Abstract: The present invention is a method and apparatus for positioning a read/write head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, where each of the tracks has a servo field with servo bits. The servo bits are read to provide a position signal for positioning a read/write head. The method determines a difference in position between an initial and a subsequent position of the read/write head on a track, where the subsequent location occurs after the read/write head has moved one revolution from the initial position on the track. The initial and subsequent positions are offset laterally. The method generates a compensation signal based on the initial position, the subsequent position and the difference. The position signal and the compensation signal are combined to provide a compensated position signal for positioning the read/write head. Various embodiments are described.

Abstract: A method and system are disclosed for compensating disturbance applied to a plant, such as a HDD component, controlled by a state control device having an estimator & controller. The estimator & controller is adapted to generate a first control signal in response to a state signal indicating an estimated state of the plant. A second control signal is generated by applying a transfer function H(s) having defined gain/frequency characteristics to a control signal derived from the first control signal. An overall control signal is generated in response to the second control signal and the control signal derived from the first control signal and applied to the plant.

Abstract: A data input/output control method and apparatus in an input/output subsystem are provided. The data input/output control method, in a system for inputting/outputting data to/from a disk sector according to an input/output command provided from a disk driver, includes: extracting the input/output commands for inputting/outputting the data to/from disk sector from the disk driver and generating a set of input/output commands; analyzing the load feature of the input/output command based on the set of input/output commands; determining whether the load of the input/output command corresponds to a multimedia application; and controlling the data which is input/output to/from the disk to correspond to the multimedia application according to the determination result.

Abstract: A method and apparatus for determining the load of an input/output command in an input/output subsystem are provided. The method for determining the load of an input/output command in a system for inputting/outputting data to/from a disk sector according to an input/output command provided from a disk driver includes: (a) extracting the input/output commands for inputting/outputting the data to/from the disk sector from the disk driver and generating a set of input/output commands from the input/output commands; (b) analyzing the load feature of the input/output command based on the set of input/output commands; and (c) determining whether the load of the input/output command corresponds to a multimedia application based on the load feature of the input/output command.

Abstract: A servo control device for a disk drive capable of effectively compensating for a low frequency disturbance incoming to the disk drive is provided. The servo control device includes: a state variable estimator calculating a position estimation error based on a control input for controlling motion of a head and a position error signal by using a predetermined state equation; an estimation filter calculating a disturbance estimation value from the position estimation error by using a mathematical relation between a disturbance and the position estimation error; and a subtractor subtracting the disturbance estimation value from the control input.

Abstract: A speed control method of controlling a stepping motor to have a uniform instantaneous speed and an apparatus suitable for the same are provided. The stepping motor speed control method includes: calculating a repeated speed error for each phase while rotating a stepping motor at a constant speed and storing the calculated repeated speed error phase by phase; measuring a rotation speed of the stepping motor based on a target speed; sequentially and repeatedly reading the stored repeated speed errors phase by phase by synchronizing with the rotation of the stepping motor; and controlling the speed of the stepping motor with reference to the target speed, the measured speed and the repeated speed error for each phase. Accordingly, the stepping motor speed control apparatus rotates a stepping motor at a uniform instantaneous speed by controlling a rotation speed of the stepping motor phase by phase.

Abstract: A servo control method of controlling a plant to track a reference trajectory with enhanced accuracy using a reference signal and its derivative signals, an apparatus and a recording medium suitable for same. The servo control method includes: determining a polynomial indicating a reference trajectory desired by a plant and derivatives of the polynomial; sampling a plant output with respect to a plant input; generating a reference signal and its derivative signals with reference to a time between samples (a relative time); and determining a plant input at a sampling time using the generated reference signal and its derivative signals, a delayed plant input and a delayed plant output. Accordingly, a plant is controlled to track a reference trajectory with enhanced accuracy using a reference signal and its derivative signals.

Abstract: An apparatus and method are provided for quickly and finely compensating for non-repeatable run out (NPRO) of a disc drive. The NPRO compensation control apparatus in a run out compensation apparatus of a system includes: a frequency estimator directly estimating a trigonometric function value of an NRRO frequency from a predetermined signal responding to the system using a correlation between a filter coefficient of a notch filter and a notch frequency; and an NRRO compensator canceling NRRO of the system using the trigonometric function value of the NRRO frequency estimated by the frequency estimator.

Abstract: A settling control method and apparatus perform an improved settling control regardless of a seek distance when a disc drive track seek control operation is performed. An adaptive settling control method used in controlling the track seek mode of the disc drive includes: controlling a head to converge into a target position and a target velocity along with an eigen vector by transiting an initial state of the head motion onto an eigen vector line of a system at the time transiting from an acceleration/deceleration control mode of the track seek mode to a settling control mode.

Abstract: A method and apparatus for enhancing work efficiency by sharing an application between a host and a hard disk drive are provided. The method includes: forming an application interface allowing the host and the hard disk drive to share an application included in the host or hard disk drive with each other; transmitting a first control code of a first application included in the host from the host to the hard disk drive through the formed application interface; and the hard disk drive controlling a process of the first application using the transmitted first control code. Accordingly, since the application is shared between the host and the hard disk drive, the workload of the host can be shared with the hard disk drive, or the workload of the hard disk drive can be shared with the host.

