MAGNETPLATTENVORRICHTUNG

Festplatte

Anordnnung zur Spurverfolging durch den Wandlerknopf in einem Plattenspeichersystem

Piezoelektrischer Aktuator und Plattenlaufwerk mit diesem

Datenlese- und -wiedergabeverfahren für Festplattenlaufwerk

Informationsspeichergerät

Servoburstmuster eines durch magnetische Verzerrungen hervorgerufenen Offsets und zugehöriges Verfahren

Single sheet differential-poled piezoelectric microactuator for a hard disk drive

A piezoelectric (PZT) microactuator 300 directly attached to a head slider 302, for mounting on a suspension for use as a third stage actuator in a hard disk drive, is fabricated from and comprises a single sheet of a piezoelectric material with the top and bottom covered with an electrically conductive material to form electrodes. The piezoelectric material is differential-poled so that one lateral portion 202 is poled in one direction and another lateral portion 204 is poled in the opposite direction. When a drive voltage is applied between the top and bottom electrodes, one portion of the piezoelectric material expands while the other portion contracts, thereby providing a rotational movement. The direction of motion of each respective portion is determined by the direction of the applied voltage and the respective direction of poling. An electric field may be applied by poling electrodes.

Method and apparatus for maintaining servo stability during actuator saturation

Single sheet differential-poled piezoelectric microactuator for a hard disk drive

Vibration control of piezoelectric microactuator

Detection and amplification circuit

A disk drive control system including servo sectors written on a disk, with each sector containing three sets of marker pulses arranged so that three adjacent marker pulses from each of the sets spans two tracks. The pulses each comprise high frequency sinusoidal signals. Servo control depends upon the pulse amplitudes sensed by the read/write head while traversing a servo sector. The system includes an amplifier to rectify and amplify the high frequency signals, a sample-and-hold circuit to hold at least three value representative of the amplified high frequency signals, and synchronizing means to synchronize the sample-and-hold circuit such that the first value sampled and held is representative of the amplitude of the first pulse read in a servo sector, the second value sampled and held is representative of the amplitude of the second pulse read in the servo sector, and so forth. A multiplexing circuit provides multiplexed signals sequentially representative of values sampled.

INFORMATION SIGNAL REPRODUCING APPARATUS AND DEVICES FOR AND METHODS OF MOVING PICK-UP MEANS THEREOF

Single sheet differential-poled piezoelectric microactuator for a hard disk drive

Method of detecting and isolating defective servo bursts

METHOD OF WRITING DATA ON A MAGNETIC RECORDING MEDIUM

REPETITION CONTROL AND SERVO-DRIVE SYSTEM THEREBY

DEVICE, AROUND THE PHOTOGRAPH DEVICE OF AN INFORMATION SIGNAL PLAYBACK UNIT RAPID INTO A DESIRED POSITION ON THE RECORDING PLATE TO MOVING

COMPONENTS OF NON REMOVABLE DISK DRIVES AND PROCEDURES FOR THEIR PRODUCTION

COMPUTER NON REMOVABLE DISK AND PROCEDURE FOR THEIR PRODUCTION

Mr head differential micro-jog

REPETITIVE CONTROLLER AND DRIVE SERVO SYSTEM INCLUDING IT

CAPACITIVE SENSING EMPLOYING THIN FILM INDUCTORS

CAPACITIVE SENSING EMPLOYING THIN FILM INDUCTORS A capacitive variation sensor includes one or more elements providing inductive reactance in the form of thin film coils. This enables a capacitive variation sensor to be integrated on a substrate along with a thin film magnetic read/write head. One element of the capacitive variation sensor is a sensing electrode, and in some embodiments of the invention a dedicated sense electrode can be eliminated by employing the pole tips of the thin film magnetic read/write head as the sense electrode.

TWIN TRACK VERTICAL MAGNETIC RECORDING SERVO CONTROL METHOD AND APPARATUS

TWIN TRACK VERTICAL MAGNETIC RECORDING SERVO CONTROL METHOD AND APPARATUS The invention discloses a twin track servoing method and apparatus useful for vertical magnetic media recordings. Vertical magnetic media are those in which the magnetic vector in the medium is oriented perpendicular to the surface of the medium instead of lying laterally or longitudinally in the surface of the medium. There are two servo tracks of essentially constant and opposite magnetic polarity recorded on the vertical magnetic medium for each data channel on the medium. The servo tracks themselves may be segmented into reference zones and control or guard zones and they may be recorded on a dedicated surface of a magnetic medium or on the same surface as the data and interleaved with data tracks. When the servo tracks are alternated with data tracks on the same surface of the medium, a single read/write head for twin track recordings may be used to simultaneously read servo signals and data signals. When the ...

DIGITAL SERVO CONTROL SYSTEM FOR A DATA RECORDING DISK FILE

Schaltungsanordnung zur Einstellung eines Magnetkopfes auf die eine Information tragende Spur eines Aufzeichnungsträgers

Method and apparatus for servo control associated with rotational speed of disk in disk drive

The invention relates to method and apparatus for servo control associated with rotational speed of disk in disk drive. According to one embodiment, a disk drive is disclosed to which a plurality of disk rotational speed modes can be set. The disk drive is configured such that input of servo data from servo sectors is thinned out by thinning out an output of an interrupt request to a CPU (21) in a high-speed rotation mode. At the time, a disk controller (22) obtains servo data reproduced from all the servo sectors at timing of servo gates and stores it to a register (30).

Vibration control of piezoelectric microactuator

压电驱动器和盘装置

... 一种采用对压电驱动器的弯曲模态进行加强、不会发生在压电驱动器伸缩时产生的弯曲共振的压电驱动器的磁盘装置。装载由缝隙分离开的柔软片基板、分别在被分离开的柔软片基板上伸缩位移的第一压电体元件单元和第二压电体元件单元，在构成当压电体元件单元被两端支撑的情况下的一次弯曲模态的腹部的位置上，设置夹着缝隙地连接柔软片基板的连接部。 ...

APPAREILLAGE POUR L'ENREGISTREMENT ET LA LECTURE D'INFORMATIONS BINAIRES SUR UN DISQUE MAGNETIQUE FLEXIBLE DE PETITES DIMENSIONS

L'invention concerne un appareillage pour l'enregistrement et/ou la lecture d'informations binaires sur un disque magnétique flexible de petites dimensions. Cet appareillage comprend un moyeu tournant solidaire d'un plateau sur lequel est formé un guide en spirale. Le moyeu est conçu pour coopérer avec un trou central du disque et est muni d'une dent radiale qui s'engage dans une entaille radiale correspondante du disque pour son entraînement. Le guide en spirale du plateau coopère avec un bras sur une extrémité duquel est montée une tête magnétique qui est déplacée radialement au disque, en synchronisme avec sa rotation. L'invention peut notamment être utilisée dans un centre de traitement informatique.

POSITION CONTROL METHOD, POSITION CONTROL DEVICE, AND MEDIUM STORAGE DEVICE HAVING DISTURBANCE SUPPRESSION FUNCTION

TRANSDUCER HEAD WITH READING SENSORS CAPABLE OF DETERMINING A READING LOCATION BY AT LEAST ONE READING SIGNAL OF SELECTED READING SENSORS

PURPOSE: A transducer head with reading sensors is provided to make a data track uniform during recording in a storage medium. CONSTITUTION: A plurality of reading sensors(116) are attached to a transducer head. The reading sensors detect a reading signal from a storage medium. A location of a recording pole is determined based on the reading signal wherein the recording pole is attached to the transducer head. A radial location of the transducer head is adjusted based on the reading signal. Each reading sensor is located in a recording pole attached to the transducer head as much as each intrinsic offset. COPYRIGHT KIPO 2012 ...

SUSPENSION SENSE CAPABILITY FOR WINDAGE CONTROL

A method and data storage device (100) are provided that reduce off-track motion due to resonant modes in the storage device (100). The off-track motion is reduced by sensing movement with a sensor (301) located on a suspension assembly (200) of the storage device (100). Based on this sensed movement, the sensor (301) generates a signal (418) that is used to drive a control system to minimize the off-track motion.

READ/WRITE HEAD AND MAGNETIC RECORDING DEVICE

L'invention concerne un dispositif d'enregistrement magnétique comprenant une source (132) laser, une tête (131) de lecture magnétique et un appareil magnétorésistant placé entre deux pôles (100, 101) magnétiques de la tête magnétique. Un organe d'actionnement rotatif (Sa) place la tête d'écriture magnétique sur une piste voulue d'un support magnétique. Le support magnétique est soumis à un rayonnement émis par un faisceau laser pour chauffer une zone aussi large que la piste de sorte qu'une force coercitive de la zone chauffée puisse diminuer lorsqu'un champ d'enregistrement est appliqué pour un enregistrement haute densité. Un angle de lacet () de l'organe d'actionnement rotatif par rapport à la piste n'empêche pas la tête (131) de lecture magnétique et le dispositif de lecture de suivre les pistes de données. La taille des pôles (100, 101) magnétiques de la tête de lecture magnétique est déterminée dans une gamme prédéterminée, ce qui permet de garder la zone (302) chauffée par laser ...

Mirror mounting assembly

A mirror mounting assembly for mounting a mirror on a vehicle bulkhead. The assembly includes a mirror element and a main support arm having a first end and a second end. The mirror element is connected to the first end of the main support arm. The second end of the main support arm is mountable to the vehicle. A pair of brackets are configured to conform to an engine bay side wall of the vehicle. Each bracket has a center portion and two laterally extending flanges that extend at an angle from the center portion in opposite directions. One of the flanges of each bracket is connectable to the bulkhead of the vehicle in the engine bay. A first additional support arm has a first end connected to a first one of the brackets and a second end connected to the main support arm. A second additional support arm has a first end connected to the main support arm and a second end connectable to the vehicle. Finally, a third additional support arm has a first end connected to the main support arm and ...

Apparatus and method for reducing vibrational excitation in storage devices with dual stage actuators

Disclosed is an apparatus and method for reducing vibration in dual stage actuators of storage devices such as hard disk drives. The apparatus comprises a compensating mass disposed on an outer arm of the storage device in order to balance the mass and inertia of the outer arm. The compensating mass is provided with an actuator that is driven in unison with a dual stage actuator also disposed on the outer arm. The excitation caused by the dual stage actuator is balanced by the excitation caused by the actuator of the compensating mass. The shape and mass of the compensating mass are selected to simulate the mass and inertia of the inner dual stage actuator. By driving the inner dual stage actuator in unison with the actuator and compensating mass, the torsional input of the voice coil motor is substantially reduced.

Fault diagnosis apparatus, recording medium recording fault diagnosis program and fault diagnosis method

A fault diagnosis apparatus are installed and used in information equipment. The information equipment has a disk drive and a vibration source that causes vibrations or being subject to vibrations from an external vibration source. The apparatus has a measuring unit and a diagnosis unit. The measuring unit performs a measurement for a functional operation in the disk drive under a condition that the vibrations are occurred. The diagnosis unit performs a fault diagnosis based on a measurement result by the measuring unit.

Magnetic storage medium

Binary bits on a magnetic storage medium are read by a magnetic head that moves at approximately constant speed relative to the medium. The medium includes several elongated adjacent magnetic tracks, each including a succession of longitudinally positioned polarized magnetic flux variations arranged in elemental areas of equal length along the length of each track. Adjacent areas are susceptible to having like and unlike magnetic flux polarizations. The head and tracks are positioned so the head straddles a pair of the tracks and is simultaneously responsive to flux variations in the straddled tracks. The head and track move relative to each other so the head is responsive to successive flux variations as time progresses. The areas are arranged so there is always a magnetic flux polarization transition at predetermined equi-spaced positions along the track length at a boundary between a pair of elemental areas. The transition direction at each boundary indicates a binary bit value. The ...

Detecting servo defects in a disc drive

Apparatus and method for detecting servo defects in a disc drive, the servo defects providing false indications of the position of a disc drive head with respect to a selected track. During use of a position error signal (PES) to position the head with respect to the selected track, the PES comprising a sequence of PES samples, the disc drive determines a first difference term as a selected combination of a first set of PES samples. A second, subsequent difference term is also generated as a selected combination of a second set of PES samples, the second set of PES samples including at least one PES sample which does not appear in the first set of PES samples. The magnitudes of the first and second difference terms are compared to a predetermined threshold, and a servo defect is detected at such time that both the first and second difference terms exceed the predetermined threshold and the first difference term exceeds the second difference term. Additionally, at such time that the first ...

Adjacent track position detectable information storage apparatus

An information storage apparatus has a disk medium setting data recording areas along a plurality of tracks concentrically arranged, a head for recording and reproducing data on tracks of the disk medium, an actuator for moving the head to a desired track among the plurality of tracks. Also included is an electric circuit for controlling recording and reproducing in response to detecting the distance from a recorded magnetization pattern on an adjacent track in the radial direction by detecting previously recorded signals on adjacent tracks while data recording. Even if the track density is increased, the upper limit of a threshold value of a function for preventing off-track recording of the information storage apparatus can be increased and a high track density of the information storage apparatus can be easily realized.

DISK DEVICE AND CONTROL METHOD

A disk device includes first and second recording surfaces, a first head for the first recording surface, including a first heater which generates heat via a first electric power, a second head for the second recording surface, including a second heater which generates heat via a second electric power, and a control circuit configured to execute a first preheating operation in which the first electric power is supplied to the first heater for a first time interval prior to starting a first writing process to write data on the first recording surface by the first head, and to execute a second preheating operation in which the second electric power is supplied to the second heater for a second time interval prior to starting a second writing process to write data on the second recording surface by the second head. The first time interval is different from the second time interval.

Magnetic disk drive

A plurality of patterns are formed beforehand so that each of those patterns is deviated slightly from another in each sector in the track width direction, then the pattern is followed up, thereby obtaining both full-track profile and micro-track profile. A variation of a position signal is detected from this profile, thereby creating a table for correcting the non-linearity error of the position signal.Consequently, the distribution of the write/read-back property is measured, thereby enabling the track density to be improved. Furthermore, a variation of the position signal caused by a property variation of the head read-back element is detected and corrected, thereby enabling a high reliability and a high track density to be realized for the object magnetic recording disk apparatus.

Apparatus and methods of generating a test pattern of data, analysing a test pattern of data, and testing a data storage disk medium and/or a read/write head

A method of generating a test pattern of data to be written to a data storage disk medium for testing includes: rotating the disk; detecting fluctuations in the speed of rotation of the disk; producing a reference clock signal in accordance with the fluctuations so as to be synchronized with the rotation of the disk; and, generating a test pattern of data using the reference clock signal as a timing reference. An apparatus for generating a test pattern of data includes a spindle for rotating a disk; a detector arranged to detect fluctuations in the speed of rotation of the disk; a processor arranged to produce a reference clock signal in accordance with fluctuations so as to be synchronized with the rotation of the disk; and, a pattern generator arranged to generate a test pattern of data using the reference clock signal as a timing reference.

Magnetic recording unit and magnetic recording medium

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

Systems and methods for rewriting user data in rotatable storage media

Systems and methods in accordance with embodiments can be used to re-write data to a rotatable storage medium. When a position of a write element is not within a threshold during a data write operation, an indication of data written while the position of the element was not within the threshold can be maintained. When the device including the rotatable storage medium is free from other data transfer operations, the data written while the element was not within the threshold can be re-written. In this manner, data that may be considered less reliable due to the misplacement of a write element during a data write operation can be re-written such that the data can be placed closer to a data track centerline.

Мirrоr mоunting аssеmblу

А mirrоr mоunting аssеmblу fоr mоunting а mirrоr оn а vеhiсlе bulkhеаd. Тhе аssеmblу inсludеs а mirrоr еlеmеnt аnd а mаin suppоrt аrm hаving а first еnd аnd а sесоnd еnd. Тhе mirrоr еlеmеnt is соnnесtеd tо thе first еnd оf thе mаin suppоrt аrm. Тhе sесоnd еnd оf thе mаin suppоrt аrm is mоuntаblе tо thе vеhiсlе. А pаir оf brасkеts аrе соnfigurеd tо соnfоrm tо аn еnginе bау sidе wаll оf thе vеhiсlе. Еасh brасkеt hаs а сеntеr pоrtiоn аnd twо lаtеrаllу ехtеnding flаngеs thаt ехtеnd аt аn аnglе frоm thе сеntеr pоrtiоn in оppоsitе dirесtiоns. Оnе оf thе flаngеs оf еасh brасkеt is соnnесtаblе tо thе bulkhеаd оf thе vеhiсlе in thе еnginе bау. А first аdditiоnаl suppоrt аrm hаs а first еnd соnnесtеd tо а first оnе оf thе brасkеts аnd а sесоnd еnd соnnесtеd tо thе mаin suppоrt аrm. А sесоnd аdditiоnаl suppоrt аrm hаs а first еnd соnnесtеd tо thе mаin suppоrt аrm аnd а sесоnd еnd соnnесtаblе tо thе vеhiсlе. Finаllу, а third аdditiоnаl suppоrt аrm hаs а first еnd соnnесtеd tо thе mаin suppоrt аrm аnd ...

