Abstract: Embodiments of the invention lower the servo sector's share of each track and ensure that servo sector numbers are reliably determined. According to the embodiment, in the servo sector number (SSA) section of each servo sector, servo sector number information whose bit length (k bits) is shorter than the bit length required to express the servo sector number itself is preliminarily written. The servo sector number of each servo sector is determined by using the servo sector number information in m successive servo sectors, that is, a total of m×k bits of information. Note that they satisfy the m(2m×k?1)?N relation where N denotes the total number of servo sectors per track.

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: A track map of a disk drive is generated to compensate for various conditions. A track map is a stored measurement of every “half” servo track width on a disk. Every servo half track width is measured in the factory on a disk and then the data is stored on the disk for use during drive operations. When an individual track is accessed, the appropriate servo half track width data is pulled from memory and is used to adjust a scale factor for that local half track width. The track map may be used to compensate for various conditions including varying servo track width, microjog distance, and data track spacing.

Abstract: Systems and techniques to write servo patterns on machine-readable media. In general, in one implementation, the technique includes: obtaining timing information from a spiral servo reference track on a machine-readable medium to determine head position, and generating a servo track with servo information based on the determined head position. Obtaining the timing information can involve determining a peak position of a diamond-shaped waveform and identifying occurrences of a timing-reference symbol in the spiral servo reference track. Moreover, identifying occurrences of the timing-reference symbol can involve decoding an encoded repeating pattern using multiple framings, correlating signal samples that indicate pattern transitions with valid pattern transitions as defined by the encoding, accumulating the transition pattern correlations for the multiple framings, selecting one of the multiple framings as a correct framing, and determining a waveform polarity for the signal.

Abstract: A magnetic disk incorporated into a magnetic disk device is divided radially into a plurality of areas. An inner-circumference area has servo information written thereon at a low frequency. An outer-circumference area has servo information written thereon at a high frequency. The magnetic disk device creates concentric tracks on the magnetic disk with a magnetic disk rotation center as the center of the concentric tracks and selects a dividing track that acts as a demarcation for switching the area from which servo information will be read. The magnetic disk device then deletes all the servo information that is not going to be read in each of the areas divided by the dividing track.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: Embodiments in accordance with the present invention control pitch variations that are not observed in self servo write (SSW). According to one embodiment of the present invention, an outer radius side area of a magnetic disk is erased using an external magnetic field, and an inner radius side area is subjected to self erase using a head. The magnetization state in the base of the inner radius side area is different from that of the outer radius side area before pattern writing. Therefore, in the inner radius side area and the outer radius side area, even if a radial pattern of the same pitch is read, the different APCs are measured. With SSW of this embodiment, a reference APC used in the inner radius side area is different from that used in the outer radius side area. In this manner, the pitch variation is prevented.

Abstract: A head position control device controls the position of a head with respect to a disk where post code is assigned to a servo frame. Servo frames of a disk is constituted by a servo frame not having a post code recorded in an inner side zone and a servo frame having a post code recorded in an outer side zone. The device reads the servo frame, demodulates a current position from the servo frame, drives an actuator according to the modulated position, and controls the position of the head to a target position. While implementing a high TPI, the inspection time for post codes can be decreased with a servo frame occupying ratio in consideration of the data format.

Abstract: Embodiments in accordance with the present invention ensure that the pitch of a servo write track is accurately controlled. According to one embodiment of the present invention, a Self Servo Write (SSW) uses different methods and sequences to identify read-write offsets (RWOs) and calculate target positions in inner and outer diameter sides of a magnetic disk. In the inner diameter-side area, the SSW controller uses the readout of a radial pattern written on a recording surface and a reference value to identify the RWO. The SSW controller uses the RWO value identified in the inner diameter-side area to anticipate an RWO value in the outer diameter-side area. In the outer diameter-side area, the SSW controller uses the anticipated RWO value to determine the target position of each servo write track.

Abstract: In an embodiment of the present invention, with Self Servo Write (SSW), a head slider is used to perform AC erase to a recording surface of a magnetic disk. The AC erase is performed asynchronously to every track. A frequency for use with AC erase, i.e., a frequency of an AC erase pattern is three times or higher than a burst frequency of a product servo pattern or a burst frequency of a radial pattern. By satisfying such requirements, for the magnetic disk of vertical magnetic recording, it becomes possible to substantially stop adversely affecting pattern reading in an AC erase area.

