Abstract: A hard disk drive using an increase in servo address mark delays to create a touchdown flag in response to a slider making contact with a rotating disk surface while accessing a track. This may be used particularly when the track being accessed is located away from the Inside Diameter (ID). The hard disk drive may further use resistive heater electrical readings to determine the touchdown flag for track locations near the ID. The hard disk drive may be calibrated during manufacture and/or may be recalibrated in the field with this method. The calibrated hard disk drive is a product of this method. The method may be used during normal access operations and/or may be embodied as a program system residing in computer readable memory for instructing a computer operating the hard disk drive, where the computer and/or the memory may or may not be included in the hard disk drive.

Abstract: Unequal zoning for track following on a hard disk drive comprising at least one magnetic disk, a read/write head connected to at least one actuator arm and capable of reading and writing data on said at least one magnetic disk, a controller capable of moving said at least one actuator arm. A track is followed using the read/write head on the surface of the at least one magnetic disk. Information is stored at the controller regarding off-track displacement of the read/write head. A plurality of unequal zone partitions is created, wherein an unequal zone partition of the plurality of unequal zone partitions represents a physical region of the at least one magnetic disk and wherein the plurality of unequal zone partitions are based on the information regarding the off-track displacement of the track and are used by the controller to compensate for the off-track displacement of the track.

Abstract: In a disk drive, a wedge-based scheme is used to determine wedge offset correction values for a track of the disk drive. Correction values for the offset of each servo wedge are calculated wedge-by-wedge, based on the position error signal (PES) of the most recently measured servo wedge in combination with the measured PES of other servo wedges. To minimize transport delay of the servo, the majority of servo-control calculations may be pre-calculated prior to measuring the PES at the current wedge. Wedge offset correction values for a given servo wedge are corrected iteratively with each revolution of the storage disk.

Abstract: A magnetic disk device includes a head that reads position information, a position-information correction value for correcting the position information, and an error correcting code for the position-information correction value from a storage medium; an MCU and an ECC circuit for correcting an error in the position-information correction value based on the error correcting code; and an SVC that performs position control based on either one of the position-information correction value read by the head and the position-information correction value with the error corrected by the MCU and the ECC circuit, and the position information read by the head so that the head is located at a target position on the storage medium.

Abstract: A magnetic hard disk drive includes a method for eliminating that portion of track following error by a read/write transducer that is caused by repeatable runout of the disk tracks. The repeatable runout is eliminated by application of an iterative algorithm that calculates feed-forward correction terms based on gain coefficients iteratively calculated from the amplitude and phase portions of a Bode plot characterizing the system. The corrective coefficients can be inserted into the hard disk drive at a summing junction that redefines the centerline of the track, or at a summing junction that causes the actuator to follow the repeatable runout and make non-repeatable runout corrections relative thereto.

Abstract: Provided is a process for manufacturing a magnetic recording medium having a magnetically partitioned magnetic recording patterns, which comprises the following steps, conducted in the order: (1) step of forming a magnetic layer on a non-magnetic substrate, (2) step of exposing the surface of regions of the magnetic layer to a reactive plasma or a reactive ion, which regions are to magnetically partition the magnetic layer for forming a magnetically partitioned magnetic recording pattern, and (3) step of exposing the magnetically partitioned magnetic layer to an inert gas irradiation. Preferably, a step of removing surface layer portions of said regions of the magnetic layer is carried out after the step (1) but before the step (2). The surface of the magnetic layer of produced magnetic recording medium exhibits good resistance to corrosion caused by oxidation or halogenation.

Abstract: A data storage apparatus includes a data storage medium, a write element, a non-volatile cache memory circuit, and a controller circuit. The controller circuit is configured to record data on the data storage medium in groups of overlapping tracks using the write element. The controller circuit is configured to store a shingle block of data from a subset of the overlapping tracks in the non-volatile cache memory circuit, while at least a portion of the data in the shingle block of data is updated.