Multi-Layer PZT Microactuator With Active PZT Constraining Layers For A DSA Suspension

A PZT microactuator such as for a hard disk drive has a restraining layer bonded on its side that is opposite the side on which the PZT is mounted. The restraining layer comprises a stiff and resilient material such as stainless steel. The restraining layer can cover most or all of the top of the PZT, with an electrical connection being made to the PZT where it is not covered by the restraining layer. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses the sign of the bending which increases the effective stroke length of the PZT even further. The restraining layer can be one or more active layers of PZT material that act in the opposite direction as the main PZT layer. The restraining layer(s) may be thinner than the main PZT layer.

IMPROVED APPARATUS, SYSTEMS AND PROCESSES FOR REDUCING A HARD DISK DRIVE'S ACCESS TIME AND CONCOMITANT POWER OPTIMIZATION

MAGNETIC DISK DEVICE CONTROLLING SYSTEM

PURPOSE: To enable stable operation by changing the inversion interval of a position bit signal of servo information according to change of angle made by the track and head on a magnetic disk. CONSTITUTION: A positioning mechanism 30 positions a head 7 at a specified track on a magnetic disk 1 from a microprocessor 36 through a controlling mechanism 32. The program of the processor 36 is stored in a main memory 39, and operation is performed according to the program. Radial position on the disk 1 and the corresponding optimum magnetizing inversion width are stored in a pair in an ROM35. When the optimum magnetizing inversion width of position bit corresponding to a position at a time when the head 7 is positioned at some point on inner periphery W outer periphery on the magnetic disk 1 is read out from the ROM35 and the position bit is read, writing is made by this value. Consequently, gain of positional signal does not change even when the position of the head changes, and stable operation ...

MAGNETIC RECORDING MEDIUM

PURPOSE: To reduce errors in the detection of recorded data information by increasing the coercive force of servo information recording regions so as to reduce the immoderate running of a head and the extent of off-track. CONSTITUTION: Data information recording regions 15 and servo information recording regions 16 are formed on a substrate 6 with a sputtered thin film of Co.γ-Fe2O3. At this time, by making the Co content of the regions 16 1W2atm% higher than that of the regions 15, the coercive force of the regions 16 is made 1.2W1.3 times that of the regions 15. COPYRIGHT: (C)1983,JPO&Japio ...

MAGNETIC DISC

PURPOSE: To make positioning of magnetic head particularly in a floppy disc easy and to enable high-density recording with narrow track width, by providing the stripe-shape servo signal region magnetized in vertical direction on the disc surface. CONSTITUTION: On the disc surface 1, the magnetic film having easy magnetization axis in the surface in parallel with the surface of disc 1 and being uniform thickness is formed to the information signal region 2. On the other hand, after forming the magnetic film in stripe shape corrsponding to the frequencies in f1, f2 toward disc running direction alternately as f1-f2-f1... to the disc, for the servo signal region 3 with the magnetic film having easy magnetization axis vertical to the plane of the disc 1, the region 3 is formed with vertical magnetization toward the disc. The tracking of the magnetic head is controlled with the signal current depending on the amplitude of magnetization from f1 and f2, allowing easy positioning for readout and ...

Schaltung für Lateral-Photoeffekt-Positionssensor

Bimorphe piezoelektrische Mikrobetätiger-Kopf-Biegeelementanordnung

ADAPTIVES DIGITALES SERVOSYSTEM

Verfahren zum magnetischen Aufzeichnen und Wiedergeben von Daten, magnetischer Auzeichnungsträger, sein Herstellungsverfahren und Gerät zur magnetischen Aufzeichnung

Magnetischer Aufzeichnungsträger und Verfahren zum magnetischen Aufzeichnen und Wiedergeben von Daten.

Magnetplattenspeicher mit breitem Servokopf.

Method of implementing a linear discrete-time state-space servo control system on a fixed-point digital signal processor in a disc drive

Method and apparatus for encoding identification information on a magnetic disc

A method and apparatus (300) for processing a magnetic disc (106, 204, 670, 314, 714, 780) prior to assembly of the disc in a disc drive storage assembly (100) includes measuring a physical characteristic of the magnetic disc (106, 204, 670, 314, 714, 780) and encoding an information pattern (220, 272, 410-414, 501-503, 602, 604, 651-653, 710-712) within the magnetic disc. The information pattern (220, 272, 410-414, 501-503, 602, 604, 651-653, 710-712) is associated with the measured physical characteristic.

Method and apparatus for maintaining servo stability during actuator saturation

A method and apparatus are provided for positioning a head (110) over a disc (106) in a disc drive (100) while maintaining servo loop stability. The apparatus includes an actuator-head assembly (310) having a large scale actuator (308) and a micro-actuator (314) that are both able to move the head over the disc. An anti-windup compensation component (312, 322, 320) detects when a micro-actuator controller (304) is producing a micro-actuator control value that will saturate the micro-actuator 314). Using the micro-actuator control value, the anti-windup compensation component generates a saturation tracking error signal w yawk. A summing component (318) then combines a position value that the head generates based on its position over the disc with the saturation tracking error signal to form a position error value that masks the saturation of the micro-actuator.

Information signal reproducing apparatus and devices for and methods of moving pick-up means thereof

A device for rapidly moving an optical pick-up device in an optical reproducing apparatus to a desired position on a record disc having a plurality of record tracks with an information signal recorded therein, includes a tracking error signal generating circuit for producing a tracking error signal corresponding to deviation of the pick-up device from the center of each record track; a drive device for moving the pick-up device in a direction transverse to the record tracks; and a track jump signal forming circuit for producing a track jump signal comprised of a drive signal followed by a brake signal, in response to the tracking error signal, the drive signal having a duration corresponding to the number of tracks traversed by the pick-up device and the brake signal having a duration corresponding to the speed of movement of the optical pick-up device in traversing the tracks, and for supplying the track jump signal to the drive device to control the latter to rapidly move the optical ...

Self-servo write non-reference head position measuring

DISK DRIVE CONTROL SYSTEM

Weighted linearization of a disc drive position error signal

Controlled tracking on grooveless recording medium having magnetic and dielectric properties

The lateral position of a magnetic head is controlled in response to tracking information derived from an adjacent guide track formed by a series of minute pits on a grooveless recording medium having ferromagnetic and dielectric properties. Microwave energy is applied to an electrode mounted for movement with the magnetic head to sense the variations in capacitance resulting from the geometrical variations of the minute pits. The recording medium comprises an underlying layer of ferromagnetic material in which the minute pits are formed in spiral or concentric pattern and an overlying layer of a dielectric material which conforms to the pit contours of the underlying layer.

LINEAR ACTUATOR FOR A DISK FILE

SYNCHRONIZATION OF SYMMETRIC TIMING BASED SERVO BURSTS

Timing based servo bursts of servo frames, in which the frames are arranged to be symmetric with the same number of servo stripes in each burst of a frame, are synchronized by shifting selected bits. For example, servo frames are arranged with four servo bursts with an equal number of servo stripes in each burst, the servo frames comprising two symmetric sub-frames, each sub-frame comprising two bursts of servo stripes that are parallel to each other within a burst, and the bursts are non-parallel with respect to each other; each servo burst is arranged to comprise at least one reference servo stripe; and each servo burst is arranged to comprise at least one shifted servo stripe, wherein the shift is in the same longitudinal direction with respect to at least one reference servo stripe for each burst of a frame and the opposite longitudinal direction for bursts of sequentially adjacent frames.

APPARATUS FOR RECORDING AND READING INFORMATION ON A MAGNETIC DISK SMALL FLEXIBLE

Reader of sound for recorded discs

SERVO SYSTEM OF POSITION FOR PLAY-BACK HEAD OF MAGNETIC DISKS HAS HIGH DENSITY OF TRACKS

PIEZOELECTRIC ACTUATOR AND DISC DEVICE

MAGNETIC TRANSFER METHOD FOR HIGH-DENSITY MAGNETIC RECORDING MEDIUM

PURPOSE: To magnetically transfer magnetic patterns to a high-density magnetic recording medium utilizing the antiferromagnetic bond of two magnetic layers with high accuracy. CONSTITUTION: A recording and reproducing layer 6 of the magnetic recording medium 1 previously subjected to initial magnetization and an information carrying surface coated with the magnetic layer 12 to the rugged patterns of a substrate 11 of a master carrier 10 are brought into tight contact with each other and a transfer magnetic field Hdu is impressed in the longitudinal direction of the tracks of the magnetic recording medium in a direction opposite to the initial magnetization direction of the second magnetic layer 5. At this time, the thickness of the magnetic layer 12 of the master carrier 20, material (magnetic permeability), the patterns of the magnetic layer 12, the separating distance between the master carrier 10 and the magnetic recording medium 1, etc., are controlled, by which the magnetic flux by ...

CREATING AN INITIAL SET OF TRACKS IN A SELF-SERVOWRITING SYSTEM USING A COMPLIANT CRASHSTOP TO CONTROL HEAD MOVEMENT

TOPOGRAPHIC FEEDFORWARD SYSTEM

A control mechanism may control the height and/or position of a read/write head configured to interact with a rotating information storage surface. A topography detection mechanism may detect topography of a side read/write track while the read/write head is interacting with a current read/write track. A memory may store the detected topography. The control mechanism may adjust the height of the read/write head based on the stored topography. The topography detection mechanism may compute the detected topography from gap measurements using a dynamic filter including a model of read/write head dynamics. The control mechanism may be a reactionless control mechanism configured to apply a counterforce to offset movements of the read/write head and/or a slider.

DETECTION OF SLIDER-DISK INTERFERENCE USING A DYNAMIC PARAMETRIC TEST

A method is described for calculating head disk interference (HDI) using a dynamic parametric test. In one embodiment, HDI is calculated based on an actual and ideal sensitivity profile based on read-back signal track profile for the slider/head.

SYSTEM AND METHOD FOR EXTENDING THE OPERATING LIFE OF A MAGNETORESISTIVE TRANSDUCER PROVIDED IN A DISK DRIVE SYSTEM

L'invention concerne un appareil et un procédé permettant de prolonger la durée de fonctionnement d'un élément MR (157) intégré dans une tête de lecture/écriture (156). Ce procédé consiste à détecter des périodes d'inactivité du système de lecture de disque et à passer sélectivement d'une tête (156) à l'autre dans le but de lire des informations de positionnement pendant les périodes inactives. L'étape de sélection d'une tête (156) peut consister à sélectionner (260) une tête (156) présentant un minimum d'utilisation, telle qu'une tête (156) pourvue d'un élément MR (157) ayant un temps cumulatif opérationnel minimum ou une dissipation d'énergie par rapport à d'autres éléments MR (157) contenus dans le système de lecture de disque (20). Ce procédé consiste aussi à réduire la vitesse d'échantillonnage (320) de positionnement pendant une période d'inactivité du système (20). Les éléments MR (307) peuvent être actionnés sélectivement pendant les périodes nulles de manière à réduire leur utilisation ...

Electrostatic track following using patterned media

A transducing head positioning system for use with patterned media. The patterned media comprises a plurality of data tracks and grooves. The grooved tracks can be used in connection with electrodes on a slider to create an electrostatic motor for microactuation of the slider.

HARD DISK DRIVE, MANUFACTURING METHOD OF THE SAME, AND SERVO DATA WRITING METHOD

A method for writing servo data includes writing servo data as a head moves outward on a disk one step at a time, so as to overwrite part of servo data that have been written in a previous step, writing servo data as the head moves inward on the disk one step at a time, so as to overwrite part of servo data that have been written in a previous step, and writing one of two-phase burst data, or address data and the other of said two-phase burst data, at the radial position, so as to overwrite at least part of servo data written in each last step of the writings as the head moves outward and inward. The same address data are written in two consecutive steps as the head moves outward and as the head moves inward.

Sealed bulkhead electrical feed-through X-Y positioning control

An electrical feed-through, such as a PCB connector, involves a connector part that includes a housing from which first and second positioning flanges extend from opposing ends. A data storage device includes an enclosure base with which the electrical feed-through is coupled, where the base comprises an annular recessed surface surrounding an aperture that is encompassed by the electrical feed-through, and first and second recessed positioning surfaces extending in directions outward from respective longitudinal ends of the annular recessed surface, where each of the recessed positioning surfaces has a corresponding wall extending vertically therefrom. When assembled, each positioning flange of the electrical feed-through mechanically mates with a corresponding recessed positioning surface of the base, such that the position of the electrical feed-through is constrained by the walls of each recessed positioning surface.

Disk drive with support structure for disk-vibration capacitive sensors

A data recording disk drive has one or more capacitive sensors for sensing out-of-plane vibration of the disk or disks. The sensors are attached to a support structure that is attached to the disk drive housing. Each sensor is associated with a disk and faces a surface of the disk near the outer perimeter of the disk and close to the recording head. The support structure can be made of a metal or a high-strength plastic and can be a separate structure mounted to the housing, or integrated as part of the single-piece housing casting. If it is metallic, as would be the case if it were integrated with the housing, then layers of insulating material separate the sensors from the support structure. A support structure that serves other functions in the disk drive can also function as the support structure for the capacitive sensors.

METHOD AND APPARATUS FOR MICRO-ACTUATOR STROKE SENSITIVITY CALIBRATION IN A HARD DISK DRIVE

A sinusoidal signal is added to the notch filtered micro-actuator control signal stimulating the micro-actuator. The voice coil control signal is notch filtered to remove the frequency component of the sinusoidal signal before it stimulates the voice coil motor. The micro-actuator control signal is notch filtered to remove the frequency component of the sinusoidal signal before it stimulates the micro-actuator. The response of the system is measured as the Position Error Signal (PES), for the magnetic head moved by the micro-actuator. The measured PES is then demodulated at the frequency of the sinusoidal signal to create a measured amplitude. The stroke sensitivity is then calculated from the measured amplitude and amplitude of the sinusoidal stimulus. The frequency of the sinusoidal signal and notch filters is essentially the same, chosen away from significant excitation frequencies and outside the bandwidth of the servo system. The invention includes using multiple frequencies, as well ...

Self-Servo Write Non-Reference Head Position Measuring

An approach to self-servo writing (SSW) in a hard disk drive involves receiving a first signal from a first reader reading from a first disk media surface while concurrently receiving a second signal from a second reader reading from a second disk media surface, where the relative position of the first and second readers is determinable based on the first and second signals. For example, the first signal may correspond to the SSW reference head while the second signal may correspond to any one of the other SSW non-reference heads, during a SSW bank writing procedure, whereby the relative position and/or motion between the reference and non-reference heads can have a deleterious effect on the servo track writing quality. Because multiple different non-reference heads may be selected for signal reception and associated position determination, the first and second disk media surfaces may be constituent to different disks.

Head positioning control method, head positioning control device and disk apparatus

A positioning control device executes disturbance observer control having a disturbance suppression function, wherein changes of control characteristics are prevented even if the disturbance frequency is suppressed. When a control value of an actuator is computed using estimated gains of the actuator and estimated gains of disturbance according to an estimated position error by disturbance observer control including a model of the actuator and model of the disturbance, the disturbance frequency is estimated according to the estimated position error, and the estimated gains of the actuator and the estimated gains of the disturbance, corresponding to the disturbance frequency, are changed. Therefore appropriate observer control according to the disturbance frequency can be implemented.

Feedforward controller and methods for use therewith

A controller includes a combining module that generates a total control signal for the drive device of a disk drive by combining a feedback control signal and a feedforward control signal. A feedback control module generates the feedback control signal in response to at least one state of the drive device. A feedforward control module generates the feedforward control signal based on a smoothing function and a feedforward control function.

Method and apparatus for estimating micro-actuator stroke sensitivity in a hard disk drive

Method of estimating the stroke sensitivity of micro-actuator coupled with slider and its read-write head. Micro-actuator stimulus signal used to drive micro-actuator, inducing noise into lateral positioning of read-write head near track by voice coil motor to create PES. Lateral position noise derived from Position Error Signal. Stroke sensitivity estimated from lateral position noise and micro-actuator stimulus signal. Apparatus supporting method estimating stroke sensitivity: servo controller, embedded circuit including servo-controller, and hard disk drive may include servo-controller and/or embedded circuit. Method making servo-controller, embedded circuit, and/or hard disk drive. Servo-controller, embedded circuit, and hard disk drive are products of these processes.

Method and apparatus for reducing seek acoustics in disk drives for AV systems

Method for performing seek operations in a disk drive including at least one data disk having multiple concentric data tracks thereon, and a transducer radially moveable relative to said data tracks by an actuator during a seek operation from a starting track to a destination track. Upon receiving a request for a seek from starting track to a destination track, a seek profile is obtained to control application of current to the actuator based on the seek profile, wherein the seek profile includes actuator current level and transducer target velocity control values for the seek operation based on said starting and destination tracks, to achieve a desirable acoustic output. Actuator current is applied to the actuator as a function of the control to perform the seek operation.

