Abstract: A hard disk drive includes a housing including a base member and a cover member, a spindle motor disposed in the housing, a data storage disk disposed on the spindle motor, an actuator disposed in the housing to move a read/write head to a position on the data storage disk, a clock signal providing unit disposed on the data storage disk to provide a clock signal of the data storage disk, a position signal providing unit disposed on the actuator to provide a position signal of the actuator, and first and second windows disposed in the housing to correspond to the clock signal providing unit and the position signal providing unit.

Abstract: A method of forming a servo track on a recording medium includes; forming a magnetic layer, defining a first servo track region having a plurality of first magnetic segments and a second servo track region having a second plurality of magnetic segments in the magnetic layer, applying a first magnetic field to induce a first magnetization direction in the first and second pluralities of magnetic segments, forming first magnetic patterns, each having a first width, and second magnetic patterns, each having a second width different from the first width, on a first side of a substrate, disposing the substrate on the recording medium, such that the first magnetic patterns are aligned in correspondence with the plurality of first magnetic segments and the second magnetic patterns are aligned in correspondence with the plurality of second magnetic segments, and applying a second magnetic field to the recording medium to selectively induce a second magnetization direction into first selected ones of the first plurali

Abstract: A hard disk drive is provided. The hard disk drive comprises a plant configured to drive the hard disk drive, a main controller configured to control the plant, and an additional controller connected in parallel with the main controller. A response function in consideration of the plant and the main controller is referred to as a main response function, and a response function in consideration of the plant and the additional controller is referred to as a first response function. The first response function cancels a function value corresponding to a section of the main response function that is associated with disturbance. The response function of the additional controller may be designed using the first response function. The hard disk drive removes a portion of the main response function to minimize the influence of the disturbance.

Abstract: A servo track writing method and a servo track write system of a hard disk drive (HDD) using the servo track write method. The servo track writing method includes performing a reference check (R/C) on a first servo pattern which is pre-written on a first surface of a disk, and if the R/C determines that a quality of the first servo pattern is not good, erasing a specific area of the first servo pattern and writing a second servo pattern on a second surface of the disk. Therefore, process time delay factors of a series of rework processes of writing servo patterns on a disk are removed to shorten a process time of the rework processes. In addition, productivity of a HDD is improved.

Abstract: A method of forming a servo track on a recording medium includes; forming a magnetic layer, defining a first servo track region having a plurality of first magnetic segments and a second servo track region having a second plurality of magnetic segments in the magnetic layer, applying a first magnetic field to induce a first magnetization direction in the first and second pluralities of magnetic segments, forming first magnetic patterns, each having a first width, and second magnetic patterns, each having a second width different from the first width, on a first side of a substrate, disposing the substrate on the recording medium, such that the first magnetic patterns are aligned in correspondence with the plurality of first magnetic segments and the second magnetic patterns are aligned in correspondence with the plurality of second magnetic segments, and applying a second magnetic field to the recording medium to selectively induce a second magnetization direction into first selected ones of the first plurali

Abstract: A hard disk drive is provided. The hard disk drive comprises a plant configured to drive the hard disk drive, a main controller configured to control the plant, and an additional controller connected in parallel with the main controller. A response function in consideration of the plant and the main controller is referred to as a main response function, and a response function in consideration of the plant and the additional controller is referred to as a first response function. The first response function cancels a function value corresponding to a section of the main response function that is associated with disturbance. The response function of the additional controller may be designed using the first response function. The hard disk drive removes a portion of the main response function to minimize the influence of the disturbance.

Abstract: A servo track writing method and a servo track write system of a hard disk drive (HDD) using the servo track write method. The servo track writing method includes performing a reference check (R/C) on a first servo pattern which is pre-written on a first surface of a disk, and if the R/C determines that a quality of the first servo pattern is not good, erasing a specific area of the first servo pattern and writing a second servo pattern on a second surface of the disk. Therefore, process time delay factors of a series of rework processes of writing servo patterns on a disk are removed to shorten a process time of the rework processes. In addition, productivity of a HDD is improved.

Abstract: Provided is a method and apparatus for controlling a motor of a disk drive. The method is used to stably control the startup current of a motor by considering a voltage drop and the disk drive uses the method. The method includes managing power-on reset retry information generated during the startup of the motor and determining the startup current of the motor that corresponds to a power-on reset retry count included in the power-on reset retry information.

