Abstract: N groups of servo patterns, each corresponding to the predetermined number of servo sectors, are recorded in a magnetic disk. The magnetic head positioning control apparatus of the present invention produces an RRO current correction table corresponding to each group of servo patters and selects the group of servo patterns that is the best in transferred quality of the sevro pattern as SPopt. For servo sectors (target servo sectors) corresponding to other groups of servo patterns and existing between two adjacent servo sectors corresponding to the SPopt, the magnetic head positioning control apparatus calculates an RRO current correction amount corresponding to the target servo sector by a linear interpolation calculation using the RRO current correction amount corresponding to each of the adjacent servo sectors in the RRO current correction table corresponding to the SPopt to perform the magnetic head positioning control based on the calculated RRO current correction amount.

Abstract: On a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region, where M is a natural number of two or higher. Each burst pattern is formed so as to include two types of burst signal units that are positioned at different distances from a center of data track patterns and have an equal length along a radial direction of the substrate. The length along the radial direction is (2·M/N) times the track pitch, where N is a natural number of two or higher.

Abstract: The information reproducing method manages an average magnetization state of each sector on a bit-patterned recording medium as sector management information and sets an information reproduction condition for the sector on the bit-patterned recording medium, based on the sector management information.

Abstract: A method of forming a reference pattern. The method includes: determining whether a boundary point of an initial reference pattern is located at an inner diameter region of a disk, which is inside an outermost circumferential track; and if the boundary point of the initial reference pattern is located at the inner diameter region of the disk, additionally forming a compensated reference pattern integrally with the initial reference pattern so that a final reference pattern extends in the direction of an outer diameter of the disk. The method allows compensation for a defective reference pattern into an effective reference pattern by extending the initial reference pattern according to whether the boundary point of the initial reference pattern is located inside the outermost circumferential track of the disk.

Abstract: According to one embodiment, a hard disc apparatus comprises a disc, wherein areas between neighboring servo areas are allocated to data areas including data sectors, a head module, and a storage module configured to store head alignment data, wherein the head alignment data are defined for the data areas, and includes information indicating an interval from the servo area to a first data sector, information indicating a data area in one track, a first data sector which is a start sector of the track, and information indicating the presence/absence of a defective sector including a primary defect, and the start sector of a track including the defective sector is a data sector next to the defective sector.

Abstract: On a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region, where M is a natural number of two or higher. Each burst pattern is formed so as to include two types of burst signal units that are positioned at different distances from a center of data track patterns and have an equal length along a radial direction of the substrate. The length along the radial direction is (2·M/N) times the track pitch, where N is a natural number of two or higher.

Abstract: According to one embodiment, a disk drive has a DTM type disk. The DTM type disk has a servo area on one recording surface. In the servo area, a servo pattern is recorded. The servo pattern is composed of a projection-depression pattern and an N- and P-pole magnetic pattern. The N- and P-pole magnetic pattern is recorded in an address-data region that contains a cylinder code.

Abstract: According to one embodiment, disclosed herein is a disk drive that has a disk of discrete-track media (DTM) type. The DTM disk has servo regions. Each servo region has dividing grooves and non-servo data parts. Each dividing grooves extends along the centerline of any projecting region having a width larger than a prescribed value. Each non-servo data part suppresses reproduction noise. The disk drive has a read/write channel that includes a reproduced-signal processing unit. This unit reproduces servo data from each servo region.

Abstract: A storage medium reproducing apparatus includes a storage medium that records data; a reproducing head that reads the data recorded in the storage medium; a positioning controlling unit that performs positioning control of the reproducing head with respect to tracks based on servo signals from the servo area included in the storage medium; and a reproducing processing unit that reproduces the data recorded in data area in the storage medium by reading recording dots of the data area using the reproducing head the position of which is decided on the tracks, wherein the reproducing head has a head width capable of simultaneously reading a plurality of servo dots.

Abstract: A gain controller changes a gain of a read amplifier depending on whether a head reads out servo data or user data. Further, a heater setting unit changes the temperature of a heater and a reading gain when detecting touchdown performed by the head. Accordingly, a dynamic range of AGC in a read-write channel is increased, so that error detection is prevented for touchdown that occurs because an AGC gain converged value remains at 0.

Abstract: In an implementation, a media drive comprises bit patterned magnetic media and one or more modules. The one or more modules are to cause data to be written on the bit patterned magnetic media in a data sector that includes a synchronization mark disposed between data blocks of the data sector.

Abstract: There is provided a method for generating acceleration data used in feed-forward control of head seeking, wherein, a seek distance and one of a seek period and the count of samples are received; a weighting factor for the change rate of acceleration between adjacent sample times is determined respectively; and an optimum acceleration at each sample time is obtained by performing an optimization calculation that minimizes an objective function under a constraint condition based on variables representing accelerations at each sample time, either the seek period or the count of samples, and the seek distance.

Abstract: There is provided with a positioning control system including: a head moving unit; a position detecting unit detecting a head position at predetermined time intervals; an error detecting unit detecting a position error of the head for a target position; a disturbance detecting unit detecting a non-periodic disturbance; a modifying unit modifying a first position error signal corresponding to a first head position detected in a first rotation period based on a second position error signal corresponding to a second head position detected one period length before; and a feedback controller, wherein the modifying unit modifies the first signal after reducing an amplitude of the second position error signal when a detected timing of the second head position is included in a predetermined time range with respect to a detected timing of the non-periodic disturbance detected in a second rotation period which is one period before the first rotation period.

Abstract: Embodiments of the present invention provide a perpendicular magnetic recording medium suitable for high density recording. According to one embodiment, a magnetic recording layer comprises four layers in which a first magnetic layer, a magnetic coupling layer, a second magnetic layer, and a third magnetic layer are formed above a substrate. The first magnetic layer and the second magnetic layer are perpendicular magnetization films containing an oxide, and ferromagnetically coupled with each other by way of the magnetic coupling layer, and they are, more preferably, a Co alloy layer containing an oxide. The third magnetic layer is ferromagnetically coupled with the second magnetic layer. The concentration of the oxide contained in the third magnetic layer is lower than the concentration of the oxide in the second recording layer, or the third magnetic layer does not contain the oxide.

Abstract: Embodiments of the present invention provide a magnetic disk drive capable of easily suppressing degradation of position error caused by disturbance resulting from vibration from the outside. According to one embodiment, the magnetic disk drive acquires, during a period of time of track following control, data necessary for determining a filtering characteristic required to newly be specified in a peak filter; in association with the start of subsequent seek control, determines the filtering characteristic required to be specified in the peak filter; and specifies the determined filtering characteristic in the peak filter.

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: A recording/reproducing apparatus includes: a rotary-type magnetic recording medium including a track pattern with concentric or spiral data recording tracks; a composite magnetic head including a reproducing element that reads magnetic signals from the medium and a recording element that writes magnetic signals on the medium; a control unit that moves the magnetic head over the medium to carry out tracking servo control on the reproducing element or the recording element to keep the element on a desired track; and a storage unit that stores offset information that specifies offsets for calculating an adjustment used to adjust a head position of the magnetic head during tracking servo control. The stored offset information specifies at least two different offsets per revolution of the medium. During tracking servo control, the control unit changes the adjustment at least once per revolution of the medium in accordance with offsets specified based on the offset information.