Abstract: Methods of controlling a transducer that is adjacent to a rotatable data storage disk in a disk drive are disclosed, the disk drive having an actuator configured to position the transducer, a rotational acceleration sensor configured to generate a rotational acceleration signal, a position error sensor configured to generate a position error signal, and a controller configured to control the actuator to move the transducer to a target track during a seek operation. The methods include dynamically adjusting a gain factor in response to the position error signal and the acceleration signal during a settle period following the seek operation, multiplying the rotational acceleration signal by the gain factor to generate an adjusted rotational acceleration signal, and adding the adjusted acceleration signal to the position error signal to generate an adjusted position error signal, and moving the transducer in response to the adjusted position error signal.

Abstract: A magnetic storage system includes a disk, a head, an actuator, a read channel, and a main controller. The main controller causes the head to read a data block of a selected track of the disk at each of a plurality of fixed offsets from a center of the selected track. The main controller samples a gain in the read channel a plurality of times while the head is reading the data block at each of the plurality of fixed offsets to obtain a plurality of gain samples for each of the plurality of fixed offsets. If the data block was written off-track with a non-constant offset, the main controller determines an approximate starting position and an approximate rate of change of an off-track deviation of the data block based on the plurality of gain samples for the plurality of fixed offsets.

Abstract: Methods and structures for detecting touchdown of the read/write head on its recording surface or for detecting other read signal amplitude modulations as proportional to variance of the value of the read channel variable gain amplifier (“VGA”). Variance in the VGA values caused by the standard feedback control electronics associated therewith is proportional to amplitude modulations of the sensed signal picked up by the read channel (or servo read sensor). These amplitude modulations are, in turn, reflective of flying height of the read/write head as well as generally indicative of other parameters of the read channel operation. Touchdown of the read/write head and other parameters of the disk drive operation may therefore be detected as variances in the VGA control values.

Abstract: A disk drive having reduced electromagnetic emission quasi-peaks is provided. The repetition rate of servo blocks or data is reduced, spread or otherwise altered. In one embodiment, the number of data zones is increased to achieve an emissions reduction goal. In one embodiment, the disk drive is configured to effectively have one track per zone. In one embodiment, the rotation rate of the disk is varied or the effective data bit density, as detected by the read/write head, is otherwise varied. In one embodiment, servo-sectors are intentionally positioned to vary the length, along the track, of inter-servo intervals.

Abstract: A technique for de-gaussing the pole tips and yoke of a write transducer in a perpendicular magnetic recording system is provided. An oscillator in the read channel is configured to produce an adjustable signal pattern output to the preamplifier when a write operation ends for a given time and at a predetermined frequency, such that as the preamplifier write current decays, it decays with transitions (polarity reversals). This results in a decaying AC field being applied to the write transducer at the end of a media write operation, effectively de-gaussing it and reducing the effects of remanent magnetization remaining in the poles and yoke of the magnetic recording head after a write current is turned off. This defeats a potential pole tip lockup or yoke lockup circumstance in the magnetic recording media which can result in an inability to write further data or a possible erasure of valid data on the hard disk with which the write head is associated.

Abstract: A pivot bearing for an actuator assembly of a disk drive includes a first stationary member, a second pivoting member, and a third flexible member interconnecting the first and second members. The first stationary member is secured preferably between the base and top cover of the drive, while the second pivotal member is secured to the actuator. The second pivoting member rotates about the stationary member, and the third flexible member bends in response to the pivoting action of the second member. Rolling contact occurs between bearing surfaces of the first and second members. Overall bearing stiffness is increased with use of the bearing, and particularly radial stiffness. Increased bearing stiffness enhances system mode frequency and thereby improves bandwidth capability for a disk drive.

Abstract: A method for manufacturing a first disk drive includes incorporating a first storage disk having a first storage surface, and a first slider having a first read/write head and a slider mover into the first disk drive. Further, the first read/write head is movably positioned a first head-to-disk spacing relative to the first storage surface. The method also includes determining an incremental power level necessary to be delivered to a second slider mover of a second slider having a second read/write head to adjust a second head-to-disk spacing relative to a second storage surface by a predetermined increment. In addition, the method includes adjusting a first head-to-disk spacing by directing an operational power level to the first slider mover. The operational power level is derived from the incremental power level.

Abstract: A controller is provided having a circuit that uses non-repeatable run-out data and temperature data to provide a compensation for a fly height of a head. A disk drive may also be provided having a head for reading data from a disk, a thermistor, and a controller for controlling a fly height of the head based on temperature data obtained from the thermistor to refine a pressure determination. A method can include estimating a first pressure by the use of non-repeatable run-out data and temperature data corresponding to a disk drive.