Abstract: Provided is a self servo writing method of writing a final servo signal based on a reference servo signal in a hard disk drive, and more particularly, a method of writing a uniform final self servo signal by compensating for a non-uniform width of tracks where a reference servo signal is written, a hard disk drive using the method, and recording medium storing the method. The self servo writing method includes measuring the width of a target track based on the reference servo information, calculating the deviation between the measured width and a target width, and writing the final servo information while following the target track based on the center position of the target track calculated using the reference servo information and the calculated deviation of track width. According to the self servo writing method, the final servo information is written on tracks having a uniform width, even if the reference servo information is written on tracks having a non-uniform width.

Abstract: A disk drive control method and apparatus. In particular, a torque constant correction method and apparatus in a disk drive using a multiple sinusoidal seek servo scheme.

Abstract: In a method of writing a reference servo signal of a hard disk drive having a spiral reference servo signal that is referred to when writing a final servo signal is written while a head is moved across a disk for a predetermined time at a target movement velocity, an actual movement velocity of the head is detected from a counter electromotive force generated in a voice coil motor that moves that head, for the predetermined time during which the spiral reference servo signal is written, and the head is controlled to maintain the target movement velocity by feeding back the detected actual movement velocity.

Abstract: An optimal track zero determination method used in a hard disk drive and a hard disk drive using the method. The method has the operations: (a) performing a sequential seek operation on target tracks of a disk, in units of predetermined numbers of tracks, outwardly, from a track separate from a physical track zero position obtained in a servo track write operation, by a predetermined distance toward the physical track zero position; (b) determining whether the target tracks belong to a region where a track-following operation is normally performed, and determining whether an actuator arm connected to a transducer is in contact with a mechanical buffering unit during the sequential seek operation of operation (a); and (c) selecting as a logical track zero, the target track belonging to the region where the track following operation is normally performed and the actuator arm is not in contact with the mechanical buffering unit.

Abstract: In a method of writing a reference servo signal of a hard disk drive having a spiral reference servo signal that is referred to when writing a final servo signal is written while a head is moved across a disk for a predetermined time at a target movement velocity, an actual movement velocity of the head is detected from a counter electromotive force generated in a voice coil motor that moves that head, for the predetermined time during which the spiral reference servo signal is written, and the head is controlled to maintain the target movement velocity by feeding back the detected actual movement velocity.

Abstract: 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.

Abstract: A method of controlling starting current of an adaptive spindle motor in consideration of maximum allowable consumption power and a disk drive using the method. The method includes measuring a supply voltage supplied to the disk drive, calculating a maximum current that can be supplied to the spindle motor in a range of maximum allowable power in correspondence to the supply voltage measured in the measuring of the supply voltage, and applying the calculated maximum current to the spindle motor to start the spindle motor.

Abstract: A disk drive control method and apparatus. In particular, a torque constant correction method and apparatus in a disk drive using a multiple sinusoidal seek servo scheme.

Abstract: An offline self servo writing method capable of improving servo writing accuracy and reducing copying time by designing a servo pattern of a reference disk to have the same resolution as a final servo pattern, and a disk drive using the method. The offline self servo writing method includes a servo information writing process performed after a reference disk, where a reference servo pattern having the same resolution as a final servo pattern, is written and one or more blank disks are assembled in the disk drive, wherein the servo information writing process is performed by simultaneously writing identical final servo information on all disks including the reference disk by using the reference servo pattern while following tracks of the reference disk.

Abstract: Provided is a self servo writing method of writing a final servo signal based on a reference servo signal in a hard disk drive, and more particularly, a method of writing a uniform final self servo signal by compensating for a non-uniform width of tracks where a reference servo signal is written, a hard disk drive using the method, and recording medium storing the method. The self servo writing method includes measuring the width of a target track based on the reference servo information, calculating the deviation between the measured width and a target width, and writing the final servo information while following the target track based on the center position of the target track calculated using the reference servo information and the calculated deviation of track width. According to the self servo writing method, the final servo information is written on tracks having a uniform width, even if the reference servo information is written on tracks having a non-uniform width.

Abstract: Provided is a method and apparatus for controlling a motor of a disk drive. The method is used to stably control the startup current of a motor by considering a voltage drop and the disk drive uses the method. The method includes managing power-on reset retry information generated during the startup of the motor and determining the startup current of the motor that corresponds to a power-on reset retry count included in the power-on reset retry information.

Abstract: An apparatus and method for removing mechanical resonance in a disc drive using an adaptive notch filter. Mechanical resonance harmful to a system is removed by a notch filter that adaptively varies the frequency characteristics of the filter with respect to the mechanical resonance frequency existing in the system.