Disk drive with support structure for damping plates and disk-vibration capacitive sensors

A data recording disk drive has one or more capacitive sensors for sensing out-of-plane vibration of the disk or disks. The sensors are attached to a support structure that is attached to the disk drive housing. Each sensor is associated with a disk and faces a surface of the disk near the outer perimeter of the disk and close to the recording head. The support structure can be made of a metal or a high-strength plastic and can be a separate structure mounted to the housing, or integrated as part of the single-piece housing casting. If it is metallic, as would be the case if it were integrated with the housing, then layers of insulating material separate the sensors from the support structure. A support structure that serves other functions in the disk drive, such as support for disk damping plates, can also function as the support structure for the capacitive sensors.

SERVO PATTERNING COMPATIBLE WITH PLANARIZATION OF PATTERNED MAGNETIC DISKS

Embodiments herein illustrate patterned servo data that allows the patterned disk to be planarized with a relatively simple planarization process. A magnetic disk, in this regard, includes a data region having a plurality of tracks. The magnetic disk also includes a plurality of servo bursts patterned in the magnetic disk at a plurality of locations in each track. The servo bursts are operable to direct a controller to center a write head over a track in the data region and write a track identification. The servo bursts include magnetic lands and nonmagnetic grooves. The magnetic lands of the servo burst are generally configured with a uniform polarity of magnetization and a first uniform width. The nonmagnetic grooves are configured with a second uniform width.

Apparatus, systems and processes for reducing a hard disk drive's access time and concomitant power optimization

Rotational latency is reduced in a standard conventional form factor HDD system by replacing, for example, the prior art rotary arm actuator of a conventional HDD, with one or more belts and pulleys and one or more read/write heads mounted on, or otherwise associated with the belts. Multiple scaled iterations facilitate energy savings and power optimized systems, without compromise to data access performance.

APPARATUS, SYSTEMS AND PROCESSES FOR REDUCING A HARD DISK DRIVE'S ACCESS TIME AND CONCOMITANT POWER OPTIMIZATION

Rotational latency is reduced in a standard conventional form factor HDD system by replacing, for example, the prior art rotary arm actuator of a conventional HDD, with one or more belts and pulleys and one or more read/write heads mounted on, or otherwise associated with the belts. Multiple scaled iterations facilitate energy savings and power optimized systems, without compromise to data access performance.

Мirrоr mоunting аssеmblу

А mirrоr mоunting аssеmblу fоr mоunting а mirrоr оn а vеhiсlе bulkhеаd. Тhе аssеmblу inсludеs а mirrоr еlеmеnt аnd а mаin suppоrt аrm hаving а first еnd аnd а sесоnd еnd. Тhе mirrоr еlеmеnt is соnnесtеd tо thе first еnd оf thе mаin suppоrt аrm. Тhе sесоnd еnd оf thе mаin suppоrt аrm is mоuntаblе tо thе vеhiсlе. А pаir оf brасkеts аrе соnfigurеd tо соnfоrm tо аn еnginе bау sidе wаll оf thе vеhiсlе. Еасh brасkеt hаs а сеntеr pоrtiоn аnd twо lаtеrаllу ехtеnding flаngеs thаt ехtеnd аt аn аnglе frоm thе сеntеr pоrtiоn in оppоsitе dirесtiоns. Оnе оf thе flаngеs оf еасh brасkеt is соnnесtаblе tо thе bulkhеаd оf thе vеhiсlе in thе еnginе bау. А first аdditiоnаl suppоrt аrm hаs а first еnd соnnесtеd tо а first оnе оf thе brасkеts аnd а sесоnd еnd соnnесtеd tо thе mаin suppоrt аrm. А sесоnd аdditiоnаl suppоrt аrm hаs а first еnd соnnесtеd tо thе mаin suppоrt аrm аnd а sесоnd еnd соnnесtаblе tо thе vеhiсlе. Finаllу, а third аdditiоnаl suppоrt аrm hаs а first еnd соnnесtеd tо thе mаin suppоrt аrm аnd ...

METHOD FOR MANUFACTURING DISK DEVICE AND COMPUTER PROGRAM PRODUCT

According to one embodiment, first, a frequency to be corrected by an MA additional filter is specified based on a head position error spectrum and a multi-rate sensitivity characteristic, in a state before the MA additional filter is added. Then, a candidate in which a peak of the multi-rate sensitivity characteristic is equal to or less than a threshold value and a head position error is minimized is determined as the MA additional filter to be used, in a state in which each of a plurality of candidates of the MA additional filter is added.

Servo system and method with multiple phase clock

A timing-based servo system for positioning a magnetic head (38) relative to a magnetic storage medium (34), the magnetic storage medium (34) having a servo pattern written thereon in a servo band (40), the servo pattern including transitions (42, 43, 44), the magnetic medium (34) being movable relative to the head (38), the system comprising a head (38) including a servo read element (39) configured to read the servo pattern and produce a signal, the signal including recognizable signal events corresponding to the servo read element (39) reading servo transitions (42, 43, 44), a servo decoder (48) configured to receive the servo signal, determine the position of the head, with respect to the servo band (40), in response to the amount of time between the signal events, and generate an error signal indicative of actual head position relative to desired head position with respect to the servo band (40), the servo decoder (48) including time capture logic (56) configured to determine the amount ...

Information storage apparatus

An information storage apparatus having a disk medium 3 with data recording areas 203 along a plurality of tracks concentrically arranged, a head 4 for recording and reproducing data on tracks of the disk medium, an actuator 5 for moving the head to a desired track among the plurality of tracks, and an electric circuit 7 for controlling recording and reproducing and for detecting the distance from a recorded magnetization pattern on the adjacent tracks in the radial direction by detecting already recorded signals of adjacent tracks during data recording. By use of this constitution, even if the track density is increased, the upper limit of the threshold value setting range in the function for preventing from offtrack recording of the information storage apparatus can be increased and a high track density of the information storage apparatus can be easily realized.

SERVO-INFORMATION PRODUCING SYSTEM

PURPOSE: To produce high servo-information signals with the use of a small track width by writing the servo-information at a preset amgle of inclination with respect to the tangential direction of the track of a positioning magnetic disc. COPYRIGHT: (C)1978,JPO&Japio ...

Verfahren zum Unterdrücken des Schüttelrauschens in einem Magnetplattenlaufwerkspeichergerät mit Dünnfilmköpfen

Verfahren zum Unterdrücken von Schüttelrauschen in einem Magnetplattenspeichergerät, welches einen magnetischen Dünnfilmkopf (12) und eine Platte (10) aufweist, die mit sich abwechselnden Servosektoren und Datensektoren versehen ist, gekennzeichnet durch absichtliches Schreiben beliebiger Daten in den Datensektor, der auf einen Servosektor folgt, wenn auf Grund von Schüttelrauschen ein Fehler während der Rückgewinnung der Servoinformation aufgetreten ist.

Magnetaufzeichnungsdiskette, zugehöriges Diskettenantriebs-Spurverfolgungssystem, und zugehöriges Verfahren

Bimorph piezoelectric microactuator head and flexure assembly

Position error signal demodulation with target-based blending

In a disk drive, a method for servo burst-decoding demodulation that accommodates track pitch variation. Depending on the distance a read head is displaced from a read head target position, a target-based blending scheme, a position-based blending scheme, or a weighted combination of both is used to determine the position of the transducer head. When the transducer head is relatively close to the target position, the target-based blending scheme is used to decode servo bursts and calculate the exact head position. When the transducer head is relatively far from the target position, the position-based blending scheme is used to decode servo bursts and calculate head position. When the transducer head is an intermediate distance from the target position, a weighted combination of the target-based and position-based blending schemes is used.

Magnetic disk drive using offset in positioning head to read data and head positioning method

According to one embodiment, a magnetic disk drive comprises a write count memory, a read offset setting module and a controller. The write count memory stores a write count for each track or for each zone on a disk. The read offset setting module sets, in accordance with a write count for an adjacent track to a target track or for a zone to which the adjacent track belongs, an offset from a predetermined position on the target track in a read position in which a head is to be positioned when the head is positioned on the target track for data read. The write count is stored in the write count memory. The controller positions the head in a position shifted from the predetermined position by the set offset.

Systems and Methods for Efficient Data Storage

Various embodiments of the present invention provide systems and methods for preparing and accessing super sector data sets. As an example, a data storage system including a storage medium is disclosed. The storage medium includes a first servo data region and a second servo data region separated by a user data region. The user data region includes at least a portion of a first codeword and a portion of a second codeword that are together associated with a common header data.

Magnetic disk drive having microactuator

According to one embodiment, a servo controller of a magnetic disk drive includes a microactuator (MA) estimator, VCM actuator (VCMA) controller, a filter and an adder. The MA estimator estimates a first displacement of an MA from a control input to be provided to the MA. The VCMA controller controls a VCMA based on a positioning error between a target track and a first position of the VCMA. The first position is estimated from a position of a head and the first displacement. The filter estimates a second position of the VCMA corresponding to a delay in a displacement of the MA caused by hysteresis of the MA, from a state of the VCMA in a seek operation, and estimates a second displacement that is the delayed displacement of the MA, from the second position. The adder adds the second displacement to an input to the MA controller.

Position demodulator and position demodulation method

According to one embodiment, a position demodulator includes a demodulator, a phase corrector, and a position demodulating module. The demodulator demodulates a first demodulated signal and a second demodulated signal having a phase difference of 90 degrees from the first demodulated signal as a result of discrete Fourier transform operation on a read signal of a null servo pattern recorded in a servo area of a medium read out by a head. The phase corrector carries out correction to tilt respective vectors of the first demodulated signal and the second demodulated signal represented on a phase plane by a predetermined angle. The position demodulating module demodulates a positional signal for determining the position of the core of the head based on the first demodulated signal and the second demodulated signal corrected by the phase corrector.

System and method for improving head positioning

Systems and methods for improving accuracy of head positioning using existing servo patterns are provided. In one embodiment, a method for improving read head positioning is provided that comprises: writing a series of tracks over a range of read offsets to be calibrated; measuring a set of raw track profiles from the series of tracks; sampling the set of raw track profiles at a series of signal amplitude levels; constructing a reference track profile from the set of sampled track profiles; calculating a set of read offset deltas from each sampled track profile; merging the sets of read offset deltas into a set of average read offset deltas; and converting the set of average read offset deltas into a read offset correction table. A similar method for improving disk write head positioning is also provided which utilizes such a read offset correction table to eventually create write offset correction table.

Writing a reference pattern to bit patterned media

A given reference pattern is written on bit patterned media that has an initial reference pattern already disposed thereon. A write phase and frequency is detected based on the initial reference pattern and the given reference pattern is written on the bit patterned media at the detected write phase and frequency.

Patterned media with an alternating series of concentric servo zones and overlap zones

Embodiments described herein provide for patterned media concentric zones with an alternating series of concentric servo zones and overlap zones. The overlap zones facilitate the writing of servo data between servo zones of different servo frequency. The overlap zones may be dual frequency zones. The dual frequency zones have a first set of overlap patterns with the substantially identical pattern as the bordering lower frequency servo zone and a second set of overlap patterns with the substantially identical pattern as the bordering higher frequency servo zone. A bootstrap zone can be included near the inner diameter to assist initial servo writing. Alternatively the overlap zones are bootstrap zones. Such bootstrap zones have both bootstrap patterns and overlap patterns, the overlap patterns have the substantially identical pattern as a bordering servo zone. Bootstrap patterns only require DC magnetization for servo operability.

Methods and apparatus for validating detection of rro address marks

Methods and apparatus are provided for validating a detection of RRO address marks. After a potential RRO address mark is detected, a disclosed RROAM validation metric evaluates the energy of the remaining RRO data bits in the servo sector, relative to a predefined energy threshold. In addition, the number of remaining RRO data bits in the servo sector is compared to an expected value. The detected RRO address mark is validated in an exemplary embodiment if the RROAM validation metric satisfies the predefined energy threshold and the proper number of remaining RRO data bits is detected in the servo sector. The potential RRO address mark can optionally be discarded if the potential RRO address mark is not validated.

Disk drive upsampling servo control signal

A disk drive is disclosed comprising a disk including a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors. The disk drive further comprises an actuator for actuating a head over the disk in response to an actuator control signal. The servo sectors are read to generate a first sequence of control samples x[k] at a sample rate corresponding to a frequency of the servo sectors. The first sequence of control samples x[k] is upsampled by a factor of N to generate a second sequence of control samples y[k i ] according to: y  [ k i  | i = 1 : N ] = ( 1 - i N - γ )  u  [ k - 1 ] + ( i N + γ )  u  [ k ] where γ is a scalar greater than or equal to zero and less than one. The actuator control signal is generated in response to the second sequence of control samples y[k i ].

Medium, method of fabricating a medium, recording system and method of controlling a recording system

A medium may be provided. The medium includes a servo layer, a data recording layer, and a heat sink layer disposed between the servo layer and the recording layer.

Methods and devices for compensating for off-track motion

In certain embodiments, a method includes sensing a mode of a motor-base assembly's response to vibration. Based on the sensed response, the method includes adjusting a head-suspension assembly to compensate for off-track motion caused by the vibration. In certain embodiments, an apparatus includes a sensor positioned on a basedeck such that the sensor senses a mode of the motor-base assembly's response to linear vibration.

METHOD AND APPARATUS FOR SERVO PATTERN WRITING

Disclosed are servo pattern writing methods and apparatuses for performing the same. In one example, a method may include providing a plurality of disks having reference servo patterns written thereon; writing align patterns aligned with each other in a horizontal direction of the disk surface, on the plurality of disks, using a reference servo pattern of one of the plurality of disks; and writing a final servo pattern on each disk, using the align pattern written on each disk. 1. A method comprising:providing a plurality of data storage discs having reference servo patterns written thereon;writing align patterns on the plurality of data storage discs using a reference servo pattern of one of the plurality of data storage discs, the align patterns aligned with each other in a horizontal direction of the surface of the data storage discs; andwriting a final servo pattern on each data storage disc, using the align pattern written on each disc.2. The method of claim 1 , wherein the reference servo patterns are written on the plurality of data storage discs by an offline servo track writer.3. The method of claim 1 , wherein the reference servo patterns written on the data storage discs include a spiral reference pattern written on each disc in a spiral shape.4. The method of claim 3 , wherein the reference servo pattern further includes a burst reference pattern radially written on at least part of an outer diameter (OD) of the data storage disc claim 3 , andwherein the align pattern is an align burst pattern written on each of the plurality of data storage discs, by using the spiral reference pattern of one of the plurality of data storage discs, after a transducer is moved to a copy start location of the burst reference pattern of one of the plurality of data storage discs.5. The method of claim 4 , wherein writing align burst patterns includes:readying one transducer head among a plurality of transducer heads, the one transducer head corresponding to the data storage ...

Magnetic disk drive and method for controlling the same

According to one embodiment, there is provided a magnetic disk device including an acceleration feedforward module, an eccentricity correction module, and a control module. The acceleration feedforward module includes a first amplification module, a second amplification module, and an addition module. The first amplification module amplify a first rotation correlation value according to a rotation component by a first gain. The second amplification module amplifies a second rotation correlation value according to a rotation synchronization component of the rotation component, by a second gain acquired by subtracting the first gain from 1. The addition module adds the first rotation correlation value amplified by the first amplification module and the second rotation correlation value amplified by the second amplification module to obtain the first correction amount.

Magnetic disk device and method of controlling head position

According to one embodiment, a magnetic disk device includes a reference head select module selects any one of magnetic heads as a reference head; a follow-up controller executes a follow-up control of a trajectory of the reference head based on a signal read by the reference head; and an eccentric controller executes an eccentric control of a trajectory of a magnetic head other than the reference head in order that an eccentric error between the trajectory of the reference head and the trajectory of the corresponding magnetic head is close to zero.

REPEATABLE RUN OUT COMPENSATION

An apparatus can include a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk 1. An apparatus , comprising:a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk.2. The apparatus of claim 1 , wherein:the at least one RRO compensator includes a plurality of RRO compensators.3. The apparatus of claim 2 , wherein:each RRO component corresponds to a multiple of the frequency at which the disk rotates.4. The apparatus of claim 2 , wherein:the disk driver controller is further configured to operate at least one other RRO compensator in response to the head assembly position changing from the one predetermined area to at least the other predetermined area of the disk.5. The apparatus of claim 2 , wherein:the disk drive controller is configured to disable a plurality of RRO components in response to the head assembly position changing from the one predetermined area of the disk to the other predetermined area of the disk.6. The apparatus of claim 1 , wherein:the one predetermined area includes an area within a predetermined diameter of the disk, andone other predetermined area includes an area outside of the predetermined diameter.7. The apparatus of claim 1 , wherein:the head assembly is includes any selected from the group of: a read head assembly to read data from the disk, a write head assembly to write data to the ...

