Abstract: Certain exemplary aspects of the present disclosure are directed towards apparatuses and methods which mitigate the effect of speaker vibration on a disc drive. Audio associated with a speaker output is detected and triggers the generation of an output signal indicative of speaker vibration associated with such an audio output of a speaker. A magnetoresistive transducer of the disc drive is positioned relative to a storage medium based on the output signal, a target data storage location in the storage medium from which data is to be accessed via the positioning, and the position of the transducer. The output signal mitigates the effect of the speaker vibration on the transducer.

Abstract: Certain exemplary aspects of the present disclosure are directed towards apparatuses and methods which mitigate the effect of speaker vibration on a disc drive. Audio associated with a speaker output is detected and triggers the generation of an output signal indicative of speaker vibration associated with such an audio output of a speaker. A magnetoresistive transducer of the disc drive is positioned relative to a storage medium based on the output signal, a target data storage location in the storage medium from which data is to be accessed via the positioning, and the position of the transducer. The output signal mitigates the effect of the speaker vibration on the transducer.

Abstract: One embodiment of the present invention is directed to a method of aligning servo wedges of a plurality of disc surfaces in a disc drive. This process of aligning servo wedges in a disc drive includes writing multiple servo wedges, one adjacent another, continuously across an entire circumference of each disc surface. Subsequently, one of the disc surfaces is designated the master surface. Every nth servo wedge on the master surface is then designated as a master wedge, where n is a positive integer. Next, the servo wedges on the non-master surfaces which are most closely axially aligned with the master wedges are selected. Subsequently, all of the non-selected and non-master wedges are erased.

Abstract: A method for minimizing once per revolution (OPT) positional errors in a single disk servo track writer (STW) comprises clamping a disc in the servo track writer; spinning the disc at a predetermined speed; determining an average OPR positional error; and adjusting a reference position for writing servo tracks on the disc to include the average OPR positional error. The apparatus includes a distance measuring device positioned adjacent the disc in the STW. Another method for reducing the effects of OPR positional error in a disc drive comprises positioning a disc on a drive motor spindle in a disc drive during assembly of the drive; spinning the disc at a predetermined speed; determining the position of maximum peak to peak OPR position error, and then readjusting the position of the disc on the spindle to minimize the error. The apparatus for this method includes a controller, a distance sensor, and a positioner for nudging the disc to an optimum position on the disc drive spindle.

Abstract: A method for minimizing once per revolution (OPR) positional errors in a single disk servo track writer (STW) comprises clamping a disc having an outer edge in the servo track writer; spinning the disc in the servo track writer at a predetermined speed; measuring distance from the disc edge to a predetermined point to determine peak to peak once per revolution positional error; determining an average once per revolution positional error from the peak to peak once per revolution positional error; and setting a reference position for writing servo tracks on the disc equal to a predetermined track reference plus the average once per revolution positional error. The servo track writer apparatus comprises a spindle motor for supporting and rotating a disc and a distance sensor such as an interferometer mounted a preset distance from the edge of the disc for measuring the once per revolution outer diameter positional error.

Abstract: An apparatus and method for minimizing the effects of rotational vibration upon a disc drive having a base deck supporting a rotatable disc and an actuator having a moveable data head. A fixed head is supported over the disc at a predetermined radius and transduces a circumferentially extending frequency pattern written to the disc at a constant frequency to generate a readback signal. A frequency modulation (FM) demodulator generates a rotational velocity signal indicative of application of rotational vibration to the base deck in relation to changes in frequency of the readback signal. A servo circuit controllably positions the moveable data head in response to the rotational velocity signal and servo information readback by the moveable data head. The servo circuit interrupts a data transfer operation between the moveable data head and a host device when a magnitude of the rotational velocity signal exceeds a predetermined threshold.

Abstract: An apparatus and method for minimizing the effects of rotational vibration upon a disc drive having first and second heads supported adjacent first and second disc recording surfaces, respectively. A frequency modulation (FM) demodulator generates a rotational velocity signal indicative of application of rotational vibration to the base deck in relation to changes in frequency of a readback signal generated from a circumferentially extending frequency pattern written to the first disc recording surface at a constant frequency. A servo circuit controllably positions the first and second heads in response to servo information stored on the second disc recording surface and the rotational velocity signal from the FM demodulator. The servo circuit further interrupts a data transfer operation between the second disc recording surface and a host device when a magnitude of the rotational velocity signal exceeds a predetermined threshold.

Abstract: An apparatus and method for detecting rotational vibration applied to a disc drive having an actuator supporting a head adjacent a rotatable disc. A spindle motor has a set of driver coils which rotate the disc through electrical commutation, and a set of velocity sense coils which sense the rotational velocity of the motor in relation to voltages established across the sense coils. Rotational vibration is detected in relation to changes in the rotational velocity of the disc. A data transfer operation between the disc and a host device is interrupted when the magnitude of the rotational vibration exceeds an acceptable level. A servo circuit compensates for the application of rotational vibration to the disc drive by adjusting current applied to the actuator in relation to the changes in the rotational velocity of the disc.

