Class / Patent application number | Description | Number of patent applications / Date published |
360770050 | By servo signal component from carrier surface separate from information signal bearing surface | 22 |
20080204926 | Techniques For Identifying Servo Sectors In Storage Devices - Techniques are provided for identifying the servo sectors in a track on a data storage device. A data storage device identifies the servo sectors in a track by reading distributed index bits from multiple servo sectors in a track. The data storage device analyzes only one index bit from each servo sector to identify the index of a track. In some embodiments, the index of a track can be identified after examining the index bits stored in a particular number of consecutive servo sectors, even in the presence of errors. The index bits in each track can have an error tolerance with a minimum Hamming distance greater than one. In other embodiments, a data storage device compares a sliding window of the index bits read from the servo sectors to all possible N-bit vectors that exist within a pattern of the index bits stored on a track. | 08-28-2008 |
20090141392 | MEASUREMENT METHOD OF MAGNETIC DISK APPARATUS, AND MAGNETIC DISK APPARATUS - 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. | 06-04-2009 |
20090168227 | Distributed track identifier on a hard disk drive - A magnetic disk for a hard disk drive comprising a distributed track identifier is described. The disk includes a first portion of a track identifier physically located at a first location on a disk sector and a second portion of the track identifier physically located at a second location on the disk sector wherein the first portion and the second portion of the track identifier are discontinuous on the sector. | 07-02-2009 |
20090168228 | DISK DRIVE HAVING A DISK OF DISCRETE-TRACK MEDIA TYPE - 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. | 07-02-2009 |
20090185307 | Fly height detection during write operation - A hard disk drive that includes a head that is coupled to a disk. The head has a flying height and an inductance. The disk drive also includes a circuit that detects a change in the flying height by sensing a change of head inductance. The circuit can inhibit a write operation if the change in inductance exceeds a threshold. | 07-23-2009 |
20090195915 | METHOD OF FORMING REFERENCE PATTERN - 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. | 08-06-2009 |
20090316297 | SERVO MASTER AND MAGNETIC TRANSFER METHOD USING THE SAME - 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. | 12-24-2009 |
20100002333 | Method to identify short spirals - A method for writing servo onto a disk of a hard disk drive with a servo writer. The method includes writing a plurality of spiral servo signals onto a disk. The spiral servo signals include a plurality of short spirals separated by unequal distances. The short spirals are detected by determining the unequal distances and used to write a plurality of servo patterns. The unequal distances provide information of the short spirals at different quadrants of the disk. The distances between a bank of odd short spirals is different than a bank of even short spirals which allows the servo writer to determine whether the bank is odd or even without switching banks. Either the even or odd bank of short spirals can be used to locate a starting reference point from which the servo writer can count spirals and write A, B, C and D servo bursts. | 01-07-2010 |
20100123972 | INFORMATION STORAGE APPARATUS, SERVO PATTERN FORMATION CONTROL APPARATUS, AND RECORDING MEDIUM - 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. | 05-20-2010 |
20100134918 | SERVO WRITE METHOD AND SERVO WRITE SYSTEM FOR HARD-DISK DRIVE - 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. | 06-03-2010 |
20100226037 | COMBINING INFORMATION FROM PARALLEL SERVO CHANNELS - 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. | 09-09-2010 |
20100284109 | METHOD AND APPARATUS FOR ESTIMATING TOUCHDOWN OF A SLIDER IN A HARD DISK DRIVE - 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. | 11-11-2010 |
20110013312 | METHOD AND APPARATUS TO POSITION A HEAD MODULE COMPRISING SERVO ELEMENTS AND A PLURALITY OF DATA ELEMENTS - A method to position a head module, where the head module comprises at least one servo element and a plurality of data elements, where the servo element and each of the plurality of data elements can detect a servo signal, wherein the method includes moving a sequential information storage medium having a servo band encoded therein across the head module and detecting the servo band using the at least one servo element or any one of the plurality of data elements. | 01-20-2011 |
20110090590 | HEAD POSITION CONTROL DEVICE, MAGNETIC RECORDING EVALUATION APPARATUS, AND HEAD POSITION CONTROL METHOD - At time to start learning feed-forward control and under the status that servo-drive is not put in execution, a positioning error of repeatable runout is detected by means of a positioning error of repeatable runout operation section and on the basis of a value of the positioning error of repeatable runout, a drive pattern and drive interval of idling are determined by means of a feed-forward data operation section. The drive pattern is stored in a feed-forward data memory and is outputted as feed-forward data in synchronism with the rotation of a spindle during drive interval, thus performing idling of a fine-movement actuator. After the idling has ended, control initiation sequence is resumed to carry out learning of feed-forward control. | 04-21-2011 |