Magnetic recording medium and method of manufacturing the same

According to one embodiment, a magnetic recording medium includes a data region and a servo region adjacent to the data region and including a magnetic recording layer, the magnetic recording layer including first and second patterned regions adjacent to each other, the first patterned region including a first nonmagnetic matrix and first magnetic particles dispersed in the first nonmagnetic matrix and having magnetization oriented in a first direction, the second patterned region includes a second nonmagnetic matrix and second magnetic particles dispersed in the second nonmagnetic matrix and having magnetization oriented in a second direction opposite to the first direction, sizes of the first magnetic particles being smaller than sizes of the second magnetic particles.

Magnetic recording disk drive with three sensors for rotational and linear vibration compensation

A magnetic recording disk drive has three vibration sensors mounted to the disk drive base to provide feedforward vibration compensation signals. First and second spaced-apart sensors are aligned generally parallel to a radius from the disk rotational axis to a head position on the disk between the inside diameter position (h ID ) and outside diameter position (h OD ) for detecting rotational vibration about the disk rotational axis and linear vibration in the cross-track direction. A third vibration sensor is aligned generally orthogonal to the primary axes of the first and second vibration sensors for detecting primarily linear vibrations in the along-the-track or track circumferential direction. The disk drive servo control processor calculates, from the signals from the three sensors, a rotational vibration feedforward signal, a radial linear vibration feedforward signal, and a circumferential linear vibration feedforward signal which are summed with the actuator control signal to compensate for the vibrations.

Disk storage apparatus and method of writing servo patterns

According to one embodiment, a disk storage apparatus includes heads, disks and a controller. The controller performs a servo write control in order to write a plurality of radial servo patterns on each surface of the disk by using the spiral servo patterns. The servo controller positions the head above the spiral servo patterns by using first position information based on the spiral servo patterns. The position information generator generates second position information based on the radial servo patterns read by the head positioned above the spiral servo patterns. The processor corrects target position information for positioning the head based on the second position information by using the spiral servo patterns read by the head.

Systems and Methods for Improved Servo Data Operation

Various embodiments of the present invention provide systems, methods and media formats for efficiently determining a position error of a head in relation to a storage medium. In one case, a system is disclosed that includes a storage medium with a series of data. The series of data includes a first defined marker and a second defined marker located a distance from the first defined marker, and position location data. The systems further include a first detector circuit that is operable to detect the first defined marker and to establish a location of the first defined marker, and a second detector circuit that is operable to detect the second defined marker and to establish a location of the second defined marker. The systems further include an error calculation circuit and an interpolation circuit. The error calculation circuit is operable to calculate an interpolation offset based at least in part on the location of the first defined marker and the location of the second defined marker. The interpolation circuit is operable to interpolate the position location data and to provide an interpolated position location data.

Perpendicular Pole Head for Servo Writing Magnetic Media

The present disclosure relates to a perpendicular pole head for creating a perpendicular magnetic moment in a concentrated pattern for writing the pattern on perpendicular magnetic media, such as BaFe based media. The pole head can have flux concentrators in the shape of the written pattern, which can be repeatedly applied to a moving magnetic medium to create a timing pattern on the media, e.g., a servo timing pattern. 1. A perpendicular write head , comprising:a primary write head configured to generate a magnetic field approximately perpendicular to a surface of the head; anda concentrator on the surface configured to concentrate the magnetic field in a pattern.2. The perpendicular write head of claim 1 , where the concentrator includes at least two servo stripes disposed at an angle with respect to each other.3. The perpendicular write head of claim 1 , wherein the magnetic field is concentrated in a medium by the concentrator such that the concentrated magnetic field is >110% of a coercivity of the medium claim 1 , and wherein the magnetic field generated by the primary write head is <90% of the coercivity of the medium claim 1 , absent the concentrator.4. The perpendicular write head of claim 1 , wherein the concentrator is substantially disposed in one of a “\/” shape claim 1 , a “/\/” shape claim 1 , a “\/” shape claim 1 , or a “//\” shape.5. The perpendicular write head of claim 1 , wherein the magnetic field generated by the primary write head is claim 1 , at least near the surface claim 1 , approximately perpendicular to the surface and the primary write head does not generate a substantial magnetic field approximately parallel to the surface.6. The perpendicular write head of claim 1 , wherein the primary write head is configured to generate the magnetic field in a first direction approximately perpendicular to and away from the surface of the head.7. The perpendicular write head of claim 6 , wherein the primary write head is configured to generate the ...

Patterned magnetic media with offset data and servo regions

A patterned magnetic media having offset servo and data regions. The media can be constructed by a method that allows both a data region and a servo region to be patterned without the patterning of one region adversely affecting the patterning of the other region. The method results in a patterned data region a patterned servo region and intermediate regions between the servo and data regions. The intermediate regions, which are most likely, but not necessarily, asymmetrical with one another indicate that the method has been used to pattern the media.

Write synchronization in bit patterned media using auxiliary read head

A method for recording data to a magnetic media while simultaneously reading sync and or servo data with reduced noise from the write head affecting the reading of the sync and or servo data. The invention records data using a write head of a first slider and reads the sync and or servo data from a read head located on a different slider that is facing a different disk surface than the first slider. In this way, magnetic or thermal noise from the write head does not affect the reading of the sync and or servo data.

Electrically-augmented damping

Provided herein are devices, systems, and methods for electrically-augmented damping of an actuator and associated devices. In particular, electrically-augmented damping derived from measurement of voltage across an actuator and current flowing through an actuator is provided.

Read/write apparatus and read/write method

According to at least one embodiment, a read/write apparatus includes a read module and a positioning module. The read module reads data of a predetermined data track using a read head. The positioning module positions the read head in accordance with an index indicating how much the read head reads data of a neighboring data track of the predetermined data track when the read head reads data of the predetermined data track.

Multi-signal realignment for changing sampling clock

An apparatus may include a circuit configured to receive first and second samples of an underlying data from respective first and second sample periods and which correspond to respective first and second sensors, a phase control value may have first and second values during respective first and second sample periods. The phase control value may be a control value for a sample clock signal. The circuit may also determine a difference in the phase control value between the first value and the second value. The circuit may then digitally interpolate the first and second samples to produce a phase shifted first and second samples where the digital interpolation of at least one of the first and second samples mat be at least in part based on the difference in the phase control value to compensate for a phase misalignment between the first sample and the second sample.

MAGNETIC TAPE APPARATUS

A magnetic tape apparatus, in which a tilt cos θ of the hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation by STEM is 0.85 to 1.00, a reading element unit includes a plurality of reading elements each of which reads data by a linear scanning method from a specific track region including a reading target track in a track region included in the magnetic tape, an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result, and the deviation amount is determined in accordance with a result obtained by reading of the servo pattern included in the magnetic layer by a servo element. 1. A magnetic tape apparatus comprising:a magnetic tape;a reading element unit; andan extraction unit,wherein the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support,the magnetic layer includes a servo pattern,the ferromagnetic powder is a hexagonal ferrite powder,a tilt cos θ of the hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 1.00,the reading element unit includes a plurality of reading elements each of which reads data by a linear scanning method from a specific track region including a reading target track in a track region included in the magnetic tape,the extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result, andthe ...

RECORDING MEDIUM AND A METHOD OF WRITING SERVO INFORMATION ON THE SAME

In various embodiments, a method of writing servo information to a recording medium may be provided. The method include forming a first servo pattern (including a servo burst pattern) on a segment of a first track of a first layer of the recording medium, the first track having a track width. The method may further include forming a second servo pattern (including addressing information) on a segment of a second track of a second layer of the recording medium. The second track is arranged from the first track by half the track width.

DATA STORAGE DEVICES AND METHODS WITH FREQUENCY-SHAPED SLIDING MODE CONTROL

A data storage device includes a disk, a head, a microactuator, a coarse actuator, and a servo controller. The microactuator is configured to position the head relative to the disk. The coarse actuator is configured to position the microactuator relative to the disk. The servo controller is configured to generate an adjusted position error signal based on a position error signal and an estimated microactuator position signal. The servo controller is also configured to filter the adjusted position error signal with a shaping filter to generate a filtered position error signal, and to provide sliding mode control of the coarse actuator based at least partially on the filtered position error signal. 1. A data storage device , comprising:a microactuator configured to position a head relative to a disk;a coarse actuator configured to position the microactuator relative to the disk; anda servo controller configured to generate an adjusted position error signal based on a position error signal and an estimated microactuator position signal, and configured to filter the adjusted position error signal with a shaping filter to generate a filtered position error signal, and configured to provide sliding mode control of the coarse actuator based at least partially on the filtered position error signal;wherein the shaping filter is configured to provide frequency dependent filtering of the adjusted position error signal to generate the filtered position error signal.2. The data storage device of claim 1 ,wherein the servo controller is further configured to generate a derivative position error signal as a derivative of the adjusted position error signal, and is configured to provide the sliding mode control of the coarse actuator based on the filtered position error signal and the derivative position error signal.3. The data storage device of claim 2 ,wherein the servo controller is further configured to scale the derivative position error signal to generate a scaled derivative ...

DISK APPARATUS, CONTROLLER, AND CONTROL METHOD

According to one embodiment, there is provided a disk apparatus including a disk medium and a controller. The disk medium has a data area and a servo area. The controller obtains offset amount of a head from a target position along an cross-track direction based on a signal read from the data area by the head and performs first control to cause the head to approach the target position based on the offset amount. 1. A disk apparatus comprising:a disk medium having a data area and a servo area, on the disk medium, a signal of three levels can be recorded onto the data area on a track including first and second sub-tracks in a form of combinations of information recorded on the first sub-track and information recorded on the second sub-track adjacent to the first sub-track, the three levels including a first level, a second level, and a third level between the first level and the second level; anda controller that obtains a likelihood ratio of likelihood of the third level to likelihood of the first level and of the second level based on a signal read from the data area by a head, obtains offset amount of the head from a target position along an cross-track direction and a direction of the offset according to the obtained likelihood ratio, and performs first control to cause the head to approach the target position based on the offset amount and the direction.2. The disk apparatus according to claim 1 , whereinthe controller performs, in parallel, the first control and an operation to read the signal from the data area by the head.3. The disk apparatus according to claim 1 , whereinthe target position is a position near a boundary between the first sub-track and the second sub-track.4. (canceled)5. The disk apparatus according to claim 1 , whereinif the likelihood ratio is at or above a threshold, the controller performs the first control and, if the likelihood ratio is below the threshold, does not perform the first control.6. The disk apparatus according to claim 1 , ...

METHOD AND APPARATUS FOR DETERMINING READ-HEAD DEVIATION USING ORTHOGONAL PREAMBLES

A storage device includes read circuitry having a read head having a detector that outputs signals representing data from a first track and an adjacent track. The read head is subject to off-track excursions during which the read head detects signals from both the first track and an adjacent track. Data on each track includes a preamble including a repeating pattern. The repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track. The read circuitry also includes respective Discrete Fourier Transform circuits to identify components in the signals corresponding to respective frequencies characteristic of the repeating pattern on the first track and the repeating pattern on the second track, and computation circuitry to determine from the components a ratio by which the read head is off-track. Corresponding methods are provided for operating such a storage device and for reading data. 1. A method of operating a storage device having a storage medium , the method comprising:writing data to tracks on the storage medium, data for each track including a preamble including a repeating pattern, wherein the repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track;detecting with a read head signals from both the first track and an adjacent track;analyzing preamble output of the read head to determine a ratio by which the read head is off-track.2. The method of wherein the analyzing comprises applying a Discrete Fourier Transform to the preamble output of the read head.3. The method of further comprising filtering the preamble output of the read head prior to the applying.4. The method of wherein the applying comprises applying a separate Discrete Fourier Transform for a frequency corresponding to the repeating pattern on the first track and a frequency corresponding to the repeating pattern on the adjacent track.5. The method of wherein the analyzing comprises ...

MAGNETIC RECORDING AND REPRODUCING DEVICE

According to one embodiment, a magnetic recording and reproducing device includes an output driver, a magnetic head, and a magnetic recording medium. The output driver outputs a recording signal corresponding to input information. The magnetic head includes a coil. A recording current includes the recording signal flows in the coil. Information corresponding to the input information is recorded in the magnetic recording medium. The input information includes first, second, and third information combinations. The first information combination includes first to fourth information. The second information combination includes fifth to eighth information. The third information combination includes ninth to twelfth information. The recording signal changes to an eleventh recording current to correspond to the eleventh information. The recording signal changes to a third recording current to correspond to the third information. An absolute value of the eleventh recording current is greater than an absolute value of the third recording current. 1. A magnetic recording and reproducing device , comprising:an output driver outputting a recording signal corresponding to input information;a magnetic head including a coil, a recording current flowing in the coil, the recording current including the recording signal; anda magnetic recording medium, information being recorded in the magnetic recording medium by the magnetic head, the information corresponding to the input information,the input information including a first information combination, a second information combination, and a third information combination,the first information combination including first to fourth information,the second information being after the first information and being continuous with the first information,the third information being after the second information and being continuous with the second information,the fourth information being after the third information and being continuous with the ...

HARD DISK DRIVE

According to one embodiment, there is provided a hard disk drive including a first recording surface, a second recording surface, a first magnetic head, a first actuator and a second actuator that move the first magnetic head, a second magnetic head, a third actuator and a fourth actuator that move the second magnetic head, a fifth actuator that moves the second actuator and the fourth actuator, a drive circuit that implements at least one of a first mode in which the second actuator and the fourth actuator operate differently from each other or a second mode in which the first and third actuators operate differently from each other, and a controller that controls the drive circuit. 1. A hard disk drive comprising:a first recording surface;a second recording surface;a first magnetic head that performs reading/writing on the first recording surface;a first actuator that moves the first magnetic head;a second actuator that moves the first magnetic head and the first actuator in an integrated manner;a second magnetic head that performs reading/writing on the second recording surface;a third actuator that moves the second magnetic head;a fourth actuator that moves the second magnetic head and the third actuator in an integrated manner;a fifth actuator that moves the second actuator and the fourth actuator in an integrated manner;a drive circuit that implements at least one of a first mode in which the first actuator and the third actuator perform same operation and the second actuator and the fourth actuator perform different operations or a second mode in which the second actuator and the fourth actuator perform same operation and the first actuator and the third actuator perform different operations; anda controller that controls the drive circuit.2. The hard disk drive according to claim 1 , whereinthe drive circuit includes a plurality of switches that switches a switching state to select, from the first actuator, the second actuator, the third actuator, and the ...

METHODS AND APPARATUS FOR IMPROVED THRESHOLD ADAPTATION FOR A EUCLIDEAN DETECTOR

Improved threshold adaptation is provided for a predefined pattern in data. A detection threshold employed by a Euclidean detector to detect a pattern (such as a Servo Address Mark) in data is adapted by determining a minimum Euclidean distance metric Dbefore the pattern is declared in a given portion of the data; determining a Euclidean distance metric Dat a time when the pattern is found in the given portion, wherein at least one of the patterns is found using a Hamming detector; determining, for a plurality of the portions, a minimum Dvalue, D, that is a substantial minimum Dvalue for the plurality of portions and a maximum Dvalue, D, that is a substantial maximum Dvalue for the plurality of portions; and determining the detection threshold based on the minimum Dvalue, D, and the maximum Dvalue, D. The detection threshold is optionally based on a configurable margin gain value. 1. A method for adapting a detection threshold employed by a Euclidean detector to detect a pattern in data , comprising:{'sub': 'p', 'determining a substantially minimum Euclidean distance metric Dbefore said pattern is declared in a given portion of said data;'}{'sub': 's', 'determining a Euclidean distance metric Dat a time when said pattern is found in said given portion, wherein at least one of said patterns is found using a Hamming detector;'}{'sub': p', 'pmin', 'p', 's', 'smax', 's, 'determining, for a plurality of said portions, a minimum Dvalue, D, that is a substantial minimum Dvalue for said plurality of portions and a maximum Dvalue, D, that is a substantial maximum Dvalue for said plurality of portions; and'}{'sub': p', 'pmin', 's', 'smax, 'determining said detection threshold based on said minimum Dvalue, D, and said maximum Dvalue, D.'}2. The method of claim 1 , wherein said pattern comprises one or more of a Servo Address Mark (SAM) claim 1 , a Repeatable Run Out data (RRO) Address Mark (RROAM) claim 1 , an image pattern and an antenna signal pattern.3. The method of claim ...

