Abstract: A method and apparatus for using cache size estimations for guiding hot-tier insertion decisions. The method and apparatus include an adaptive management element that determines what accesses of a resource should be logged and the parameters for logging. The determinations are used to configure an adaptive logging element to log only accesses corresponding to the selected resource(s) and to log only those accesses that match the identified parameters. The adaptive management element operates in a feedback loop: first determining what will be logged and second implementing that determination by an adaptive logging element. Upon a triggering event, the process returns to the first determination based on any then current parameters. In some embodiments, the parameters include a size estimate to achieve a given target hit rate (target hit rate size estimate) that is used in generating a score or weighting to identify the highest/best scoring/weighted disk(s) for logging.

Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.

Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.

Abstract: An actuator supports a head at one end of a rotatably supported shaft unit and supports a coil of a voice coil motor at the other end, and moves the head to an arbitrary track position of a recording medium. A sensor, attached to a coil support unit of the actuator, detects the coil vibration and outputs a vibration detected signal. A control unit controls the actuator to reduce a head position error signal based on the vibration detected signal of the sensor in time of seek and in time of settling of moving the head to a target track position on the medium through drive of the actuator and drawing the same. The vibration detected signal of the sensor includes bending vibration component of the coil and the twisting vibration component of the coil when the actuator is driven.

Abstract: A disk drive is disclosed including a disk, an actuator arm, a head attached to a distal end of the actuator arm, a mechanical position sensor operable to generate a position signal representing a position of the head relative to the disk, and a voice coil motor for rotating the actuator arm about a pivot. The disk is rotated at a predetermined velocity, a control signal is generated in response to the position signal generated by the mechanical position sensor, and the control signal is applied to the voice coil motor in order to seek the head radially over the disk while writing a spiral track to the disk. The spiral track is then processed to maintain the head along a servo track while writing product servo sectors along the servo track.

Abstract: An information recording apparatus comprises a recording medium, a swing arm driven by an actuation unit, the swing arm swinging over a surface of the medium in response to driving by the actuation unit, a recording head carried by the swing arm and scanning over the surface of the medium with a swinging motion of the swing arm by the actuation unit, the recording head recording information to the medium, a head retracting mechanism retracting the recording head out of the medium in a state where no recording is to be made on the medium, an optical injection unit injecting a light into the recording head, the recording head including an optical irradiation part irradiating the light injected to the recording head upon the medium when recording information to the medium. The optical injection unit is integrated with the head retracting mechanism to form a unitary optical-injection and head-retraction mechanism.

Abstract: A disk drive is disclosed comprising a disk, an actuator arm, a head coupled to the actuator arm, a base, and an optical sensor operable to detect a position of the actuator arm. The optical sensor comprises a light source that is stationary relative to the base, a plurality of light sensitive sensors positioned to receive light from the light source, and a substantially opaque element positioned between the light source and the light sensitive sensors configured to control an amount of light at least one of the plurality of light sensitive sensors detects relative to the position of the actuator arm.

Abstract: A data recording disk drive has a plurality of capacitive sensors, each sensor facing a surface of an associated disk, a capacitance sensing circuit for converting the sensed capacitance to a voltage representative of the distance between the sensor and the disk surface, and a feedforward controller that receives the voltage signal. The feedforward controller has a transfer function with gain and phase characteristics designed to match the transfer function from the out-of-plane disk vibration to the position of the read/write head while accounting for the effects of the sensor dynamics and the dynamics of the actuator. The output from the feedforward controller is combined with the output from the disk drive's servo feedback controller so that the effects of disk vibration on track misregistration of the head are removed from the control signal to the actuator.

Abstract: A system and methods for efficiently performing media writing functions is disclosed. The system and methods include: detecting media movement with respect to a base and heads during reading and writing, and moving the heads in response; using an interferometer, such as a dual beam differential interferometer, to dynamically monitor disk position and address perceived errors; and minimizing repeatable and non repeatable runout error by writing data, such as servo bursts, in multiple revolutions to average adverse runout conditions. The present system has the ability to use an interferometer to enhance media certification and perform on line, in situ monitoring of the media, and includes shrouding, head mounting, disk biasing, and related mechanical aspects beneficial to media writing.

