Abstract: A disk drive. The disk drive includes a head, a motion mechanism, and a controller. The head is configured to access a disk configured to store data. The motion mechanism is configured to move the head. The controller is configured to determine a seek direction when an error occurred; and, the controller is configured to repeat a seek as a repeat seek to a target radial position from a direction opposite to the seek direction in an error-recovery process for the error which occurred in the seek in which the head moved to the target radial position.

Abstract: A disk drive configured to control spindle spin is provided. The disk drive includes a spindle motor for spinning a disk configured for storing data, a nonvolatile memory comprising instructions associated with a first process for spin-up of the spindle motor from a power-on mode and the nonvolatile memory comprising instructions associated with a second process for spin-up of the spindle motor from a power save mode, a controller for determining which of the first or the second process for spin-up of the spindle motor to implement in accordance with the instructions stored in the nonvolatile memory and a motor driver for spinning up the spindle motor according to the first process or according to the second process for spin-up of the spindle motor.

Abstract: A disk drive. The disk drive includes a head, a motion mechanism, and a controller. The head is configured to access a disk configured to store data. The motion mechanism is configured to move the head. The controller is configured to determine a seek direction when an error occurred; and, the controller is configured to repeat a seek as a repeat seek to a target radial position from a direction opposite to the seek direction in an error-recovery process for the error which occurred in the seek in which the head moved to the target radial position.

Abstract: Embodiments of the present invention provide a magnetic disk drive capable of controlling write/read positions by a method that takes the disturbance in the circumferential direction of a magnetic disk into consideration, thereby making it possible to improve the positioning accuracy. A magnetic disk drive in accordance with an embodiment of the present invention comprises: a magnetic recording medium on which information is written to each track thereof, the recording medium having a servo signal formed in the each track at specified intervals; a magnetic head including a read head for reading a signal from the magnetic recording medium, and a write head for writing information to the magnetic recording medium. At the time of writing/reading information by the magnetic head, a servo signal is detected from among signals read out by the read head.

Abstract: A disk drive configured to control spindle spin is provided. The disk drive includes a spindle motor for spinning a disk configured for storing data, a nonvolatile memory comprising instructions associated with a first process for spin-up of the spindle motor from a power-on mode and the nonvolatile memory comprising instructions associated with a second process for spin-up of the spindle motor from a power save mode, a controller for determining which of the first or the second process for spin-up of the spindle motor to implement in accordance with the instructions stored in the nonvolatile memory and a motor driver for spinning up the spindle motor according to the first process or according to the second process for spin-up of the spindle motor.

Abstract: Embodiments of the invention eliminate the unnecessary disk format margin to raise the format efficiency. In one embodiment, a disk control unit (MPU) predicts the variation of the next servo sector pulse interval based on each learnt servo sector pulse interval. From this predicted interval, an optimal variation of the data sector pulse interval is determined for the current servo sector pulse. This optimal variation is set to an internal register of the hard disk controller (HDC). Based on this set variation, an internal calculation circuit calculates a corrected data sector pulse interval. Thus, data sector pulses are output at intervals optimized on an individual servo sector basis.

Abstract: When an idle seek operation of a magnetic disk drive is executed under a velocity control utilizing a back electromotive force of a VCM actuator, the accuracy of the velocity control is deteriorated due to temperature variation of the VCM. To eliminate this disadvantage, a calibration of the velocity control is executed by using control information, such as a track number read from the magnetic disk medium. After the velocity control has been executed for an appointed period, by detecting the back electromotive force from the VCM actuator, an MR sense current and a power of a read write LSI are turned on for a time, positioning information on the magnetic disk medium is read out, parameters to be used for the velocity control are calibrated, and thus a stability of the control can be obtained.

Abstract: Embodiments of the present invention provide a magnetic disk drive capable of controlling write/read positions by a method that takes the disturbance in the circumferential direction of a magnetic disk into consideration, thereby making it possible to improve the positioning accuracy. A magnetic disk drive in accordance with an embodiment of the present invention comprises: a magnetic recording medium on which information is written to each track thereof, the recording medium having a servo signal formed in the each track at specified intervals; a magnetic head including a read head for reading a signal from the magnetic recording medium, and a write head for writing information to the magnetic recording medium. At the time of writing/reading information by the magnetic head, a servo signal is detected from among signals read out by the read head.

Abstract: Embodiments of the invention provide a magnetic disk drive and magnetic disk drive control method for unloading a head safely with a simple configuration when a positioning control signal cannot be detected due, for instance, to a seek error. In one embodiment, when a head cannot detect servo information prerecorded on a disk, a positioning control section resets and starts a time counting section, and switches to an unloading control section for causing the unloading control section to output a position control signal to a VCM driver. The time counting section counts tacho-pulses generated by a motor driver, and outputs time information. The unloading control section receives the time information from the time counting section. In accordance with the received time information, the unloading control section computes the position control signal that the positioning control section outputs to the VCM driver.

Abstract: Embodiments of the invention provide a magnetic disk drive and magnetic disk drive control method for unloading a head safely with a simple configuration when a positioning control signal cannot be detected due, for instance, to a seek error. In one embodiment, when a head cannot detect servo information prerecorded on a disk, a positioning control section resets and starts a time counting section, and switches to an unloading control section for causing the unloading control section to output a position control signal to a VCM driver. The time counting section counts tacho-pulses generated by a motor driver, and outputs time information. The unloading control section receives the time information from the time counting section. In accordance with the received time information, the unloading control section computes the position control signal that the positioning control section outputs to the VCM driver.

