Class / Patent application number | Description | Number of patent applications / Date published |
360770070 | By tracking signal recorded on or immediately beneath surface | 57 |
20090290252 | INFORMATION MEMORY DEVICE - 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. | 11-26-2009 |
20090290253 | SERVO INFORMATION CORRECTING METHOD - 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. | 11-26-2009 |
20100053800 | PHASE DETECTOR THAT COMPENSATES FOR FREQUENCY VARIATION INDUCED BIAS IN PHASES OF SERVO BURST FIELDS - 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. | 03-04-2010 |
20100128386 | REDUCING EFFECT OF FREQUENCY ACQUISITION ERROR IN A POSITION ERROR SIGNAL RESPONSIVE TO SPLIT SERVO BURST PATTERNS - 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). | 05-27-2010 |
20100134919 | MICROACTUATOR CONTROL THAT AVOIDS THERMAL ASPERITIES ON DISK SURFACES - 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. | 06-03-2010 |
20110058276 | SERVO CONTROL OF A DISK DRIVE - A disk drive comprising a head for accessing a disk, an actuator for moving the head in the radial direction of the disk and a controller. The controller for servo control of the actuator based on servo data read out from the disk by the head. The controller is configured for maintaining a width of the adaptive chasing notch filter below a specified value in servo system control and estimating an oscillation frequency of the actuator. | 03-10-2011 |
20110080672 | METHOD FOR WRITING SERVO DATA TO A DISK AND DISK DRIVE CONFIGURED TO WRITE SERVO DATA UTILIZING THE METHOD - A method for writing servo sector sets that include a plurality of separate servo sectors on a disk so that servo sectors are present at same circumferential positions but different radial positions. The method includes reading a first servo sector set in a track with a read element such that the track includes first, second and third servo sector sets. The method also includes writing the third servo sector set with a write element at a different radial position from the read element with positional control and timing control using the first servo sector set while skipping the second servo sector set if all servo sectors of the first servo sector set are non-defective. Moreover, the method includes using positional control and timing control using the second servo sector set in the writing of the third servo sector set if the first servo sector set includes a defective servo sector. | 04-07-2011 |
20110109987 | WRITING AND READING MULTI-LEVEL PATTERNED MAGNETIC RECORDING MEDIA, WITH MORE THAN TWO RECORDING LEVELS - A method and apparatus for writing magnetization states in magnetic islands of a multi-level patterned magnetic recording medium with more than two recording levels and a method and apparatus for reading readback waveforms representing written magnetization states of the magnetic islands in the multi-level patterned magnetic recording medium. Writing each magnetization state includes selecting the magnetization state, determining a write current sufficient to write the magnetization state, and applying the write current to a magnetic write head to write the magnetization state, including simultaneously writing associated magnetic states in each magnetic island of at least one pair of magnetic islands. Reading the readback waveform representing a written magnetization state is implemented through use of a magnetic read head and includes: identifying the written magnetization state by decoding the readback waveform; and displaying and/or recording the written magnetization state. | 05-12-2011 |
20160171996 | POSITION ERROR SIGNAL COMPENSATION TO PREVENT ADJACENT TRACK ERASURE | 06-16-2016 |
20160180873 | MAGNETIC DISK DEVICE AND DETERMINING METHOD OF CROSSING A ZONE BOUNDARY | 06-23-2016 |
360770080 | Distinct servo sector | 47 |
20080239555 | Multi-quadrant wedge offset reduction field values for disk drive servo - A method for servo correction includes determining a first wedge offset reduction field value for a read element from information in a servo burst area of a wedge on a disk, storing the first wedge offset reduction field value, determining a second wedge offset reduction field value for the read element from information in the servo burst area of the wedge on the disk, storing the second wedge offset reduction field value, and estimating an offset value of the read element from a desired track on the disk using at least one of the first wedge offset reduction value or second wedge offset reduction field value. | 10-02-2008 |