20110134565 | MAGNETIC RECORDING DISK AND DISK DRIVE WITH TRACK IDENTIFICATION USING PHASE-TYPE SERVO PATTERNS - A magnetic recording disk drive has a disk with a head positioning servo pattern of multiple circumferentially-spaced chevron patterns of discrete patterned servo islands. The disk drive has servo electronics that decodes the chevron patterns to determine the absolute radial position of the head without the need for separate track identification fields. The chevron pattern with the smallest radial period has a radial period P | 06-09-2011 |
20110310507 | RECORDING DEVICE AND METHOD FOR POSITIONING ELECTROMAGNETIC TRANSDUCER - According to one embodiment, a recording device comprises: a recording medium, an arm, a positioning module, a self-servo write clock generator, and an on-track module. The positioning module positions the arm at a position at which the electromagnetic transducer detects a rotational synchronization component of an intermediate pattern comprised in the recording medium. The self-servo write clock generator generates a self-servo write clock based on the detected rotational synchronization component. The on-track module positions the electromagnetic transducer to the intermediate pattern serving as a position for starting self-servo write based on the generated self-servo write clock. Until the on-track module appropriately completes the positioning, the self-servo write clock generator sequentially changes a decoding gate interval corresponding to the intermediate pattern in accordance with the rotational synchronization component, and captures a spiral reproduction waveform. | 12-22-2011 |
20120063027 | BIT PATTERNED MAGNETIC STORAGE MEDIUM - A magnetic storage medium comprises a plurality of discrete magnetic elements and first and second adjoining servo sectors. Each of the servo sectors comprises first and second rows of the discrete magnetic elements extending in a track direction. The second row of the discrete magnetic elements are stacked relative to the discrete magnetic elements of the first row in a cross-track direction that is perpendicular to the track direction. The discrete magnetic elements of the first servo sector are staggered in the cross-track direction relative to the discrete magnetic elements of the second servo sector. | 03-15-2012 |
20140285922 | MAGNETIC DISK DEVICE AND CONTROL METHOD OF MAGNETIC DISK DEVICE - A magnetic disk device includes a magnetic disk, a head and a control section. The head writes data to the magnetic disk. The control section controls the head to move along a virtual circular orbit of the magnetic disk that includes a first servo sector region and a second servo sector region. The second servo sector region has a larger servo interval than the first servo sector region, and stores a larger number of write bits than the first servo sector region. | 09-25-2014 |
20140340787 | METHOD AND SYSTEM FOR HARD DISK DRIVE THROUGHPUT OPTIMIZATION USING POSITION ERROR SIGNALING - Systems and methods are provided for throughput optimization of a hard disk drive (HDD) using position error signaling (PES) that includes determining a PES for a HDD mounted in a chassis based on a dynamic disturbance. The method also includes calculating a critical parameter of the PES. The method further includes indicating a mechanical design modification of the HDD or the chassis if the critical parameter of the PES exceeds a pre-defined threshold. | 11-20-2014 |
20150015991 | MAGNETIC INDEX MARK BIAS POINT OFFSET - The embodiments disclose an orientation control bias point coupled to a magnetic index mark and having a bias point offset set at predetermined coordinates configured to substantially prevent concentricity run-out. | 01-15-2015 |
20150092296 | METHOD AND APPARATUS FOR DETERMINING POSITION OF MULTIPLE DRIVE HEADS - Determining the radial position of a first read head of a storage device includes reading servo data from a storage media platter surface using the first read head, deriving from that servo data a first positron error signal representing a first estimate of the radial position of the first read head, reading the servo data from the storage media platter surface using a different read head, deriving from that servo data a second position error signal representing an estimate of the radial position of the different read head, and combining the first estimate of the radial position of the first read head and the estimate of the radial position of the different read head to obtain a revised estimate of the radial position of the first read head. The combining could include taking account of a known positional offset between the first read head and the different read head. | 04-02-2015 |
20150109701 | ELECTRONIC SYSTEM WITH MEDIA PREPARATION MECHANISM AND METHOD OF OPERATION THEREOF - An apparatus includes: a media; a head over the media; and control circuitry configured to cause the head to: write a first precondition track with a preconditioning pattern on the media, and write a data track on the media at a first inter-track spacing with the head positioned in a first direction from the first precondition track. | 04-23-2015 |