Abstract: Embodiments of the invention efficiently conduct servo corrections for preventing error propagation during SSW. In an example of the present invention, a servo position signal generator generates a servo position signal indicative of the current position of a read element on the basis of a servo signal from a servo channel. A target position generator generates correction data from multiply and add operations between the PES generated when the track that the read element is following is written, and pre-registered correction coefficients. A correction target position is generated from the correction data and a reference target position, and then output to a position error calculator. The position error calculator generates a position error signal (PES) from the servo position signal and the target position signal, and outputs PES to a servo controller.

Abstract: A magnetic disk apparatus is configured so as to read trace information from a discrete track recording medium recording the trace information for making a servo locus of a magnetic head trace the center line of physical tracks and control the servo locus of the magnetic head onto the center line of the physical tracks.

Abstract: A magnetic recording medium having a magnetic layer containing magnetic powder provided on a support is disclosed. The magnetic layer possesses a servo band in which a servo signal for controlling tracking of a magnetic head, and a data band on which a data is recorded. The servo signal is magnetized and recorded on the servo band, having been magnetized in one direction of the track direction thereof, in the direction other than the one direction. The thickness of the magnetic layer ranging from 10 to 180 ?m, and variation [standard deviation of Mrt] of the product [Mrt] of the residual magnetism by the thickness of the magnetic field being not more than 30%.

Abstract: A magnetic recording device includes a composite magnetic head, which includes a recording head and a reproduction head, and a magnetic recording medium. The magnetic recording medium includes a data region for recording data using the recording head, a mask pattern region in which an area in which servo information can be magnetically recorded and an area in which information cannot be magnetically recorded are formed in a predetermined pattern, and an initial positioning region in which a magnetic area and a nonmagnetic area that record information for positioning one of the recording head and the reproduction head in the mask pattern region.

Abstract: A storage device has a separate type magnetic head and a discrete type magnetic recording medium on which recording tracks and recording disabled areas are alternately formed. An accurate offset of the magnetic head with respect to the magnetic recording medium is measured even if the widths of the elements of the separate type head differ. While changing the write position and read position of a magnetic recording head, a write element writes measurement data to a magnetic recording medium, a read element reads the written measurement data, and the signal quality is measured and the write offset value and the read offset value are calculated from the inflexion points of a contour line on the two-dimensional map on the measured signal quality. Even if the widths of the write element and the read element differ depending on the individual magnetic recording head, an offset with respect to the separated recording tracks can be accurately measured.

Abstract: The present invention has been made to provide a control apparatus, a storage apparatus, and a head control method capable of preventing a use of a correction value that has improperly been read out. A control apparatus according to the present invention uses a correction value for head position written in a recording medium to control head position. The apparatus comprises: an allowable range acquisition section that acquires a correction value allowable range which is a previously set allowable range of a correction value; and a head position control section that controls head position using a read out correction value in the case where the correction value that has been read out from the recording medium falls within the correction value allowable range acquired by the allowable range acquisition section.

Abstract: A method of reducing microjog errors in a disk drive having a data recording disk with data tracks and a transducer head positionable on the tracks. The head includes a writer element offset from a reader element. To reduce microjog errors, track squeeze is measured at a number of locations across the surface, wherein the squeeze is due to mis-positioning of the track relative to neighboring tracks. A microjog distance for the destination track is provided, and a microjog correction value based on the measured track squeeze is calculated. The correction value is applied to the microjog distance to obtain a corrected microjog distance that reduces microjog errors due to track squeeze.

Abstract: Embodiments in accordance with the present invention relate to a positioning control system of a magnetic disk drive. Even if there is no phase correlation in a specific vibration component before and after a seek operation of a magnetic head, a resonance filter in accordance with an embodiment of the present invention follows the vibration at the frequency at high speed. A frequency showing a periodic disturbance is selected as a target frequency Ft[Hz]. A resonance filter showing a peak gain at a frequency Ft is designed. For an input to the resonance filter, a time-variable gain K(t) is used that varies depending on the time lapsed after the completion of a seek operation. This time-variable gain K(t) takes a value larger than 1 when the resonance filter starts operating, and after the lapse of a fixed length of time, the value becomes 1 by degrees.