20080239556 | Linearizing position error signal using spiral servo information - A method for determining a position error signal in a disk drive includes writing a servo signal that has a variable offset from a track center for a plurality of concentric tracks in a servo wedge on a disk surface, forming a spiral servo track, observing the offset values for the servo signal in the servo wedges at a first of the plurality of tracks, and observing the offset values for the servo signal in the servo wedges at a second of the plurality of tracks. The method also includes determining the first error amounts from the offset values at the first of the plurality of tracks, and determining the second error amounts from the offset values at the second of the plurality of tracks. If the first error amounts and the second error amounts are equal, using one of the first or second error amounts as a correction update to a head non-linearity look-up table. | 10-02-2008 |
20080239557 | Multi-directional self servo-writing for a disk drive - A method of self servo-writing servo information to a plurality of disk surfaces in a disk drive that includes writing servo information to a plurality of disk surfaces in a first direction, writing servo information to a plurality of disk surfaces in a second direction, and determining an amount of overlap to be written on a reference surface with the reference head that will produce an overlap of servo information on each of the surfaces in the disk drive to which servo information is to be written. The method also includes switching to different tables when seeking across the overlap or border areas. | 10-02-2008 |
20080239558 | METHODS AND APPARATUS FOR DURATION CONTROL OF HARD DRIVE WRITE SIGNALS - Methods and apparatus for controlling the duration of a pulse in a hard drive write system are disclosed. A disclosed method comprises generating a current pulse, reducing the current of the pulse and conveying a portion of the current pulse to a hard drive write system. In addition, a method is disclosed whereby a portion of the current pulse is truncated. | 10-02-2008 |
20080253018 | Method for determining read/write head position based on phase detection of a servo pattern - A method determines RW head radial position relative to tracks within a magnetic data disc. This involves sensing both a S-burst signal and a P-burst signal with the RW head. The S-burst signal and P-burst signal are associated with a two-burst servo pattern on the magnetic disc. The S-burst pattern has a phase that remains constant radially across tracks within the magnetic disc. The P-burst has a second phase that rotates radially across tracks within the magnetic disc. By determining a phase difference between a sensed S-burst signal and P-burst signal, it is possible to determine the RW head radial position relative to the tracks on the magnetic disc. | 10-16-2008 |
20080259488 | Method and apparatus improving prevention of off-track writing in a hard disk drive - Embodiments of the invention include: a hard disk drive using a read track to position for writing to a write track and generating a position error signal (PES) based upon all four servo offset bursts used to disable writing when the PES exceeds a position error threshold; a preamplifier generating the PES from four bursts from a slider reading the read track to position when the write track is to be written, and methods of writing the write track using PES from four bursts of the read track that disables writing when the PES is above the position error threshold. | 10-23-2008 |
20080259489 | Apparatus and Method for Generating a Servo Pattern - A method of writing a servo pattern to a disk, wherein a servo pattern is generated in a processor. The generated servo pattern is then written to a disk. The servo pattern for a servo sector is preferably generated in a single routine. | 10-23-2008 |
20080316638 | MAGNETIC RECORDING DISK DRIVE WITH HEAD POSITIONING SERVO CONTROL SYSTEM FOR DISK SURFACES WITH IDENTICAL SERVO PATTERNS - A magnetic recording disk drive has disks with identical pre-patterned servo patterns on their front and back surfaces and a servo control system for positioning the read/write heads using the servo signals from the identical servo patterns. The servo sectors on the two disk surfaces form identical patterns of angularly spaced arcuate-shaped lines that extend generally radially across the data tracks. The arcuate-shaped lines on one surface, the front surface, generally replicate the path of the recording head as it is moved across the data tracks by a rotary actuator, so that there is a constant sampling rate of the servo sectors on the front surface regardless of radial position of the head. However, the arcuate-shaped lines on the other surface, the back surface, do not replicate the path of the recording head so the servo sampling rate is not constant but varies with radial position of the head. The disk drive servo control system implements a method to enable track seeking from one data track to another data track, regardless of whether the initial disk surface and the destination disk surface are front or back surfaces. | 12-25-2008 |