Abstract: In an information recording apparatus such as a hard disk drive, a ramp for retreating its head from a recording medium when the apparatus is stopped is provided opposing the information recording medium. In such an information recording apparatus, the information recording medium may sometimes collide with the ramp when the apparatus falls down. By inclining a portion opposing the ramp of a glass substrate in the information recording medium, even if the information recording medium strikes the ramp, the information recording medium is prevented from being cracked.

Abstract: A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module servo module comprises two servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted metric and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. A first multiplying node receives a first unweighted metric and a first weight signal and is operable to output a first weighted metric. A second multiplying node receives a second unweighted metric and a second weight signal and outputs a second weighted metric. A summing node receives the first and second weighted metrics and outputs a combined weighted metric to an LPOS word decoder.

Abstract: A data storage medium comprises a plurality of data regions, and a plurality of servo regions configured to provide positioning information to a reading device. Each of the plurality of data regions corresponds to more than one of the plurality of servo regions. The more than one of the plurality of servo regions are configured to provide positioning information to the reading device at discrete times corresponding to a data operation of a corresponding data region.

Abstract: According to one embodiment, a magnetic storage medium, includes a magnetic recording layer that includes: a servo area including predetermined servo information; a user data area including predetermined user information; two preamble areas including a plurality of magnetic bodies made of magnetic particles, the magnetic bodies being arranged in a staggered pattern so that the staggered pattern is inverted with respect to an axis of symmetry at a track center; and a re-sync mark area positioned at a head of the preamble areas and indicates a start of the preamble areas.

Abstract: According to one embodiment, a storage device includes: a control circuit configured to perform a write retry when data writing fails, wherein the control circuit recognizes that read commands are issued at regular intervals for reproducing continuous pieces of data, and upon detecting an error requiring the write retry to be performed in the data writing by a write command received during the reproduction, the control circuit interrupts the data writing, perform data reading to store the data in the buffer memory after allocating a storage area for the data in the buffer memory, and then resumes the data writing.

Abstract: Drive waveforms with which extension and contraction characteristics of an actuator corresponding to a number of track eccentricity amounts are stored as data. By reading servo information written in a disk is obtained as a signal indicating a head displacement amount from a track. The head is moved in a direction in which the track is displaced by obtaining an amplitude corresponding to a slip amount of the head position and a rotation angle of maximum eccentricity, reading drive waveforms which is optimal in driving the actuator from the memory and driving the actuator with a drive waveform matched with the rotation angle at which the eccentricity is maximum.

Abstract: A read signal for one revolution of each of a plurality of tracks jitter of which is cancelled is obtained and a binary-coded image data for the read signal is generated and the track number position of each servo area is specified from the binary-coded image data. Further, a read signal in this position in radial direction is obtained from the track number position of each of the specified servo areas and the servo area is tested by the read signal.

Abstract: A hard disk drive with a patterned disk that has a discrete track. The disk drive includes a controller that controls a head and a voice coil motor to optimize a writing of information onto the discrete track. Writing optimization can occur by initially writing a track of information and recording the write position. The written track is then located by reading the information with a read element of a drive head and analyzing a quality of the read signal, such as signal amplitude or error rate. The read position is then recorded. The information is erased and the head is moved. The process of writing, finding the written track location, storing the write and read positions and again moving the head is repeated. The write and read positions that provide the best quality signal is saved and subsequently used to write and read data on the discrete track.

Abstract: A data-storage device with a security function for user data stored in a data-storage medium. The data-storage device includes: the data-storage medium for storing data; an authentication processing section for performing an authentication process with a key obtained from a host; an error correction circuit for performing error correction in reading data at an address designated by a read command from a host which has been recognized as an authorized user for analysis access by the authentication processing section; and an analysis processing section for generating data indicating the positions of the error correction and transferring the data to the host.

Abstract: According to one embodiment, a magnetic disk drive uses a patterned medium on which data tracks having a recording layer and grooves having no recording layer as a disk. The magnetic disk drive includes a correction unit which corrects the head center position of a write head so that a head edge portion on the side to which the top edge of the write head is tilted falls within or substantially falls within a groove on the side to which the top edge of the write head is tilted.

