Samsung Electronics Co., Ltd.

Cheol-hoon Park

Sang-hoon Chu

Nam-guk Kim

Yong-gwon Lee

Chul Wan Park

Kyoung-whan Oh

Kwang-jo Jung

Jae-hyeong Kim

Ho-Joon Choi

Sang-Hoon Chu

Kang-seok Lee

Soo-young Choi

Yong-Gwon Lee

Provided is an apparatus and method of adjusting reference clock frequency in a disk drive. The reference clock frequency adjustment method includes; measuring each servo sector detection time interval, generating an error signal by subtracting initially set reference time interval information between servo sectors from the measured servo sector detection time interval information, and adjusting the reference clock frequency using the error signal such that a constant number of reference clock pulses are generated in each servo sector detection time interval regardless of variation in each servo sector detection time interval.

Method and apparatus adjusting reference clock frequency and disk drive using same

A method of determining a size of an error generated in a servo sector, a write control method of controlling whether to write data to data sectors successive to a servo sector according to the size of the error generated in the servo sector therein, a HDD using the write control method, and a recording media storing computer programs for executing the methods. A method of determining a size of an error generated in a servo sector of a HDD includes: reading servo information from the servo sector in which the error was generated; and determining the size of the error by the number of corresponding bits that differ from each other between the read servo information and a normal servo information.

Method of determining size of error and write control method for hard disc drive, hard disc drive using the write control method, and media storing computer programs for executing the methods

A method of searching to find a servo pattern corresponding to a servo pattern copy includes unparking a magnetic head and moving the magnetic head onto an intermediate area of a rotating disk, moving the magnetic head to a servo pattern copy start area by applying an initial search current to a voice coil of a voice coil motor (VCM), periodically measuring the speed of the magnetic head, controlling the speed of the magnetic head by adjusting a search current to the voice coil so that the speed of the magnetic head converges to a pre-set speed, and confirming the servo pattern recorded in the servo pattern copy start area using the magnetic head.

Method of searching to find a servo pattern corresponding to a servo pattern copy process

A method used in a disk drive system for compensating a frequency component affecting servo control performance. The method includes detecting a frequency component affecting a servo control output in a disk drive/head during a manufacturing process and storing the detected frequency component in a nonvolatile memory device. A frequency component is read from a nonvolatile memory device corresponding to a selected head each time the disk drive is turned on by a user. A parameter value of a filter is determined by using a servo control circuit of the disk drive to suppress the read frequency component.

Disk drive adaptive resonance compensation method and apparatus

In a method of measuring track widths in a hard disk drive a plurality of estimation values are calculated based on differences in intensity between a plurality first measurement signals produced in relation to a head of the hard disk drive based on a plurality of burst signals stored in servo sectors of a track when the head moves along the track on a first side of a center of the track, and a plurality of second measurement signals produced in relation to the head of the hard disk drive based on the plurality of burst signals when the head moves along the track on a second side of the center of the track opposite the first side. The estimation values are then normalized, and excessive variation in the track widths is detected based on the normalized estimation values.

Method for measuring track width of hard disk drive

A method, medium, and apparatus for controlling a spindle motor of a disk drive. Particularly provided is a method, medium, and apparatus changing a current gain of a spindle motor driver according to the operating environment of the spindle motor. The method of controlling the spindle motor, using the current gain change of the spindle motor driver, includes monitoring a spindle drive control signal indicating the operating environment of the spindle motor and changing a current gain of the spindle motor driver based on the indicated operating environment.

Method, medium, and apparatus controlling current gain change of a spindle motor driver

A method and apparatus for driving a spindle motor using adaptive feedforward control. The method includes: detecting a temperature of a drive; calculating a feedforward value corresponding to the detected temperature; and generating a first control signal that is a drive current according to a calculated feedforward value and applying the generated first control signal to the spindle motor.

Method and apparatus for driving spindle motor using adaptive feedforward control

An apparatus, medium, and method to control a disk drive, and in particular, an apparatus, medium, and method controlling a disk drive to perform a seek mode at an optimum state with respect to an operational temperature. A seek servo control method considering temperature change in controlling a disk drive may includes determining a seek time considering a given seek length and operational temperature change in a seek mode, and generating position, velocity, and acceleration trajectories to move a transducer according to the determined seek time.

