Abstract: Embodiments of the invention compensate for repeatable run-out errors without causing servo system instability. In one embodiment, HDD has a peak filter on a feedback route of a servo system. The peak filter is designed so that a rotating frequency of a magnetic disk, the high-frequency components contained in the rotating frequency and a peak match the rotating frequency and the high-frequency components. Insertion of a required peak filter into the servo system allows compensation for a repeatable run-out (RRO) error due to an event such as a deviation from the roundness of a track. Also, since a Nyquist diagram of the system satisfies required characteristics, a repeatable run-out error may be compensated for without causing instability of the servo system due to use of the peak filter.

Abstract: A technique for adaptively and stably updating the feed forward value required to drive the head of a rotational recording apparatus. A trajectory of a target position is generated for each seek command by using a compound function comprising a ramp function and a sine-wave function. The sine-wave element of the target position is transmitted to an adaptive filter for updating coefficients of the compound formula. All elements other than the sine-wave element are removed to provide a smooth update of the compound function's coefficients.

Abstract: Embodiments of the invention provide a servo information write method that makes it possible to properly locate the last-written servo information even when old servo information is overwritten by new servo information. In one embodiment, a servo track writer controller, which is within a servo track writer, reads a serial number (S/N) from a HDD (step 101), and acquires a magnetic disk drive servo information write count (P-ID) from a manufacturing process host (step 102). The next step (step 103) is then performed to control a positioner and a read/write channel so as to start writing servo information onto a magnetic disk. Servo information is sequentially written until the last track is written into (step 104). When the Nth servo information is to be written, a P-ID (N) is written subsequently to a burst signal (step 105). When the last track is written into in step 104, step 106 is performed to notify the manufacturing process host that the Nth servo information write is performed.

Abstract: Embodiments of the invention reduce the information (storage) overhead for determining the rotational position of a magnetic disk medium, as well as reducing the rotational position detection time. In one embodiment, a sector servo magnetic disk medium is configured such that: each track is divided into blocks each including a series of sectors; each block stores a positional information bit string as rotational position information; the positional information bit string is made up of a position code and an identification code, the position code including a block number, the identification code being used to identify the start or the end of the position code; and each bit of the positional information bit string is stored in a different sector of the block. When each block is made up of 12 sectors, for instance, if the block number is denoted as b0b1b2b3b4b5, the positional information bit string may be expressed as 00001b0b1b21b3b4b5, where the first 5 bits “00001” constitute an identification code.

Abstract: Embodiments of the invention provide a magnetic disk drive that exhibits excellent overall stability of a feedback control system even when the preset frequency for a peak filter significantly changes. In one embodiment, the symbol P denotes a VCM model, which outputs a head current position signal. The symbol C denotes a controller. The controller inputs a position error signal PES that is derived from a head current position signal output from the P, and outputs to addition point a control signal of a drive device for moving a magnetic head. Signal x to which disturbance noise is added enters a peak filter. The output y from the peak filter is output to addition point via a phase determination filter and added to a control signal output from the controller.

Abstract: Disclosed is a data storage device, a servo control method, and a program to reduce effects of a resonance frequency of an actuator or the like without reduction in servo control performance. A band-pass filter comprising a first all pass filter (APF) and a second adder, a second APF, and a multiplier are used to detect how much a current resonance frequency of the actuator deviates from a set value of a center frequency of the first APF, and based on a result of the detection, the center frequency of the first APF is properly adjusted. The adjustment of the center frequency of first APF enables a center frequency of a notch filter comprising the first APF and a first adder to be automatically approximated to a current resonance frequency of the actuator.

Abstract: An information recording method in a rotating storage apparatus comprising a rotating recording medium for recording information, a head for performing at least a write operation onto the rotating recording medium, and an acceleration sensor for detecting a shock. The method comprises outputting a shock out signal if an output from the acceleration sensor exceeds a predetermined threshold. A signal is output at a first level during a write inhibit period in response to the input of the shock out signal, where the write inhibit period is selected based at least in part on a time span in which the output of the acceleration sensor exceeds the predetermined threshold. Writing to the rotating recording medium is prohibited during the write inhibit period.

Abstract: The object is to raise controller gain while absorbing magnet position dispersion in a motor, and implement rotation control that is resistant to the influence of disturbance. There are provided a spindle motor 3 that performs rotational drive of a predetermined drive object, and a controller 121 that controls rotational drive of this spindle motor 3 by comparing a pulse time in rotational drive of this spindle motor 3 with a predetermined target time and performing feedback; and also provided is a peak filter 122 that compensates control by the controller 121 by varying the target time dynamically so as to suppress the rotation frequency and higher harmonic components thereof contained in the drive current waveform of the spindle motor 3.

Abstract: A rotating storage apparatus is provided for high recording reliability in an environment in which a shock or vibration exists. Provided are means for outputting a shock out signal (SO) if an output from an acceleration sensor exceeds a predetermined threshold, a latch circuit 21 for outputting a latch signal at high level during a predetermined write inhibit period after the shock out signal (SO) is input, and a write gate signal (WG) which goes high when a write is enabled. A write enable signal is generated by an AND circuit 23 having a NOT output of the latch signal as well as the write gate signal WO as its inputs.

Abstract: Embodiments of the invention compensate for repeatable run-out errors without causing servo system instability. In one embodiment, HDD has a peak filter on a feedback route of a servo system. The peak filter is designed so that a rotating frequency of a magnetic disk, the high-frequency components contained in the rotating frequency and a peak match the rotating frequency and the high-frequency components. Insertion of a required peak filter into the servo system allows compensation for a repeatable run-out (RRO) error due to an event such as a deviation from the roundness of a track. Also, since a Nyquist diagram of the system satisfies required characteristics, a repeatable run-out error may be compensated for without causing instability of the servo system due to use of the peak filter.