Abstract: A magnetic recording disk drive has a position-error-signal (PES) servo pattern divided into at least two circumferentially adjacent fields that extend radially across the data tracks and include PES blocks that are DC magnetized in one direction, with each PES block having a magnetization opposite to the magnetization of its radially adjacent neighboring PES blocks. Each PES field is contiguous with and shifted radially relative to its circumferentially adjacent neighbor PES fields. Each PES block has a single DC magnetization, and the length of the magnetization is substantially longer than the length of the magnetizations in the other fields of the servo pattern.

Abstract: A method for controlling the effects of seek-induced vibration of a component part in a hard-disk drive. The method includes determining a resonant frequency of seek-induced vibration of the component part and a reference amplitude of a frequency-component in a first voice-coil-motor signal (VCMS) at the resonant frequency. The method also includes synthesizing a second VCMS with an amplitude of a frequency-component attenuated below the reference amplitude of the frequency-component in the first VCMS at a frequency in a resonance-band bracketing the resonant frequency. The method also includes driving a voice-coil of a voice-coil motor with the second VCMS to reduce an amplitude of a frequency-component at the resonant frequency in a second PES of the seek of the data track associated with the second VCMS below a reference amplitude of a frequency-component at the resonant frequency in the first PES associated with the first VCMS.

Abstract: To avoid the occurrence of a recording error by suppressing the influence that a magneto-static interaction acting between the pattern dots exerts on a recording process and expand a margin for recording synchronization timing lag or tracking misregistration on the pattern dot. Each pattern dot has a structure in which a plurality of parts having different magnetization reversal fields are bonded with exchange interaction in the in-plane direction of a medium, substrate. The positional relationship between the parts having different magnetization reversal Fields is substantially coincident between the adjacent pattern dots, which are arranged to have a gradient of magnetization reversal field in a track direction or track transverse direction. Further, the recording is performed by adapting a gradient of recording magnetic field to the gradient of magnetization reversal field. Other methods and systems are described as well.

Abstract: A servo write method for a hard-disk drive. The method includes generating, with an input of characteristics of a magnetic-recording head and a magnetic-recording disk which are incorporated into the hard-disk drive, a yield prediction model from a correlation between yields of the hard-disk drive, and characteristics of the magnetic-recording head and the magnetic-recording disk of the hard-disk drive in a process. The method also includes predicting a yield which is obtained when each magnetic-recording head is used as a position control head, selecting as the position control head a magnetic-recording head that has a highest predicted yield, and writing a servo signal.

Abstract: While a microactuator is controlled to cause a head to follow a track on a disk surface, one or more other microactuators are separately controlled to offset other heads away from locations of thermal asperities on other associated disk surfaces.

Abstract: According to one embodiment, a disk drive capable of performing a dynamic offset control (DOC) is provided. The disk drive has an offset module and an updating module. The offset module calculates an offset value that changes during a one-rotation period of a disk, from the offset-measuring position data recorded in the disk. The updating module updates the offset value to a new one if a disk shift has occurred.

Abstract: In a servo control loop, servo burst signals that are read from a plurality of servo burst patterns that include a split servo burst pattern contain frequency acquisition error. The frequency acquisition error is at least partially removed to generate a frequency acquisition error compensated position error signal (PES).

Abstract: According to one embodiment, a magnetic recording medium to which a signal is recorded by reversing magnetization of a magnetic body, includes: a servo region to which a servo signal is written; a data region configured to include a magnetic region of a track to which data is written, the magnetic region being separated from other magnetic region of other track; and a periodic magnetic pattern region configured to be provided at a head portion of the data region following the servo region, and is inclined at a predetermined angle with respect to a circumferential direction of the magnetic recording medium, over a predetermined length in a radius direction of the magnetic recording medium.

