3268results about "Driving/moving recording heads" patented technology

A micro-actuator is comprised of a piezoelectric motor mounted on a flexure tongue with offsetting hinges, to perform a fine positioning of the magnetic read / write head. The substantial gain in the frequency response greatly improves the performance and accuracy of the track-follow control for fine positioning. The simplicity of the enhanced micro-actuator design results in a manufacturing efficiency that enables a high-volume, low-cost production. The micro-actuator is interposed between a flexure tongue and a slider to perform an active control of the fly height of the magnetic read / write head. The induced slider crown and camber are used to compensate for thermal expansion of the magnetic read / write head, which causes the slider to be displaced at an unintended fly height position relative to the surface of the magnetic recording disk. The enhanced micro-actuator design results in reduced altitude sensitivity, ABS tolerances, and reduced stiction. The controlled fly height of the magnetic read / write head prevents a possibility of a head crash, while improving the performance and data integrity.

A method and system for providing a disk drive is described. The disk drive includes media such as one or more disks, a slider, and a head residing on the slider. The head has an air-bearing surface (ABS), a portion of which contacts the media during touchdown. The head further includes a plurality of touchdown sensors. A first touchdown sensor is proximate to the ABS, while a second touchdown sensor is distal from the ABS. The touchdown sensors are capable of detecting a temperature change of 0.1 degree Celsius or, in some embodiments, smaller.

A portable digital audio recorder provides a first set of control or editing options with respect to a first category of voice data files stored in the recorder, and provides a different set of control or editing options with respect to a second category of voice data files stored in the recorder. The recorder may also be conveniently shared among a number of users and adapts various operating parameters to the preferences of the current user.

A method and system for providing a disk drive is described. The disk drive includes media such as one or more disks, a slider and a head residing on the slider. The head has an air-bearing surface (ABS) and includes a touchdown sensor proximate to the ABS. The touchdown sensor is capable of detecting a temperature change of 0.1 degree Celsius or, in some embodiments, smaller. The disk drive also includes touchdown sensor control circuitry coupled with the touchdown sensor. The touchdown sensor control circuitry drives a current through the touchdown sensor and converts a signal from the touchdown sensor into an indication of whether touchdown has occurred.

A disk drive is disclosed including a disk having a plurality of tracks, and a head actuated over the disk. A write frequency of write data received from a host is monitored. When the write frequency falls below a threshold, the disk drive is configured to operate in a low frequency access mode when accessing the disk, wherein a parameter of the disk drive is configured to increase the reliability of the disk drive. When the write frequency rises above a threshold, the disk drive is configured to operate in a high frequency access mode when accessing the disk, wherein the parameter of the disk drive is configured to increase the performance of the disk drive.

A method of writing product servo sectors to a disk of a disk drive is disclosed. A plurality of spiral tracks are written to the disk, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. During the product servo writing process, the sync marks in the spiral tracks are read to generate a coarse timing recovery measurement, and the high frequency signal in the spiral tracks is read to generate a fine timing recovery measurement. The coarse and fine timing recovery measurements are processed to synchronize a servo write clock used to write the product servo sectors to the disk. In one embodiment the control circuitry within the disk drive synchronizes the servo write clock by reading the spiral tracks, and in an alternative embodiment an external product servo writer synchronizes the servo write clock by reading the spiral tracks.

A method adjusts a flying-height distance between a magnetic write head and a magnetic medium. The method includes positioning the write head in a location spaced from the magnetic medium by the flying-height distance. The write head includes a magnetic yoke and a proximal region in proximity to the magnetic medium. The write head further includes a resistive heater and at least a portion of the resistive heater is within the magnetic yoke and is in proximity to the proximal region. The resistive heater is configured to heat the proximal region. The proximal region has a coefficient of thermal expansion. The proximal region is configured to expand and to contract in response to a temperature of the proximal region. The method further includes flowing an electric current through the resistive heater. The method further includes controlling the electric current to adjust the temperature of the proximal region to selectively expand and contract the proximal region and thereby control the flying-height distance. Controlling the electric current includes pulsing the electrical current and adjusting a time interval between pulses.

A method of writing product servo sectors to a disk of a disk drive is disclosed. The disk comprises a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted by a sync mark at a sync mark interval. The head internal to the disk drive is used to read the spiral tracks to generate a read signal. The read signal is integrated to generate a ramp signal, wherein a position error signal is generated from the ramp signal. The position error signal is used to maintain the head internal to the disk drive along a servo track while writing product servo sectors along the servo track.