Abstract: Embodiment of the invention inhibit an effect of repeatable runout errors without expanding servo data areas of the magnetic disk. With regard to low frequency components of positional information read by a magnetic head, which are substantially equivalent to a rotational frequency of a magnetic disk, a servo controller according to one embodiment includes: a peak filter for removing such low frequency components from the positional information; a correction module for correcting the positional information by using repeatable runout compensation data; a phase correction circuit for calculating the amount of control based on an output of the correction module; and an adding circuit for adding an output of the peak filter and an output of the phase correction circuit.

Abstract: Embodiments of the invention eliminate noise from burst signals by use of a reliable and simple method. In one embodiment, the read processor of the HDD has a noise elimination circuit. The noise elimination circuit retains multiple integral values of the waveform absolute values for each period in the burst signals read out from the head, then removes a maximum value and/or a minimum value from the multiple integral values, and transmits the remainder as noise-eliminated signal data. The noise elimination circuit is a circuit for eliminating noise from an N number of periods of burst signal data, and this circuit integrates the absolute values of the waveforms for each period in the N number of periods of burst signal data, compares the integral values of each period with one another, and outputs the remainder obtained by removing the maximum and minimum integral values, to the servo data decoder of the following stage.

Abstract: A rotational recording apparatus that comprises a shock sensor and that adaptively processes the output of the shock sensor to obtain a feed forward signal, so as to implement a stable operation within a practical range. In a rotational recording apparatus wherein a VCM system having a transfer function (G) and a controller having a transfer function (H) perform feedback, the band of a signal(s) of a shock sensor (S) is limited by a bandpass filter (F), and a resultant signal (f) is employed to obtain the output of an adaptive filter (FIR). A signal (p) that a phase shift filter (P) outputs by shifting the phase of the signal f is employed as a signal to be transmitted to a parameter adaptation algorithm (PAA). Within the limited band, the phase of the phase shift filter P matches the phase of G/(1+GH) within a range of ±90 degrees.

Abstract: A rotating storage apparatus is provided for high recording reliability in an environment in which a shock or vibration exists. Provided are means for outputting a shock out signal (SO) if an output from an acceleration sensor exceeds a predetermined threshold, a latch circuit 21 for outputting a latch signal at high level during a predetermined write inhibit period after the shock out signal (SO) is input, and a write gate signal (WG) which goes high when a write is enabled. A write enable signal is generated by an AND circuit 23 having a NOT output of the latch signal as well as the write gate signal WO as its inputs.

Abstract: A rotating storage apparatus is provided for high recording reliability in an environment in which a shock or vibration exists. Provided are means for outputting a shock out signal (SO) if an output from an acceleration sensor exceeds a predetermined threshold, a latch circuit 21 for outputting a latch signal at high level during a predetermined write inhibit period after the shock out signal (SO) is input, and a write gate signal (WG) which goes high when a write is enabled. A write enable signal is generated by an AND circuit 23 having a NOT output of the latch signal as well as the write gate signal WG as its inputs.

Abstract: A method and apparatus for controlling an access mechanism within a disk drive are disclosed. A servo apparatus comprises a first detection module for discretely detecting a displacement value of an access mechanism from a target position at predetermined time intervals, a first feedback module for calculating a first feedback value on the basis of the detected displacement value, a second detection module for discretely detecting a physical value, including the speed of the access mechanism, at least once at each of the predetermined time intervals, a second feedback module for calculating a second feedback value on the basis of the physical value, including the speed, and a motor driving module for driving a motor according to the first feedback value and the second feedback value.

Abstract: A disk drive has a data recording medium such as a disk, a spindle motor for rotating the disk, disk rotation speed controlling logics for supplying a spindle current to the above described spindle motor to rotate the disk at a constant speed, a head unit for accessing the disk, an actuator for moving the head unit, and head position controlling logics for driving the actuator and controlling the position of the head unit. The head position controlling logic obtains the value of the spindle current and controls the position of the head unit on the basis of the above described spindle current value by using the fact that the spindle current varies according to variations in the position of the head unit.

Abstract: Disclosed is a data storage device, a servo control method, and a program to reduce effects of a resonance frequency of an actuator or the like without reduction in servo control performance. A band-pass filter comprising a first all pass filter (APF) and a second adder, a second APF, and a multiplier are used to detect how much a current resonance frequency of the actuator deviates from a set value of a center frequency of the first APF, and based on a result of the detection, the center frequency of the first APF is properly adjusted. The adjustment of the center frequency of first APF enables a center frequency of a notch filter comprising the first APF and a first adder to be automatically approximated to a current resonance frequency of the actuator.

Abstract: The object is to raise controller gain while absorbing magnet position dispersion in a motor, and implement rotation control that is resistant to the influence of disturbance. There are provided a spindle motor 3 that performs rotational drive of a predetermined drive object, and a controller 121 that controls rotational drive of this spindle motor 3 by comparing a pulse time in rotational drive of this spindle motor 3 with a predetermined target time and performing feedback; and also provided is a peak filter 122 that compensates control by the controller 121 by varying the target time dynamically so as to suppress the rotation frequency and higher harmonic components thereof contained in the drive current waveform of the spindle motor 3.

Abstract: A technique for adaptively and stably updating the feed forward value required to drive the head of a rotational recording apparatus. A trajectory of a target position is generated for each seek command by using a compound function comprising a ramp function and a sine-wave function. The sine-wave element of the target position is transmitted to an adaptive filter for updating coefficients of the compound formula. All elements other than the sine-wave element are removed to provide a smooth update of the compound function's coefficients.