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. 1. A method for fabricating an orientation control bias point , comprising:creating a marking structure including a magnetic index mark and an orientation control bias point;determining an offset based of the control bias point on specific coordinates used to substantially prevent concentricity run-out; andestablishing a magnetically writable area within the orientation control bias point.2. The method of claim 1 , further comprising integrating close to a 0° zero point of a first sector where servo writing is done claim 1 , and wherein the magnetic index mark is integrated and created on both sides of a bit patterned media (BPM) stack pattern for master imprint templates.3. The method of claim 1 , wherein the magnetic index mark is includes being larger than any one sector and therefore larger than a degree of rotation.4. The method of claim 1 , wherein the specific coordinates include x claim 1 ,y coordinate offsets from a spindle center of rotation to the bit patterned media pattern center of rotation uniformly on fabricated bit patterned media stacks claim 1 , and wherein these are used to establish a center of rotation of the bit patterned media stack pattern and servo signal to prevent run-out.5. The method of claim 1 , further comprising using a writable section of the magnetic index mark used to record identification information claim 1 , orientation control bias point offset coordinate data and other magnetic index mark information during a servo writing process.6. The method of claim 1 , further comprising determining an orientation control bias point offset coordinate value based on x claim 1 ,y coordinate offsets from an eccentric bit patterned media pattern center of rotation relative to the location of a spindle center of rotation.7. The ...

STORAGE DEVICE SYSTEM PERFORMANCE MANAGEMENT

The technology disclosed herein pertains to a method for determining expected command completion time (CCT), the method including receiving a plurality of position error signals (PESs) for an HDD over a predetermined time period, determining sigma of the plurality of PESs, retrieving upper off-track limits (UOL) for one or more data sectors of the HDD, calculating average number of retrieved sectors (A) between two consecutive occurrences of the |PES|>UOL for the HDD, and determining required number of revolutions (CCT) to collect data based on the average number of retrieved data sectors (A) and a total number of requested data sectors (N). 1. A method , comprising:receiving a plurality of position error signals (PESs) for an HDD over a predetermined time period;determining sigma of the plurality of PESs;receiving upper off-track limits (UOLs) for one or more data sectors of the HDD;calculating average number of retrieved sectors (A) between two consecutive occurrences of the |PES|>UOL for the HDD;determining required number of revolutions (CCT) to collect data based on the average number of retrieved data sectors (A) and a total number of requested data sectors (N); andin response to determining the CCT to be above a threshold, collecting data from a mirrored HDD.2. The method of claim 1 , further comprising formulating a data request based on the determined required number of revolutions.3. The method of claim 2 , wherein formulating a data request based on the determined required number of revolutions further comprising requesting data from an alternative storage device configured to provide data redundancy to the HDD.4. The method of claim 1 , further comprising determining a probability of the PES being above the UOL based on the sigma of the plurality of PESs claim 1 , wherein the average number of retrieved data sectors (A) is calculated using the probability of the PES being above the UOL based on the sigma of the plurality of PESs.5. The method of claim 1 ...

Generating position error signal based on data tracks for rotating storage data storage

A system including an inter-track interference detection module and a position error signal generation module. The inter-track interference detection module determines a first inter-track interference value based on a first signal from a first sensor positioned over a first track of a rotating storage medium. The first inter-track interference value indicates energy contributed by tracks adjacent to the first track compared to energy contributed by the first track. The inter-track interference detection module determines a second inter-track interference value based on a second signal from a second sensor positioned over a second track of the rotating storage medium. The second inter-track interference value indicates energy contributed by tracks adjacent to the second track compared to energy contributed by the second track. The position error signal generation module generates a position error signal based on the first inter-track interference value and the second inter-track interference value.

Disk Drive Suspension Tri-Stage Actuator Having Pseudo Feature Integrally Constructed On Trace Gimbal

A dual stage actuated suspension has a first piezoelectric microactuator on the trace gimbal assembly (TGA), and a pseudo feature located laterally opposite the microactuator. The pseudo feature is formed integrally with the TGA from at least one of the base metal layer, the insulative layer, and the conductive layer that make up the TGA. The pseudo feature helps to balance the suspension. The suspension can optionally have a second microactuator located proximal of the first microactuator in order to perform coarser positioning than the first microactuator, such that the suspension is a tri-stage actuated suspension. 1. A dual stage actuated disk drive suspension comprising:a beam; a metal base layer;', 'an insulating layer on the metal base layer; and', 'a conductive layer on the insulating layer;', 'the TGA having a first lateral side and a second lateral side opposite the first lateral side;, 'a trace gimbal assembly (TGA) attached to the beam, the TGA comprisinga head slider mounted to the TGA;a piezoelectric device mounted on the first lateral side of the TGA and arranged for moving the head slider, the first piezoelectric device having a mass thereof;wherein:the suspension has a second piezoelectric device that is disposed on the second lateral side of the TGA generally opposite the piezoelectric device; andthe suspension does not have a counterbalancing mass on the second lateral side of the suspension to balance out a mass of the piezoelectric device, and having a mass of at least one quarter of the mass of the first piezoelectric device, and which was formed separately from the TGA and affixed thereto.2. The suspension of further comprising:a counterbalancing mass disposed laterally opposite the piezoelectric device and having a mass of at least 50% of the mass of the piezoelectric device, the counterbalancing mass comprising at least one of the metal base layer, the insulating layer, and the conductive layer, the counterbalancing mass having been formed ...

APPARATUS AND METHODS FOR ALIGNED SERVO-RELATED FEATURES

Provided herein is an apparatus, including a first region of a substrate corresponding to a data region in a patterned recording medium; a first set of protrusions etched out of the first region of the substrate, wherein the protrusions of the first set of protrusions are rectangle shaped; a second region of the substrate corresponding to a servo region in a patterned recording medium; and a second set of protrusions etched out of the second region of the substrate, wherein the second set of protrusions includes radial lines etched into the substrate across chevrons etched out of the substrate. 1. An apparatus , comprising:a first region of a substrate corresponding to a data region in a patterned recording medium; 'wherein the protrusions of the first set of protrusions are rectangle shaped;', 'a first set of protrusions etched out of the first region of the substrate,'}a second region of the substrate corresponding to a servo region in a patterned recording medium; and 'wherein the second set of protrusions includes radial lines etched into the substrate across chevrons etched out of the substrate.', 'a second set of protrusions etched out of the second region of the substrate,'}2. The apparatus of claim 1 ,wherein the protrusions of the second set of protrusions are radially aligned along the radial lines etched into the substrate.3. The apparatus of claim 1 ,wherein the protrusions of the first set of protrusions are radially aligned along the radial lines etched into the substrate and circumferentially aligned along circumferential lines etched into the first region of the substrate.4. The apparatus of claim 1 ,wherein the substrate is configured to transmit ultraviolet light.5. The apparatus of claim 1 ,wherein the apparatus comprises a UV-transmissible nanoimprint template comprising the first and second sets of protrusions for patterned recording media.6. A method claim 1 , comprising: 'wherein the first region and the second region respectively correspond ...

SERVO CONTROL METHOD HAVING FIRST AND SECOND TRAJECTORY GENERATION UNITS

A control device, a method of controlling the control device and recording medium are provided. Ranges of movement of a plurality of servo control systems are effectively used. A controller generates a corrected trajectory in which a high frequency component is removed from a first inverse kinematics trajectory so that no phase delay occurs as a command trajectory of a first servo control system. 1. A control device comprising:a first trajectory generation unit configured to generate a first command trajectory in which a high frequency component is removed from a reference trajectory in a manner without occurring phase delay as a command trajectory of a first servo control system;a second trajectory generation unit configured to generate a second command trajectory including a trajectory corresponding to the high frequency component as a command trajectory of a second servo control system; anda prediction unit configured to predict a response of the first servo control system corresponding to the first command trajectory using a dynamic characteristics model of the first servo control system.2. The control device according to claim 1 ,wherein the first trajectory generation unit performs low pass filter processing on the reference trajectory in both directions of a forward direction and a reverse direction of a time axis and generates the first command trajectory.3. The control device according to claim 2 ,wherein the first trajectory generation unit performs the low pass filter processing on the reference trajectory in order from the reverse direction to the forward direction of the time axis and generates the first command trajectory.4. The control device according to claim 1 ,wherein the first trajectory generation unit generates the first command trajectory from an average of upper and lower envelopes of a curve showing the reference trajectory.5. (canceled)6. (canceled)7. (canceled)8. (canceled)9. The control device according to claim 1 ,wherein the prediction ...

DISK DEVICE

According to one embodiment, in a disk device, a first pattern cut out from a burst region at a certain servo track by a first length and with a first start position, does not match a second pattern cut out from the burst region at an adjacent servo track by the first length and with an arbitrary second start position including first timing. The burst region at the servo tracks includes a first burst pattern including a first magnetized portion where a first value is recorded and a second magnetized portion where a second value reverse to the first value in polarity is recorded, the second magnetized portion being adjacent to the first magnetized portion in a down track direction. A width of the first magnetized portion in the down track direction and a width of the second magnetized portion in the down track direction are different from each other. 2. The disk device according to claim 1 , wherein a third magnetized portion where the second value is recorded, the third magnetized portion being adjacent to the first magnetized portion in a cross track direction, and', 'a fourth magnetized portion where the first value is recorded, the fourth magnetized portion being adjacent to the third magnetized portion in the down track direction, and, 'the first burst pattern further includes'}a border line between the first magnetized portion and the second magnetized portion and a border line between the third magnetized portion and the fourth magnetized portion are present along a straight line extending in the cross track direction.3. The disk device according to claim 2 , whereina width of the third magnetized portion in the down track direction and a width of the fourth magnetized portion in the down track direction are different from each other.4. The disk device according to claim 1 , whereinthe burst region at the servo tracks further includes a second burst pattern, a fifth magnetized portion where the first value is recorded, the fifth magnetized portion being ...

DIRECT CURRENT MAGNETORESISTIVE JOG OFFSET COMPENSATION

Systems and methods for compensating for magnetoresistive (MR) jog offset direct current (DC) drift in a disc drive are described. In one embodiment, a method may include determining an occurrence of NOS, for example, by monitoring disc slip, to determine when the method should proceed. An MR jog offset DC drift amount is determined for each head of the disc drive. One of several approaches may be employed for determining the MR jog offset DC drift amount. By determining an MR jog offset DC drift amount for each head, a compensation profile is determined for the drive. The determined compensation profile may then be used during operation of the disc drive to compensate for the DC drift. One of several approaches may be employed for compensating based on the compensation profile. 1. A storage device comprising:a non-operating shock (NOS) detector to determine an occurrence of NOS; andan MR jog offset direct current (DC) drift detector to select a first read/write head of the storage device, use the first read/write head to perform a first variable read of a first test track over one revolution of a first disk surface, determine a highest bit error rate (BER) value of the first disk surface based at least in part on the first variable read, and assign the highest BER value of the first disk surface as a first DC drift amount for the first read/write head.2. The storage device of claim 1 , the MR jog offset DC drift detector to determine whether the storage device includes one or more read/write heads in addition to the first read/write head for which the DC drift remains to be determined.3. The storage device of claim 2 , upon determining the storage device does not include any further read/write heads for which the DC drift remains to be determined claim 2 , an MR jog offset compensator to perform write seek forward compensation based at least in part on the first DC drift amount for each write operation occurring after the NOS that involves the first read/write head ...

WRITE TIMING FOR RRO FIELD IN A CONSTANT DENSITY SERVO SYSTEM

A method for writing repeatable run-out data, representing a recurring contribution to position error, to a rotating constant-density magnetic storage medium, includes repeating, for each respective track at a respective radius of the constant-density magnetic storage medium, (1) determining a respective track pattern frequency based on track location and desired data density, (2) locating a position in a respective servo wedge on the respective track based on servo sync mark detection, (3) writing the repeatable run-out data to the respective servo wedge at a time delay, from the location of the position in the respective servo wedge, that is inversely proportional to the respective radius, to achieve a predetermined offset, and (4) repeating the determining, the locating and the writing for each servo wedge on the respective track of the constant-density magnetic storage medium. 1. A method for writing repeatable run-out data , representing a recurring contribution to position error , to a rotating constant-density magnetic storage medium , the method comprising:repeating, for each respective track at a respective radius of the constant-density magnetic storage medium:determining a respective track pattern frequency based on track location and desired data density,locating a position in a respective servo wedge on the respective track based on servo sync mark detection,writing the repeatable run-out data to the respective servo wedge at a time delay, from the location of the position in the respective servo wedge, that is inversely proportional to the respective radius, to achieve a predetermined offset, andrepeating the determining, the locating and the writing for each servo wedge on the respective track of the constant-density magnetic storage medium.2. The method of wherein:locating the position in the respective servo wedge based on servo sync mark detection comprises locating the position in each respective servo wedge by detecting a respective servo sync ...

Vibration control in data storage devices

A storage device has a device body and a read/write head for reading and writing data in a data track of a storage medium. An actuator system is mounted on the device body for effecting movement of the read/write head relative to the data track to align the head with the data track. The actuator system has a plurality of degrees of freedom, and a controller controls the actuator system to effect the movement. A body vibration sensor provided on the device body generates a signal indicative of vibration of the body. An actuator vibration sensor generates a signal indicative of vibration of the actuator system. The controller is adapted to process the signals from the sensors to derive a coupling signal indicative of vibration coupling between the degrees of freedom, and to control the actuator system dependent on the coupling signal and the signal from the body vibration sensor.

Methods and Apparatus for Improved Pattern Detection

Improved pattern detection is provided for a predefined pattern in data. A detection threshold employed by a Euclidean detector to detect a pattern (such as a Servo Address Mark) may be adjusted based upon data gathered that corresponds to an indication of a detected pattern by one of a plurality of pattern detectors.

SERVO PARAMETERIZATION FOR MULTI-SENSOR READER

A storage media includes a plurality of servo sectors with embedded servo patterns characterized by one or more servo pattern parameters. Each of the servo sectors has a servo pattern parameter based on a separation between read sensors of a transducer head reading the servo sector. 1. A system comprising:a storage media with a plurality of servo patterns, each of the servo patterns characterized by a servo pattern parameter based on a separation between read sensors of a transducer head when the transducer head reads the servo pattern.2. The system of claim 1 , wherein the separation is a cross-track separation of the read sensors.3. The system claim 1 , wherein the storage media further comprises a plurality of radial zones claim 1 , each of the radial zones associated with a value of the servo pattern parameter that is different from the value of the servo pattern parameter associated with at least another one of the radial zones.4. The system of claim 1 , wherein the servo pattern parameter is a servo pattern density.5. The system of claim 1 , wherein the servo pattern parameter is servo tracks per inch (STPI).6. The system of claim 1 , wherein the servo pattern parameter is a servo pattern length.7. The system of claim 1 , wherein the servo pattern parameter is a servo pattern density and the storage media further comprises:a first servo sector with a first servo pattern density associated with a first cross-track separation between the read sensors; anda second servo sector with a second servo pattern density associated with a second cross-track separation between the read sensors, wherein the second cross-track separation is greater than the first cross-track separation and the second servo pattern density is greater than the first servo pattern density.8. The system of claim 1 , wherein the servo pattern parameter is a servo pattern length and the storage media further comprises:a first servo sector with a first pattern length associated with a first cross- ...

MAGNETIC DISK DEVICE AND SECTOR PROCESSING METHOD

According to one embodiment, a magnetic disk device includes a disk having a first sector including first servo data, first user data, and first correction information used to correct a data error, a head that writes data to the disk and that reads data from the disk, and a controller that changes, according to a first defect length of a defect generated in the first sector in a circumferential direction of the disk, a first sector length of the first sector in the circumferential direction.

DATA STORAGE APPARATUS AND METHOD FOR CORRECTING REPEATABLE RUNOUT

According to one embodiment, a data storage apparatus includes a disk, a head and a controller. In each track, first and second correction values for correcting a track runout in synchronization with rotation of the disk are recorded. The first correction value is for a first position located within a first track, and the second correction value is for a second position located within a second track adjacent to the first track, and separated from the first track by a predetermined distance. The head writes data to or read data from the tracks. The controller corrects the track runout with the first and second correction values, when the head is controlled to position at a target track. 1. A data storage apparatus comprising:a disk comprising tracks which are arranged as data recording areas in a radius direction of the disk, and in each of tracks, N correction values including first and second correction values for making a correction for a track runout in synchronization with rotation of the disk are recorded, the first correction value being a correction value for a first position located within a first track, the second correction value being a correction value for a second position which is located within a second track adjacent to the first track, and which is separated from the first position by a predetermined distance, and the N correction values being obtained with learning at each of N positions into which an area between a center of the first track and a center of the second track is divided into N, N being a positive integer more than one;a head configured to write or read data to or from the tracks; anda controller configured to make the correction for the track runout with two of the first to N-th correction values, which are obtained for positions close to a target one of the tracks, when the head is controlled to be positioned at the target track.2. The data storage apparatus of claim 1 , wherein the controller is configured to:make the correction ...

