Abstract: A computer-implemented method to detect a damaged tunneling magnetoresistance (TMR) sensor includes applying current at at least two different current values to the TMR sensor and measuring a resistance, RTMR, at each current value. The method also includes measuring a slope in resistance vs. bias current, RDSLP, using the measured resistances RTMR and the at least two different current values. The method includes calculating a ?RDSLP value as a difference between the RDSLP value and an expected value, RDSLP-expected, for the TMR sensor. The method includes determining whether the ?RDSLP value is within a predefined range. In response to determining that the ?RDSLP value is outside the predefined range, the method includes outputting an indication that the TMR sensor fails. In response to determining that the ?RDSLP value is within the predefined range, the method includes outputting an indication that the TMR sensor passes.

Abstract: An apparatus includes a slider body of a disk drive. The slider body is electrically coupled to a plurality of end bond pads. A voltage applied to one more of the end bond pads sets a surface potential of the slider body.

Abstract: Systems, methods, and firmware for operating data storage devices and storage processors are provided herein. In one example, a data storage device is provided. The data storage device includes magnetic storage media configured to store data, read heads configured to read data from the magnetic storage media at associated areal densities, and a storage processor. The storage processor is configured to monitor read error rates of the read heads during operation of the data storage device to identify a degraded one of the read heads, and process at least the read error rates and an areal density of the degraded one of the read heads to modify the areal density of at least the degraded one of the read heads.

Abstract: Technologies are described herein for utilizing a head heater to test temperature stability of a head of a storage device and to prevent the head from operating in an unstable temperature condition. A first power level may be applied to a head heater of a head in a storage device, the first power level configured to simulate a temperature condition in the head. An instability of the head is determined and the temperature condition and the instability of the head are recorded in a memory. The process may be repeated to develop a range of temperature conditions in which the head exhibits instability. The range of temperature conditions and the head heater may then be utilized to prevent the head from operating in an unstable temperature condition during normal operation.

Abstract: A heat generating component of a slider is energized at a predetermined frequency. The heat generating component changes a spacing between a medium and the slider. A temperature response proximate a media-facing surface of the slider is measured while the heating element is energized. Based on the measured temperature response, a determination is made as to whether the media-facing surface is contaminated. In response to determining that the media-facing surface is contaminated, remedial action is taken.

Abstract: A method for measuring noise of a magnetic head includes setting a plurality of threshold values, applying bias current or voltage to a read element of the magnetic head, applying an external transverse magnetic field to the magnetic head, amplifying output signal from the read element to produce an amplified signal, filtering the amplified signal to produce a filtered signal, generating an enable signal for each threshold value in a predetermined time window by a counting control means with input signals which include the filtered signal and the threshold value, measuring the cumulative time duration of each enable signal, making an amplitude-duration distribution according to the cumulative time durations and the threshold values, calculating a plurality of parameters according to the amplitude-duration distribution and analyzing the parameters with a plurality of predetermined criteria to determine the defects of the magnetic head.

Abstract: A spectral simulation method during a noise testing for a magnetic head, includes steps of (a1) detecting several first noise profiles for several magnetic head samples under a first frequency bandwidth range by a dynamic testing machine; (b1) separating each first noise profile into at least two noise curves including a first noise curve and a second noise curve at a predetermined frequency bandwidth, wherein the first noise curve has a frequency bandwidth range lower than that of the second noise curve; (c1) fitting several mathematical equations according to the second noise curves; and (d1) establishing a correlative equation among the mathematical equations, so as to simulate the second noise curve for each magnetic head. The present invention can simulate a second noise curve of the noise profile in a higher frequency bandwidth and establishing the correlative equation according to the second noise curve.

Abstract: A hard-disk drive having a structurally efficient magnetic head slider utilizes a MAMR-based spin torque oscillator (STO) for head-disk contact detection and for flying height sensing. Contact detection and spacing estimation techniques consider the nominal temperature difference, and thus different criteria, between read and write operations.

Abstract: The present inventions are related to systems and methods for determining contact between two elements, and more particularly to systems and methods for determining contact between a head assembly and a storage medium.

Abstract: The present inventions are related to systems and methods for determining contact between two elements, and more particularly to systems and methods for determining contact between a head assembly and a storage medium.