Abstract: According to one embodiment, an information storage device includes a recording/reproducing head, a positioning controller, a position detector, a storage module, and a position error detector. The position detector detects the position of the recording/reproducing head. The storage module stores servo control filters. The position error detector generates a new position error signal from a target position and the position of the recording/reproducing head when the positioning controller performs positioning control with control current obtained from a position error signal having passed through each servo control filter. Upon occurrence of a recording/reproducing error, learning to calculate a vibration amount from the position of the recording/reproducing head is sequentially performed for the servo control filters for a predetermined time.

Abstract: According to one embodiment, an information storage apparatus, includes: a recording medium with a first servo pattern having absolute position information and a second servo pattern having relative position information; a record reproducing head; a standard position detector calculating a standard position of the second servo pattern where an absolute position on the recording medium is specified, from a positional relationship between the first servo pattern and the second servo pattern; a head position controller positioning the record reproducing head in a target position on the recording medium, using the absolute position information of the first servo pattern, the standard position, and the relative position information of the second servo pattern; and a record signal generator generating a record signal to record a third servo pattern having absolute position information on the recording medium in the target position by the record reproducing head.

Abstract: According to one embodiment, an information storage medium includes a plurality of sectors arranged in a circumferential direction of a disk-shaped substrate, each sector having a servo pattern that is formed on the substrate and in which information indicating a position in a radial direction of the substrate is magnetically recorded, and a plurality of recording dots that is arranged with a predetermined pitch in the circumferential direction of the substrate and in which information is to be magnetically recorded. The servo pattern has a magnetic pattern arranged in the circumferential direction with a pitch having a predetermined integral ratio to the pitch of the recording dots. A recording dot arranged nearest to the servo pattern among the recording dots in each sector is arranged at a position having a constant phase relationship to the pitch of the servo pattern of the sector comprising the recording dots in any of the sectors.

Abstract: A self servo writing disk controller detects a plurality of spiral sync marks and a plurality of spiral bursts corresponding to one of a plurality of servo spirals from a read signal from the read/write head. A timing reference signal is generated based on timing of at least one of the plurality of the spiral sync marks. A position error signal is generated based on timing of at least one of the plurality of spiral sync marks and a magnitude of at least one of a plurality of spiral bursts. The timing reference signal and the position error signal are used by the disk drive for timing and positioning in self writing initial servo wedges to the disk.

Abstract: A control method includes determining whether a size of write data specified by a command supplied from a host is smaller than a size of a physical sector of a recording medium, lowering priority of the write data when the size of the write data is smaller than the size of the physical sector, continuously reading, when a plurality of commands for write data having lowered priority are supplied, data in physical sectors specified in the plurality of commands, and executing a modify write process on the basis of a result of continuously reading the data.

Abstract: Data recovery information characterizes data recovery procedure (DRP) steps to be performed within a hard disk drive (HDD) in response to a miss. Particular data recovery information corresponds to a radial position of the actuator and, therefore, the position of the magnetic recording read/write head relative to the associated storage media at the location at which the miss occurred. The data recovery information is based on the physical shape of a write pole and on how the physical shape of the pole inherently affects operational data error associated with the head. Because of the foregoing characteristics of such data recovery information, a more efficient and performant data recovery procedure is performed based thereon.

Abstract: A method of writing information to an area of a bit-patterned medium, in which a magnetized probe generates a magnetic probe field at the area of bit-patterned medium to be written, applying an oriented static magnetic field, and applying an oriented microwave field at a selected frequency, resulting in the writing of information onto the area of bit-patterned media.

Abstract: A bit patterned media (BPM) encoded recordable medium includes a servo control field including servo bits. Each servo bit is represented by a servo bit pattern of dots and gaps on the recordable medium. In the servo bit patterns, substantially no two dots are placed immediately next to one another, and substantially all servo bit patterns start with a gap and/or substantially all servo bit patterns end with a gap.