METHODS FOR STORING AND ACCESSING ADDRESS INFORMATION IN A SERVO LAYER OF A STORAGE MEDIUM

A method including determining a first frequency for (i) a first track in a servo layer of a storage medium, or (ii) a first sector in the servo layer. The servo layer is dedicated to storing servo information. The method further includes: obtaining first address information addressing the first track or the first sector; modulating the first address information according to the first frequency; and storing the modulated first address information in the servo layer. Subsequent to the storing of the modulated first address information, the servo information includes the modulated first address information. 1. A method comprising:determining a first frequency for (i) a first track in a servo layer of a storage medium, or (ii) a first sector in the servo layer, wherein the servo layer is dedicated to storing servo information;obtaining first address information addressing the first track or the first sector;modulating the first address information according to the first frequency; andstoring the modulated first address information in the servo layer, wherein, subsequent to the storing of the modulated first address information, the servo information includes the modulated first address information.2. The method of claim 1 , wherein the first address information includes a sector address mark.3. The method of claim 1 , wherein the first address information includes Gray code.4. The method of claim 1 , further comprising modulating the first address information according to a second frequency for (i) a second track in the servo layer claim 1 , or (ii) a second sector in the servo layer claim 1 ,wherein the modulated first address information stored in the servo layer is modulated according to both the first frequency and the second frequency.5. The method of claim 4 , wherein the first address information includes a sector address mark and a Gray code.6. The method of claim 4 , further comprising determining a position of a head based on (i) the first address information ...

DISC DEVICE, CONTROLLING DEVICE AND METHOD

According to one embodiment, a disc device outputs a first signal for canceling out a first disturbance at a predetermined frequency of a position error, outputs a second signal which gain or phase of the first signal are changed, and corrects an operation amount or the position error by using the second signal. 1. A disc device comprising:a head for writing and reading data relative to a disc;an actuator to move the head over a disc surface of the disc; anda processor to includea comparison unit to determine a position error between a control position and a target position of the head to the disc surface;a controller to output to the actuator an operation amount for decreasing the position error;a first filter to output a first signal for canceling out a first disturbance at a predetermined frequency of the position error;a second filter to output a second signal which gain or phase of the first signal are changed; anda correction unit to correct the operation amount or the position error by using the second signal.2. The disc device of claim 1 , wherein the second filter is expressed as a second transfer function in which the gain or phase of the first signal are changed by gain or phase of inverse characteristics of a first transfer function including the first disturbance.3. The disc device of claim 2 , wherein the second filter changes the gain or phase of the first signal by the gain or phase of inverse characteristics of the first transfer function claim 2 , at frequencies within a predetermined range with reference to the predetermined frequency.7. A controlling device comprising:a processor to includea comparison unit to determine a position error between a control position and a target position of a control target;a controller to output to the control target an operation amount for decreasing the position error;a first filter to output a first signal for canceling out a first disturbance at a predetermined frequency of the position error;a second filter to ...

METHOD AND ADEVICE FOR DOWNLOADING RESOURCES

Method and device for downloading resources, applicable to a peer to peer (P2P) network. The method includes: initiating a downloading task according to a downloading request from a resource requester; acquiring data of the downloading task and writing the data of the downloading task to a memory; and reading the data from the memory and providing the data to the resource requester. The present invention can reduce the amount of magnetic disk consumption due to resource downloading. 1. A method for downloading resources , applied to a peer-to-peer (P2P) network , comprising:initiating a downloading task according to a downloading request from a resource requester;acquiring data of the downloading task and writing the data of the downloading task to a memory; andreading the data from the memory and providing the data to the resource requester.2. The method according to claim 1 , wherein the method further comprises:determining whether the downloading task is complete when data in the memory reaches a preset upper limit of use, wherein the downloading task being complete indicates that a complete resource is able to be acquired by the downloading task; andfiltering out the downloading task when the downloading task is incomplete so that the data in the memory will not be written to a magnetic disk.3. The method according to claim 1 , wherein the method further comprises:determining whether the downloading task is complete when data in the memory reaches a preset upper limit of use, wherein the downloading task being complete indicates that a complete resource is able to be acquired by the downloading task; andwriting the data in the memory to a magnetic disk when it is determined that the downloading task is complete.4. The method according to claim 2 , wherein the method further comprises:determining whether the downloading task is complete according to Range information in the downloading request.5. The method according to claim 4 , wherein the method further ...

HARD DISK DRIVE AND HEAD POSITIONING METHOD

According to one embodiment, a hard disk drive includes a disk including a plurality of data areas, and a plurality of servo areas between the plurality of data areas, an arm holding a write head and a read arm, and a positioning module which positions the read head or the write head by rotating the arm, wherein the positioning module positioning the write head by positioning the read head, and adjusting a position of the read head or the write head, based on an output of the read head located in a data area between two servo areas adjacent in a peripheral direction, of the plurality of servo areas. 1. A hard disk drive , comprising:a disk comprising a plurality of data areas, and a plurality of servo areas between the plurality of data areas;an arm holding a write head and a read arm; anda positioning module which positions the read head or the write head by rotating the arm,wherein the positioning module positions the write head by positioning the read head, and adjusts a position of the read head or the write head, based on an output of the read head located in a data area between two servo areas adjacent in a peripheral direction, of the plurality of servo areas.2. The hard disk drive of claim 1 , whereinthe positioning module calculates a bit error rate of read data from the read head or a frequency characteristic of a read signal from the read head, and adjusts the position of the read head or the write head, based on the bit error or the frequency characteristic.3. The hard disk drive of claim 1 , further comprising a variable gain amplifier which amplifies a read signal from the read head claim 1 ,wherein the positioning module adjusts the position of the read head or the write head, based on a gain of the variable gain amplifier.4. The hard disk drive of claim 1 , whereinthe disk comprises a plurality of concentric tracks, andthe positioning module adjusts the position of the read head or the write head, based on the output of the read head, when same data ...

Disturbance Observer with Energy Reducing Filter

Disturbance rejection in a closed loop multi-actuator system. In some embodiments, a first disturbance observer (DOB) circuit is configured to inject a first disturbance rejection signal into an input control signal of a first stage of a multi-stage actuator. A second DOB circuit is configured to concurrently inject a second disturbance rejection signal into an input control signal of a second stage of the multi-stage actuator. Each of the first and second DOB circuits includes a band pass filter and an energy reducing filter. In some embodiments, the energy reducing filter has at least one notch filter and at least one anti-notch filter. In other embodiments, the energy reducing filter is a low-pass filter (LPF).

MAGNETIC DISK DEVICE AND WRITE CONTROL METHOD

A magnetic disk device according to an embodiment includes a disk including a plurality of tracks, a head configured to write and read data to and from the disk, and a controller configured to control an off-track of the head, which occurs when data is written to one track included in the plurality of tracks, within an allowable range of an amount of the off-track, which is set based on a count value of at least another track other than the one track. 1. A magnetic disk device comprising:a disk including a plurality of tracks;a head configured to write and read data to and from the disk; anda controller configured to control an off-track of the head, which occurs when data is written to one track included in the plurality of tracks, within an allowable range of an amount of the off-track, which is set based on a count value of at least another track other than the one track.2. The magnetic disk device of claim 1 , wherein:the controller sets a first allowable range of an amount of an off-track to an inner side of the one track in a radial direction of the disk, based on a first count value of a first track of a plurality of tracks on the inner side of the one track;sets a second allowable range of an amount of an off-track to an outer side of the one track in the radial direction of the disk, based on a second count value of a second track of a plurality of tracks on the outer side of the one track; andcontrols an off-track to the inner side from a center of the one track within the first allowable range and an off-track to the outer side from the center of the one track within the second allowable range.3. The magnetic disk device of claim 2 , wherein the first track is a track adjacent to the inner side of the one track and the second track is a track adjacent to the outer side of the one track.4. The magnetic disk device of claim 3 , wherein:the controller stops write to the one track if the amount of the off-track exceeds the first allowable range or the second ...

DISK DEVICE HAVING CONVENTIONAL MAGNETIC RECORDING REGION AND SHINGLED MAGNETIC RECORDING REGION OF DIFFERENT LINEAR DENSITY

According to one embodiment, a magnetic disk device includes a disk, a head which writes data to the disk and reads data from the disk, and a controller which executes, in a first region segmented in a radial direction of the disk, at least one of conventional recording processing which writes a plurality of tracks with a space in between in the radial direction at a first linear recording density and shingled recording processing which writes a plurality of tracks on top of one another in the radial direction at a second linear recording density which is less than or equal to the first linear recording density. 1. A magnetic disk device comprising:a disk;a head which writes data to the disk and reads data from the disk; anda controller which executes, in a first region segmented in a radial direction of the disk, at least one of conventional recording processing which writes a plurality of tracks with a space in between in the radial direction at a first linear recording density and shingled recording processing which writes a plurality of tracks on top of one another in the radial direction at a second linear recording density which is less than or equal to the first linear recording density, whereinthe controller executes the shingled recording processing at the second linear recording density and at a track density at which a product of the second linear recording density and the track density becomes maximized in the first region.2. (canceled)3. The magnetic disk device of claim 1 , wherein a first recording density at which a plurality of tracks are written with a space in between in the radial direction at the first linear recording density in the first region is less than a second recording density at which a plurality of tracks are written on top of one another in the radial direction at the second linear recording density in the first region by 10% to 23%.4. The magnetic disk device of claim 1 , wherein the controller executes the conventional recording ...

CURRENT-LIMITING IN AN AMPLIFIER SYSTEM

One example includes an amplifier system. The system includes a gain stage configured to conduct a gain current in response to an input voltage. The system also includes a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition. The system further includes an output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude. 1. An amplifier system comprising:a gain stage configured to conduct a gain current in response to an input voltage;a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition; andan output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude.2. The system of claim 1 , wherein the input voltage is a differential input voltage comprising a first input voltage and a second input voltage claim 1 , wherein the current limit stage comprises:a first current limit stage configured to sink the gain current through the gain stage based on a positive difference between the first input voltage and a second input voltage; anda second current limit stage configured to source the gain current through the gain stage based on a negative difference between the first input voltage and the second input voltage.3. The system of claim 1 , wherein the output stage comprises a source-follower arrangement of transistors claim 1 , such that the output stage one of sources and sinks the output current ...

DATA STORAGE DEVICE USING WINDOWED DELTA-SIGMA ANALOG-TO-DIGITAL CONVERTER IN DIGITAL CURRENT CONTROL LOOP

A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration. 1. A data storage device comprising:a disk;a head;a voice coil motor (VCM) configured to actuate the head over the disk;{'claim-text': ['measure a vibration of the data storage device; and', 'configure at least one of a gain or a window of the windowed delta-sigma ADC based on the measured vibration.'], '#text': 'control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM, wherein the control circuitry is configured to:'}2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to decrease the window of the windowed delta-sigma ADC when the measured vibration increases.3. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to increase the gain of the windowed delta-sigma ADC when the measured vibration increases.4. The data storage device as recited in claim 1 , wherein the windowed delta-sigma ADC operates linearly when an input value is inside the window and operates non-linearly when the input value is outside the window.5. The data storage device as recited in claim 4 , wherein:the windowed delta-sigma ADC operates inside the window while tracking a centerline of a data track on the disk during an access operation; andthe windowed delta-sigma ADC operates outside the window while seeking the head over the disk.6. The data storage device as recited in claim 1 , wherein the windowed delta-sigma ADC ...

MAGNETIC DISK DEVICE AND READ PROCESSING METHOD

According to one embodiment, a magnetic disk device includes a disk, a head that has a write head that writes data to the disk and a read head that reads data from the disk, and a controller that changes an offset amount during read processing according to a vibration applied by a disturbance. 1. A magnetic disk device comprising:a disk;a head that has a write head that writes data to the disk and a read head that reads data from the disk; anda controller that changes an offset amount during read processing according to a vibration applied by a disturbance.2. The magnetic disk device according to claim 1 , wherein claim 1 , in a case where the vibration is not detected during the read processing claim 1 , the controller arranges the read head at a first position where a first track is readable at a smallest first error rate and reads the first track.3. The magnetic disk device according to claim 2 , wherein claim 2 , in a case where the vibration is detected during the read processing claim 2 , the controller arranges the read head at a second position different from the first position and reads the first track.4. The magnetic disk device according to claim 3 , wherein the second position corresponds to a position intermediate between two boundary positions of a radial area where the first track is readable and a radial area where the first track is not readable.5. The magnetic disk device according to claim 2 , wherein claim 2 , in a case where the vibration is detected when a first sector in the first track is written claim 2 , the controller records first information indicating detection of the vibration in the first sector to a recording area of the disk.6. The magnetic disk device according to claim 5 , wherein claim 5 , in a case where the first information is not detectable when the recording area is read claim 5 , the controller arranges the read head at a first position where the first sector is readable at the first error rate and reads the first sector.7. ...

ADJUSTMENT METHOD OF PARAMETERS OF MULTISTAGE NOTCH FILTER

According to one embodiment, a method of adjusting parameters set of a multistage notch filter includes calculating a first value which is a square sum of an error between a frequency response characteristic of a reference notch filter and a frequency response characteristic of the notch filter in evaluation points of a low-frequency band, calculating a second value which is a square sum of an amount in which an open-loop gain response characteristic which is series coupling of the object and the controller is protruded from an inverse gain response characteristic of the notch filter in evaluation points of a high-frequency band, and adjusting the parameters by simultaneously minimizing the first and second values. 1. An adjustment method of adjusting parameters of a multistage notch filter regarding to a controlled object , in a head positioning control system of a magnetic disk apparatus , the method comprising:calculating a first objective function value which is a square sum of an error between a frequency response characteristic of a reference notch filter having a reference transfer characteristic of the multistage notch filter in a low-frequency band and a frequency response characteristic of the multistage notch filter in a plurality of evaluation points of the low-frequency band of a plurality of evaluation points set from 0 Hz to a sampling frequency;calculating a second objective function value which is a square sum of an amount in which an open-loop gain response characteristic which is series coupling of the controlled object and the positioning feedback controller is protruded from an inverse gain response characteristic of the multistage notch filter drawn from a set robust stability evaluation reference line in a plurality of evaluation points of a high-frequency band of the plurality of evaluation points; andadjusting the parameters of the multistage notch filter by simultaneously minimizing the first objective function value and the second ...

METHOD AND APPARATUS FOR DETERMINING READ-HEAD DEVIATION USING ORTHOGONAL PREAMBLES

A storage device includes read circuitry having a read head having a detector that outputs signals representing data from a first track and an adjacent track. The read head is subject to off-track excursions during which the read head detects signals from both the first track and an adjacent track. Data on each track includes a preamble including a repeating pattern. The repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track. The read circuitry also includes respective Discrete Fourier Transform circuits to identify components in the signals corresponding to respective frequencies characteristic of the repeating pattern on the first track and the repeating pattern on the second track, and computation circuitry to determine from the components a ratio by which the read head is off-track. Corresponding methods are provided for operating such a storage device and for reading data. 120-. (canceled)21. A method of operating a storage device having a storage medium , the method comprising:writing data, including both user data and servo data, in a shingled manner to each of two adjacent tracks on the storage medium;detecting, during a single pass, signals from the two adjacent tracks using a first read head in a first position and a second read head in a second position, each read head detecting signals from both tracks;analyzing outputs of the first read head and the second read head to derive, from the signals from the two adjacent tracks detected by the first read head during the single pass, and from the signals from the two adjacent tracks detected by the second read head during the single pass, the user data that was written to the two adjacent tracks.22. The method of wherein the writing servo data comprises writing patterns on each track claim 21 , outside servo wedges of the storage medium claim 21 , so that the pattern on a first one of the two adjacent tracks and the pattern on a second one of the ...

MAGNETIC DISC DEVICE AND POSITION CONTROL METHOD

A magnetic disc device according to an embodiment has a head, a position detector, and a filter unit. The position detector detects position information of the head on the basis of servo information. The filter unit performs filtering of an estimated frequency estimated by a quadratic adaptive digital filter that performs self-adaptation for a transfer function on the basis of positional difference information between position information and target position information of the head and adjusts all filter coefficients included in the transfer function on the basis of the estimated frequency. 1. (canceled)3. The magnetic disc device according to claim 2 , further comprising a memory unit that stores information regarding the filter coefficients P claim 2 , Q claim 2 , R claim 2 , E claim 2 , and F that change depending on the estimated frequency claim 2 ,wherein the filter unit adjusts the filter coefficients P, Q, R, E, and F on the basis of the estimated frequency, the estimated frequency being estimated by the adaptive digital filter and the information stored in the memory unit.4. The magnetic disc device according to claim 3 , wherein the memory unit stores a coefficient of a quadratic function that calculates the filter coefficients P claim 3 , Q claim 3 , R claim 3 , E claim 3 , and F when the estimated frequency is substituted.5. The magnetic disc device according to claim 2 , wherein the adaptive digital filter is an infinite impulse response (IIR) type digital filter.6. The magnetic disc device according to claim 2 , further comprising a fixed filter unit that performs phase compensation or gain compensation in order to stabilize a feedback control in a position control of the head for information filtered by the adaptive digital filter.7. (canceled)9. The position control method according to claim 8 , wherein the position control device has a memory unit that stores the filter coefficients P claim 8 , Q claim 8 , R claim 8 , E claim 8 , and F that change ...

