Abstract: The present application discloses a transducer head comprising a read element that reads data from a storage media and an asperity sensor that detects a dimension of an asperity on a surface of the storage media using a temperature change at the asperity sensor. The asperity may be one or both of a void in the surface of the storage media and a protrusion from the surface of the storage media.

Abstract: In certain embodiments, a method includes calculating a mixing ratio of air internal to a disk drive. In response to the calculated mixing ratio, a head-to-media spacing is adjusted. In certain embodiments, a system includes a controller that adjusts head-to-media spacing in response to a calculated mixing ratio of air internal to a disk drive.

Abstract: A DFH (Dynamic Flying Height) type slider ABS design has significantly improved DFH efficiency and back-off efficiency as well as uniform touchdown detectability. This is the result of decoupling the local pressure variations at the read/write head that result from skew angle variations across a disk, from local stiffness due to ABS protrusion caused by heater activation. The decoupling, which allows the heater activation stiffness to be carefully tuned, is a result of the effects of airflow channeled by a wide down-track channel onto a narrow down-track channel formed in an extended finger of the central pad of the slider. Airflow impinges on the finger channel in a manner that eliminates variations in air pressure at the central pad due to variations in skew angle.

Abstract: A reference circuit comprises a first proportional to temperature component providing a first quantity exhibiting a first type of variation as a function of temperature, a first complementary to temperature component providing a second quantity exhibiting a second type of variation as a function of temperature that is complementary to the first type of variation, and curvature correction circuitry. An output of the reference circuit provides a reference signal generated based on a combination of the first and second quantities. The curvature correction circuitry is coupled to the reference circuit output and comprises at least one additional complementary to temperature component. The curvature correction circuitry adjusts the reference signal in a feedback arrangement to compensate for a temperature response bowing effect attributable to combining the first and second quantities. The reference circuit may be implemented in a disk-based storage device for use in fly height control or other control functions.

Abstract: Various embodiments of the present invention provide systems and methods for determining contact between a head and a storage medium.

Abstract: Approaches are provided for a hard-disk drive (HDD) and a method for measuring the contact potential between head and disk interfaces within a hard-disk drive. In one example, a voltage bias is applied to a head slider at discrete increments, and the touchdown power is determined at each increment. The voltage bias at which the TDP maximizes equals the inverse polarity of the inherent contact potential between the head slider and disk, and this value may be used to apply a voltage that neutralizes the contact potential.

Abstract: In one general embodiment, a magnetic head includes a slider having a media-facing surface; and a device coupled to the slider and being selectively extendible for selectively contacting a magnetic medium at a frequency of between about 200 and about 600 kHz. Other magnetic heads and methods of use are described according to additional embodiments.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, and a fly height transducer operable to generate a fly height signal for the head. The disk drive further comprises control circuitry comprising a current sensor operable to detect a current flowing through the fly height transducer. The current sensor comprises a differential amplifier operable to amplify the current flowing through the fly height transducer over a first range using a first gain, and amplify the current flowing through the fly height transducer over a second range using a second gain less than the first gain, wherein at least part of the second range is different than the first range.

Abstract: A method to compensate for spacing variations between a dynamic fly height (DFH) controlled read/write head and a rotating disk surface. Using a HDI sensor or equivalent indicator of touchdowns, a power profile is calculated for an arbitrary track on a disk. The profile tracks disk topography by recording touchdown power at each of a series of sectors into which the track is subdivided. The resulting power profile, smoothed and expressed as a function of sector position, substitutes for the usual constant TD power setting that provides only an uncompensated range of spacing variations. A fixed back-off spacing power is added to the power profile enabling the head to fly over the track at a constant spacing. The power profile can be calculated to account for various temperature and pressure conditions.