Abstract: A testing method of a magnetic head includes: applying a first magnetic field with a constant intensity in a first direction that is the same with that of the longitudinal bias field to the magnetic head, simultaneously applying a second magnetic field with variant intensities in a second direction traversing the air bearing surface, and measuring a first noise; applying a third magnetic field with a constant intensity in a third direction that is opposite to the first direction to the magnetic head, simultaneously applying the second magnetic field with variant intensities in the second direction, and measuring a second noise; and analyzing noise change between the first noise and the second noise. The invention can screen out defective magnetic heads that possess poor noise characteristic and unstable performance.

Abstract: Provided herein is an apparatus, including a spinstand configured to position a disk in a testing orientation and a motor coupled to the spinstand, configured to rotate the disk. The motor comprises a fluid dynamic bearing.

Abstract: The application discloses a sensor device to measure friction force at a head-media interface. As disclosed, the sensor device has a transducer element oriented to provide an electrical output responsive to force or strain imparted to the transducer element along an in-plane axis. Sensor circuitry is coupled to the transducer element to process the electrical output to provide an output measure of friction force. In illustrated embodiments, the head includes an actuator element which is powered on/off at an on/off frequency to cyclically protrude a localized portion of the head. The on/off frequency of the actuator is used by the sensor circuitry to detect excitation of the sensor device due to friction force at the head-media interface.

Abstract: Various embodiments concern a method for manufacturing a disk drive head suspension component. Such methods can comprise providing a head suspension component comprising a layer of insulating material on a spring metal layer. Such methods can further comprise forming a strain gauge element and a trace seed layer by depositing a first metal on the insulating material layer, such as by sputtering. The strain gauge element and the trace seed layer can be formed simultaneously by the depositing of the first metal as part of the same process step. The first metal can be of a strain gauge class of metal having relatively high resistivity, such as constantan. Such methods can further comprise plating a second metal on the trace seed layer to form one or more traces.

Abstract: A polarization microscope optically detects the effect of the magnetic field from a sub-optical resolution magnetic structure on a magneto-optical transducer. The magneto-optical transducer includes a magnetic layer with a magnetization that is changed by the magnetic field produced by the magnetic structure. The saturation field of the magnetic layer is sufficiently lower than the magnetic field produced by the magnetic structure that the area of magnetization change in the magnetic layer is optically resolvable by the polarization microscope. A probe may be used to provide a current to the sample to produce the magnetic field. By analyzing the optically detected magnetization, one or more characteristics of the sample may be determined. A magnetic recording storage layer may be deposited over the magnetic layer, where a magnetic field produced by the sample is written to the magnetic recording storage layer to effect the magnetization of the magnetic layer.

Abstract: A method, system and apparatus for fault protection using a linear feedback shift register are presented. The system comprises a protected register containing a first portion for holding a value for a sequence of numbers and a second portion for other parameters. The system also comprises a linear feedback shift register circuit configured to write the sequence of numbers to the first portion of the protected register. If the written sequence of numbers of the protected register matches a reference sequence of numbers, a rewrite circuit is configured to write the second portion of the protected register.

Abstract: An apparatus for inspecting a thermal assist type magnetic head is constituted by a scanning probe microscope means including a cantilever having a probe with a magnetic film formed on the surface of a tip portion thereof; a probe unit which provides an alternating current to a terminal formed on the thermal assist type magnetic head element and causes a pulse drive current or pulse drive voltage; a scattered light detection means which scans the near-field light emitting part with the probe to detect the scattered light generated from the probe in the generation region of the near-field light; an imaging means which image the thermal assist type magnetic head element; and a signal process means inspects the thermal assist type magnetic head element and an output signal outputted from the scanning probe microscope means by scanning with the probe while providing an alternating current to the terminal.

Abstract: An apparatus for inspecting a thermal assist type magnetic head is configured to include a scanning probe microscope unit comprising a cantilever having a probe with a magnetic film formed on the surface of a tip portion thereof; a prober unit which provides an alternating current to a terminal formed on the thermal assist type magnetic head element; a scattered light detection unit which detects scattered light generated from the probe; and a signal process unit which detects defect by using an output signal from the scanning probe microscope unit by scanning the surface of the thermal assist type magnetic head element with the probe in a state that the magnetic field is generated and the near-field light is stopped, and an output signal from the scattered light detection unit by scanning the surface with the probe while near-field light is generated and the magnetic field is off.