Abstract: A magnetic disk includes: a data recording region having first magnetic parts; the first magnetic parts being arranged in a circumferential direction in the nonmagnetic region and form tracks, and the tracks being arranged in a radial direction at a track pitch Tp; and a burst pattern region having burst patterns making a magnetic head follow the first magnetic parts, the burst patterns having second magnetic parts, the second magnetic parts forming base units arranged at a pitch Sp in a radial direction of the disk, the pitch Sp being more than large as the track pitch Tp, the base units including a plurality of base units arranged in a circumferential direction of the disk, and the base units adjacent to each other in the circumferential direction being displaced from each other by the pitch Sp in the radial direction of the disk.

Abstract: In a particular embodiment, a storage system is disclosed that includes a discrete track media having a plurality of concentric data tracks to store data and including a respective plurality of non-magnetic regions to separate adjacent data tracks. The non-magnetic regions include encoded position information. The storage system further includes a controller adapted to adjust a position of a read/write head relative to a center of a particular track based on the encoded position information.

Abstract: A recordable medium according to some embodiments includes a servo control field having a bit patterned media (BPM) pattern. The pattern includes a plurality of isolated magnetic islands or dots arranged in a down-track orientation and in a cross-track orientation. A phase of dots arranged on the medium in the servo control field varies in a first cross-track direction. The dots arranged on the medium may include a first phase pattern that has a first phase gradient in the first cross-track direction and a second phase pattern that has a second phase gradient, different from the first phase gradient, in the first cross-track direction. The dots may include a plurality of dot composites including a plurality of dots.

Abstract: In a servo control loop, phase detection between a clock signal and servo burst fields on a movable storage media is carried out with compensation for the effects of frequency variation in the timing of servo burst fields.

Abstract: One embodiment of the invention includes a disk-drive motor control system. The system comprises a seek mode power supply configured to provide a first voltage corresponding to a seek mode associated with a disk-drive voice control motor (VCM). The system also includes a track mode power supply configured to provide a second voltage corresponding to a tracking mode associated with the disk-drive VCM. The first voltage can be greater than the second voltage. The system further includes a disk-drive motor driver configured to provide a current to the disk-drive VCM at a first magnitude in the seek mode based on the first voltage, at a second magnitude in the tracking mode based on the second voltage, and at a third magnitude in a head-retraction mode.

Abstract: A recording system for magnetic storage devices, including a beam column for generating a beam, a platform for moving a magnetic storage medium relative to the beam, and a signal generator for sequentially, or in a continuously alternating manner, deflecting the beam. In turn, the beam is directed according to displacement of dots on the extent of the magnetic storage medium such that dots of a plurality of dot groupings can be written to on the extent during a single pass of the beam column above the extent.

Abstract: In a recording device, a bit patterned medium comprises a track of bit cells, each settable to one of two distinct bit states. The track comprises two generally parallel rows of bit cells. The bit cells in one row are offset in a down track direction from the bit cells in the other row. A write head spans the two rows. A controller synchronously applies write signals to the write head to set the trailing bit cell covered by the write head as the track moves relative to the write head, and thereby write data to the track. The trailing bit cell covered by the write head alternates from being in one row to being in another row. Read sensors are positioned to independently read bit cells in respective rows, as the track moves relative to the write head along the down track direction.

Abstract: A magnetic disk apparatus includes a magnetic disk, a magnetic head, a servo reproduction signal generator and a magnetic head controller. The disk includes a data recording area and a servo-pattern area. The data recording area includes a non-magnetic area scattered with magnetic regions, and the servo-pattern area includes uniformly magnetized magnetic regions larger than the magnetic regions in the recording area. The magnetic head reciprocates radially of the disk, giving a magnetization direction to the magnetic regions in the data recording area and reading the magnetization direction of the magnetic regions in the data recording area and the servo-pattern area. The servo reproduction signal generator reads the servo-pattern area, using the magnetic head, via an absolute-value calculation circuit to generate a servo reproduction signal before the recording or reading with respect to the data recording area.

Abstract: A servo master having a pattern capable of being magnetically transferred as a servo pattern to a magnetic recording medium, wherein the servo master is formed of a material having a magnetic anisotropic constant perpendicular to a surface of the magnetic recording medium. The magnetic transfer method can include preparing a servo master patterned with a servo pattern to be formed on a magnetic recording medium, and arranging the servo master on the magnetic recording medium and applying an external magnetic field to the servo master in a first direction perpendicular to a recording surface of the magnetic recording medium, and in a second direction parallel to the recording surface of the magnetic recording medium.