Abstract: A conductor assembly for carrying electrical signals is provided for a disk drive having an actuator arm. The actuator arm includes a first surface lying in a first plane, a second surface lying in a second plane and an outer edge. The conductor assembly includes a first trace segment, a second trace segment and one or more segment guides for urging the trace segments together between the first and second planes. Alternatively, the conductor assembly includes a first conductor platform that supports at least the first trace segment between the first and second planes. The conductor assembly can include a first platform step so that the first conductor platform is positioned parallel to the first and second planes. In an alternate embodiment, the first trace segment that has been reshaped to be positioned between the first and second planes.

Abstract: A locking data cable (24) is disclosed. The data cable (24) includes a data plug (26) and an associated lock (32). When the data plug (26) is engaged with a data port (16) of a data storage device (12), an actuator (38) of the locking data cable (24) may be used to change the lock (32) from an unlocked position to a locked position.

Abstract: A disk drive electrical interconnect includes one or more electrical contacts for providing a controlled discharge form a disk drive head in a manner that reduces the potential for damaging the head in preparation for testing or the like. In some embodiments the electrical interconnect includes a charge dissipation electrical contact that is interconnected with a read element of the head using an electrical trace. A resistor is disposed in series between the charge dissipation electrical contact and the read element. A probe may engage the charge dissipation electrical contact to remove the electrical charge from the read element at a desired rate because of the resistor. Once the electrical charge has been sufficiently dissipated, another probe may engage another contact of the electrical interconnect to provide a desired electrical signal to the head.

Abstract: A control source and drivers for a thermal actuator fly height controlled heads in a disk drive system includes provisions for driving a heater element to dissipate various levels of power, and thus actuate the head by a desired amount, depending on whether the head is in a write mode or a read mode. Further, overshoot and undershoot are achieved as desired by providing initial values and equilibrium values and through the use of a control capacitor to provide a time constant to the drive signal to the heater element.

Abstract: The present invention is directed to a method and apparatus for modifying a spiral profile using reference tracks written onto a disk surface of a disk drive. In one embodiment, a disk drive includes a disk surface having both a read head and a write head associated therewith. A servo track writer is provided for moving the write head and the read head relative to the disk surface. The write head, under control of the servo track writer, is used to write both a first reference track near an outer diameter of the disk surface and a second reference track near an inner diameter of the disk surface. The servo track writer is used to move the write head according to a spiral profile when writing spiral servo information onto the disk surface, and the first and second reference tracks are used to modify the spiral profile.

Abstract: A method of providing a control output by selecting a controller to an actuator is discussed. A first controller having an estimator-compensator architecture is selected if the actuator is in a settle stage. A second controller having an architecture other than that of the first controller is selected when the actuator is in a track follow stage. The control output is provided from the selected controller to the actuator. The control output is indicative of the control signal.

Abstract: A disk drive for storing data includes a drive housing, a storage disk that is rotatably coupled to the drive housing, a slider assembly positioned near the storage disk, and a drive circuitry. The slider assembly includes a head that interacts with the storage disk during a data transfer operation. The drive circuitry performs a performance test on the head at a first HtD spacing and at a second HtD spacing that is different than the first HtD spacing while the drive is operation. The slider assembly includes a slider mover that moves the head between the first HtD spacing and the second HtD spacing. The slider mover can move the head to the first HtD spacing during the data transfer operation if the result of the performance test is a first test result and the slider mover moves the head to the second HtD spacing during the data transfer operation if the result of the performance test is a second test result.

Abstract: A read trajectory and/or a write trajectory of a read/write head of a rotatable disk drive is adjusted using a compensation signal that compensates for a time-varying difference between the read trajectory and the write trajectory.

Abstract: Methods are disclosed for detecting a thermal asperity condition of a head that is configured to generate a read signal by reading data on a rotatable data storage disk in a disk drive. The read signal includes a data component and a thermal component. The read signal is compared to a thermal asperity threshold to detect occurrence of an excessive level of the thermal component of the read signal as a thermal asperity condition of the head. The thermal asperity threshold is varied in response to a rate of occurrence of data value transitions in the data component of the read signal. The thermal asperity threshold can be increased in response to a decrease in the rate of occurrence of data value transitions, and can be decreased in response to an increase in the rate of occurrence of data value transitions. By varying the thermal asperity threshold, the sensitivity of the thermal asperity detector may be improved to allow lower level thermal asperity conditions to be detected with increased accuracy.

Abstract: An adapter which allows two or more hard disk drives to conduct self-testing in a single test rack slot is provided. Testing can be individually controlled for the various HDDs in a slot. Peltier cell devices or other cooling or heating devices can be controlled to achieve individualized temperature control for HDDs in the test rack slot.

Abstract: An apparatus and associated method for observing an analog position signal of a control object in relation to positional indicia, recalling a previously stored runout correction value associated with the positional indicia, and calculating a corrected position signal for the control object in relation to the position signal and the runout correction value.

Abstract: An apparatus and associated method is provided for observing a positional misplacement of a control object at a first commanded position, defining a fault threshold as a function of the observed positional misplacement, and signaling a write unsafe command to the control object in relation to comparing an instantaneous positional misplacement of the control object to the defined fault threshold during self servo writing with the control object.