Abstract: In one embodiment, a magnetic head slider includes at least one magnetic head element chosen from a group consisting of: a write element adapted for writing data to a magnetic recording medium and a read element adapted for reading data from the magnetic recording medium, a heater element adapted for controlling a flying height of the at least one magnetic head element above the magnetic recording medium, a contact sensor element adapted for detecting contact between the magnetic head slider near the at least one magnetic head element and the magnetic recording medium, and shared terminals adapted for supplying voltage to the heater element and for conveying signals from the contact sensor element. Other magnetic head sliders and methods of use are described according to additional embodiments.

Abstract: A magnetic-recording head with touch-down detector incorporating a carbon nano-tube (CNT). The magnetic-recording head includes a write element, a read element and a touch-down detector. The write element is configured to write data to a magnetic-recording disk. The read element is configured to read data from the magnetic-recording disk. The touch-down detector includes a thermal sensor, and a CNT portion. The thermal sensor is configured to convert heat to a voltage signal. The CNT portion is configured to touch down on the magnetic-recording disk. The CNT portion is also coupled to the thermal sensor, and is configured to transfer heat generated by contact between the CNT portion and the magnetic-recording disk to the thermal sensor. A hard-disk drive (HDD) including the magnetic-recording head with touch-down detector incorporating a CNT, and a method for detecting contact between the magnetic-recording head and a recording surface of a magnetic-recording disk are also provided.

Abstract: In one embodiment, a magnetic disk device includes a magnetic disk medium, at least one magnetic head having at least one of: a magnetic read element adapted for reading data from the magnetic disk medium and a magnetic write element adapted for writing data to the magnetic disk medium, and a heating element adapted for generating heat upon application of a voltage/current thereto, wherein the heating element is positioned on, near, or within the magnetic head, a drive mechanism for passing the magnetic disk medium over the at least one magnetic head, and a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head, wherein the controller is configured to retract the at least one magnetic head from a flying state above the magnetic disk medium and apply the voltage/current to the heating element while the magnetic head is retracted.

Abstract: Dynamic fly height (DFH) controlled read/write heads using multiple heaters have their heater powers set within a range of ratios that allows minimum clearances to be set between the read-gap and the write-gap and the surface of a disk, thereby providing improved touch-down detection. Determining the correct range of power ratios requires varying the ratio to create an adjustable protrusion profile for the read and write elements in the head and measuring values of the ratio and corresponding values of read gap and write gap clearances that create points of minimum clearance. By adjusting the ratio of power supplied to the heaters, different protrusion profiles can be produced, clearance control for sigma reduction can be obtained and read/write readiness and operation consistency and reliability can be improved.

Abstract: A manufacturing method of a glass substrate for a magnetic disk is provided whereby nano pits and/or nano scratches cannot be easily produced in polishing a principal face of a glass substrate using a slurry containing zirconium oxide as an abrasive. The manufacturing method of a glass substrate for a magnetic disk includes, for instance, a polishing step of polishing a principal face of a glass substrate using a slurry containing, as an abrasive, zirconium oxide abrasive grains having monoclinic crystalline structures (M) and tetragonal crystalline structures (T).

Abstract: A current sensor is disclosed comprising a differential amplifier including a first node, a second node, and an output. The current sensor further comprises a first resistor having a first end coupled to the first node and a second end for coupling to a transducer, and a second resistor having a first end coupled to the second node and a second end. When the second end of the second resistor is unconnected and the differential amplifier is driven with a supply voltage, the first node is biased by a first leakage current and the second node is biased by a second leakage current such that the output represents a current flowing through the transducer.

Abstract: A head assembly including one or more transducer elements for controlling head-media spacing is disclosed. The assembly includes detection circuitry configured to receive an input detection signal responsive to the spacing between the head and the data storage media and provide an output measure indicative of the head-media spacing. The output signal is utilized by control circuitry to provide a control input to one of a plurality of transducer elements on the head to protrude a localized portion of the head to adjust head-media spacing.

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: There is disclosed a hard disk drive and a method of controlling a flying height of a magnetic head of the hard disk drive. A method of controlling a flying height of the magnetic head in a hard disk drive according to an embodiment of the present invention may include (a) providing a FOD sensitivity through a FOD test; (b) reading a preamble signal of a servo pattern; (c) calculating a flying height of the magnetic head from the preamble signal; and (d) applying FOD power for adapting the flying height of the magnetic head to a target flying height of the magnetic head based on the calculated flying height of the magnetic head and the FOD sensitivity.