Abstract: In order to enable inspection of the physical shape of a near-field light emitting portion of a thermal assist type magnetic head, a thermal assist type magnetic head device is placed on a table movable in a plane, a probe fixed to a cantilever scans a plane apart at a constant distance from the surface of the sample placed on the table while moving the table in a plane, the displacement of the cantilever is detected by applying light to the scanning cantilever and detecting reflected light from the cantilever, an atomic force microscope (AFM) image of the thermal assist type magnetic head device is formed using information about the detected displacement of the cantilever and positional information about the table, and the quality of a physical shape including the size or typical dimensions of the near-field light emitting portion is determined by processing the formed AFM image.

Abstract: A data storage system includes a recording head and a compensating resistor. The recording head has a heating element. The compensating resistor is in electrical series with the heating element and is external to the recording head. A method includes applying an alternating current at a first angular frequency to a recording head. A voltage drop across the recording head heating element is measured. A component of the voltage drop is extracted. The component has a frequency that is three times the frequency of the first angular frequency.

Abstract: A storage system includes plural drive devices and a control device. Each of the plural drive devices reads or writes data from or to a portable recording medium. The control device performs a parallel process in which a first process and a second process are performed in parallel. The first process is to write specified data to a first portable recording medium via a first drive device of the plural drive devices. The second process is to write the specified data to a second portable recording medium via a second drive device of the plural drive devices. The control device cancels, upon completion of either one of the first process and the second process, the other one of the first process and the second process.

Abstract: An optical disc apparatus includes an optical pickup that emits light to an optical disc and receives reflection light reflected by the optical disc, a temperature sensor for detecting ambient temperature of the optical pickup, a temperature control processing portion that performs a process corresponding to temperature information obtained by the temperature sensor, and a filter portion that performs filtering of a signal about the temperature information during a period until the temperature information detected by the temperature sensor is input to the temperature control processing portion.

Abstract: A testing device tests a magnetic head with a read head structure including a read head element while applying an external magnetic field to the magnetic head. The testing device receives signals from the read head element and processes the signals to generate a spectral power density for the signals. The spectral power density is characterized for at least one frequency range. The characterization of the spectral power density is used to determine a characteristic of noise from the read head structure. The signals from the read head may be received with different applied magnetic fields and/or before or while thermally exciting the magnetic head. Additionally, a histogram of the signals may be generated and used to determine a second characteristic of the noise.

Abstract: A method, system and apparatus for fault protection using a linear feedback shift register are presented. The system comprises a protected register containing a first portion for holding a value for a sequence of numbers and a second portion for other parameters. The system also comprises a linear feedback shift register circuit configured to write the sequence of numbers to the first portion of the protected register. If the written sequence of numbers of the protected register matches a reference sequence of numbers, a rewrite circuit is configured to write the second portion of the protected register.

Abstract: A magnetic head slider inspection device including a motor unit for revolving a disk medium, a slider unit provided with a reproducing head, which is levitated from a surface of the disk medium under force generated by the revolving disk medium, a magnetic field generator positioned at an opposite side of the disk medium with respect to the slider unit for generating a magnetic field substantially perpendicular to the disk medium surface, and a circuit unit for generating the magnetic field from the magnetic field generator, and measuring a resistance value of the reproducing head levitated from the disk medium surface.

Abstract: A storage system includes plural drive devices and a control device. Each of the plural drive devices reads or writes data from or to a portable recording medium. The control device performs a parallel process in which a first process and a second process are performed in parallel. The first process is to write specified data to a first portable recording medium via a first drive device of the plural drive devices. The second process is to write the specified data to a second portable recording medium via a second drive device of the plural drive devices. The control device cancels, upon completion of either one of the first process and the second process, the other one of the first process and the second process.