Abstract: Apparatus and method for improved disc drive data storage capacity and seek performance. The disc drive includes a rotatable disc with a recording surface on which a plurality of tracks are defined and an actuator which supports a head adjacent the tracks. A servo circuit uses a velocity profile to position the head adjacent a destination track, with the servo circuit adaptively selecting the velocity profile in relation to the physical location of the destination track. The servo circuit preferably uses a reduced maximum velocity and a decreased deceleration rate when the deceleration track is adjacent an innermost or outermost diameter of the disc, thereby reducing the risk of damage as a result of contact between the actuator and a limit stop used to limit radial excursion of the head.

Abstract: An apparatus and method for detecting rotational vibration applied to a disc drive having a rotary actuator adjacent a rotatable disc. The actuator supports a head adjacent a recording surface of the disc and an actuator coil in a magnetic field of a magnetic circuit of a voice coil motor. A second, velocity sense coil is further coupled to the actuator and immersed in the magnetic field of the magnetic circuit, with the velocity sense coil being electrically isolated from the actuator coil. Rotational vibration is detected in relation to a sense voltage induced across the velocity sense coil as the magnetic circuit is moved relative to the velocity sense coil. A data transfer operation between the head and a host device is interrupted when the magnitude of the rotational vibration exceeds a specified magnitude.

Abstract: Method and apparatus for dynamically compensating for servo burst measurement offsets in a disc drive. A first type of servo position error signal is used during a compensation routine to position a head adjacent a selected track on a disc, the first type of servo position error signal determined from servo burst signals read by the head from servo position fields on the disc. A second type of servo position error signal is also generated from the servo burst signals and the difference between selected values of the second type of servo position error signal is compared to an acceptance limit. Compensation terms are incrementally added to the servo burst signals used to generate the second type of servo position error signal until the difference is below the acceptance limits. Thereafter, the compensation terms are stored and retrieved during normal track following operations to generate a compensated servo position error signal.

Abstract: A method for calibrating the position error signal in a servo system of a disc drive. The disc drive comprises a disc and an actuator adjacent the disc, the actuator including a head which is controllably positionable relative to data tracks on the surface of the disc using a servo position error signal generated using a scale factor generally indicative of the ratio of the width of the head to the width of the tracks on the disc. The head is positioned at the center of a selected track using an initial scale factor for the position error signal, the selected track having servo position fields comprising a plurality of burst patterns. The burst patterns include a first burst pattern extending radially from a first track boundary to a second track boundary of the selected track, a second burst pattern extending radially from the center of the selected track to the first track boundary and a third burst pattern extending radially from the center of the selected track to the second track boundary.

Abstract: A method for reducing noise during track seeking in a disc drive wherein transducers proximate the surfaces of discs of the drive are accelerated away from an initial track in a first sequence of successive time interval and subsequently decelerated toward a destination track in a second sequence of successive time intervals in proportion to the difference between the actual velocity of the transducers and a demand velocity for each of the intervals. The demand velocity in each time interval is the sum of the demand velocity for the previous interval and a velocity demand fraction of the difference between an adjusted profile velocity and the demand velocity for the previous time interval. The adjusted profile velocity is the difference between a stored profile velocity and an anticipator that is maintained at a selected value during acceleration of the transducers and decremented to zero during initial time intervals in which the transducers are decelerated.

Abstract: A method for effecting seeks of a transducer head across a data storage disk wherein the head is accelerated over a first sequence of time intervals and decelerated over a second sequence of time intervals. In each time interval of the first sequence, the head is accelerated in relation to the difference between the actual head velocity and a current demand velocity that is determined by incrementing the demand velocity for the previous interval by an amount that is a fraction of the difference between the previous demand velocity and a stored profile velocity selected in accordance with the current location of the head. In each time interval of the second sequence, the head is decelerated in relation to the difference between the actual head velocity and a stored profile velocity selected in accordance with the current location of the head.

Abstract: A method for following data tracks on data surfaces of a disc drive by organizing the data tracks in concentric cylinders including servo tracks on a dedicated servo surface and following servo tracks with a servo transducer that is offset from the servo track to align selected data transducers with the data tracks. To measure the offset for each data surface, a calibration correction track is written to one data surface while a track on the servo surface is followed and the correction track is read by a thermal calibration circuit while following the servo track with an offset to obtain a calibration correction indicative of electronic offsets in the thermal calibration circuit.

Abstract: A hard disc drive having a digital servo system for controlling the position of a servo head on a dedicated servo surface. The servo surface is formatted in a series of consecutive frames along concentric tracks, each frame passing the servo head in a time that defines a sampling interval for the servo system. The frames contain track address and position fields for locating the servo head and location can be effected in relation to limited or extended fine control regions about the tracks via signals transmitted to a position circuit utilized to generate a servo position error from the position field. The position circuit generates a track phase code for checking track addresses generated by a track address circuit used to generate a track address from the address field.