Abstract: A head using heaters or actuators to control head media spacing is disclosed. In embodiments disclosed the heaters are selectively energized to control a close point of the head for read and/or write operations. As disclosed power is supplied to multiple heaters to generate heat induced protrusion data and the heat induced protrusion data is used to apply power to the multiple heaters for head media spacing control.

Abstract: A close loop method for measuring head SNR, for a storage device comprising a storage media and a head, comprising steps of: (a) loading the head on the media with a dynamic fly height; (b) measuring an initial environmental temperature value Ti and measuring the head signal signalload; (c) unloading the head; (d) adjusting a power which controls the dynamic fly height until a real-time environmental temperature value T2 is equal to the initial environmental temperature T1; (e) measuring the head noise value noiseunload, (f) calculating the head SNR with the follow equation: Head_SNR = 20 × log ? ( signal load noise unload ) . The method of the present invention can obtain a fair condition between the signal and noise measurement, thereby a reliable and accurate head SNR can be obtain. The present invention also provides a close loop method for measuring media SNR.

Abstract: A tape drive system according to one embodiment includes a support for engaging a tape; and a head directly opposing the tape engaging portion of the support, the head being for performing at least one of reading from a tape and writing to a tape. During an operation period, the head is positioned such that at least one of the following occurs: the head does not contact the tape for a majority of the operation period; the head does not contact the tape for at least a portion of the operation period; and the head engages the tape for at least a portion of the operation period when the tape is lifted from the support by a cushion of air formed between the support and the tape, the head pressing the tape into the air cushion when engaging the tape.

Abstract: A locking media pusher is coupled to a servo controlled stage and includes a protruding probe and a locking mechanism. The stage moves forward and backward along a base toward and away from a storage medium. If an eccentricity of a track on the storage medium exceeds a threshold, the storage medium is rotated to an orientation where the greatest eccentricity is directed toward the media pusher. The media pusher is moved toward the storage medium until a probe extending from the media pusher contacts the storage medium. The probe is locked within the media pusher. The stage and attached media pusher are retracted from the storage medium and the storage medium is unlocked. The magnitude of retraction of the stage is recorded. The stage is moved toward the storage medium a distance corresponding to the probe contact position plus the eccentricity magnitude to correct the eccentricity.

Abstract: A method for driving an optical pickup apparatus which improves the durability of components that drive a movable lens that moves back and forth between an original position and a drive-limit position and achieves stable operability and an extended lifetime of the optical pickup apparatus performs a first step-drive in which a movable lens moves to an original-restoration start position by being driven a specified distance toward a drive-limit position, a second step-drive in which the movable lens thereafter moves to an original position by being driven toward the original position a distance equivalent to the distance from the drive-limit position to the original position, and a third step-drive in which the movable lens thereafter moves to a default position by being driven a specified distance.

Abstract: An aspect of the present invention relates to a glass substrate for a magnetic recording medium, which is comprised of glass with a glass transition temperature of equal to or greater than 600° C., an average coefficient of linear expansion at 100 to 300° C. of equal to or greater than 70×10?7/° C., a Young's modulus of equal to or greater than 81 GPa, a specific modulus of elasticity of equal to or greater than 30 MNm/kg, and a fracture toughness value of equal to or greater than 0.9 MPa·m1/2.

Abstract: A temperature sensor of a head transducer measures temperature near or at the close point. The measured temperature varies in response to changes in spacing between the head transducer and a magnetic recording medium. A detector is coupled to the temperature sensor and is configured to detect a change in a DC component of the measured temperature indicative of onset of contact between the head transducer and the medium. Another head transducer configuration includes a sensor having a sensing element with a high temperature coefficient of resistance to interact with asperities of the medium. Electrically conductive leads are connected to the sensing element and have a low temperature coefficient of resistance relative to that of the sensing element, such thermally induced resistance changes in the leads have a negligible effect on a response of the sensing element to contact with the asperities.