20080316639 | Large data block written on overlapping tracks in a hard disk drive - A hard disk drive with a disk that includes a first group of tracks and a second group of tracks. The second group of tracks are used to write large blocks of data. For example, data in the second group may be video or audio. The second group of tracks has a higher track density than the first group of tracks. The large data block is written sequentially in the second group of tracks so that there is only one adjacent track write within the group. Using only one adjacent track write allows the tracks within the second group to be overlapped to increase track density. | 12-25-2008 |
20090002875 | MAGNETIC RECORDING MEDIUM AND METHOD OF FABRICATING THE SAME - A magnetic recording medium and a method of fabricating the same are provided. The magnetic recording medium in which a position for magnetic recording is patterned with a magnetic material, includes a magnetic recording layer which includes a data area having a plurality of data tracks, and a servo area having a servo burst for following the data tracks, wherein the servo burst includes a plurality of bursts disposed in a zigzag structure along a downtrack direction, and each of the bursts includes a plurality of burst pieces having different coercivities from each other. The magnetic recording medium is subjected to two servo-recording processes, so that a signal similar to an alternative signal written in a burst having a burst pattern used in a related art continuous medium can be obtained. | 01-01-2009 |
20090002876 | METHOD AND APPARATUS FOR WRITING SERVO DATA, USING SPIRAL SERVO PATTERNS IN A DISK DRIVE - According to one embodiment, a servo-writing method for use in a disk drive, in which a CPU causes a head to record final patterns in a disk, by using the multi spiral servo pattern recorded in the disk. The CPU uses a designated spiral servo pattern, positioning the head at a target position, so that the head may write the final patterns at the target position and may read sector-address data contained in the final patterns. | 01-01-2009 |
20090027802 | MAGNETIC RECORDING APPARATUS - Provided is a magnetic recording apparatus including a magnetic recording medium having a magnetic recording position patterned of a magnetic substance and a read head reading information from the magnetic recording medium, wherein the magnetic recording medium includes: a data area having the magnetic recording position patterned including a plurality of data tracks; and a servo area including a servo burst for tracking the data tracks, wherein the servo burst includes a plurality of bursts deviating from one another in a downtrack direction, and a width of each of the bursts is equal to or greater than a width of the read head and narrower than twice the width of the read head. According to this structure, although data is reproduced using a read head having a greater width than a width of each of data tracks, a linear section in which an output voltage is reduced depending on a size of an off-track is formed. As a result, a dead zone can be removed. | 01-29-2009 |
20090034115 | MAGNETIC RECORDING MEDIUM, RECORDING /REPRODUCING APPARATUS, AND STAMPER - A servo pattern is formed in a servo pattern region on at least one surface of a substrate of a magnetic recording medium by a concave/convex pattern including a plurality of convex parts, at least protruding end parts of which are formed of magnetic material, and at least one concave part. The servo pattern region includes an address pattern region and a burst pattern region. The at least one concave part is formed in the servo pattern region so that a larger of an inscribed circle with a largest diameter out of inscribed circles on protruding end surfaces of the convex parts formed in the address pattern region and an inscribed circle with a largest diameter out of inscribed circles on protruding end surfaces of the convex parts formed in the burst pattern region is an inscribed circle with a largest diameter out of inscribed circles on protruding end surfaces of the convex parts formed in the servo pattern region. | 02-05-2009 |
