports a slider as a single body, and an investigating apparatus that is electrically connected to the slider supported by the set plate and investigates the characteristics of the slider. A movable support part 30 that tiltably supports the slider is provided on the set plate. There is also provided a pressing mechanism that elastically presses the slider via the movable support part toward a surface of the medium to dispose the slider floating over the surface of the medium. The pressing mechanism includes an elastic body 56 composed of a plate spring that contacts the movable support part and elastically presses the movable support part.

Abstract: A storage drive implements a method for operating the storage drive between a plurality of operational modes. For a test mode of the storage drive, a write current driver circuit and a test current sensor are electrically connected to the write head, wherein the test current sensor generates a sense signal indicative of a degree of a flow of a test current through the write head to thereby facilitate a detection of any presence of an open write condition of the storage drive (i.e., any impedance condition impeding a flow of a write current through the write head). For a write mode of the storage drive, the write current driver circuit is electrically connected to the write head and the test current sensor is electrically disconnected from the write head, wherein the write head records data on a magnetic media based on a flow of the write current through the write head.

Abstract: A quasi-static tester is disclosed. The quasi static tester comprises: a mount configured to fix a head gimbal assembly in a given position; a camera configured to observe the head gimbal assembly when the head gimbal assembly is fixed in the mount, wherein the camera is used to position the head gimbal assembly in an observation position; and a magnet for performing quasi-static testing of the head gimbal assembly when the head gimbal assembly is fixed in the mount, wherein the observation position and a testing position in a uniform area of the magnet are a predetermined distance apart.

Abstract: A magnetic head and disk tester comprises a base, a spindle for rotationally supporting a magnetic disk, a carriage for supporting a magnetic head support which carries a magnetic head with a magnetic read/write element, and a dual-stage positioning system that moves the carriage in two perpendicular directions X and Y. The magnetic head support, the magnetic head and the magnetic read/write element have a common longitudinal axis Z. The head support is positioned such that the longitudinal axis Z forms a predetermined angle between 0° and 90° with respect to the Y direction. Preferably the predetermined angle is about 45 degrees. When the head is driven from one point of an inner track to a point of an outer track, the displacement of the head along X axis is relatively large and the displacement of the head along Y axis is relatively small.

Abstract: The invention includes a conductor with a first side and a second side. The conductor may be sized to have a cross-section diameter substantially similar to a Fermi wavelength of electrons in the conductor, the cross-section diameter being taken substantially perpendicular to a primary direction in which current could flow through the conductor. The conductor size may be selected so that when a magnetic field less than a threshold value is applied to the conductor, the first side of the conductor has a first magnetic state and the second side of the conductor has a second magnetic state. However, when a magnetic field of sufficient strength is applied to the magnetic conductor the first side and the second side will be caused to have the same magnetic state.

Abstract: The method of testing a magnetic head is capable of purely evaluating characteristics of the magnetic head without influences caused by external factors. The method of testing a magnetic head comprises the steps of: detecting amount of noises, which are included in output signals of a reading element of the magnetic head, a plurality of times in a state of reading no magnetic data; and comparing an amount of variation between the detected amounts of noises with a threshold value.

Abstract: When testing the quality of shield films of magnetoresistive effect heads, a method of testing and a testing apparatus can detect heads where the shield magnetic domain is susceptible to changing that could not be completely detected by conventional methods of testing that use normal magnetization. The method of testing applies an external magnetic field to a magnetoresistive effect head as external stress, measures the output voltage of the head, and repeats the applying of the external magnetic field and the measuring a plurality of times to test the quality of the shield film. The magnetic field is applied in a direction parallel to the shield film and at an angle to a floating surface of the magnetoresistive effect head. The intensity of the applied magnetic field is smaller than the coercive force of a hard bias film and larger than the coercive force of the shield film.

Abstract: A method for monitoring the operability of a slider of a disk drive includes the steps of providing a slider that includes a read/write head that magnetically interacts with a storage disk, and a slider mover that adjusts a head-to-disk spacing, controlling an electrical stimulus to the slider mover with a drive circuitry, measuring an actual electrical response from the slider mover with the drive circuitry, and comparing the actual electrical response to an expected electrical response to determine an operability status of the slider mover. Further, changes in the actual electrical response can be monitored and used to predict future failure of the slider mover.