Abstract: Self-servo-writing of multi-slot timing patterns is described. Individual timing marks are replaced with groups of timing mark slots. At each timing mark location, a time measurement is made by detecting a timing mark in one of the slots. Also, extensions to the existing timing marks are written in other slots. The combination of timing measurements at every timing mark and extensions to those timing marks written at every opportunity improves the overall precision of the timing propagation. The improved accuracy of timing mark placement produces a commensurate improvement in the placement of the concomitantly written servo-data. In addition, the alignment accuracy of the written pattern is less sensitive to variations in rotation speed and variations in the shape of written transitions. Moreover, only a single disk revolution is required at each servo radius to write servo data and propagate the timing marks to maintain timing alignment.

Abstract: The periodic component of a timing mark position error of a self-servo write pattern on a disk of a disk drive is determined based on measurements that are made of the timing mark position error at selected radial track locations. The determined periodic component of the timing mark position error is then removed based on the radial location on the disk.

Abstract: A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.

Abstract: Track mis-registration (TMR) correction is conditionally made in a hard disk drive using servo data in a closed loop servo control scheme, along with one or more alternative sensing schemes when an external shock or vibration occurs. The alternative sensing schemes include measurement of spindle motor speed using a frequency of servo markers read from a rotating disk, voice control motor (VCM) back emf, spindle motor speed back emf, and accelerometer readings. The predicted TMR resulting from the signal generated by the alternative sensing scheme(s) is simulated based upon a model of the disk drive system, and corrections are applied only if the expected TMR due to the disturbances is large enough that application of the corrections using the alternative sensing scheme would be likely to reduce the overall TMR.

Abstract: The misplacement of a servo burst during a servowriting or self-servowriting process can be corrected by erasing and re-writing that burst. A servo pattern can be selected that has sufficient radial separation between bursts such that if a burst is re-written and trimmed there should be no damage to adjacent bursts. The radial separation can be selected to be greater than the width of the appropriate write element in order to allow for some misplacement of the element during the erasing and/or re-writing of the misplaced burst. Alternatively, a batch writing approach can be used to minimize the time needed to re-write misplaced bursts. In addition, WORF information of a track can be saved in memory for future servowriting and/or can be utilized to calculate a threshold for identifying servo bursts to be repaired. This description is not intended to be a complete description of, or limit the scope of, the invention.

Abstract: A magnetic recording medium includes a servo area where servo data used for detecting a position of a magnetic head on a magnetic recording medium is recorded; and a writable data area, arranged side by side with the servo area in a track direction, on which user data is written by the magnetic head. The servo area includes a preamble area where a preamble recording pattern that represents data used for providing a clock synchronization of the servo data is formed by a plurality of magnetic sections; and a burst area where data used for detecting a relative position of the magnetic head with respect to a track center position of the servo data is recorded and on which a single burst recording pattern which is a layout pattern that tilts to the preamble recording pattern with a predetermined tilt angle is formed by a plurality of magnetic sections.

Abstract: Disturbances to actuator control caused by external vibrations are corrected using feed-forward techniques that are selectively enabled or disabled based on signal values within a track follow loop. An increase in data integrity and reliability may be achieved by reducing off-track reads and writes caused by physical disturbances to disk drives during operation. Accelerometers detect external forces imparted on a disk and an acceleration feed-forward (AFF) signal is generated to compensate for disturbances to the location of a head caused by such external forces. Application of the AFF signal to an actuator may be based on whether signal values along the track follow loop exceed a certain threshold.

Abstract: A method for writing servo information onto a disk of a hard disk drive with a servo writer. The disk has a circumferential index and a band of servo reference tracks. The circumferential index is detected from a clock signal generated from a clock track of the disk. The reference tracks include radial indices. A spiral servo pattern is written upon the detection of the circumferential index and a radial index. The servo writer includes a phase detector that detects changes in the relative position of the circumferential and radial indices and a delay circuit that delays the clock signal to offset such changes.

Abstract: Embodiments of the invention provide techniques to inspect the track pitch of a magnetic disk. In one embodiment, the track pitch is inspected using the servo information that was written onto the magnetic disk. A PES gain is set to be PG0. A head is moved to a position K near the position where control is to switch between MPES and SPES, and then MPES and SPES are calculated using reproduced burst signals and PG0. The quantity of change in the inspection HSP which is a half-servo pitch of an inspection-related burst pattern, with respect to an ideal half-servo pitch, is detected by calculating PES?, the difference between the MPES and SPES at position K. The track pitch is thus judged whether it is abnormal.