Apparatus, medium, and method with seek servo control considering temperature change

A method, medium, and apparatus controlling a hard disk drive, and particularly, embodiments include methods, media, and apparatuses compensating for torque variations with respect to temperature variations in a seek servo operation, compensating for differences between modeling torque constants, used for servo designing, and actual torque constants. The method includes controlling gain of a seek control loop to vary depending on a torque constant temperature compensation value corresponding to a measured temperature of the hard disk drive, the seek control loop generating a seek driving current to be applied to a voice coil in the seek mode.

Method, medium, and apparatus compensating for torque variations based on temperature

The present invention relates to a write control method of a hard disk drive, a hard disk drive adapting the method, and a recording medium storing a program for executing the method. The write control method of a hard disk drive having a disk where servo bursts are written radially comprises: generating a primary position error signals (PESs) with respect to a target offtrack based on a difference between servo burst signals read from two adjacent servo bursts; generating a secondary PES with respect to the target offtrack based on a sum of the primary PESs or a difference there between; determining whether both the primary PESs and the secondary PES are within a predetermined write bump limit; and performing a write operation at the target offtrack if both the primary PESs and the secondary PES are within the predetermined write bump limit, otherwise prohibiting the write operation.

Write control method of hard disk drive, hard disk drive adapting the method and recording medium thereof

A seek servo control method and device for a disk drive device for performing seek servo control according to a variation in a power supply voltage for the disk drive. The seek servo control method includes: detecting a supply voltage for the disk drive; and adjusting a seek time according to a track seek length based on the detected supply voltage.

Seek servo control method for adapting to supply voltage variation and disk drive using the same

A method, medium, and apparatus controlling a hard disk drive, and more particularly, a method, medium, and apparatus controlling a track seek of a hard disk drive, where the hard disk drive compensates for a gain distortion and a phase delay caused by a notch filter and a VCM driver using a sinewave acceleration trajectory. According to the method of controlling a track seek of a hard disk drive, an ideal sinewave for obtaining a position y*(n), a velocity v*(n), and an acceleration a*(n), according to a sinewave acceleration trajectory, and a sinewave indicating a gain distortion and a phase delay may be integrated and a VCM driving current u(n) can be generated by the integrated sinewave for compensating for gain distortion and phase delay, compensating for a value C(j2&#x3c0;f) of the gain distortion and the phase delay caused by the notch filter and the VCM driver.

Method, medium, and apparatus controlling track seek in a recording and/or reproducing apparatus

A method of testing quality of a servo burst signal recorded on a hard disk drive and a recording medium adapted therefor, the hard disk drive including a plurality of sectors within one track and the burst signals for servo control recorded radially on each sector. The method includes: detecting peak positions at a radial position in which amplitudes of the recorded burst signals peak respectively on each track; comparing the detected peak positions of the burst signals on each track; detecting peak position error count, the peak position error count being a number of tracks in which offset of the detected peak positions exceed an offset limit within a predetermined number of tracks; and if the peak position error count exceeds the offset limit, determining a write quality of the servo burst signal to be low. A servo burst signal recorded with uniform intensity and a servo burst signal recorded with shift from normal position can be detected. Therefore, the quality of a servo burst signal can be managed efficiently.

Method of testing servo burst signals of hard disk drive and recording medium adapted therefor

For unlatching a head within a data storage device, such as a HDD (hard disc drive), a VCM (voice coil motor) amplifier with a switch is used for applying at least one cycle of an acceleration current pulse to a voice coil motor (VCM) for unlatching the head during an acceleration time zone. An analog to digital converter samples a characteristic of the VCM for indicating a speed of the head during the acceleration time zone. An unlatch controller terminates the acceleration time zone when the speed of the head is higher than a threshold speed, for more stable operation of the head but with guarantee of unlatching, regardless of the latch force within the HDD.

Apparatus and method for unlatching a head within a data storage device

A method and apparatus to compensate for a difference between an actual torque constant and a modeling torque constant used for servo design in a disc drive. The method has operations of: performing predetermined test seeks with respect to test seek positions into which a disc is divided; obtaining torque compensation constants from the test seeks; storing the torque compensation constants in a torque compensation constant table; and compensating for a gain of a seek control loop at a position where a seek is performed in a seek mode, using the torque compensation constants stored in the torque compensation constant table.

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Suwon-si, South Korea

Cheol-hoon Park