20090040652 | MAGNETIC RECORDING DISK AND DISK DRIVE WITH PATTERNED PHASE-TYPE SERVO FIELDS FOR READ/WRITE HEAD POSITIONING - A magnetic recording disk drive uses a disk having pre-patterned servo sectors extending generally radially across the data tracks. The servo sectors include at least two position error signal (PES) bursts or fields. The phases of the PES fields in the servo readback signal are demodulated to generate a PES to control the disk drive actuator for positioning the read/write heads. Each field contains generally radially directed magnetized stripes, with each stripe comprising a plurality of islands forming a zigzag pattern. The stripes have alternating polarity of magnetizations in the along-the-track direction. In one implementation there are four fields: a first pair of fields A and B wherein the zigzag pattern of the radial stripes in field A is the mirror image about a radial line of the zigzag pattern of the radial stripes in field B, and a second like pair of fields C and D, but wherein the radial stripes in fields C and D are shifted radially by one-half the island radial height from the radial stripes in fields A and B. | 02-12-2009 |
20090052081 | Compensation for Variable Servo Track Width - 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. | 02-26-2009 |
20090073602 | SERVO INFORMATION WRITING METHOD, MAGNETIC HEAD TESTER AND MAGNETIC DISK TESTER USING THE SERVO INFORMATION WRITING METHOD - A mark information is recorded in an area which is on a circumference of a magnetic disk corresponding to a last track in which a servo information write is ended or a track, which is one or two in front of the last track in which servo information is not written and the mark information is detected by returning a magnetic head in a radial direction of the magnetic disk by a fine movement stage after the magnetic head is moved to a next aimed track by a coarse movement stage. The servo information write position is detected by the magnetic head and the servo information is written in a servo information write position of a next track by positioning the magnetic head therein by using the fine movement stage. | 03-19-2009 |
20090097156 | MAGNETIC RECORDING DISK AND DISK DRIVE WITH PATTERNED PHASE-TYPE SERVO FIELDS FOR READ/WRITE HEAD POSITIONING - A magnetic recording disk drive uses a disk having pre-patterned servo sectors extending generally radially across the data tracks. The servo sectors include at least two position error signal (PES) bursts or fields. The phases of the PES fields in the servo readback signal are demodulated to generate a PES to control the disk drive actuator for positioning the read/write heads. Each field contains generally radially directed magnetized stripes, with each stripe comprising a plurality of discrete radially-spaced generally parallelogram-shaped islands, each island having its length oriented at an acute angle relative to a track centerline. The stripes have alternating polarity of magnetizations in the along-the-track direction. In one implementation there are four fields: a first pair of fields A and B wherein the pattern of the radial stripes in field A is the mirror image about a radial line of the pattern of the radial stripes in field B, and a second like pair of fields C and D, but wherein the radial stripes in fields C and D are shifted radially from the radial stripes in fields A and B. | 04-16-2009 |
20090097157 | METHOD AND SYSTEM FOR HEAD POSITION CONTROL IN EMBEDDED DISK DRIVE CONTROLLERS - A track follow controller includes a burst selector selecting at least one burst pair based on burst pair selection data. A linear position calculator calculates a primary head position and a secondary head position based on the at least one burst pair, and calculates a head linear position based on the primary head position and the secondary head position. | 04-16-2009 |
20090122441 | Bit Patterned Magnetic Media Data Format - 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. | 05-14-2009 |
20090168229 | SERVO PATTERNS FOR SELF-ASSEMBLED ISLAND ARRAYS - Servo patterns and associated methods of fabricating servo patterns are described. For patterned storage media, data sectors and servo sectors may be patterned using self-assembly. In one embodiment, self-assembly is used to form a first array of islands and a second array of islands in servo sectors that are track-wise offset. A servo writing process is then performed to write a desired servo pattern in the arrays, such as for burst fields, synchronization fields, etc. | 07-02-2009 |
20090168230 | Mixed format disk drive - A magnetic disk for a hard disk drive comprising a plurality of physical sector sizes is disclosed. The magnetic disk includes a first sector size area physically formatted according to a first physical sector size and a second sector size area physically formatted according to a second physical sector size different from the first sector size by a multiple of the first sector size wherein the second sector size can be presented externally as multiple sectors of said first sector size. | 07-02-2009 |