Abstract: Embodiments of the invention eliminate the unnecessary disk format margin to raise the format efficiency. In one embodiment, a disk control unit (MPU) predicts the variation of the next servo sector pulse interval based on each learnt servo sector pulse interval. From this predicted interval, an optimal variation of the data sector pulse interval is determined for the current servo sector pulse. This optimal variation is set to an internal register of the hard disk controller (HDC). Based on this set variation, an internal calculation circuit calculates a corrected data sector pulse interval. Thus, data sector pulses are output at intervals optimized on an individual servo sector basis.

Abstract: In a disk drive system, a data transducer control during a seek operation is based on the distance to be traversed. Acceleration of a motor coupled to the head initiates movement of the head. Deceleration of the motor is initiated based on the distance traversed by the head.

Abstract: To control load/unload operation of a slider with magnetic head mounted thereon, by which the speed can always be controlled stably while avoiding the slowdown or temporary stop of an actuator during load/unload operation, a magnetic disk drive is configured using magnetic disk media with the servo information written therein beforehand up to the track located at a position corresponding to the landing zone for the load operation of the magnetic head (slider). The speed of the magnetic head (slider) withdrawn to the ramp is controlled at the unload operation. In the stage of initialization for controlling the speed of the load/unload operation, various parameters are recorded and updated to apply a voltage to power amplifier for compensating for the external forces caused by the friction mainly exerted between ramp and slider support members, with reference to the take-off track or the landing track specified in the landing zone.

Abstract: In a disk drive system, a data transducer control during a seek operation is based on the distance to be traversed. Acceleration of a motor coupled to the head initiates movement of the head. Deceleration of the motor is initiated based on the distance traversed by the head.

Abstract: To control load/unload operation of a slider with magnetic head mounted thereon, by which the speed can always be controlled stably while avoiding the slowdown or temporary stop of an actuator during load/unload operation, a magnetic disk drive is configured using magnetic disk media with the servo information written therein beforehand up to the track located at a position corresponding to the landing zone for the load operation of the magnetic head (slider). The speed of the magnetic head (slider) withdrawn to the ramp is controlled at the unload operation. In the stage of initialization for controlling the speed of the load/unload operation, various parameters are recorded and updated to apply a voltage to power amplifier for compensating for the external forces caused by the friction mainly exerted between ramp and slider support members, with reference to the take-off track or the landing track specified in the landing zone.

Abstract: In a magnetic disk device and other memory devices, the scale and cycle of disturbance applied to each memory device are monitored to make a distinction between a harmful shock and harmless vibrations and detect the disturbance. Values at at least two points, of a waveform signal corresponding to the disturbance are captured. A) The above distinction is carried out from the size or magnitude of the inclination of a straight line defined by the two points. B) The function of capturing and storing the waveform signal corresponding to the disturbance as digital data, and outputting a slice level value for providing suitable detection sensitivity from a conversion table based on the digital data, or correcting and adjusting it and outputting the result is further set.

Abstract: A sector servo type magnetic disk apparatus is provided with, in addition to servo signals, a sensor such as an accelerometer for detecting a state of a magnetic head or a support for the magnetic head at a period shorter than a sampling period of the servo signals. Since an accelerometer mounted on the magnetic head or the support for the magnetic head detects an acceleration, the control performance of a servo control system can be improved, such as reduction of generation of mechanism resonance vibrations of a carriage and improvement on detection precision of a speed signal.

Abstract: In a magnetic disk device and other memory devices, the scale and cycle of disturbance applied to each memory device are monitored to make a distinction between a harmful shock and harmless vibrations and detect the disturbance. Values at at least two points, of a waveform signal corresponding to the disturbance are captured. A) The above distinction is carried out from the size or magnitude of the inclination of a straight line defined by the two points. B) The function of capturing and storing the waveform signal corresponding to the disturbance as digital data, and outputting a slice level value for providing suitable detection sensitivity from a conversion table based on the digital data, or correcting and adjusting it and outputting the result is further set.

Abstract: A sector servo type magnetic disk apparatus is provided with, in addition to servo signals, a sensor such as an accelerometer for detecting a state of a magnetic head or a support for the magnetic head at a period shorter than a sampling period of the servo signals. Since an accelerometer mounted on the magnetic head or the support for the magnetic head detects an acceleration, the control performance of a servo control system can be improved, such as reduction of generation of mechanism resonance vibrations of a carriage and improvement on detection precision of a speed signal.

Abstract: An apparatus for positioning a magnetic head includes a servo signal detection circuit for detecting a servo signal recorded on a magnetic disk in a predetermined first period, an acceleration measuring portion which is fitted to a part of a mechanism for mounting a magnetic head, outputs an acceleration signal in a direction of positioning the magnetic head, and samples the acceleration signal in a second period shorter than the first period, a comparison processing portion for comparing a deviation value computed from at least either one of the acceleration signal and the servo signal with a predetermined value, a write inhibit signal generating portion for generating a signal inhibiting write of data on a magnetic disk in accordance with the result of comparison in the comparison processing portion, and a manipulated variable compensation portion for generating manipulated variable for adjusting the position of the magnetic head from at least either one of the servo signal and the acceleration signal and a