Abstract: Measuring method of a magnetic head includes (a) placing the magnetic head at normal position, defining a first direction parallel to an air bearing surface and two shielding layers of the magnetic head, and defining a second direction perpendicular to the first direction; (b) tilting the magnetic head at an angle to the second direction, applying a plurality of first magnetic fields with different intensities in the first direction, and measuring out a first output parameter curve; (c) repeating the step (b) with different angles and measuring out a plurality of first output parameter curves; (d) calculating a plurality of pinned direction tilt ratios that a pinned direction of a pinned layer of the magnetic head tilts towards the second direction according to the parameter curves; and (e) calculating a pinned direction tilt angle that the pinned direction tilts towards the second direction according to the pinned direction tilting ratios.

Abstract: A stepping-motor-driving circuit for an optical pickup: includes a control-signal-generating circuit to generate a plurality of control signals for supplying driving currents to driving coils having a plurality of phases during energized periods, with a de-energized period therebetween; a plurality of output circuits to supply the currents to the respective coils, in response to the signals; an induced-voltage-detecting circuit to compare a voltage generated each in the coils with a threshold voltage during the de-energized period; a threshold-voltage-setting circuit; and a determining circuit to determine whether a collision state is present where the pickup reaches an end of a movement range, based on an induced-voltage-detecting-circuit-detection result, the threshold voltage set at a voltage between a voltage generated each in the coils during the de-energized period when the stepping motor stops or rotates in the state, and a voltage generated therein in the de-energized period when no collision state is

Abstract: An apparatus comprises a root mean square (‘RMS’) value generator; an integrator coupled to the RMS value generator; a sample and hold switch coupled to an output of the integrator; a capacitor coupled between the sample and hold switch and a ground; an input of the analog to digital convertor (‘ADC’) coupled to the capacitor; an adder coupled to an output of the ADC; a register, wherein an output of the register is coupled to an input of the adder; and wherein an output of the adder is coupled to an input of the register; and a logic coupled to the register for comparing an output of the register to an RMS threshold value for determining whether a touch-down has occurred.

Abstract: Various embodiments of the present invention provide systems and methods for calculating and/or modifying fly height. For example, a circuit for calculating fly height is disclosed that includes: a first pattern detector circuit, a second pattern detector circuit, a first pattern fly height calculation circuit, a second pattern fly height calculation circuit, a first averaging circuit, a second averaging circuit, and a combining circuit.

Abstract: Various embodiments of the present invention provide systems and methods for detecting contact. For example, a method for detecting head contact is disclosed that includes: receiving an interface signal operable to indicate a physical contact between a sensing device and a storage medium; band pass filtering a data set derived from the interface signal to yield a band pass filtered output; comparing the band pass filtered output to a level threshold to yield a comparator output; summing the comparator output with at least one prior instance of the comparator output to yield an aggregated value; and comparing the aggregated value to an aggregate threshold to yield a contact output.

Abstract: An optical disk apparatus includes a light focusing element arranged to face a disk and to focus light emitted from a light source on the disk, an actuator to move the light focusing element towards and away from the disk according to an actuator driving voltage, a light intensity detection unit to detect an intensity of light reflected by the light focusing element and generate a gap error signal based on the detected intensity, a servo unit to generate the actuator driving voltage and a predetermined threshold voltage based on the gap error signal generated by the light intensity detection unit and to provide the actuator driving voltage to the actuator, a distance detection unit to detect a first distance at which the actuator driving voltage is maintained when the threshold voltage is detected using the gap error signal and to detect a second distance at which a gap between the light focusing element and the disk is shorter than the first distance and at which a gap servo operation is started based on the

Abstract: A property, such as a quality parameter, of a write pole in a write head is determined using an optical metrology device, where the write pole is smaller than the optical resolution limit of the metrology device. The metrology device produces polarized light that is reflected off the write pole while the write pole is magnetized either during or after excitation with a write current. The magnetization alters the polarization state of the light, which can be analyzed to transform the altered polarization state into intensity. The intensity of the light is detected over the point spread function of the optics in the metrology device and an intensity value is generated. The intensity value is used to determine the quality parameter of the write pole, e.g., by comparison to a threshold or reference intensity value, which may be generated empirically or theoretically.