Abstract: Method and apparatus for performing a seek operation to move a data transducing head from an initial track to a destination track on a rotatable recording surface. A servo control circuit operates to sweep the head across the recording surface. Servo data from an intermediary track are transduced to obtain a detected angular position value for the head with respect to the recording surface. When the detected angular position value differs from a predicted angular position value for the head, the servo control circuit initiates an index qualification routine at the conclusion of the seek. The qualification routine involves transducing the servo data from the destination track to verify the accuracy of the predicted angular position value. In this way, the effects of spurious (false) index signals obtained from the servo data transduced during the seek operation are minimized, and unnecessary reinitializations of the servo control circuit are avoided.

Abstract: Described herein is a read/write transducer for a hard disk drivewith dual actuation stage, comprising at least one hard disk and at least one suspension carrying the read/write transducer. The read/write transducer comprises a supporting body having a substantially parallelepipedal shape, a read/write head arranged on a front face of the supporting body, and a grating defined on one of the side faces of the supporting body during the process of manufacture of the read/write transducer. The grating enables measurement of the position of the read/write transducer with respect to the corresponding suspension in an optical way using a laser transmitter emitting and directing towards the grating a laser beam, and a laser receiver arranged to intercept the laser beam reflected by the grating and outputting a position signal on the basis of which it is possible to calculate, in a simple way, the position of the read/write transducer with respect to the corresponding suspension.

Abstract: A magnetic recording apparatus which, even when crosstalk occurs between signals from three photosensitive parts of a photodetector, can detect a high-precision tracking error signal with stability. In a signal processing unit which processes electrical signals outputted from a photosensitive part of a photodetector to detect a tracking error signal, an output signal from and I-V converting unit is subjected to voltage division by voltage-dividing units, and voltage-divided output signals and output signals from I-V converting units are subjected to differential calculation by differential arithmetic units, respectively.

Abstract: A disk drive (HDD) (and method) subject to linear and rotational vibration, includes an independent sensing unit for sensing a rotational velocity component of the rotational vibration in a predetermined frequency range, and an optimal filter combination for receiving an output from the sensing unit.

Abstract: A method of aligning a magnetic read/write head to data tracks on a magnetic surface of a digital linear tape. The method includes writing a signal over a track of optical servo marks located on the magnetic surface of the tape with a servo channel writer, generating a position error signal from read back signals obtained from a servo channel reader and positioning the magnetic read/write head in accordance with the position error signal.

Abstract: An apparatus and method of indirectly measuring half frequency whirl in a spindle motor having a rotor adapted to rotate a disc having a track which is followed by a transducer head that is actuated by a control system is provided. Vibration signals produced at the transducer head while the transducer head follows the track are detected. The half frequency whirl is determined as a function of the detected vibration signals.

Abstract: An apparatus for optically detecting rotational position information of a rotating object, includes a light source, a detector which is located at a position to receive scattered light from the rotating object when the rotating object is irradiated with a light beam from the light source, and outputs a frequency signal based on the scattered light, a signal processing system for detecting rotational position information by performing signal processing for the frequency signal from the detector, and a rotation control system for controlling rotation of the rotating object. The rotation control system preliminarily rotates the rotating object in detecting the rotational position information.

Abstract: Methods and computer program products for determining accurate estimates of coil resistance are provided. Current differences between pairs of current values are determined. Additionally, voltage differences between pairs of actuator coil voltages (corresponding to the current values) are determined. Coil resistance is estimated based on the current differences and the voltage differences. These coil resistance estimates can be useful for accurately estimating actuator coil, actuator arm and/or head velocity.

Abstract: A disk drive has a data recording medium such as a disk, a spindle motor for rotating the disk, disk rotation speed controlling logics for supplying a spindle current to the above described spindle motor to rotate the disk at a constant speed, a head unit for accessing the disk, an actuator for moving the head unit, and head position controlling logics for driving the actuator and controlling the position of the head unit. The head position controlling logic obtains the value of the spindle current and controls the position of the head unit on the basis of the above described spindle current value by using the fact that the spindle current varies according to variations in the position of the head unit.

Abstract: A data storage device includes a head suspension assembly having an attached airfoil. The airfoil is coupled to an active (i.e., movable) element that responds to signals from height control circuitry. A method of controlling a height of an air bearing surface includes positioning a suspension assembly having an airfoil and an air bearing disk head over a surface of a rotating data storage disk. A position (e.g., an angle) of the airfoil can then be dynamically altered to change a distance of the disk head perpendicular to the surface of the disk.

Abstract: A positioning mark of a soft magnetic film is provided at the center of a master disk, and a beam from a light source irradiates the position of the mark. When a optical reception sensor using a CCD recognizes the mark, the recognizability of the positioning mark can be improved by using a wavelength selective filter or a laser as the light source. Additionally, the recognizability of the positioning mark can be improved by forming the positioning mark using a material other than a soft magnetic material.