Abstract: A method for writing a spiral reference servo signal suitable for a self-servo writing method in a hard disk drive includes writing a first reference pattern in an end direction of a spiral reference servo signal writing concentrically on the disk; writing a spiral reference servo signal on a current spiral track from a reference writing start position of the current spiral track; detecting a moving angle of a head to the first reference pattern, which corresponds to a distance from the reference writing start position to a reference writing end position of the spiral reference servo signal in the case that thermal expansion of the disk does not exist; compensating for a driving speed of the head with reference to the detected moving angle of the head; and writing the spiral reference servo signal on a next spiral track at a compensated driving speed of the head.

Abstract: The present invention is a method and apparatus for positioning a read/write head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, where each of the tracks has a servo field with servo bits. The servo bits are read to provide a position signal for positioning a read/write head. The method determines a difference in position between an initial and a subsequent position of the read/write head on a track, where the subsequent location occurs after the read/write head has moved one revolution from the initial position on the track. The initial and subsequent positions are offset laterally. The method generates a compensation signal based on the initial position, the subsequent position and the difference. The position signal and the compensation signal are combined to provide a compensated position signal for positioning the read/write head. Various embodiments are described.

Abstract: The present disclosure relates to a system for detecting a plurality of defect types on the surface of a disk in a hard disk drive. In particular, the disclosure relates to utilizing information obtained from a plurality of servo bits to determine if a sector contains a physical defect. Where such a defect is found, the sector's write gate is disabled and its burst signal data is ignored for track following purposes. In addition, large changes in PES are used to identify closure spike defects. Such defects are managed by providing a compensation signal to the read value of the PES to improve track following. Finally, high PES values are used to signal a third defect type where no other signs of defect are present. In such case, the sector is mapped as defective, but the burst signals continue to be used for track following purposes.

Abstract: A method, apparatus and computer program for performing a servo seek according to a voltage-constrained sinusoidal acceleration trajectory. In one embodiment, the apparatus comprises a hard disk drive which has a disk with a surface, spin motor, transducer, and an actuator arm to move a transducer across the surface of the disk. The apparatus further includes a controller that controls the actuator arm and to perform a seek having a length. The actuator arm moves the transducer across the surface of the disk with an essentially sinusoidal acceleration trajectory using a substantially constant voltage. In another embodiment, the substantially constant voltage is based on the maximum voltage from a power supply.

Abstract: An apparatus, method and computer program product for a hard disk drive defect detection system. In one embodiment, a method of detecting defects on the surface of a disk having a plurality of tracks is recited. The method comprises reading, one or more times, the servo bits for a plurality of sectors and determining a burst measure for at least one sector, where the burst measure is a function of the burst signals for the sector. This method further comprises determining a reference value, where the reference value is a function of the burst signals of the plurality of sectors, and comparing the burst measure of at least one sector to the reference value to identify a potential defect. In one embodiment, a sector is mapped as defective where its burst measure differs from the reference value by at least 5 percent.

Abstract: A method, apparatus, and computer program product for a hard disk drive servomechanism. In one embodiment, the apparatus comprises a disk which has a surface, a spindle motor that rotates the disk, a transducer which can write information onto the disk and read information from the disk, and an actuator arm that can move the transducer across the surface of the disk. The apparatus further includes a controller. The controller can determine a seek length from a first track to a second track, determine a seek time based on the seek length, scale the seek time in response to a velocity error between a calculated velocity and a design velocity for the seek length, and control the actuator arm to move the transducer across the disk surface from the first track to the second track using an acceleration trajectory.

Abstract: The present invention is a method and apparatus for positioning a read/write head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, where each of the tracks has a servo field with servo bits. The servo bits are read to provide a position signal for positioning a read/write head. The method determines a difference in position between an initial and a subsequent position of the read/write head on a track, where the subsequent location occurs after the read/write head has moved one revolution from the initial position on the track. The initial and subsequent positions are offset laterally. The method generates a compensation signal based on the initial position, the subsequent position and the difference. The position signal and the compensation signal are combined to provide a compensated position signal for positioning the read/write head. Various embodiments are described.

Abstract: A method, apparatus, and computer program product for a hard disk drive servomechanism. In one embodiment, the apparatus comprises a disk which has a surface, a spindle motor that rotates the disk, a transducer which can write information onto the disk and read information from the disk, and an actuator arm that can move the transducer across the surface of the disk. The apparatus further includes a controller. The controller can determine a seek length from a first track to a second track, determine a seek time based on the seek length, scale the seek time in response to a velocity error between a calculated velocity and a design velocity for the seek length, and control the actuator arm to move the transducer across the disk surface from the first track to the second track using an acceleration trajectory.

Abstract: An apparatus, method and computer program product for a hard disk drive defect detection system. In one embodiment, a method of detecting defects on the surface of a disk having a plurality of tracks is recited. The method comprises reading, one or more times, the servo bits for a plurality of sectors and determining a burst measure for at least one sector, where the burst measure is a function of the burst signals for the sector. This method further comprises determining a reference value, where the reference value is a function of the burst signals of the plurality of sectors, and comparing the burst measure of at least one sector to the reference value to identify a potential defect. In one embodiment, a sector is mapped as defective where its burst measure differs from the reference value by at least 5 percent.

Abstract: A method, apparatus and computer program for performing a servo seek according to a voltage-constrained sinusoidal acceleration trajectory. In one embodiment, the apparatus comprises a hard disk drive which has a disk with a surface, spin motor, transducer, and an actuator arm to move a transducer across the surface of the disk. The apparatus further includes a controller that controls the actuator arm and to perform a seek having a length. The actuator arm moves the transducer across the surface of the disk with an essentially sinusoidal acceleration trajectory using a substantially constant voltage. In another embodiment, the substantially constant voltage is based on the maximum voltage from a power supply.