Abstract: According to one embodiment, there is provided a disk drive. In the disk drive, a calibration module calibrates a write condition using a first area in a sequential access area on a disk to which data is to be written next time as a calibration area if the calibration is required. A manager enters the calibration area in a management table in association with a physical address of the first area used as the calibration area. A sequential write module continues a sequential writing from a second area following the first area based on skipping the first area.

Abstract: According to one embodiment, a disk storage apparatus includes an interrupt controller and a servo controller. The interrupt controller determines whether or not to carry out servo interrupt processing and holds a number of negative results of the determination. The servo controller includes an internal model configured to calculate an estimated current position of the head. The servo controller corrects a state of the internal model based on the number of negative results of the determination and performs head positioning control based on a result of a calculation of the internal model, if the result of the determination by the interrupt controller is affirmative.

Abstract: According to one embodiment, a disk storage apparatus includes a servo system. The servo system includes a state observer and performs a seek operation up to a target position with a current position of a head undetermined. The servo system performs the seek operation based on initial values including a temporary position, while allowing the state observer to operate based on the initial values, until the current position is determined. The servo system determines the current position based on the servo data read from the plurality of servo areas by the read module and a result of estimation by the state observer.

Abstract: According to one embodiment, an information write apparatus writes a track on a magnetic disk by a shingled write recording method. The information write apparatus calculates a write target position of the track based on a pitch. The information write apparatus calculates a positioning error. The information write apparatus stores the calculated positioning error. The information write apparatus integrates positioning errors of tracks written before the predetermined track is written, and corrects a write target position based on the integrated positioning error. The information write apparatus controls the position of the write head based on the corrected write target position.

Abstract: According to one embodiment, there is provided a disk drive. In the disk drive, a calibration module calibrates a write condition using a first area in a sequential access area on a disk to which data is to be written next time as a calibration area if the calibration is required. A manager enters the calibration area in a management table in association with a physical address of the first area used as the calibration area. A sequential write module continues a sequential writing from a second area following the first area based on skipping the first area.

Abstract: According to one embodiment, a frequency control apparatus includes an eccentric component storage module, a frequency correction amount calculating module, and an oscillator control module. The eccentric component storage module stores in advance an eccentric component calculated by a discrete Fourier transform of the number of clock signals measured for each servo frame. The frequency correction amount calculating module calculates the number of clock signals corresponding to the servo frame based on the eccentric component stored in the eccentric component storage module and calculates a frequency correction amount corresponding to the servo frame based on the number of clock signals. The oscillator control module controls the operation of a frequency oscillator such that a frequency for oscillating a clock signal in the frequency oscillator is adjusted according to the frequency correction amount calculated by the frequency correction amount calculating module.

Abstract: An information storage apparatus includes a disc-shaped recording medium in which control marks aligned in a predetermined rule are recorded, a head contacting or approaching a recording medium surface to reproduce/record information of the recording medium and detecting the control marks, a head driving section holding the head to move the head in a direction of coming near or away to/from a recording medium rotation center, a driving force control section controlling a driving force for head driving section, a driving time control section controlling a driving time for the head driving section using an interval of the detection of the plural control marks as a time unit, and a driving force correcting section obtaining a difference between an ideal interval based on the rule of the control marks and an actual interval of the control marks to correct the control of the driving force based on the difference.

Abstract: For a feedforward controller for controlling a position of a magnetic head in a magnetic disk drive, a vibration of the magnetic head is measured in a state in which a magnetic disk is rotated in the magnetic disk drive. From a spectrum of the measured vibration, a flutter frequency which is a frequency of a vibration caused by the magnetic disk fluttering is obtained. A filter is designed for each flutter frequency having a peak of a gain for a respective one of obtained flutter frequencies. The feedforward controller for controlling a position of the magnetic head is obtained by combining filters designed for the respective flutter frequencies.

Abstract: An actuator supports a head at one end of a rotatably supported shaft unit and supports a coil of a voice coil motor at the other end, and moves the head to an arbitrary track position of a recording medium. A sensor, attached to a coil support unit of the actuator, detects the coil vibration and outputs a vibration detected signal. A control unit controls the actuator to reduce a head position error signal based on the vibration detected signal of the sensor in time of seek and in time of settling of moving the head to a target track position on the medium through drive of the actuator and drawing the same. The vibration detected signal of the sensor includes bending vibration component of the coil and the twisting vibration component of the coil when the actuator is driven.