Abstract: A magnetic-disk evaluation apparatus includes a magnetic head positioned relative to a magnetic disk including temporary servo signals. Fluctuation of a magnetic head in a seek direction is measured using a measurement device. A measuring rotating arm moves in tandem with a rotating stage holding a rotary positioner. The measurement device is on the measuring rotating arm. The rotary positioner is controlled on the basis of temporary servo signals to position the magnetic head on a circle, concentric from a center of a spindle motor. Fluctuation of the magnetic head in the seek direction is measured to detect the displacement of the magnetic head and to determine whether the temporary servo signals are acceptable based upon the displacement and an outside standard.

Abstract: An apparatus having a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of split light beams.

Abstract: A position sensor includes a stationary platform and a moveable platform. The position sensor further includes at least one beam coupling the moveable platform to the stationary platform. The at least one beam includes piezoresistive material that is positioned to provide an indication of a movement of the moveable platform relative to the stationary platform.

Abstract: A servo system and method position a head laterally with respect to magnetic tape longitudinal defined servo bands arranged in a longitudinally shifted pattern for identification, and separated by data tracks. A servo controller responds to a loss of lateral position, sensing an estimated longitudinal position of the magnetic tape. If the estimated longitudinal position is within a predetermined distance of an end of the tape, the servo controller operates a drive to continuously move the tape away from the sensed end. The servo controller senses a home lateral position sensor to determine whether a compound actuator is within a predetermined distance of the edge of the magnetic tape. If so, it operates the coarse actuator portion of the compound actuator to move laterally away from the edge of the magnetic tape; else, to move toward the edge.

Abstract: A magnetic recording medium is formed with a distribution of laser micromachined servo-marks in the form of pits or indentations with an attendant reduction in servo-tracking area and increased data-recording speed. Embodiments include laser texturing to form a radially extending linear or arcuate series of circular or elliptical pits across the data zone. The micromachined servo-marks are detected by mechanical or electrical means and denote the beginning and end of magnetically recorded servo-information in a data track, thereby enabling accurate and timely positioning of the read/write head by the servo-controller of the hard drive.

Abstract: A disk drive system includes a light source (110), such as an LED, mounted on the magnetic head. The LED (110) is patterned to form a fine pitched mask. The diverging light off the LED radiates toward a fixed, faceted optical reflector (112). The faceted array includes a plurality of spaced aspherical reflectors. The faceted array projects a portion of the light to a diffraction limited focus detector (114).

Abstract: A head-controlling device of a disk apparatus is provided that can precisely move a head stepwise to the position of each track on a recording surface of a disk. When detection output values A1 and B1 of phases A and B that are out of phase satisfy a relational value, a determination is made that a magnetic head is aligned with the position of a track. The calculation of the relational value of the phase A and the phase B detection values makes it possible to reliably align the head with each track position even when the phase difference of the two phases is not correct.

Abstract: A method and apparatus for transducer position detection uses inert contact surfaces to engage an actuator temporarily. The inert contact surfaces are part of an apparatus that also includes an optical sensor such as a retroreflector or diffraction grating. The assembly is thus configured to permit multiple uses while exerting a near-zero net torque about the length of the arm that supports the transducer. This is useful where there is a temporary need for especially precise position control, such as when servowriting a data storage media surface.

Abstract: An HDA includes a base, a disc stack coupled to a spindle rotatably attached to the base by a spindle shaft and spindle bearing. An actuator assembly is pivotally attached to the base at a pivot shaft. Attached to one end of the actuator assembly proximal the disc stack is one or more transducers for reading/writing information from/to the discs. A servo writer includes a controller for moving the actuator during the servo writing process. The controller moves the servo writer at the cage frequency of the spindle bearing to lessen the relative motion between the transducer head and the disc as the servo information is written to the disc. The controller also may be programmed to move the transducer at both the spindle rotation frequency and the cage frequency of the spindle bearing to lessen the relative motion between the transducer and the disc during the servo writing process.

Abstract: A disk drive has a data recording medium such as a disk, a spindle motor for rotating the disk, disk rotation speed controlling logics for supplying a spindle current to the above described spindle motor to rotate the disk at a constant speed, a head unit for accessing the disk, an actuator for moving the head unit, and head position controlling logics for driving the actuator and controlling the position of the head unit.