Abstract: An information recording/reproducing device is provided with a recording medium with a recording surface, a plurality of probes that carry out at least either record processing or reproduction processing by scanning a plurality of information tracks on the recording surface, a position detecting means that detects a position of at least one information track by using the probe for every plural divided regions into which the recording medium is divided in a direction intersecting the plural information tracks and which contain at least one information track, and a track control means that controls tracking of the probe used for at least either record processing or reproduction processing for every plural divided regions. Thus, the device structure can be simplified.

Abstract: Reflected and scattered electrons generated by emitting an electron beam onto a substrate are detected by a detecting unit. The product of the area (SN) and the irradiation time (tN) of the Nth shot in a predetermined measurement unit obtained from writing data is computed by a computing unit. The value obtained by accumulating an instructed equivalent value in the predetermined measurement unit and the value obtained by integrating the signal (DN) from the detecting unit in the predetermined measurement unit are compared and determined by a comparing unit to determine whether or not abnormality occurs in the irradiation amount of the electron beam.

Abstract: A magnetic head slider inspection device including a motor unit for revolving a disk medium, a slider unit provided with a reproducing head, which is levitated from a surface of the disk medium under force generated by the revolving disk medium, a magnetic field generator positioned at an opposite side of the disk medium with respect to the slider unit for generating a magnetic field substantially perpendicular to the disk medium surface, and a circuit unit for generating the magnetic field from the magnetic field generator, and measuring a resistance value of the reproducing head levitated from the disk medium surface.

Abstract: To locate an access head element of a head assembly for a tape storage device, a storage tape having a data track that contains servo information is provided. The data track further contains data. The servo information that is in the data track is used to determine a position of the access head element.

Abstract: A method of adjusting gain balance of an optical transducer includes the following steps. First, two external gains are predetermined. Next, the projection position of a reflection spot is adjusted toward one side of the optical transducer, and the current output values of the optical transducer each corresponding to one of the external gains are measured, respectively. Next, the projection position of the reflection spot is adjusted toward the other side of the optical transducer, and the current output values of the optical transducer each corresponding to one of the external gains are measured, respectively. Then, a gain balance value of the optical transducer is adjusted, and is set as the external gain. Next, the projection position of the reflection spot is adjusted. Finally, the projection position of the reflection spot, where the current output value of the transducer is equal to 0, is locked to complete the adjustment rapidly.

Abstract: A method and apparatus to control a flying height of a head in a disk drive by detecting a flying state of the head just before it touches down to a disk. The method includes detecting approximate touch-down based on detecting a motion change of a head in a disk track direction by changing a flying height of the head on a rotating disk and determining that the head approaches a touch-down approximated flying height when the detected motion change of the head in the disk track direction exceeds a threshold value.

Abstract: A recording and/or reproducing apparatus, medium, and method controlling a write speed of a disk drive. The method may includes measuring a predetermined disk quality evaluating factor affecting a servo control performance in multiple areas of a disk, determining an optimal write speed of the areas of the disk corresponding to the disk quality evaluating factor, and controlling a rotation speed of the disk at an optimal write speed of a corresponding area of the disk, depending on a position of the disk in which writing is to be performed, in a writing mode.

Abstract: The problem of magneto-resistive sensor drift with age has been solved by normalizing the sensor's output relative to its output when it is in a selected reproducible state. Details for the method to accomplish this normalization are disclosed together with several examples of how the method can be utilized.

Abstract: Methods and apparatus to monitor and control hard-disk drive head position are described. In one example, a hard-disk drive system includes a hard-disk drive platter, a hard-disk drive read head configured to read information from the hard-disk drive platter, and a hard-disk drive head position controller configured to a receive a signal via the hard-disk drive read head and to determine if the received signal indicates that a distance between the hard-disk drive platter and the hard-disk drive is less than a predetermined distance and to vary a temperature of the read head based on the determination.

Abstract: An optical position tracking device and a method of testing the same are provided. The device includes: a controller for generating at least one test operation signal in response to a command signal; a test signal generator for generating a test signal during a test operation in response to the test operation signal; a motion calculator for receiving the test signal during the test operation and performing operations in response to the test operation signal to output an output signal; and an output signal analyzer for determining whether the output signal is correct during the test operation in response to the test operation signal to output a result signal. Thus, the complexity of the method of testing the optical position tracking device can be markedly reduced and it is unnecessary to employ a high-performance test apparatus.