DATA STORAGE DEVICE ENCODING AND INTERLEAVING CODEWORDS TO IMPROVE TRELLIS SEQUENCE DETECTION

A data storage device is disclosed comprising a storage medium. First data is encoded into a first codeword comprising a plurality of i-bit symbols, and second data is encoded into a second codeword comprising a plurality of j-bit symbols, wherein i is different than j and a first code rate of the first codeword is less than a second code rate of the second codeword. The first codeword and the second codeword are symbol interleaved to generate an interleaved codeword, and the interleaved codeword is written to the storage medium. 124-. (canceled)25. A controller for use in a data storage device , comprising:a communication interface configured to communicate data with a storage medium of a data storage device; and encode first data into a first codeword comprising a plurality of i-bit symbols;', 'encode second data into a second codeword comprising a plurality of j-bit symbols, wherein i is different than j and wherein a first code rate of the first codeword is less than a second code rate of the second codeword;', 'interleave the first codeword and the second codeword to generate an interleaved codeword; and', 'control the communication interface to write the interleaved codeword to the storage medium., 'a processor in data communication with the communication interface and configured to26. The controller as recited in claim 25 , wherein i is less than j.27. The controller as recited in claim 26 , wherein i is 1.28. The controller as recited in claim 25 , wherein the processor is further configured to:read the interleaved codeword from the storage medium to generate a read signal;sample the read signal to generate signal samples;process the signal samples with a trellis detector to generate a sequence of reliability metrics representing the interleaved codeword;de-interleave the sequence of reliability metrics into a first set of reliability metrics representing the first codeword and a second set of reliability metrics representing the second codeword;decode the ...

Writer with protruded section at trailing edge

A writer includes a leading edge, a trailing edge, a longitudinal axis defined between the leading and trailing edges, and a transverse axis orthogonal to the longitudinal axis. A writer region is provided at a protruded section of the trailing edge oriented along the longitudinal axis. A write pole is arranged at the protruded section to write data to two locations spaced apart from one another relative to the transverse axis for a range of skew angles.

METHOD FOR MANUFACTURING MAGNETIC DISK DEVICE

According to one embodiment, a method for manufacturing a magnetic disk device includes: moving a magnetic head such that a read head is located on a first learning position among a plurality of learning positions set in a radial direction of a magnetic disk; and learning RRO correction information related to the first learning position using the read head. The method further includes: moving the magnetic head such that the read head is located on a second learning position among the plurality of learning positions; and executing writing of the RRO correction information related to the first learning position using the write head in parallel while learning RRO correction information related to the second learning position using the read head when the read head is located on the second learning position. 1. A method for manufacturing a magnetic disk device including a magnetic disk and a magnetic head , the manufacturing method comprising:setting a plurality of learning positions in a radial direction of the magnetic disk;moving the magnetic head such that a read head of the magnetic head is located on a first learning position among the plurality of learning positions;learning repeatable run-out (RRO) correction information related to the first learning position when the read head is located on the first learning position using the read head;moving the magnetic head such that the read head is located on a second learning position among the plurality of learning positions, a write head of the magnetic head being located at a position passing through a part of a first range including the first learning position when the read head is located on the second learning position; andexecuting writing of the RRO correction information related to the first learning position to the first range using the write head in parallel while learning RRO correction information related to the second learning position using the read head when the read head is located on the second learning ...

Multi-Layer PZT Microacuator with Active PZT Constraining Layers for a DSA Suspension

A PZT microactuator such as for a hard disk drive has a restraining layer bonded on its side that is opposite the side on which the PZT is mounted. The restraining layer comprises a stiff and resilient material such as stainless steel. The restraining layer can cover most or all of the top of the PZT, with an electrical connection being made to the PZT where it is not covered by the restraining layer. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses the sign of the bending which increases the effective stroke length of the PZT even further. The restraining layer can be one or more active layers of PZT material that act in the opposite direction as the main PZT layer. The restraining layer(s) may be thinner than the main PZT layer. 1. A multi-layer piezoelectric microactuator assembly for effecting fine positional movements , the microactuator assembly comprising:a first piezoelectric layer and a second piezoelectric layer, the first piezoelectric layer being closest to a surface to which the microactuator assembly is bonded;a first electrode on a bottom side of the first piezoelectric layer;a second electrode on a top side of the first piezoelectric layer and disposed underneath the second piezoelectric layer, there being no electrode between the first and second electrodes such that a distance between the first and second electrodes defines a thickness of the first piezoelectric layer, and such that a voltage applied across the first and second electrodes induces an electric field across the first piezoelectric layer thereby causing the first piezoelectric layer to expand or contract; anda third electrode on a top side of the second piezoelectric layer, there being no electrode between the second and third electrodes such that a distance between the second and third electrodes defines a thickness of the second piezoelectric layer, and such that a voltage applied across the second and third ...

DATA STORAGE DEVICE COUPLING/DECOUPLING ACTUATOR ARM TO/FROM AN ACTUATOR

A data storage device is disclosed comprising a first head connected to a distal end of a first actuator arm, a second head connected to a distal end of second first actuator arm, a first coupler configured to couple the first actuator arm to an actuator, and a second coupler configured to couple the second actuator arm to the actuator. Access commands stored in a command queue are sorted into an execution order based on a selective coupling of the first and second actuator arms to the actuator. At least one of the access commands is executed based on the execution order in order to access at least one of a first and second disk surfaces using at least one of the first and second heads. 1. A data storage device comprising:a first disk surface;a first actuator arm;a first head connected to a distal end of the first actuator arm;a second disk surface;a second actuator arm;a second head connected to a distal end of a second actuator arm;an actuator;a first coupler configured to couple the first actuator arm to the actuator;a second coupler configured to couple the second actuator arm to the actuator; and store a plurality of access commands in a command queue;', 'sort the access commands into an execution order based on a selective coupling of the first and second actuator arms to the actuator; and', 'execute at least one of the access commands based on the execution order in order to access at least one of the first and second disk surfaces using at least one of the first and second heads., 'control circuitry configured to2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to:actuate the first coupler in order to couple the first actuator arm to the actuator;move the actuator in order to first seek the first head to a first data track on the first disk surface; and actuate the first coupler to decouple the first actuator arm from the actuator;', 'actuate the second coupler in order to couple the second actuator arm to ...

DATA STORAGE DEVICE ENCODING AND INTERLEAVING CODEWORDS TO IMPROVE TRELLIS SEQUENCE DETECTION

A data storage device is disclosed comprising a storage medium. Input data is encoded according to at least one channel code constraint to generate first data and second data. The first data is encoded into a first codeword, and the second data is encoded into a second codeword, wherein a first code rate of the first codeword is less than a second code rate of the second codeword. The first codeword and the second codeword are interleaved to generate an interleaved codeword, and the interleaved codeword is written to the storage medium. 130-. (canceled)31. A controller for use in a data storage device , comprising:a communication interface configured to communicate data with a storage medium of a data storage device; and encode input data according to at least one channel code constraint to generate first data and second data;', 'encode the first data into a first codeword;', 'encode the second data into a second codeword, wherein a first code rate of the first codeword is less than a second code rate of the second codeword;', 'interleave the first codeword and the second codeword to generate an interleaved codeword; and', 'control the communication interface to write the interleaved codeword to the storage medium., 'a processor in data communication with the communication interface and configured to32. The controller as recited in claim 31 , wherein the interleaved codeword comprises parity data not encoded according to the at least one channel code constraint.33. The controller as recited in claim 31 , wherein the at least one channel code constraint is a maximum transition run (MTR) constraint.34. The controller as recited in claim 31 , wherein the at least one channel code constraint is a run-length limit (RLL) constraint.35. The controller as recited in claim 31 , wherein the first encode and the second encode implement a low density parity check (LDPC) code.36. The controller as recited in claim 31 , wherein:the channel code constraint limits at least one of a ...

Servo integrated bpm template

Provided herein is a method including forming a data zone guiding pattern and forming a servo zone guiding pattern. A servo pattern and a data pattern are simultaneously formed. Directed self-assembly of block copolymers is guided by the data zone guiding pattern and the servo zone guiding pattern.

Generating position error signal based on data tracks for magnetic data storage

A hard disk drive circuit includes first and second inter-track interference detection modules. The first inter-track interference detection module is configured to generate a first measured inter-track interference value based on a first read signal from a first read sensor positioned over a magnetic medium. The second inter-track interference detection module is configured to generate a second measured inter-track interference value based on a second read signal from a second read sensor positioned over the magnetic medium. A position error signal generation module is configured to generate a position error signal based on the first measured inter-track interference value and the second measured inter-track interference value. An arm control module is configured to control rotation of an arm in response to the position error signal. The first read sensor and the second read sensor are located at a distal end of the arm.

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. 1. A method of determining radial position of a first read head of a storage device , where the first read head is one of at least two read heads carried by a common actuator relative to a storage media platter surface of the storage device , there being a known positional offset between the first read head and each other one of the at least two read heads , the method comprising:reading servo data from the storage media platter surface using the first read head;deriving, from the servo data read from the storage media platter surface using the first read head, a first position 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 one of the at least two read heads;deriving, from the servo data read from the storage media platter surface using the different one of the at least two read heads, a second position error signal representing an estimate of the radial position of the different one of the at least two read heads; andcombining the first estimate of the radial position of the first ...

DISK DEVICE THAT UPDATES WRITE COUNTS OF TRACKS BASED ON A HEAD OFFSET DURING WRITING OF ADJACENT TRACKS

A disk device includes a magnetic disk, a head configured to write data into the magnetic disk, a memory in which a write count and a offset amount of the head during a write operation are stored for each of a plurality of tracks of the magnetic disk, and a processor. The processor is configured to determine an inner offset and an outer offset of the head with respect to a target track of a write operation, and update the write count for an adjacent inner track of the target track based on the inner offset, and the write count for an adjacent outer track of the target track based on the outer offset. 1. A disk device comprising:a magnetic disk;a head configured to write data onto the magnetic disk;a memory in which a write count and an offset amount of the head during a write operation are stored for each of a plurality of tracks of the magnetic disk; and determine an inner offset and an outer offset of the head with respect to a target track of a write operation, and', 'update the write count for an adjacent inner track of the target track based on the inner offset, and the write count for an adjacent outer track of the target track based on the outer offset., 'a processor configured to'}2. The disk device according to claim 1 , whereinthe processor is further configured to update the offset amount of the target track to a larger value of the inner offset and the outer offset, when the larger value is greater than the offset amount of the target track stored in the memory.3. The disk device according to claim 1 , whereinthe processor is further configured to carryout a refresh operation of rewriting data stored in a track when the write count of the track, which is stored in the memory, is greater than a threshold.4. The disk device according to claim 1 , whereinthe write count for the adjacent inner track is updated by incrementing an amount calculated based on a weighting coefficient, the offset amount of the adjacent inner track stored in the memory, and the ...

Recording device, control device, recording method, recording tape cartridge, and data recording and reproducing system

A recording device, a control device, a recording method, a recording tape cartridge, and a data recording and reproducing system capable of accurately positioning a data recording and reproducing head are obtained. A recording device includes a recording unit that records information on linearity of a servo signal recorded on a magnetic tape included in a recording tape cartridge on an RFID tag included in the recording tape cartridge.

MAGNETIC DISK DEVICE AND METHOD

According to an embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, and a controller. The magnetic disk records servo marks thereon. The controller determines, based on a time interval at which the servo marks are read by the magnetic head, whether the magnetic disk device has transitioned from a first state where a position of the magnetic disk device does not vary with time to a second state where a position of the magnetic disk device varies with time. 1. A magnetic disk device comprising:a magnetic disk on which servo marks are recorded;a magnetic head; anda controller that determines, based on a time interval at which the servo marks are read by the magnetic head, whether the magnetic disk device has transitioned from a first state where a position of the magnetic disk device does not vary with time to a second state where a position of the magnetic disk device varies with time.2. The magnetic disk device according to claim 1 , whereinthe controller starts loop shaping control for positioning the magnetic head, in a case that the magnetic disk device has transitioned from the first state to the second state.3. The magnetic disk device according to claim 1 , whereinthe controller determines whether the magnetic disk device has transitioned from the first state to the second state, based on comparison between a first value that is a difference of the time interval from a second value, and a third value.4. The magnetic disk device according to claim 1 , whereinthe second state is a state where vibration occurs at the position.5. The magnetic disk device according to claim 1 , whereinthe controller determines, based on comparison between a first value and a second value, whether the magnetic disk device has transitioned from the first state to the second state, the first value being an amount of a change of a third value in time, the third value being a difference of the time interval from a fourth value.6. The magnetic disk device ...

Loop shaping methods and devices for disturbance observer in servo control systems

An apparatus includes voice coil motor (VCM) control circuitry and microactuator control circuitry. The VCM control circuitry includes a VCM disturbance observer configured to generate a VCM disturbance compensation signal. The microactuator control circuitry includes a microactuator disturbance observer configured to generate a microactuator disturbance compensation signal. The VCM disturbance observer and the microactuator disturbance observer are decoupled from each other.

ENHANCED LOW OVERHEAD DATA PROTECTION IN DATA STORAGE DRIVES

To provide enhanced operation of data storage devices and systems, various systems, apparatuses, methods, and software are provided herein. In a first example, a data storage device is presented that performs a write process to store data on a storage medium of the data storage device responsive to one or more write operations received over a host interface. The data storage device monitors a quality of the write process and determines when the quality of the write process falls below a threshold quality. Responsive to the quality of the write process falling below the threshold quality, the data storage device indicates the quality of the write process to a data protection node for determination of data parity information that compensates for the quality of the write process, where the data parity information is provided by the data protection node for storage in a selected parity storage device. 1. A data storage device , comprising: perform a write process to store data on a storage medium of the data storage device responsive to one or more write operations received from a host system over a host interface;', 'monitor a quality of the write process and determine whether the quality of the write process falls below a threshold quality; and', 'responsive to the quality of the write process falling below the threshold quality, indicate the quality of the write process to a data protection node for determination of data parity information that compensates for the quality of the write process, wherein the data parity information is provided by the data protection node for storage in a selected parity storage device., 'a storage control system configured to2. The data storage device of claim 1 , wherein the storage control system is further configured to:detect squeezed sectors during the write process based on at least position error signal (PES) metrics monitored during the write process; anddetermine the quality of the write process based at least on a quantity of ...

RESTRICTION OF SUSPENSION DIMPLE CONTACT POINT

A head gimbal assembly (HGA) for a hard disk drive includes a primary dimple having a secondary structure protruding from the primary dimple, where a flexure is movably coupled with a load beam via the primary dimple, and where the secondary structure is configured to restrict the point of contact between the load beam and the flexure. Such an arrangement avoids any shift in the axis of rotation of the flexure, and the attached slider, due to any undesirable protrusion from the primary dimple which may arise in the manufacturing process. Examples of secondary structures include a micro-dimple, a ridge, and an embedded mass of material.

Converter digital control circuit with adaptive feedforward compensation

A control circuit for a voltage regulator includes a divider coupled to the regulated output voltage to generate a divided voltage having a value that is a fraction of the regulated output voltage, an ADC responsive to the divided voltage to generate a feedback control signal, a digital compensator responsive to the feedback control signal and to a feedforward control signal scaled by a feedforward gain value to generate a compensator signal, and a pulse width modulator responsive to the compensator signal to generate a voltage control signal to control a switch of the voltage regulator. The digital compensator includes a register configured to store a value indicative of the input voltage and a feedforward gain unit configured to generate the feedforward gain value in response to the value indicative of the input voltage. In embodiments, the feedforward gain value is generated in response to the square of the value indicative of the input voltage. The feedforward gain value can be updated each time the value indicative of the input voltage is updated.

MAGNETIC DISK DEVICE AND HEAD POSITION CORRECTION METHOD

According to one embodiment, a magnetic disk device includes a disk including a recording region including a servo sector, a head configured to write data to the disk and read data from the disk, and a controller configured to acquire a plurality of correction data for a repeatable runout of the recording region, the correction data respectively corresponding to a plurality of measurement positions set based on a first linearity error acquired by reading the servo sector, and to correct a position of the head based on the correction data. 1. A magnetic disk device comprising:a disk including a recording region including a servo sector;a head configured to write data to the disk and read data from the disk; anda controller configured to acquire a plurality of correction data for a repeatable runout of the recording region, the correction data respectively corresponding to a plurality of measurement positions set based on a first linearity error acquired by reading the servo sector, and to correct a position of the head based on the correction data.2. The magnetic disk device according to claim 1 , wherein the controller makes an interval of the measurement positions smaller as the first linearity error becomes larger.3. The magnetic disk device according to claim 1 , wherein the controller sets the measurement positions based on a parameter corresponding to the first linearity error acquired when the servo sector is read.4. The magnetic disk device according to claim 3 , wherein the controller sets the measurement positions based on the parameter and a first expression indicating a relationship between the parameter and the measurement positions.5. The magnetic disk device according to claim 1 , wherein the controller sets the measurement positions based on a second linearity error acquired by reading the servo sector after correcting the first linearity error.6. The magnetic disk device according to claim 5 , wherein the controller sets the measurement positions to ...