Abstract: The diffraction-based monitoring techniques described herein can be used, for example, as quality assurance measure in manufacture of magnetic recording media with servo tracking. In one embodiment, the invention presents a system comprising a light source such as a laser that directs light upon a surface of a magnetic recording medium. The magnetic recording medium has two or more physical marks, and the light striking the magnetic recording medium produces a diffraction pattern. A light detector such as a photodiode detects some or all of the diffraction pattern. The physical marks may be servo tracks on the magnetic recording medium, and the detected diffraction pattern is a function of the characteristics of the servo tracks.

Abstract: A mass data storage device (10) and methods for making and using it are disclosed. The mass data storage device (10) has a read/write head (18) carried in proximity to one end of a selectively positionable arm (42), and an actuation device (20) in proximity to another end of the arm for moving the arm in response to an input signal (31). The mass data storage device (10) has a sensor, such as an accelerometer (38), or the like, carried on the arm (42) for generating a motion signal for use in position control of the arm (42). The sensor (38) is located on the arm (42) at a location at which the motion signal (39) and the actuator input signal (31) have a minimum phase difference. The signal (39) from the sensor (38) may be fed back to control the actuation device (20), and may include a filter (60) that shapes the motion signal to equalize any resonances in the arm or rejects torque effects of the arm (42).

Abstract: A magnetic disk medium patterned linear magnetic channels in a radial direction of the disk is employed in a magnetic disk drive unit. The magnetic channels are patterned by high-resolution patterning techniques and are separated by channel boundaries to reduce magnetic coupling between the magnetic channel. The lithographically determined magnetic channel widths are matched with the head width to optimize the storage capability of the disk drive unit. The magnetic medium is further patterned into spatially modulated sections that provide for an inherent servo-signal that reduces or eliminates the need for pre-recorded servo data.

Abstract: A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the invention describes a magnetic disk drive employing a laser system to form and sense optical clock patterns placed on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder.

Abstract: In a recording/reproducing apparatus, a controller includes a counter responsive to incoming track feed requesting pulses to count the number of the pulses, a head movable state detection unit for detecting a movable state of a magnetic head, and a track feed controller responsive to the count value of the track feed requesting pulse counter to effect track feed of the magnetic head. Detection of the movable state depends on the recording medium being loaded and on completion of the formulation of track position information that is derived from an optical signal that varies as a function of track position. The track feed controller effects track feed of the magnetic head, responsive to the count value of the track feed requesting pulse counter, following detection of the movable state of the magnetic head.

Abstract: A magnetic disk tester has a head clamp (35, 218) to position a magnetic head (15, 289). The head clamp has a micromotion stage (55, 273) provided with a stage (59, 205) which is horizontally moved by a piezo-element (77). The magnetic head is attached to the piezo-stage (55, 273).

Abstract: A method and apparatus for estimating position and speed of a read/write head in a disc drive, based upon the back EMF of the voice coil motor involves estimating the voltage across the voice coil motor and estimating the voltage across a current-sensor resistor in the voice coil circuit, preferably with a differential amplifier. Further, a coil resistance voltage is estimated by measuring the voltage across the current-sensor resistor with a differential amplifier and amplifying the voltage across the current-sensor resistor by a gain value. Finally, the combined voltage across the current-sensor resistor and the characteristic coil resistance is subtracted from the voltage across the voice coil motor, yielding the back EMF of the voice coil motor. The back EMF is representative of head velocity which may be integrated to yield position. Accordingly, the back EMF can be used to control the speed and position of the read/write head.

Abstract: A method of handling multiple resonance frequencies in a disc drive includes monitoring a position error signal (PES) for an actuator arm, generating a plurality of feedforward compensation signals from the PES using a plurality of bandpass filters, and applying the compensation signals to a servo control signal. Each filter has a center frequency that is set to a problematic resonance frequency. The method may also include identifying the problematic frequencies by, for example, commanding a movement of the actuator arm, collecting data points for the PES that are associated with the movement, and performing a digital fourier transform of the data points to identify resonant frequencies. Other methods of identifying problematic frequencies include analyzing PES zero-crossing data, or using principal component analysis.

Abstract: To detect the position of an object in a non-contact state at high reliability, high accuracy, and high resolving power, a linearly polarized light beam from a semiconductor laser source is converted into an almost parallel light beam by a collimator lens, transmitted through a non-polarization beam splitter, focused by an objective lens, and transmitted through a crystal plate. When an appropriate thickness t is given to the crystal plate, the principal rays of polarized light beams o and e emerge while being shifted by a predetermined amount and are focused into a spot or line having a width w near a slit-shaped marking (M) formed on a head arm whereby portions shifted from each other are illuminated. The two reflected light beams pass through the crystal plate. The principal rays of the two light beams match again and are returned to the non-polarization beam splitter, split into transmitted light and reflected light.