A method of writing product servo sectors to a disk of a disk drive is disclosed. An external spiral servo writer writes a plurality of reference servo sectors at an outer diameter of the disk and a plurality of spiral tracks that spiral from an outer diameter to an inner diameter of the disk. At the beginning of the product servo writing process, the reference servo sectors are demodulated to initially synchronize a servo write clock. The spiral tracks are then demodulated to maintain synchronization of the servo write clock as well as maintain the head along a target circumferential path while writing product servo sectors to the disk.

A method monitors operation of a disk drive. The method includes providing a disk drive which includes a rotating disk and a head having a read transducer in proximity to a surface of the disk and an adjustment mechanism which controllably adjusts an average relative spacing between the read transducer and the surface. The method further includes generating a read-back signal by reading from the surface using the read transducer. The read-back signal includes a high frequency carrier signal having an envelope that is modulated by a lower frequency signal. The method further includes varying the average relative spacing between the read transducer and the surface using the adjustment mechanism. The method further includes analyzing the envelope in the frequency domain and detecting an emergence of at least one frequency component of the envelope within an air bearing resonance range of frequencies.

Disclosed is a self-heating disk drive that comprises a voice coil motor (VCM), a spindle motor, and a temperature sensor. The VCM includes a VCM coil and the VCM is configured to move an actuator having a head attached to a distal end of the actuator. The spindle motor includes a plurality of spindle coils to spin a disk of the disk drive. The temperature sensor is used to read an internal temperature of the disk drive. Circuitry is configured to: command the application of current to the VCM coil without loading the head onto the disk and to the spindle coils of the spindle motor in a manner so as not to spin the disk; and, if the internal temperature reading reaches a pre-determined spindle temperature, the spindle motor is allowed to spin-up the disk.

A disk drive is disclosed comprising a disk having a plurality of tracks, and a head actuated over the disk. Control circuitry heats the head in order to reduce a fly-height of the head, and computes a target servo sector to begin a preheat period. The control circuitry decreases the heat so that the fly-height is increased during at least part of a seek operation to seek the head from a first track to a second track. When the head reaches the target servo sector, the control circuitry increases the heat to decrease the fly-height during the preheat period.

A method and apparatus is disclosed for writing product servo sectors to a disk of a disk drive to define a plurality of data tracks. The disk drive comprises the disk and a head actuated over the disk. The disk comprises a plurality of spiral tracks which are read using the head to synchronize a write clock and to generate a position error signal (PES) according to a PES algorithm used to maintain the head along a first servo track while writing product servo sectors along the first servo track. The PES algorithm is adjusted to seek the head to a second servo track, and the head is used to write product servo sectors along the second servo track.

A method and apparatus is disclosed for adjusting the track density over the disk radius by changing the slope of spiral tracks used to servo write a disk drive. A plurality of spiral tracks are written to the disk wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. A slope of the spiral tracks over a first radial segment of the disk is substantially steeper than the slope of the spiral tracks over a second radial segment of the disk. The head internal to the disk drive is used to read the spiral tracks in order to write product servo sectors to the disk to define a plurality of data tracks. The steeper slope of the spiral tracks over the first radial segment causes a track density of the data tracks to be lower over the first radial segment compared to the track density of the data tracks over the second radial segment.

A disk drive is disclosed which generates a pole tip protrusion (PTP) measurement by performing a write operation to heat the transducer while measuring a fly height of the transducer. A first data sequence written to the disk is read without heating the transducer to generate a first signal measurement. A second data sequence is then written to the disk in order to heat the transducer, and the first data sequence is again read to generate a second signal measurement. The PTP measurement is then generated in response to the first and second signal measurements.

Disclosed is a method for generating a repeatable runout (RRO) compensation value set for a circular track on a magnetic medium on a surface of a disk in a disk drive. The magnetic medium has a plurality of previously written spiral servo tracks for providing position information during a self servo-writing operation. In the method, servo burst patterns are written at a plurality of radial locations on the magnetic data storage surface during circular tracking operations using the spiral servo tracks, and respective position error signals generated during the circular tracking operations are stored. The servo burst patterns at the plurality of radial locations define a circular data track. The RRO compensation value set for the circular data track may be generated based on the respective stored position error signals generated during the circular tracking operations for writing the servo burst patterns at the plurality of radial locations.

