Abstract: Method and apparatus for controlling the position of a control object in a closed loop control system, such as a servo control system used in a data storage device. In some embodiments, spaced apart first and second data tracks are written to a rotatable data recording medium without using repeated runout (RRO) compensation values to correct for RRO error in servo data written to the medium. A third data track is subsequently written so as to be interspersed between and partially overlap the first and second data tracks. The third data track is written using a set of RRO compensation values to correct for the RRO error in the servo data.

Abstract: A slider having a reader and a writer is moved relative to a magnetic bit pattern medium comprising magnetic dots arranged to include a plurality of pre-written servo sectors, data fields defined between servo sectors to which data can be written and erased, and pre-written timing synchronization fields interspersed within the data fields. In some approaches, two different tone patterns are read from one or more of the timing synchronization fields, and fly height of the slider is determined using the two different tone patterns. In other approaches, two odd harmonics are demodulated from a mixed tone pattern read from one or more of the timing synchronization fields, and fly height of the slider is determined using the two odd harmonics.

Abstract: The present invention realizes a calibration operation for detecting a motor speed, without employing digital correcting by an external CPU. The calibration operation calculates a comparison reference value corresponding to aback EMF detection signal of a back EMF detector circuit when a zero current flows through a motor and when an arm is fixed. Accordingly, the back EMF detection signal of the back EMF detector circuit is set as the first value and the second value responding to the non-zero current flowing through the motor, and the semiconductor integrated circuit calculates the comparison reference value from the first value and the second value. The difference between the comparison reference value and the comparison input value as the back EMF detection signal of the back EMF detector circuit is reduced by adjusting the gain of an internal amplifier of the back EMF detector circuit by an adjustment unit.

Abstract: In one embodiment, a computer-implemented method includes acquiring, by the computer, position information from encoding on a magnetic medium, calculating, by the computer, an estimated position information of the magnetic medium using a media thickness value, comparing, by the computer, the estimated the estimated position information with the position information acquired from encoding, determining, by the computer, whether an error between the estimated position information and the acquired position information is within a specified range. In response to the determining that the error is within the specified range, the media thickness value is stored by the computer to a memory. In response to the determining that the error is outside the specified range, the media thickness value is changed by the computer to make the estimated position information fall within the specified range.

Abstract: A method of controlling clearance in a disk drive, including the steps of: mounting a recording head having at least one heating element at a first distance from a top surface of the disk; measuring a first passive fly height between the top surface of the disk and a bottom surface of the head; applying a first quantity of energy to the heating element(s) to permanently deform the head and change the distance between the top surface of the disk and a bottom surface of the head to a second passive fly height that is less than the first passive fly height; and applying a second quantity of energy to the heating element(s) to temporarily deform the head and change the distance between the top surface of the disk and a bottom surface of the head to an operational clearance distance that is less than the second passive fly height.

Abstract: A magnetic recording head comprises a transducer, a heater, a writer and a laser. The transducer is configured to write to a magnetic recording medium during a write operation. The heater, writer and laser are configured to affect a protrusion of the transducer. The heater is calibrated to produce a pre-write heater power to obtain a target pre-write clearance for a write operation through use of a clearance-heater power curve. The curve is generated by measuring a clearance between the transducer and the medium as the heater is cycled from zero to a contact power.

Abstract: A computer program product, according one embodiment, includes a computer readable storage medium having program instructions embodied therewith, the program instructions readable and/or executable by a processing circuit to cause the processing circuit to: determine, by the processing circuit, an actual spacing between at least two servo tracks written on a magnetic tape based on signals from at least two servo writer elements; compare, by the processing circuit, the actual spacing with an intended spacing between the at least two servo tracks; and use, by the processing circuit, at least one actuator sandwiched between the servo writer elements to adjust a distance between the servo writer elements in response to determining that a difference between the actual spacing and the intended spacing is in a predetermined range.

Abstract: In a correction value calculating method according to an embodiment, a first distance is measured as a distance actually traveled by a head while the head is unloaded. Meanwhile, a first correction value is generated. The first correction value is used to correct a first torque value exerted on a coil when the head is unloaded. Then, a second torque value is obtained with the first correction value. The second torque value is exerted on the coil when the head is actually unloaded. Based on the second torque value, a second distance traveled by the head is calculated. Then, a second correction value used to correct the second torque value is calculated based on the first correction value, and the ratio of the first distance to the second distance.

Abstract: A method and apparatus for determining the wear on a hard disk drive. Specifically, determining the overcoat wear of a head and/or disk during operation. In one embodiment, the magnetic head is disposed adjacent to the disk. A slider voltage is applied between a disk having a first overcoat and a head having a second overcoat as the disk is spinning By monitoring in real time a change in both touchdown power and a change in an interfacial current at a head disk interface, an electrochemical oxidation of the first overcoat can be determined. Additionally, by changing the polarity of the slider voltage, an electrochemical oxidation of the second overcoat can be determined. Finally, by measuring a passivation current produced between the head and the disk, the precise location of a touchdown event can be determined.

Abstract: An apparatus according to one embodiment includes a motor having: a rotor, a magnet, and a damping layer positioned between the rotor and the magnet. The damping layer is constructed of a material characterized by converting kinetic energy into heat.