Abstract: A recording processing unit sets a track pitch narrower than a writing width of a recording element so that part of the recorded track overlapped with the unused track is overwritten, and continuously records information on a disk medium toward one direction in accordance with the track pitch. A first offset correcting unit reads a write/read offset from a storage table, in which the write/read offset is measured and saved in advance, and corrects the write/read offset in the state that a reading element is positioned at a target track. A second offset correcting unit corrects a write-once center offset, which is a positional deviation between a read center position of the reading element, which has undergone correction of the write/read offset by the first offset correcting unit, and a center position of an effective track width caused by write-once recording.

Abstract: In a dual-stage actuator magnetic drive having a coarse actuator and a fine actuator, an amplitude level of a command signal for the fine actuator during a decoupling-path control depends on a gain of an applied fine actuator model. The fine actuator model gain depends on the amplitude level of the fine actuator command signal and needs to be calibrated to avoid performance degradation. The gain is calibrated by determining a deviation of the fine actuator model gain from the fine actuator gain during decoupling-path control. This deviation is obtained by comparing gain values of the open-loop transfer functions measured for the decoupling-path control case and the single coarse actuator control case with respect to the feedback loop of the coarse actuator at an excitation signal frequency, when the excitation signal is added to the coarse actuator.

Abstract: An apparatus, system, and method are disclosed for the cancellation of repeatable runout signals. A signal processing module receives a position error signal and outputs a position compensated signal. A feed forward module receives the position error signal and outputs one or more cancellation signals to cancel one or more repeatable runout components from the position error signal when combined with the position compensated signal. A combining module combines the position compensated signal and the cancellation signals into a position command signal. A feedback module receives the position command signal and outputs the position error signal.

Abstract: A operation of storing a post code, which is read from each servo frame on a target track of a disk recording medium, in a memory if an on-track condition for determining that a head is controlled to be positioned on the target track is satisfied is executed. Next, a operation of using the post code, which is stored in the memory, for a correction of a demodulation position if the post code corresponding to each servo frame is stored in the memory and the on-track condition is satisfied in the correction of the demodulation position in each servo frame is executed.

Abstract: A control circuit which controls recording of data in a disk recording medium in an information memory device provided with the disk recording medium that rotates and has tracks of plural data sectors; a head that relatively moves along the tracks; and a recording section that records data in plural data sectors by using the head, the control circuit including: a detection section which detects whether the head is positioned at a track where a recording target exists; and a control section which makes the recording section record the data if the head is positioned at the track; or interrupts the recording if the head runs off from the track; and resumes the recording from a data sector subsequent to the data sector where the head is again positioned at the track and begins recording in the interrupted data sector when the head is rotated to the interrupted data sector.

Abstract: A hard disk drive includes a magnetic head, at least one disk and a controller. A location signal is recorded on the at least one disk for determining a location of the magnetic head in relation to the at least one disk. The controller controls the location of the magnetic head based on the location signal decoded through the magnetic head. At least one of frequency and amplitude of the location signal is variable.

Abstract: According to one embodiment, a disk drive is disclosed which has an offset measuring function for measuring a dynamic offset value necessary to a dynamic offset control using a DTM type disk. A CPU included in the disk drive writes offset measuring position information to an optimum position of lands on the disk and calculates a dynamic offset value based on the offset measuring position information.

Abstract: A controller for a positioning device is constructed and arranged to receive a position signal indicative of a position of the positioning device, compare the position signal to a set-point signal indicative of a desired position of the positioning device to obtain an error signal, selectively modify the error signal based on the amplitude and the frequency content of the error signal to obtain a modified error signal, generate a control signal for controlling the positioning device on the basis of the modified error signal. The controller may be applied to control a positioning device in a lithographic apparatus.