20090168231 | METHOD AND APPARATUS FOR REPRODUCING SERVO DATA FROM A DISCRETE TRACK MEDIA IN A DISK DRIVE - 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. | 07-02-2009 |
20090185308 | MAGNETIC RECORDING MEDIUM, RECORDING REPRODUCING APPARATUS, AND STAMPER - 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. In a predetermined range where both ends in the radial direction do not match a center in the radial direction of a burst pattern, (2·M) centers in the radial direction of the burst patterns are present at intervals of (1/N) times the track pitch in the radial direction, the two types of burst signal units are formed of recording regions and do not overlap each other in the direction of rotation, centers of the burst signal units in the radial direction are separated by (M/N) times the track pitch, and facing end parts in the radial direction of the burst signal units are separated via non-recording regions. | 07-23-2009 |
20090195917 | HARD DISC APPARATUS AND HEAD ALIGNMENT METHOD - 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. | 08-06-2009 |
20090195918 | METHOD AND APPARATUS FOR REPRODUCING INFORMATION ON BIT-PATTERNED RECORDING MEDIUM - 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. | 08-06-2009 |
20090207522 | MAGNETIC RECORDING MEDIUM, RECORDING/REPRODUCING APPARATUS, AND STAMPER - 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. In a predetermined range where both ends in the radial direction do not match a center in the radial direction of a burst pattern, (2·M) centers in the radial direction of the burst patterns are present at intervals of (1/N) times the track pitch in the radial direction, the two types of burst signal units are formed of non-recording regions and do not overlap each other in the direction of rotation, centers of the burst signal units in the radial direction are separated by (M/N) times the track pitch, and facing end parts in the radial direction of the burst signal units are separated via recording regions. | 08-20-2009 |
20090237832 | ERROR CORRECTION CODING OF LONGITUDINAL POSITION INFORMATION - A sequential data storage medium, comprising a sequence of plurality of servo patterns that provide lateral position information and longitudinal position information, wherein each of the plurality of servo patterns comprises a first burst comprising a first plurality of pulses, a second burst comprising a second plurality of pulses, a third burst comprising a third plurality of pulses, and a fourth burst comprising a fourth plurality of pulses. The spacings between the first plurality of pulses, in combination with the spacings between the second plurality of pulses, encode a first bit without affecting the recovery of lateral position information. The spacings between the third plurality of pulses, in combination with the spacings between the fourth plurality of pulses, encode a second bit without affecting the recovery of lateral position information. The sequence of plurality of servo patterns comprises a sequence of the first bits and a sequence of the second bits to form an error-correction codeword providing error-correction capability. | 09-24-2009 |
20090290254 | CONTROLLING DEVICE, MAGNETIC STORAGE MEDIUM, STORAGE DEVICE, AND METHOD FOR DETERMINING OFFSET AMOUNT - A magnetic storage medium has tracks and guard bands magnetically separating adjacent tracks. The tracks and the guard bands are alternately and concentrically disposed. The tracks includes a plurality of data tracks in which data can be written and from which data can be reproduced and servo patterns disposed between the data tracks and allowing reproduction of positional information of the data tracks. The magnetic storage medium includes an offset-amount measurement area in which traverse tracks are formed so as to traverse adjacent tracks via each of the guard bands so that writing regarding offset measurement data for measuring an offset amount between a storage element and a reproducing element of a magnetic head unit is allowed at a center position of the storage element. | 11-26-2009 |
20100020436 | MAGNETIC DISK APPARATUS AND MAGNETIC DISK ACCESS CONTROLLING METHOD - 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. The magnetic head controller performs recording or reproducing with respect to the data recording area by controlling the magnetic head based on the servo reproduction signal. | 01-28-2010 |
20100067142 | Phase Servo Patterns for Bit Patterned Media - 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. | 03-18-2010 |
20100073810 | Encoding Scheme for Bit Patterned Media - 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. | 03-25-2010 |
20100073811 | MAGNETIC DISK AND MAGNETIC DISK DEVICE - 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. | 03-25-2010 |