Abstract: An electronic component includes a semiconductor chip with a chip topside, an integrated circuit, and a chip backside. The chip backside includes a magnetic layer. The electronic component further includes a chip carrier with a magnetic layer on its carrier topside. At least one of the two magnetic layers is permanently magnetic such that the semiconductor chip is magnetically fixed on the chip carrier.

Abstract: Embodiments of the present invention include a method and System for Hard Drive component testing, particularly for magnetic recording head testing. The method of testing magnetic recording heads includes: performing a magnetic write width test (on a plurality of disk drive heads), sorting the plurality of heads into a first group and a second group based on the magnetic write width test, testing the first group with signal to noise ratio tests with adjacent tracks present under a first set of parameters, wherein the first set of parameters are based on the magnetic write width test, testing the second group with signal to noise ratio tests with adjacent tracks present under a second set of parameters, wherein the second set of parameters are based on the magnetic write width test.

Abstract: A precisely machined test nest holds a single hard disk drive slider. The test nest is fabricated to contain a micro pickup coil that is positioned to be able to detect magnetic flux from a write element of the slider. The micro pickup coil has highly repeatable and controllable positioning with respect to the write element. This technique also allows local magnetic field to be applied to the read element, and its small size allows excitation at higher frequencies than are currently achievable today. The coil is lithographically defined and integrated into the test nest and used on single slider testers. The low inductance of the coil allows it to be driven at high frequencies. Its position within the test nest ensures good heat sinking and enables large current pulses to be employed.

Abstract: An apparatus for reader characterization is described. The apparatus includes a rotator for rotating a media. The media can contain a signal having a value for a function of a read/write head being assessed. The rotator is operable in conjunction with said apparatus. The apparatus also includes a proximator for proximalizing the media to the read/write head. The proximator is operable in conjunction with said apparatus. The apparatus further includes a writer operable in conjunction with said assembly. The writer writes the signal upon the media. The signal emits the value of the function. The signal is detectable by a reader of the read/write head. The apparatus additionally includes an interface operable in the apparatus for providing removable orientation of the read/write head in an assessing position. The assessing position enables a reader of the read/write head to detect the signal upon rotation of the signal through the assessing position.

Abstract: In the present invention, a coil generating DC magnetic field applied to a magnetic head is divided into two in that a first coil and a second coil, which are provided on a frame shape core. An distance of an air gap is shortened, a slider head is held on a table having a top end portion of thin thickness, while advancing and retreating the table in the direction perpendicular to the core, the head slider is inserted into the air gap from the lateral direction. Thereby, the distance of the air gap is reduced to about half of the conventional one and a reduction of inductance of the first coil and the second coil is realized.

Abstract: A probe card method, wherein a base supports a probe pin and an electromagnet. When the probe pin contacts a magnetic-sensor terminal on a chip on a wafer, magnetic force is applied to a magnetic-field sensing section in the chip.

Abstract: A method of evaluating can evaluate the bias magnetic field strength of hard films that construct a magnetoresistance effect read head, the magnetic coercivity of the hard films, and variations in the magnetic domain of shield films from measurement results for the resistance-parallel magnetic field strength characteristics. A magnetizing magnetic field is applied in a direction parallel to the air bearing surface of a magnetoresistance effect read head equipped with hard films to magnetize the hard films in a direction of a horizontal bias magnetic field applied to a free layer of the read element. After this, the resistance of the read element is detected and the resistance-parallel magnetic field strength characteristics of the read head are measured while applying a test magnetic field with increasing and decreasing intensity in a direction parallel to the horizontal bias magnetic field.

Abstract: Provided is a method for testing a head element that enables proper evaluation of the head element based on a characteristic of the head element under high-temperature and high-stress conditions. The testing method can be performed on a thin-film magnetic head including a head element and a heating element capable of applying a heat and stress to the head element, or performed on a row bar or a substrate wafer on which a plurality of the head elements and a plurality of the heating elements are disposed. The testing method comprises the steps of: causing the heating element to generate heat to apply a heat and stress to the head element; and measuring a characteristic of the head element under the heat and stress to evaluate the head element.