Abstract: An apparatus, system, and method are disclosed for utilizing a “shadow mask” approach to fabricate servo patterns on high density patterned media. The apparatus may include a deposition mask having a plurality of apertures generated by a conventional lithographic process. Material may be deposited onto a substrate through the deposition mask apertures from at least one deposition source oriented at unique deposition angles. In this manner, each aperture may correspond to multiple deposition locations. Apertures may be precisely dimensioned and positioned to create servo pattern features from the resulting deposition locations. The deposition mask may also include a plurality of bit pattern apertures adapted to direct a material to a plurality of deposition locations on the substrate, the deposition locations forming a bit pattern concurrent with formation of a servo pattern.

Abstract: A method for formatting a magnetic recording disk with patterned nondata islands having alternating magnetization polarity in the along-the-track direction involves clocking write pulses to switch the magnetization direction of alternate, i.e., every other, nondata island. The clocking is controlled by the previously determined phase of the regions containing the nondata islands and the known offset along-the-track between the read head and write head. In each nondata region, every other nondata island in the along-the track direction has the same magnetization direction, with adjacent nondata islands having antiparallel magnetization directions. The disk may be either a horizontal magnetic recording disk, wherein the antiparallel magnetization directions are in the plane of the recording layer and parallel to the along-the-track direction, or a perpendicular magnetic recording disk, wherein the antiparallel the magnetization directions are “into” and “out of” the recording layer.

Abstract: A disk drive includes a data storage disk that has servo information thereon which includes first servo bursts and second servo bursts. The first servo bursts are at least substantially radially aligned with each other, and have low frequency regions therebetween. Adjacent ones of the low frequency regions between the first servo bursts have magnetic polarities that are opposite to one another. The second servo bursts are at least substantially radially aligned with each other and have low frequency regions therebetween. The first and second servo bursts are in a single servo region.

Abstract: A method for manufacturing a magnetic recording medium that has a sufficiently flat surface and includes a recording layer having a concavo-convex pattern that provides favorable accuracy of recording and reproduction. The manufacturing method includes the steps of: forming a lower non-magnetic film over a recording layer having a concavo-convex pattern; and forming an upper non-magnetic film on the lower non-magnetic film to fill concave portions 34 of the concavo-convex pattern. A bias power is applied to an object to be processed at least in the step of forming the upper non-magnetic film, and no bias power or a smaller bias power than the bias power applied in the step of forming the upper non-magnetic film is applied in the formation of the lower non-magnetic film.

Abstract: A magnetic recording and reproducing apparatus includes a magnetic head having a main magnetic pole, a magnetic recording medium of a discrete type having a predetermined convex-concave structure at data tracks and servo tracks, and a drive device body that can operate to rotationally drive the magnetic recording medium in a constant direction and cause the magnetic head to be movable in substantially radial directions of the magnetic recording medium. A relationship among parameters specifying a predetermined convex-concave shape of the data track, parameters specifying the main magnetic pole, and a skew angle is defined by a predetermined inequality. By setting a specification of the magnetic recording and reproducing apparatus in the range defined by the inequality, it is possible to prevent unwanted writing into the adjacent track to thereby realize high-density recording having extremely high reliability.

Abstract: A magnetic disk apparatus formats a single data frame as a single sector. The magnetic disk apparatus includes a read-out control unit that controls to read-out sector data by emulating an existing format (e.g., “512 bytes/sector”), and a write-in control unit that controls to write sector data by emulating the existing format (e.g., “512 bytes/sector”), when the magnetic disk apparatus receives a read command or a write command based on a format (e.g., “512 bytes/sector”) that is different from a format of the magnetic disk apparatus (i.e., one sector/one data frame) from a host.

Abstract: A magnetic recording disk drive uses a phase-quadrature position-error-signal (PES) pattern and a servo signal demodulator that is insensitive to clock errors and phase-misalignment errors. The disk has angularly-spaced servo sectors, with each servo sector having radially-spaced servo tracks that contain a phase-quadrature pattern of servo blocks. A first band in each servo sector contains two generally like patterns radially-spaced in the servo track with the second pattern phase-shifted 90 degrees along-the-track from the first pattern. A second band in each servo sector is spaced along-the-track from the first band and also has two patterns like those in the first band, but with the phase shift of the second pattern being in the opposite direction to the phase shift of the second pattern in the first band. The demodulator calculates the true amplitudes of the servo signal from the measured amplitudes of the servo signals from each band to thereby remove clock errors and phase-misalignment errors.