Abstract: A head transducer, configured to interact with a magnetic recording medium, includes a first sensor having a temperature coefficient of resistance (TCR) and configured to produce a first sensor signal, and a second sensor having a TCR and configured to produce a second sensor signal. One of the first and second sensors is situated at or near a close point of the head transducer in relation to the magnetic recording medium, and the other of the first and second sensors spaced away from the close point. Circuitry is configured to combine the first and second sensor signals and produce a combined sensor signal indicative of one or both of a change in head-medium spacing and head-medium contact. Each of the sensors may have a TCR with the same sign (positive or negative) or each sensor may have a TCR with a different sign.

Abstract: A hard disk drive includes a controller that optimizes a flying height of a head of a hard disk drive. The controller determines an optimal flying height of a head based on a preset table value and an MRR value of a head measured during a hard disk drive manufacturing process and sets the head according the determined optimal flying height such that recording capacitance is improved.

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 hard disk drive (HDD) including a first resistive temperature detector (RTD) configured to detect a temperature generated by proximity of a slider and a media. The first RTD is proximate an air bearing surface (ABS) of the slider. The HDD also includes a second RTD configured to detect at least one temperature correlated to a fly-height of the slider. The second RTD is not required to be proximate the ABS of the slider. HDD also includes a read/write integrated circuit (IC) configured to determine the fly-height of the slider based on detection of temperatures by the first RTD and the second RTD.

Abstract: A head-stack assembly. The head-stack assembly includes: a magnetic-recording head; a lead-suspension supporting the magnetic-recording head on an actuator arm; a metal plate coupled with the actuator arm; a resin layer disposed on the metal plate; a flexible-printed-circuit board disposed on the resin layer, and substantially perpendicularly connected to the lead-suspension; a arm-electronics module disposed on the flexible-printed-circuit board configured to shape a write-signal current waveform of a write signal to said magnetic-recording head; transmission lines disposed on the flexible-printed-circuit board configured to transmit the write signal to, and a read-back signal from, the lead-suspension; and, a single intermediate conductor layer that is disposed between the resin layer and the flexible-printed-circuit board, and having a planar shape substantially facing a bottom of the arm-electronics module and a bottom of the transmission lines.

Abstract: A disk drive. The disk drive includes a disk configured to store data, a motor configured to rotate the disk, a head-slider and a controller. The head-slider includes a slider configured to fly in proximity to a recording surface of the disk, and an element on the slider. The controller is configured to measure a fly height between the head-slider and the disk at different common-mode voltages of the element to determine an operational common-mode voltage from a measurement result.

Abstract: A hard-disk drive. The hard-disk drive includes a head-slider configured to fly in proximity with a recording surface of a magnetic-recording disk, and a fly-height variation compensator configured to generate a signal for compensating variation in fly height of a write element of the head-slider. The head-slider further includes the write element configured to write data to the magnetic-recording disk, a fly-height-adjustment heating element configured to displace the write element towards the magnetic-recording disk, and a position-adjustment heating element configured to displace the write element in at least a direction perpendicular to a flying direction. The fly-height variation compensator is further configured to add the signal for compensating variation in fly height to a control signal for output to the fly-height-adjustment heating element.

Abstract: Embodiments of the present invention help provide a simple and inexpensive actuator mechanism for a magnetic disk drive. The actuator mechanism includes an approximately circular coil and a simple shaped magnet, and is capable of displaying adequate performance required for the magnetic disk drive. According to one embodiment, the magnetic disk drive includes an actuator mechanism which has an approximately circular coil and an approximately rectangular magnet. The long axis direction of the rectangular magnet is oriented in parallel to a straight line connecting the center of the inner circle of the circular coil in a state in which the actuator is positioned at the outermost circumference of a data area and the center of the inner circle of the circular coil in a state in which the actuator is positioned at the innermost circumference of the data area.