A method and system for actuating a pole tip of a write head is disclosed. The write head includes a first pole and a second pole. The method and system include providing a strain element and providing a coil. The strain element is electrically insulated from the first pole and the second pole. The strain element is further configured to produce a strain for actuating the pole tip in response to a magnetic field. The coil carries a current capable of producing the magnetic field at the strain element.

A method is disclosed for reducing disk expansion effects while writing spiral reference patterns on a disk of a disk drive. The disk drive comprises control circuitry and a head disk assembly (HDA) for positioning a head radially over the disk. In the method, an external spiral servo writer is used to control a radial location of the head for writing a plurality of the spiral reference patterns between inner and outer seed tracks. A head velocity profile is adjusted for writing each spiral reference pattern to account for thermal disk expansion. The head internal to the disk drive is used to read the spiral reference patterns in order to write product servo bursts to the disk that define a plurality of radially-spaced circular data tracks.

A disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors. The disk drive further comprises a plurality of heads, such as a top head and a bottom head. Control circuitry within the disk drive determines a head-switch preheat period used to format the disk. The head-switch preheat period is calibrated by selecting one of the heads to write a test pattern to the disk, and then preheating the selected head for a preheat period prior to reading the test pattern from the disk to generate a read signal. The head-switch preheat period is determined for the selected head in response to the read signal.

A disk drive is disclosed comprising a disk and a head actuated radially over the disk. An external servo writer is used to write reference servo bursts to the disk at a coarser radial resolution than product servo bursts. During a self servo writing operation, the reference servo bursts are processed to servo circularly to write a first set of product servo bursts to the disk. The reference servo bursts are also processed to servo spirally to write a second set of product servo bursts to the disk.

A method for constructing and linearizing a position error signal (PES) derived from primary and quadrature servo burst pairs in an embedded servo disk drive. The construction method mathematically provides predetermined transition values at the commutation positions connecting adjacent PES segments so that the overall, indicated position signal is numerically continuous from segment to segment. The linearization method compensates for nonlinearity in the PES segments, and thereby in the indicated position signal, without affecting the predetermined transition values at all, or by modifying the predetermined transition values while maintaining continuity.

A method of writing product servo sectors on a disk of a disk drive is disclosed. The disk comprises a reference pattern having a plurality of sync marks written around the disk. The sync marks are detected to generate a sync mark detect signal, and a timing recovery measurement is generated in response to the sync mark detect signal. A frequency control signal is generated in response to the timing recovery measurement, and a servo write clock is generated in response to the frequency control signal. A feed-forward compensation value is generated in response to the timing recovery measurement and the frequency control signal, and the timing recovery measurement is adjusted in response to the feed-forward compensation value to compensate for a repeatable phase error in the timing recovery measurement. The servo write clock and the head internal to the disk drive are used to write the product servo sectors to the disk.

A disk drive is disclosed comprising a disk, and a head actuated radially over the disk. A first linear acceleration signal is generated representing a first acceleration disturbance, a second linear acceleration signal is generated representing a second acceleration disturbance, and a third linear acceleration signal is generated representing a thermal popping disturbance. The first linear acceleration signal is combined with the third linear acceleration signal to generate a fourth linear acceleration signal representing a combined physical shock disturbance and thermal popping disturbance.

A method of writing product servo sectors to a disk of a disk drive is disclosed. A plurality of spiral tracks are written to the disk, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. During the product servo writing process, the sync marks in the spiral tracks are detected and a sync mark reliability metric is generated, wherein the sync mark reliability metric represents a probability that the sync mark was detected accurately. A timing recovery measurement is generated in response to the detected sync marks and the sync mark reliability metrics. A servo write clock is synchronized in response to the timing recovery measurement and used to write the product servo sectors to the disk while serving on the spiral tracks.

A disk drive is disclosed wherein a BEMF speed error is measured during a BEMF spindle speed control mode, and a spindle control current is updated in response to the BEMF speed error to drive the disk at an operating speed. A reference time period (RTP) is calibrated, and a sinusoidal error in a wedge time period (WTP) due to eccentricity in the disk rotating is estimated to generate an eccentricity compensation value. After switching to a wedge spindle speed control mode, an actual WTP is detected and a wedge speed error is generated in response to the RTP, the detected actual WTP, and the eccentricity compensation value. The disk is then maintained at the operating speed by updating the spindle control current in response to the wedge speed error.