20100079904 | STORAGE CONTROL METHOD, STORAGE CONTROL UNIT AND STORAGE APPARATUS - 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. | 04-01-2010 |
20100123973 | INFORMATION STORAGE MEDIUM AND INFORMATION STORAGE APPARATUS - 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. | 05-20-2010 |
20100226038 | SERVO DESIGN IN DATA STORAGE MEDIA - 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. | 09-09-2010 |
20100246056 | DETERMINATION OF WEDGE OFFSET CORRECTION VALUES FOR A DISK DRIVE - 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. | 09-30-2010 |
20100290153 | SERVO PROCESSORS THAT ALTERNATELY CONTROL HEAD POSITIONING RELATIVE TO SEQUENTIAL SERVO PATTERNS - The operational bandwidth of a servo control circuit can be increased using a plurality of servo processors that handoff between them the responsibility for controlling head positioning in response to sequentially occurring servo patterns. | 11-18-2010 |
20110149432 | Information storage device with multiple-use fields in servo pattern - An embodiment of the present invention implements some or all major servo subfunctions for a storage device in integrated servo fields comprising sequences of encoded bits having selected mathematical properties. The integrated servo field is composed of a number of encoded sequences, which are members of a selected sequence set that is constrained to preferably provide some or all of the following functions: the Servo Track Mark (STM), the Position Error Signal (PES) and location information such as the track-ID. The juxtaposition of sequences in the servo wedges is additionally constrained to increase the detectability of the contribution of adjacent sequences in the read signal. The integrated servo fields can provide a Position Error Signal (PES) in relation to the center of a data track through the amplitude of the signal read for adjacent sequences. | 06-23-2011 |
20110149433 | Information storage device with multiple-use fields in servo pattern - An embodiment of the present invention implements some or all major servo subfunctions for a storage device in integrated servo fields comprising sequences of encoded bits having selected mathematical properties. The integrated servo field is composed of a number of encoded sequences, which are members of a selected sequence set that is constrained to preferably provide some or all of the following functions: the Servo Track Mark (STM), the Position Error Signal (PES) and positional information such as the track-ID. In one embodiment the plurality sequences encoding a location identifier such as a track-ID are distributed across a set of servo wedges. A method of encoding the location identifier using a Chinese Remainder Theorem is described. | 06-23-2011 |
20110149434 | Information storage device with multiple-use fields in servo pattern - An embodiment of the present invention implements some or all major servo subfunctions for a storage device in integrated servo fields comprising sequences of encoded bits having selected mathematical properties. The integrated servo field is composed of a number of encoded sequences, which are members of a selected sequence set that is constrained to preferably provide some or all of the following functions: the Servo Track Mark (STM), the Position Error Signal (PES) and positional information such as the track-ID. The integrated servo fields can provide a Position Error Signal (PES) in relation to the center of a data track through the amplitude of the signal read for adjacent sequences. The servo system detects the sequences in the signal from the read head using a set of digital filters for the set of encoded sequences. | 06-23-2011 |
20120087037 | Patterned media with structured PES servo segments encoding local track position - Patterned magnetic media are described in which the servo sectors include at least two PES offset segments that can be used for the position error signal (PES) and identification of local track position. The two PES offset segments deviate from the track centerline in opposite directions. The lengths of the offset PES offset segments are systematically varied in a repeating pattern to provide a unique servo signal pattern for each track in a local group of adjacent tracks. The locally unique servo sector pattern allows the servo system to use the pattern of the signals generated from the offset and non-offset segments to determine the local track position, which is similar to information provided by the low order Gray code bits in prior art designs. Therefore, the number of bits in the track ID code can be reduced. | 04-12-2012 |