Abstract: An actuator supports a head at one end of a rotatably supported shaft unit and supports a coil of a voice coil motor at the other end, and moves the head to an arbitrary track position of a recording medium. A sensor, attached to a coil support unit of the actuator, detects the coil vibration and outputs a vibration detected signal. A control unit controls the actuator to reduce a head position error signal based on the vibration detected signal of the sensor in time of seek and in time of settling of moving the head to a target track position on the medium through drive of the actuator and drawing the same. The vibration detected signal of the sensor includes bending vibration component of the coil and the twisting vibration component of the coil when the actuator is driven.

Abstract: A plurality of HDDs 12-1˜12-n connected around a host 10 can be made to directly communicate with each other. For example, an HDD 12-1 makes another HDD to perform long distance seek using this communication line and measures the influence of vibration caused at that time. The measurement result is formed into a transfer function indicating the position change of the head of the relevant HDD against the operation of another HDD. An HDD is actually driven by a current value obtained by correcting the normal driving current of the driving motor of the head by the transfer function.

Abstract: A plurality of HDDs 12-1˜12-n connected around a host 10 can be made to directly communicate with each other. For example, an HDD 12-1 makes another HDD to perform long distance seek using this communication line and measures the influence of vibration caused at that time. The measurement result is formed into a transfer function indicating the position change of the head of the relevant HDD against the operation of another HDD. An HDD is actually driven by a current value obtained by correcting the normal driving current of the driving motor of the head by the transfer function.

Abstract: A resonance-frequency measuring method is used for measuring a resonance frequency of an information recording/reproducing device reproducing information recorded on a medium by driving a mechanism unit. The resonance-frequency measuring method includes the measuring step of applying sine-wave oscillations at different frequencies one by one to the mechanism unit, and counting the number of times information reproduced upon application of each of the sine-wave oscillations differs from information indicating an aimed location, and the resonance-frequency determining step of determining the resonance frequency according to the number of times counted in the measuring step.

Abstract: A disk device performs position control of a head. An acquiring unit acquires correction information and check information from a disk for checking the correction information. A judging unit judges whether the correction information acquired should be used for correcting position information recorded in the disk, based on the correction information acquired and the check information acquired.

Abstract: A head position control method performs virtual circular control which does not follow the eccentricity of a disk, and implements high precision virtual circular control, even if the servo signals of an area demodulation method are used. The method performs virtual circular control by demodulating position signals in the area demodulation method and calculates the demodulation position with the velocity offset correction of 2-phase servo signals by using both the head velocity V of the virtual circular orbit reference and the relative velocity ?V of the virtual circular orbit and the position signal.

Abstract: Position information PosN and PosQ are compared and position information Pos1 and Pos2 in which influences of an error of a position sensitivity gain appear oppositely are calculated. Subsequently, a weight gain G1=M and a weight gain G2=(1?M) are obtained from the position information Pos1. A multiplication value obtained by multiplying the third position information Pos1 by the weight gain G1 and a multiplication value obtained by multiplying the fourth position information Pos2 by the weight gain G2 are added and synthesized, thereby calculating a decoded position.

Abstract: A disk device performs position control of a head. An acquiring unit acquires correction information and check information from a disk for checking the correction information. A judging unit judges whether the correction information acquired should be used for correcting position information recorded in the disk, based on the correction information acquired and the check information acquired.

Abstract: A resonance-frequency measuring method is used for measuring a resonance frequency of an information recording/reproducing device reproducing information recorded on a medium by driving a mechanism unit. The resonance-frequency measuring method comprises the measuring step of applying sine-wave oscillations at different frequencies one by one to the mechanism unit, and counting the number of times information reproduced upon application of each of the sine-wave oscillations differs from information indicating an aimed location, and the resonance-frequency determining step of determining the resonance frequency according to the number of times counted in the measuring step.

Abstract: A resonance-frequency measuring method is used for measuring a resonance frequency of an information recording/reproducing device reproducing information recorded on a medium by driving a mechanism unit. The resonance-frequency measuring method comprises the measuring step of applying sine-wave oscillations at different frequencies one by one to the mechanism unit, and counting the number of times information reproduced upon application of each of the sine-wave oscillations differs from information indicating an aimed location, and the resonance-frequency determining step of determining the resonance frequency according to the number of times counted in the measuring step.

Abstract: A disk device includes a head part, an actuator part for moving the head part to an objective position, and a control part for controlling the actuator part, wherein the control part makes the actuator part shift to a reverse direction of the movement direction of the head part before a settling action of the head part starts being implemented.