Abstract: A system including a read channel module, a signal generating module, and a position module. The read channel module is configured to read, using a head of the disk drive, servo bursts from a servo region of a track of a disk drive. The signal generating module is configured to generate signals based on a position of the head relative to the servo bursts. The position module configured to generate a first difference and a second difference based on the signals, and determine the position of the head relative to the track based on (i) the first difference and (ii) the second difference.

Abstract: A system including a self-servo-write, a position measuring module, and a compensation module. The self-servo-write module is configured to position a head of a hard disk drive to write a first set of servo wedges on a magnetic medium of the hard disk drive. The position measuring module is configured to measure a first position of the head when the head writes the first set of servo wedges on the magnetic medium. The compensation module is configured to generate first data to compensate a repeatable error based on the first position of the head measured by the position measuring module. The first data to compensate the repeatable error is written on the magnetic medium along with the first set of servo wedges.

Abstract: A system including a signal generating module and a position control module. The signal generating module generates position error signals based on servo bursts read from a servo region of a track of a disk drive. The servo bursts are read by a head of the disk drive and include first, second, third, and fourth servo bursts. The position control module generates differences between the position error signals and determines a position of the head relative to the track based on (i) a first difference of the differences and (ii) a second difference of the differences. The first difference is based on the first servo burst and the second servo burst. The second difference is based on (i) the third servo burst and (ii) the first servo burst or the second servo burst and is independent of the fourth servo burst.

Abstract: An evaluation apparatus for evaluating a transfer characteristic of a controlled object of a controller is disclosed. The evaluation apparatus includes a response detection section that detects an input/output response of a control system, based on a signal detected in the control system. The control system includes the controller and the controlled object. The evaluation apparatus further includes a transfer characteristic calculating section that calculates the transfer characteristic of the controlled object, based at least on the input/output response.

Abstract: A system includes a servo writing module, a position measuring module, and a compensation module. The servo writing module writes a first set of servo wedges on a magnetic medium of a hard disk drive (HDD) using a head of the HDD. The position measuring module measures a position of the head when the head writes the first set of servo wedges and generates a first measured head position. The compensation module generates first compensation data based on the first measured head position to compensate a repeatable error component of the first measured head position. The servo writing module writes the first compensation data on the magnetic medium when writing the first set of servo wedges and writes second compensation data generated based on the first set and the first compensation data read from the magnetic medium when writing a second set of servo wedges on the magnetic medium.

Abstract: A magnetic disk apparatus capable of generating a reference clock signal without using an external reference by writing a clock track only once using a head of the magnetic disk apparatus even if the head is of a read/write element separation type. Using the head of the magnetic disk apparatus, a clock track is recorded only once and the recorded clock track is played back to measure the total number of clock bits in one revolution. A time interval between servo sectors is determined by dividing the total number of clock bits thus measured by the number of servo sectors. By using as a timing reference the clock bits produced by playing back the clock track, the servo sectors are recorded in such a manner that they are located at the determined interval.

Abstract: A magnetic disk apparatus and a servo pattern recording method therefor, enabling writing of servo signal with high quality, without being affected with ill influences due to fluctuation on a rotation speed when conducting the self servo write operation, comprises: a magnetic disk 102; a head 103 having a write element for use of recording information onto the magnetic disk and a read element for reproducing information from the magnetic disk; and an actuator for moving said head to a desired radial position on the magnetic disk, wherein on the magnetic disk is recorded servo patterns 110 for positioning the head on a recording surface thereof, and within each of the servo patterns are recorded, a pattern sector marker 208a as a marker for detecting passage time of the head, a track ID code 209, and a burst pattern 210 for use of detection of the radial position of the head, following a preamble 207a for use of synchronization of time-base circuit, and further recorded and disposed a second preamble 207b and

Abstract: The center of rotation of a disk medium 1 when servo information is written thereto coincides as accurately as possible with its center of rotation in the drive into which the disk medium 1 is assembled. The magnetic disk medium 1 is fixed to a spindle hub 4. A centering pin 8a of a push-aside mechanism 9 pushes aside the magnetic disk medium 1 with respect to the center of the spindle hub 4 until the disk-to-hub gap is moved to one side. Then, with a centering pin 8b of a come-back mechanism 10 placed in the same line intersecting with the center of the spindle, the magnetic disk medium 1 is pushed back to the opposite side.

Abstract: In order to achieve narrow track pitch by measuring, storing and compensating common average values for repeatable runout components between adjacent tracks in a head positioning control system for a magnetic disk drive, there are provided: means for calculating a compensated signal for the average value of the repeatable runout of each servo sector of at least two tracks of servo information reproduced from a magnetic disk, on the basis of an inverse function of the sensitivity characteristics of the tracking control system; means for storing the calculated signal; and means for compensating the servo signal on the basis of this signal.

Abstract: In order to achieve narrow track pitch by measuring, storing and compensating common average values for repeatable runout components between adjacent tracks in a head positioning control system for a magnetic disk drive, a compensation signal is calculated for the average value of the repeatable runout of each servo sector of at least two tracks of servo information reproduced from a magnetic disk, on the basis of an inverse function of the sensitivity characteristics of the tracking control system. The compensation signal is stored, and thereafter used for compensating the servo signal.

Abstract: A magnetic disk apparatus and a servo pattern recording method therefor, enabling writing of servo signal with high quality, without being affected with ill influences due to fluctuation on a rotation speed when conducting the self servo write operation, comprises: a magnetic disk 102; a head 103 having a write element for use of recording information onto the magnetic disk and a read element for reproducing information from the magnetic disk; and an actuator for moving said head to a desired radial position on the magnetic disk, wherein on the magnetic disk is recorded servo patterns 110 for positioning the head on a recording surface thereof, and within each of the servo patterns are recorded, a pattern sector marker 208a as a marker for detecting passage time of the head, a track ID code 209, and a burst pattern 210 for use of detection of the radial position of the head, following a preamble 207a for use of synchronization of time-base circuit, and further recorded and disposed a second preamble 207b and

Abstract: A magnetic disk apparatus capable of generating a reference clock signal without using an external reference by writing a clock track only once using a head of the magnetic disk apparatus even if the head is of a read/write element separation type. Using the head of the magnetic disk apparatus, a clock track is recorded only once and the recorded clock track is played back to measure the total number of clock bits in one revolution. A time interval between servo sectors is determined by dividing the total number of clock bits thus measured by the number of servo sectors. By using as a timing reference the clock bits produced by playing back the clock track, the servo sectors are recorded in such a manner that they are located at the determined interval.

Abstract: The center of rotation of a disk medium 1 when servo information is written thereto coincides as accurately as possible with its center of rotation in the drive into which the disk medium 1 is assembled.

Abstract: In order to achieve narrow track pitch by measuring, storing and compensating common average values for repeatable runout components between adjacent tracks in a head positioning control system for a magnetic disk drive, there are provided: means for calculating a compensated signal for the average value of the repeatable runout of each servo sector of at least two tracks of servo information reproduced from a magnetic disk, on the basis of an inverse function of the sensitivity characteristics of the tracking control system; means for storing the calculated signal; and means for compensating the servo signal on the basis of this signal.