Abstract: A storage media is disclosed and comprises a storage body and a readable indelible mark formed in the body such that portions thereof are indelibly altered. The mark is read by writing first data to the body in the region of the mark, and reading second data from the body in such region. The written first data is not accepted where the portions of the body are indelibly altered. Accordingly, the read second data corresponds to the written first data with segments thereof missing. The missing segments of the first data correspond to the portions of the body indelibly altered. In a preferred embodiment, the storage media comprises a magnetic rotatable disk having a substantially planar substrate and a magnetizable layer deposited thereon. The reading and writing are therefore performed magnetically.

Abstract: The method of the present invention is capable of shortening the time required for positioning an inner actuator and writing servo track signals on a magnetic disc, and improving the quality of the written servo track signals. The amount of displacement between the inner actuator and an external actuator is detected with a present position of the external actuator. A first deviation between a travel destination of the external actuator and a present position of the inner actuator is detected on the basis of the amount of the displacement, the present position of the external actuator and the travel destination thereof. The inner actuator is controlled so as to make the first deviation within a predetermined standard range.

Abstract: A recording/reproducing method and apparatus having the function of tracking a head on a data track formed on a recording medium of a lower-order specifications and on a data track formed on a recording medium of the upper-order specifications. During calibration, a controller 10 causes a locally maximum value and a locally minimum value of the signal level of a sine wave signal to be sequentially stored as the table information in a storage unit 11, as a magnetic head is moved by a head driving unit 7 in a direction perpendicular to the plural tracks. The sine wave signal is generated by an optical encoder and represents a substantially sinusoidal signal which completes its full cycle on the track basis. During tracking, the locally maximum value and the locally minimum value associated with a targeted track are read out from the storage unit 11 and a target sine wave level information is generated based on the generated locally maximum value and the locally minimum value.

Abstract: Apparatus and method for improving operational performance of a disc drive by detecting and compensating for translational vibration modes in a disc drive actuator. The actuator is configured to support a head adjacent a recording disc and pivots about a stationary shaft by way of a cartridge bearing assembly having a pair of ball bearing assemblies. A proximity probe detects translational movement of the actuator assembly relative to the shaft due to, for example, abrupt acceleration and deceleration of the head during a seek operation, or externally applied mechanical shocks. The output of the proximity probe is used to generate a bearing translation signal which is fed into an actuator control servo circuit to modify the amount of current applied to an actuator motor to compensate for the translational vibrations during track following and seek operations.

Abstract: Drive systems for moving the optics sled in a laser servowriting system used to provide a servo pattern on the media of a magnetic data storage disk are disclosed. The drive systems include multiple actuators located about the centroidal axis of the optics sled. Moments induced by the multiple actuators acting on the optics sled can be balanced by varying the forces applied to the optics sled by the actuators. Also disclosed are control systems and methods for balancing the forces provided by the actuators by varying the gains on the signals driving the actuators.

Abstract: A method and apparatus for start-stop testing magnetic heads and hard disks in real disk-drive environment is provided. The tester has essentially the same dimensions as a conventional disk drive so that rotation of the disk pack inside the tester housing generates the same aerodynamic conditions as in a real disk drive. An accurate head positioning system, the operation of which does not depend on the deterioration of the magnetic conditions of the head and disk, is located inside the tester housing, and the friction and sticking forces can be measured till the moment of physical crash inside the housing. An essential advantage of the tester of the invention in that the measurement and positioning systems are combined into a single unit. The aforementioned combined system is based on the use of a Hall-effect sensor attached to the voice coil of the type used in the disk drive.

Abstract: A servowriter positioning apparatus for hard disk drives comprises an optical read head 2 for directing three focussed light beams on grating sections formed at the end of a grating member 1 connected to the servo write head(s) 3 in order to indicate the position and movement of the head(s) 3. The optical read head 2 may be based on CD or DVD technology. The servo write head(s) 3 are mounted on an actuator arm 5 to which the grating member 1 is fixed for rotation therewith and which are both driven in rotation by a rotary actuator. The grating member 1 comprises two grating sections 11,12 separated by a smooth section 13 for generating a focus error correction signal. The apparatus of the invention can be used to sense and control the position and movement of the servo write heads, or of the read/write heads of the hard disk themselves, thus eliminating the need for any servo pattern.