20130010384 | SERVO PATTERN COMPATIBLE WITH PLANARIZATION CONSTRAINTS OF PATTERNED MEDIA AND USE OF A SINGLE MASTER TEMPLATE - Embodiments described herein provide for robust servo patterns that comply with planarization constraints and also allow use of a single master template for manufacture of both the front and back of a magnetic disk. Planarization constraints are met because only a portion of servo data is hard patterned on the magnetic disk and the hard patterned servo data areas comply with planarization constraints. The servo pattern has two symmetrical servo write assist patterns, one on each side of a central burst pattern. The servo sync, SAM, track-ID, sector-ID, and/or RRO values can be written magnetically by the write head onto these servo write assist patterns after the completion of the planarization process. The symmetric design of the servo pattern allows both a left-to-right and a right-to-left servo write and read back, thereby enabling use of a single master template in magnetic disk manufacture. | 01-10-2013 |
20130010385 | SERVO PATTERN COMPATIBLE WITH PLANARIZATION CONSTRAINTS OF PATTERNED MEDIA AND USE OF A SINGLE MASTER TEMPLATE - Embodiments described herein provide for robust servo patterns that comply with planarization constraints and also allow use of a single master template for manufacture of both the front and back of a magnetic disk. Planarization constraints are met because only a portion of servo data is hard patterned on the magnetic disk and the hard patterned servo data areas comply with planarization constraints. The servo pattern has two symmetrical servo write assist patterns, one on each side of a central burst pattern. The servo sync, SAM, track-ID, sector-ID, and/or RRO values can be written magnetically by the write head onto these servo write assist patterns after the completion of the planarization process. The symmetric design of the servo pattern allows both a left-to-right and a right-to-left servo write and read back, thereby enabling use of a single master template in magnetic disk manufacture. | 01-10-2013 |
20130194699 | INFORMATION RECORDING DEVICE AND INFORMATION RECORDING METHOD - According to one embodiment, there is provided an information recording device that records information on a magnetic disk using a magnetic head. The registering module registers position data of a temporary defective sector using a sector where an off-track has occurred as a temporary defective sector. The reading module reads data from a target track. The cancellation processing module performs inter-track interference component cancellation processing with respect to the data read by the reading module using data written to a track adjacent to the target track, in which when a sector adjacent to a processing target sector in a track width direction is a temporary defective sector registered in the registering module, inter-track interference component cancellation processing is performed using data written to a substitute sector corresponding to the registered temporary defective sector. | 08-01-2013 |
20140055883 | METHOD AND STRUCTURE FOR IMPROVING PERFORMANCE AND STORAGE DENSITY IN A DATA STORAGE DEVICE - A data storage device with improved data storage densities, coupled with lower hard error and write-inhibit events is described. A feed-forward write inhibit (FFWI) method enables data tracks to be written more densely. Alternatively, the FFWI method may reduce the hard error and write inhibit events to improve data storage performance. A concept of virtual tracks enables the FFWI method to be applied to the writing of circular data tracks with non-circular servo tracks, or to the writing of non-circular data tracks with PES data from circular servo tracks—in both cases, improvements to performance and/or storage densities are enabled. The FFWI method may also be applied to the case of both non-circular servo and data tracks. | 02-27-2014 |
20150103435 | HEAD POSITION DEMODULATING METHOD AND MAGNETIC DISK DEVICE - According to one embodiment, a head position demodulating method and a magnetic disk device switch a demodulation window such that an amplitude of a fundamental wave component of a null-type burst pattern transitions from a decreasing direction to an increasing direction along with an increase in seek speed during demodulation of the null-type burst pattern recorded on a magnetic disk. | 04-16-2015 |
20150332719 | SERVO TRACKING USING A SINGLE SERVO WRITING PASS PER TRACK FOR MULTI SENSORS - At least a portion of a first servo mark is read using a first read head during a rotation of a disk, the rotation comprising no more than 360 degrees. At least a portion of a second servo mark is read using a second read head during the rotation of the disk. Tracking positions of the first read head and the second read head are determined during the rotation based on reading the first servo mark and the second servo mark. | 11-19-2015 |