Abstract: A method, computer-readable medium, and apparatus for measuring properties of a magnetic read head are provided. In one embodiment, the method includes providing a first and a second magnetic read head. A first dimension of the first magnetic read head is different from a corresponding first dimension of the second magnetic read head. The method further includes determining a first change in conductance of the first magnetic read head resulting from an applied magnetic field and a second change in conductance of the second magnetic read head resulting from the applied magnetic field. The first change in conductance and the second change in conductance are used to determine a change in the first dimension and the corresponding first dimension of the first and second magnetic read heads, respectively. The change in the first dimension and the corresponding first dimension results from a manufacturing process of the first and second magnetic read heads.

Abstract: The method of testing a magnetic head is capable of purely evaluating characteristics of the magnetic head without influences caused by external factors. The method of testing a magnetic head comprises the steps of: detecting amount of noises, which are included in output signals of a reading element of the magnetic head, a plurality of times in a state of reading no magnetic data; and comparing an amount of variation between the detected amounts of noises with a threshold value.

Abstract: Described are system for recording piston rod position information in a magnetic layer on the piston rod. A piston rod has a magnetically hard layer formed thereon to provide a recording medium. A magnetic pattern is recorded in the magnetically hard layer. A magnetic field sensor disposed adjacent to the piston rod senses the recorded magnetic pattern while the piston rod is moving and generates signals in response to the magnetic pattern that are used to determine a position of the piston rod.

Abstract: When testing the quality of shield films of magnetoresistive effect heads, a method of testing and a testing apparatus can detect heads where the shield magnetic domain is susceptible to changing that could not be completely detected by conventional methods of testing that use normal magnetization. The method of testing applies an external magnetic field to a magnetoresistive effect head as external stress, measures the output voltage of the head, and repeats the applying of the external magnetic field and the measuring a plurality of times to test the quality of the shield film. The magnetic field is applied in a direction parallel to the shield film and at an angle to a floating surface of the magnetoresistive effect head. The intensity of the applied magnetic field is smaller than the coercive force of a hard bias film and larger than the coercive force of the shield film.

Abstract: A dynamic electrical tester (DET) for testing head gimbal assemblies (HGA) is disclosed. The DET simulates disk drive operation while significantly reducing tester capital investment. Multiple HGAs are tested simultaneously using modular spin stands with shared electronics. This design increases utilization of electronics and minimizes the effect of spindle start/stop time. A parallel array of spin stands with shared electronics is used to reduce tester component and materials cost by multiplexing between the spin stands. The DET has the significant advantage of reducing wait time by making use of the electronics while they are idle during mechanical-related delays. In addition, the DET includes more channels per test head that can readily switch back and forth between the products being tested.

Abstract: A disk drive that contains a fly on demand head (FOD) and a process for determining contact between the FOD head and a disk. The head includes a heating coil that can receive various levels of power. The process includes using a routine to obtain head position estimate error data. A standard deviation of the estimate error data is then determined. Standard deviation values for estimate error data are generated for different power values and used to determine a contact point between the head and the disk.

Abstract: A magnetic characteristic inspecting apparatus including a plurality of disk rotating devices or a plurality of magnetic heads include a unit for switching output signals of write signal production units or allocating the output signals to the magnetic heads, a unit for switching signals read from the magnetic heads or allocating the read signals to measurement resources, and a unit for selecting any of the disk rotating devices synchronously with which the measurement resources will perform measurement. The write signal production units and measurement resources are shared among inspections of the plurality of disk rotating devices or the plurality of heads.

Abstract: A head holder includes a first and second blocks connected each other with a predetermined gap between the blocks by a flexible coupling portion. The second block supports the first block swingably by increasing a width of either one of spaces of the predetermined gap on opposite sides of the coupling portion and narrowing the other space by bending the coupling portion by a piezo actuator. A magnetic head is dynamically moved in a direction crossing a track by swinging a head assembly fixed to the first block.