Abstract: A tape appliance that includes two read heads and two write heads arranged along a magnetic tape path. The heads are configured such that for a first longitudinal direction of tape travel along the tape path, the tape engages the tape bearing surface of a first one of the write heads followed by engaging the tape bearing surface of a first one of the read heads and flies over the tape bearing surfaces of the other write head and the other read head. For the reverse longitudinal direction of tape travel along the tape path, the tape engages the tape bearing surface of the other write head followed by engaging the tape bearing surface of the other read head and flies over the tape bearing surfaces of the first write head and the first read head.

Abstract: A method, apparatus, and system are provided for implementing touchdown measurement using thermal and voltage actuation for hard disk drives (HDDs). The touchdown measurement uses a constant power applied to a thermal flyheight control (TFC) and an electrostatic voltage bias pulse is applied between the slider body and the disk to actuate the slider into contact with the disk.

Abstract: A disk apparatus control device including an A/D converting section that samples an analog current amount signal indicating a current amount for a drive current of a motor that moves a head for accessing a storage disk of a disk apparatus, and converts the analog current amount signal into a digital current amount signal indicating the current amount. The device can further include a control signal generating section that, according to digital control, generates a digital control signal corresponding to a manipulation amount of the drive current, based on a difference between the current amount indicated by the digital current amount signal and a target value for the current amount of the drive current. Additionally, the device can include a D/A converting section that converts the digital control signal into an analog control signal, and outputs the analog control signal to a drive current generating section that generates the drive current.

Abstract: A data storage device is disclosed comprising a spindle motor configured to rotate a disk, wherein the spindle motor comprises a stator, a rotor, and a plurality of windings. The data storage device further comprises an isolation circuit configured to isolate the windings from a supply voltage, a head actuated over the disk, and control circuitry comprising a spindle motor driver comprising a plurality of switches including a first switch and a second switch configured to commutate the windings. While driving the isolation circuit with a first calibration current, the first switch is driven with a second calibration current and a first current flowing through the first switch is measured. While driving the isolation circuit with the first calibration current, the second switch is driven with the second calibration current and a second current flowing through the second switch is measured.

Abstract: A storage device has a device body and a read/write head for reading and writing data in a data track of a storage medium. An actuator system is mounted on the device body for effecting movement of the read/write head relative to the data track to align the head with the data track. The actuator system has a plurality of degrees of freedom, and a controller controls the actuator system to effect the movement. A body vibration sensor provided on the device body generates a signal indicative of vibration of the body. An actuator vibration sensor generates a signal indicative of vibration of the actuator system. The controller is adapted to process the signals from the sensors to derive a coupling signal indicative of vibration coupling between the degrees of freedom, and to control the actuator system dependent on the coupling signal and the signal from the body vibration sensor.

Abstract: A library apparatus includes an initialization processing unit and an operation processing unit. The initialization processing unit, when accepting an initialization request to initialize a storage medium to which a wireless communication device is added, the wireless communication device including an IC chip with management information and including an electronic paper with a display unit for displaying the management information, stores a label name of the storage medium and data in the management information, the label name being acquired through the initialization request, and the data being written to a block used as an index label of the storage medium. The operation processing unit, when loading the storage medium into a drive, writes the data that the initialization processing unit has stored in the management information corresponding to the storage medium to the block used as the index label of the storage medium.

Abstract: An apparatus for operating a tape storage device comprises a tape skew estimation unit for estimating a value related to a skew of a tape storage medium arranged in the tape storage device relative to a head module of the tape storage device. A servo pattern decoder is configured to decode information encoded in a servo pattern written to one or more servo bands of the tape storage medium based on read-back signals of at least two servo readers of the tape storage device arranged for reading the servo pattern from the one or more servo bands and based on the estimated skew related value.

Abstract: A system including an inter-track interference detection module and a position error signal generation module. The inter-track interference detection module determines a first inter-track interference value based on a first signal from a first sensor positioned over a first track of a rotating storage medium. The first inter-track interference value indicates energy contributed by tracks adjacent to the first track compared to energy contributed by the first track. The inter-track interference detection module determines a second inter-track interference value based on a second signal from a second sensor positioned over a second track of the rotating storage medium. The second inter-track interference value indicates energy contributed by tracks adjacent to the second track compared to energy contributed by the second track. The position error signal generation module generates a position error signal based on the first inter-track interference value and the second inter-track interference value.

Abstract: Systems and methods for reducing problems and disadvantages associated with protecting data during cold excursions are provided. A method for preventing unreliable data operations at cold temperatures may include determining whether a first internal temperature of a hard disk drive (HDD) is below a threshold temperature. The method may also include initiating an artificial seek operation if the first internal temperature is below the threshold temperature.

Abstract: An apparatus, according to one embodiment, includes a magnetic head having a plurality of servo writer elements, and an actuator, the actuator being sandwiched between first and second servo writer elements of the plurality of servo writer elements. The actuator is also configured to actively adjust a distance between the first and second servo writer elements. Other systems, methods, and computer program products are described in additional embodiments.