Abstract: Servo regions are re-magnetized in the present invention. A magnetic storage device measures a first amount which is indicative of the magnitude of magnetization of a servo region, by a read head portion. The first amount may be a reproduced output, or an inverse of a gain used in an automatic gain control, etc. Servo regions are re-magnetized by a write head portion, when a servo region is detected in which a ratio of the measured first amount to an initial value of the first amount is smaller than a predetermined value, i.e., it is determined that the magnetization is reduced.

Abstract: The magnetic recording and reproducing device has a magnetic recording medium, a recording head for writing magnetic data on the magnetic recording medium, and a reproducing head for reading magnetic data from the magnetic recording medium. In the magnetic recording medium, each track is formed by a convex portion with a predetermined track width, and a plurality of the tracks are arranged in parallel at intervals of a predetermined track gap. The relationship represented by the following formula (I) is satisfied: {Tw+(2×Tg)}/1.2?MWw??(I) wherein Tw represents the track width, Tg represents the track gap, and MWw represents the magnetic write width of the recording head.

Abstract: 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.

Abstract: The present invention provides a magnetic recording unit, including: a magnetic head; a magnetic recording medium having a servo pattern for adjusting a position of the magnetic head; a frequency detecting element for detecting a frequency in the servo pattern on a track corresponding to the position in a radial direction of the magnetic recording medium, on the basis of a reproduction signal obtained by reading the servo pattern with the magnetic head; a storage element for storing in advance information on predetermined frequencies corresponding to the positions of tracks of the magnetic recording medium; a tracking element for comparing the frequency detected on the track by the frequency detection element and the information on the frequency corresponding to the same track, the information being stored in the storage element, and for generating a signal for adjusting the position of the magnetic head, the signal being generated on the basis of a difference between the frequencies.

Abstract: A recording apparatus capable of securely reading out data for causing a head to follow along circular tracks set virtually. Therefore, on-track control along the virtual tracks is possible by the conversion data on the discoid record medium even when, for example, the printed circuit board in a recording apparatus has been replaced.

Abstract: A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.

Abstract: The amount of position error written into a servo burst pattern can be reduced by using additional media revolutions to write the pattern. Where the edges of two servo bursts are used to define a position on the media, trimming the first burst and writing the second burst on separate revolutions will result in a different amount of position error being written into each burst. The end result will be a reduction in the overall error in position information. In order to further reduce the position error given by a burst pair, each burst also can be trimmed and/or written in multiple passes. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: An apparatus, method, and system for providing a fine adjustment for transducing head positioning in a hard disk drive (HDD). The apparatus, method, and system include reading a positioning error field wherein the resulting signal is a substantially sinusoidal position error signal (PES), filtering the PES to remove low frequencies and attenuate high frequencies, sample the filtered PES at a multiple of the channel frequency, filter the higher frequency harmonics, down sample the PES, and provide a signal proportional to the amplitude of the down sampled PES. This signal is the reference signal to the head positioning servo.

Abstract: The present invention is a method and apparatus for positioning a read/write head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, where each of the tracks has a servo field with servo bits. The servo bits are read to provide a position signal for positioning a read/write head. The method determines a difference in position between an initial and a subsequent position of the read/write head on a track, where the subsequent location occurs after the read/write head has moved one revolution from the initial position on the track. The initial and subsequent positions are offset laterally. The method generates a compensation signal based on the initial position, the subsequent position and the difference. The position signal and the compensation signal are combined to provide a compensated position signal for positioning the read/write head. Various embodiments are described.

Abstract: The present invention is a method and apparatus for providing positional information of a disk. The disk has at least one side with a plurality of tracks, each having a first burst in a first servo field and a second burst in a second servo field. The first burst provides a first portion of track position information while the second burst provides a second portion of track position information. When combined, the first and second portions provide a position of a corresponding track. Each track further includes a third and a fourth burst that provides a first portion and a second portion of disk side position information. When combined, the first and second portions of disk side position information provide the disk side position of the disk. Each track also includes a burst that provides the quadrant position of the disk.