Abstract: A hard disk drive control module has a feed-forward signal input port communicatively coupled with a reference model. The hard disk drive control module has a tracking error signal input port communicatively coupled with a magnetic transducer of the hard disk drive. The hard disk drive control module has an error calculator module configured for determining a difference between an estimated tracking error signal in response to a first feed-forward signal and an actual tracking error signal of the magnetic transducer in response to the first feed-forward signal. The hard disk drive control module has a feed-forward signal adjuster module configured for adjusting a gain and a phase for a second feed-forward signal based on the difference between the estimated tracking error signal in response to the first feed-forward signal and the actual tracking error signal of the magnetic transducer.

Abstract: Methods and apparatus to monitor and control hard-disk drive head position are described. In one example, a hard-disk drive system includes a hard-disk drive platter, a hard-disk drive read head configured to read information from the hard-disk drive platter, and a hard-disk drive head position controller configured to a receive a signal via the hard-disk drive read head and to determine if the received signal indicates that a distance between the hard-disk drive platter and the hard-disk drive is less than a predetermined distance and to vary a temperature of the read head based on the determination.

Abstract: An optical position tracking device and a method of testing the same are provided. The device includes: a controller for generating at least one test operation signal in response to a command signal; a test signal generator for generating a test signal during a test operation in response to the test operation signal; a motion calculator for receiving the test signal during the test operation and performing operations in response to the test operation signal to output an output signal; and an output signal analyzer for determining whether the output signal is correct during the test operation in response to the test operation signal to output a result signal. Thus, the complexity of the method of testing the optical position tracking device can be markedly reduced and it is unnecessary to employ a high-performance test apparatus.

Abstract: A magnetism test method for a tray-type optical drive is disclosed. A preliminary input voltage is provided to a DC motor of the tray-type optical drive for performing a preliminary ejection on a tray and a magnetic clamper of the tray-type optical drive. Then, a test voltage smaller than the preliminary input voltage is provided to the DC motor to partially eject the tray, in which the tray is ejected to a point short of the complete distance of ejection. When the incomplete distance is longer than a predetermined distance, the magnetic force of the magnetic clamper is determined to abnormal.

Abstract: An apparatus is provided for inspecting a recording medium, for thereby detecting a defect in the recording medium, in which the apparatus includes inspection subjects made up of first to fourth recording media on which audio signals having a constant frequency are recorded. The apparatus further includes first to fourth non-defective drives for reading out signals from the first to fourth recording media and for outputting signals therefrom, a detector for detecting the audio signals from among the signals output from the first to fourth drives, and a determining means for determining that the first to fourth recording media are defective when the audio signals output from the detector deviate from the constant frequency.

Abstract: The record condition extraction system (1) of a dielectric recording medium is intended to obtain an applied voltage and an applied time length to be recorded when recording information in the dielectric recording medium. The record condition extraction system (1) is provided with: an applied voltage setting device (11); an applied time length setting device (12); a record control device (13); an applied voltage/applied time length record device (14); a record device (15); a dot radius measurement device (16); a dot radius record device (17); an optimum dot radius detection device (18); a record condition determination device (19); and an output device (20). The applied voltage setting device (11) and the applied time length setting device (12) set a voltage and a time applied to a probe (31) of the record device (15), respectively.

Abstract: A process, computer program product, and apparatus for detecting and quantifying crosstalk instability in a read/write mechanism are provided. A write current is varied in a write circuit for exciting the write head. Measurements are taken of a magnetoresistive impedance of a read current of a read circuit. Measurements are also taken of a signal amplitude in the read circuit. A bit error rate of the overall system is also measured. The read/write mechanism is failed if the signal amplitude changes by a predetermined amount during the varying of the write current. Likewise, the read/write mechanism is failed if the error rate changes by a predetermined amount during the varying of the write current. The write-to-read signal coupling of HGA (Head Gimbal Assembly) and HSA (Head Stack Assembly), including GMR sensor, suspension and flex cable on the actuator arm, can be evaluated at component design level. The methodologies successfully simulate GMR cross talk instability inside a drive on magnetic testers.