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.

SHINGLED MAGNETIC RECORDING SYSTEM WITH ADAPTIVE WRITE BUFFER AREA

Techniques for writing data to a buffer region of a magnetic disk are described. In one example, a hard disk drive comprises a magnetic disk comprising a data buffer region including a first zone and a second zone. Data may be written to the magnetic disk using shingled magnetic recording (SMR) and the buffer region may be an exception region (E-region). A hard disk drive may be configured to calculate a position accuracy value associated with a data writing head. The hard disk drive may select one of the zones based on the position accuracy value. Further, a selected zone may have a determined zone format. The hard disk drive may be configured to write data to the selected zone using the determined zone format. 1. A method of writing data to a buffer staging region of a shingled magnetic recording disk , the method comprising:calculating a position accuracy value associated with a data writing head;selecting one of a first zone and a second zone of the buffer region based on the position accuracy value, wherein the first zone includes an initial track density that is greater than an initial track density of the second zone; andwriting data to the selected zone of the buffer staging area; andtransferring the written data in the selected zone of the buffer staging area to another area of the magnetic disk.2. The method of claim 1 , wherein calculating the position accuracy value includes calculating a run out value based at least in part on a servo signal.3. The method of claim 1 , wherein calculating the position accuracy value includes determining a vibration measurement based on a signal received from an accelerometer.4. The method of claim 1 , further comprising adjusting the initial track density of the first zone based on the position accuracy value.5. The method of claim 1 , wherein the first zone has an initial track density of 350 claim 1 ,000 tracks per inch and the second zone has an initial track density of 325 claim 1 ,000 tracks per inch.6. The method ...

ACCURATE SPIRAL GATE POSITIONING IN THE PRESENCE OF LARGE NON-REPEATABLE RUNOUT

A magnetic write head is positioned based on position signals generated by a read head as the read head crosses a plurality of reference spirals. The spiral gate for monitoring a particular reference spiral is timed to begin at a time based on the radial position of the magnetic head when crossing the preceding reference spiral. In this way, the spiral crossing time for the particular reference spiral can be estimated with sufficient accuracy that the spiral gate coincides with the magnetic head crossing the particular reference spiral. Consequently, spiral detection is assured, even in the presence of large non-repeatable runout. 1. A method of positioning a write head based on position signals generated by a read head as the read head crosses a plurality of reference spirals , including first and second spirals that are adjacent , the method comprising:demodulating the position signals generated by the read head as the read head crosses the first spiral during a first demodulation period; anddemodulating the position signals generated by the read head as the read head crosses the second spiral during a second demodulation period that is determined based on the demodulated position signals obtained during the first demodulation period.2. The method of claim 1 , wherein demodulating the position signals generated by the read head as the read head crosses the first spiral comprises determining a first radial position of the write head.3. The method of claim 2 , further comprising claim 2 , based on the first radial position of the write head claim 2 , determining a start time for the second demodulation period.4. The method of claim 3 , wherein determining the start time for the second demodulation period comprises determining a predicted crossing time at which the read head crosses the second spiral.5. The method of claim 4 , wherein determining the start time for the second demodulation period comprises selecting the start time so that the predicted crossing time ...

INTEGRATED SERVO FIELD FOR MEMORY DEVICE

A pattern of features of a storage medium includes first features having a first logical state and second features having a second logical state, wherein a cross track dimension of the first features is different from a cross track dimension of the second features. A transducer of a memory device senses the pattern of features and generates a transducer signal. Read circuitry samples the transducer signal at a frequency of a sampling clock signal and generates a read signal from the sampled transducer signal. Servo electronics includes a demodulator that demodulates at least first and second orthogonal frequency components of the read signal. Timing circuitry synchronizes a phase of the sampling clock signal with a phase of the pattern of features using the first orthogonal frequency component. Position error circuitry generates a signal indicating a cross track positional offset of the transducer relative to the features using the first and second orthogonal frequency components. 119-. (canceled)20. A device , comprising:a patterned storage medium including one or more tracks having multiple correction fields, the multiple correction fields comprising at least:a first correction field storing a correction value; anda second correction field redundantly storing the correction value, each second correction field offset along a cross track direction by a fraction of a track width with respect to a first correction field that stores the same correction value as the second correction field.21. The device of claim 20 , wherein the first correction field is a first repeatable runout (RRO) field and the second correction field is a second RRO field.22. The device of claim 20 , wherein the first and second correction field fields comprise rectangular magnetic features at least partially surrounded by non-magnetic material claim 20 , and each magnetic feature is a single magnetic domain.23. The device of claim 20 , wherein an error detection code or an error detection and ...

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. 1. A method for throughput optimization of a hard disk drive (HDD) using position error signaling (PES) comprising: determining a PES based on a dynamic disturbance;', 'calculating a critical parameter of the PES; and', 'determining a performance parameter;, 'for each of a plurality of HDDs in an array mounted in a chassisgenerating a performance map of the array; andindicating a mechanical design modification of a particular HDD in the array or the chassis if the critical parameter of the PES for the particular HDD exceeds a pre-defined threshold or the performance parameter for the particular HDD fails to meet a pre-defined tolerance.2. The method of claim 1 , wherein the critical parameter is a mean.3. The method of claim 1 , wherein the dynamic disturbance is from a fan associated with the chassis.4. The method of claim 1 , further comprising:correlating the PES for the particular HDD to throughput of the particular HDD;indicating a mechanical design modification of the particular HDD or the chassis based on the correlation between the PES for the particular HDD and the throughput of the particular HDD.5. The method of claim 1 , further comprising:correlating the PES for the particular HDD to dynamics of a fan associated with the chassis;indicating a mechanical design modification of the particular HDD, the fan, or the chassis based on the correlation between the PES for the particular HDD and the fan dynamics.6. (canceled)7. The method of claim 6 , wherein the performance map comprises a location in the chassis ...

Adaptive guard band for improved data storage capacity

An adaptive guard band for a ramp load/unload device is disclosed to provide extended data storage. In illustrated embodiments, an adaptive guard band algorithm is configured to format one or more discs or media having a lower capacity device with the adaptive guard band and extended data zone utilizing capacity measurements. The algorithm formats the media to provide a track zero at a first cylinder if the capacity is at or above the threshold capacity and a second cylinder if the capacity is below the threshold capacity to provide the extended data storage zone. A size or width of the extended data zone is variable to provide additional capacity to meet the threshold capacity.

ACCURATE REPEATABLE RUNOUT COMPENSATION IN DISK DRIVES DURING SEEKS

A repeatable runout (RRO) is accurately compensated for while moving a magnetic head radially across a disk surface. An iterative learning control algorithm is employed to determine appropriate feed-forward coefficients for an RRO compensation signal for each of a plurality of radial locations across the disk surface. The feed-forward coefficients are determined by performing multiple iterations of continuously moving the magnetic head across the disk surface along a target path while measuring a position error signal that indicates the radial error between the magnetic head and the target path. With each iteration, the iterative learning control algorithm computes new feed-forward coefficients for each of the plurality of radial locations, where the new feed-forward coefficients are selected to reduce the measured position error signal when employed to move the magnetic head along the target path. 1. A method of controlling a read head in a magnetic storage device , the method comprising:rotating the disk having a surface with servo wedges;moving the read head continuously across the disk in a radial direction from a first radial location to a second radial location while positioning the read head based on the servo wedges and a feed-forward correction signal and generating a position error signal (PES); andmeasuring the generated PES at multiple radial locations of the disk as the read head is moved continuously in the radial direction, wherein each measured PES is input to an adaptive learning algorithm that corrects feed-forward coefficients for the feed-forward correction signal,wherein the first radial location is one of an inner diameter of the disk or an outer diameter of the disk and the second radial location is the other of the inner diameter of the disk or the outer diameter of the disk.2. The method of claim 1 , further comprising:determining that the measured PES at one of the multiple radial locations between the first radial location and the second ...

METHOD AND APPARATUS FOR DETERMINING READ-HEAD DEVIATION USING ORTHOGONAL PREAMBLES

A storage device includes read circuitry having a read head having a detector that outputs signals representing data from a first track and an adjacent track. The read head is subject to off-track excursions during which the read head detects signals from both the first track and an adjacent track. Data on each track includes a preamble including a repeating pattern. The repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track. The read circuitry also includes respective Discrete Fourier Transform circuits to identify components in the signals corresponding to respective frequencies characteristic of the repeating pattern on the first track and the repeating pattern on the second track, and computation circuitry to determine from the components a ratio by which the read head is off-track. Corresponding methods are provided for operating such a storage device and for reading data. 120-. (canceled)21. A method of operating a storage device having a storage medium , the method comprising:writing user data in a shingled manner to two adjacent tracks on the storage medium, including writing patterns on each track so that the pattern on a first one of the two adjacent tracks and the pattern on a second one of the two adjacent tracks are mutually exclusive;detecting, with a first read head in a first position during a pass, signals from the two adjacent tracks;detecting, with a second read head in a second position during the pass, signals from the two adjacent tracks;analyzing outputs of the first read head and the second read head to derive, from the signals from the two adjacent tracks detected by the first read head during the pass, and from the signals from the two adjacent tracks detected by the second read head during the pass, the user data that was written to the two adjacent tracks.22. The method of wherein the patterns are written outside servo wedges of the storage medium.23. The method of wherein the ...

APPARATUS FOR METHODS FOR ALIGNED SERVO-RELATED FEATURES

Provided herein is a method, including creating a first pattern in a data region of a substrate, and creating a second pattern in a servo region of a substrate. A circumferential line pattern is created overlapping the first pattern to create rectangle-shaped protrusions in the data region of the substrate. A chevron pattern is created overlapping the second pattern to create chevron-derived protrusions in the servo region of the substrate. 1. A method , comprising:creating a first pattern in a data region of a substrate;creating a second pattern in a servo region of a substrate;creating a circumferential line pattern overlapping the first pattern to create rectangle-shaped protrusions in the data region of the substrate; andcreating a chevron pattern overlapping the second pattern to create chevron-derived protrusions in the servo region of the substrate.2. The method of claim 1 , further comprising: wherein a first sub-template comprises the second pattern, and', 'wherein a second sub-template comprises the chevron pattern., 'superimposing the second pattern and the chevron pattern in a cross-imprinting process,'}3. The method of claim 1 ,wherein the rectangle-shaped protrusions and the chevron-derived protrusions have the same circumferential pitch in accordance with radial lines of the first pattern.4. The method of claim 1 ,wherein transferring the second pattern and the chevron pattern to the substrate further creates radially aligned, line-shaped protrusions or radially aligned, square-shaped protrusions in the servo region of the substrate.5. The method of claim 1 ,wherein transferring the first pattern and the second pattern to the substrate comprises etching the first pattern and the second pattern into a UV-transmissible substrate.6. The method of claim 2 ,wherein the second pattern and the chevron pattern are superimposed with a radial displacement 10 nm.7. The method of claim 2 ,wherein the second pattern and the chevron pattern are superimposed with an ...

Magnetic writer having multiple gaps with more uniform magnetic fields across the gaps

A magnetic device according to one embodiment includes a source of flux and a magnetic yoke coupled to the source of flux. The source of flux includes a thin film coil having multiple turns. The magnetic yoke has a pole with two or more gaps, wherein the coil turns have a non-uniform placement in the magnetic yoke for creating a higher magnetic field at one of the gaps than another of the gaps during writing. A magnetic device according to another embodiment includes a source of flux. A geometry of the magnetic pole near or at one of the gaps is different than a geometry of the magnetic pole near or at another of the gaps to help equalize fields formed at the gaps when the source of flux is generating flux.

MAGNETIC TAPE DEVICE AND HEAD TRACKING SERVO METHOD

The magnetic tape device includes: a magnetic tape; and a servo head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec, the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and a coefficient of friction measured regarding a base portion of a surface of the magnetic layer is equal to or smaller than 0.30. 1. A magnetic tape device comprising:a magnetic tape; anda servo head,wherein the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,the magnetic layer includes a servo pattern, anda coefficient of friction measured regarding a base portion of a surface of the magnetic layer is equal to or smaller than 0.30.2. The magnetic tape device according to claim 1 ,wherein the coefficient of friction measured regarding the base portion of the surface of the magnetic layer is 0.20 to 0.30.3. The magnetic tape device according to claim 1 ,wherein a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.8 nm.4. The magnetic tape device according to claim 3 ,wherein the center line average surface roughness Ra is equal to or smaller than 2.5 nm.5. The magnetic tape device according to claim 1 ,wherein the magnetic tape includes a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer, anda total thickness of the magnetic layer and the non-magnetic layer is equal to or smaller than 1.8 μm.6. The ...

HEAD POSITION DEMODULATION METHOD AND MAGNETIC DISK DEVICE

According to one embodiment, at demodulation of an A-phase burst pattern and a B-phase burst pattern arranged in a down-track direction so as to be different from each other in phase in a cross-track direction, the demodulated position of a magnetic head is calculated based on a sin component and a cos component in the A-phase burst pattern and a sin component and a cos component in the B-phase burst pattern. 1. A head position demodulation method comprising: at demodulation of an A-phase burst pattern and a B-phase burst pattern arranged in a down-track direction so as to be different in phase in a cross-track direction , calculating a demodulated position of a magnetic head based on a sin component and a cos component of the A-phase burst pattern and a sin component and a cos component of the B-phase burst pattern.2. The head position demodulation method according to claim 1 , wherein claim 1 , assuming that phase differences in the A-phase burst pattern and the B-phase burst pattern in the down-track direction are designated as Δφa and Δφb claim 1 , respectively claim 1 , when absolute values of Δφa and Δφb are equal; a cos component of a readback signal in the A-phase burst pattern is designated as cA and a sin component of the same as sA; a cos component of a readback signal in the B-phase burst pattern is designated as cB and a sin component of the same as sB; and sgn=Δφa/Δφb claim 1 , the demodulated position of the magnetic head is calculated using coefficients ca claim 1 , sa claim 1 , cb claim 1 , and sb based on N and Q calculated as:{'br': None, 'i': 'N=cA·ca−sA·sa+cB·cb−sB·sb·sgn'}{'br': None, 'i': 'Q=cA·sa+sA·ca+cB·sb+sB·cb·sgn.'}3. The head position demodulation method according to claim 2 , wherein claim 2 , assuming that the phase difference in the B-phase burst pattern in the cross-track direction is designated as Δθo with respect to the A-phase burst pattern claim 2 , the coefficients ca claim 2 , sa claim 2 , cb claim 2 , and sb at an arbitrary ...

Virtual window mode for guide spiral servo demodulation

A write head is positioned over a disk surface of a hard disk drive during a self-servo write process. A virtual window mode is employed for positioning the write head, in which the read channel of the hard disk drive continuously searches for servo spirals, but spiral detection is disabled except during specific time intervals, or “virtual windows.” Each virtual window is associated with one specific servo spiral on the disk surface, and has a predetermined duration. The duration and timing of these virtual windows may be selected to ensure that spiral detection is enabled while a read head of the hard disk drive passes over the associated servo spiral, even when servo spiral placement is not ideal.

MINIMIZATION OF THERMAL MAGNETORESISTIVE OFFSET CHANGE

Provided herein is an apparatus including a disk drive base, wherein the disk drive base includes a first metal composition with a first CTE (“coefficient of thermal expansion”). A disk drive cover is attached to the disk drive base, wherein the disk drive cover includes a second metal composition with a second CTE that are different from the first metal composition and the first CTE. An arm is connected to a reader and a writer, wherein the arm is coupled to the disk drive base, the reader and the writer are separated by a distance, and the distance affects an MR (“magnetoresistive”) offset. In response to temperature changes between 0° C. and 60° C., the first material and the second material expand and contract comparably and proportionally. In further response to the temperature changes between 0° C. and 60° C., a change in the MR offset is less than 10% or a preferably defined range of a track pitch on a recording medium attached to the disk drive base. 1. An apparatus comprising:a disk drive base, wherein the disk drive base comprises a first material with a first metal composition with a first CTE (“coefficient of thermal expansion”);a disk drive cover attached to the disk drive base, wherein the disk drive cover includes a second material with a second metal composition with a second CTE that are different from the first metal, the first metal composition, and the first CTE; and the arm is coupled to the disk drive base,', 'the reader and the writer are separated by a distance,', 'the distance affects an MR (“magnetoresistive”) offset, and', the first material and the second material expand and contract in equal or substantially equal proportions and scales, and', 'a change in the MR offset is less than 10% of a track pitch on a recording medium., 'in response to temperature changes between 0° C. and 60° C.,'}], 'an arm connected to a reader and a writer, wherein'}2. The apparatus of claim 1 , wherein the arm includes a third material with a third CTE claim ...

SLIDER UTILIZING MULTIPLE TRANSDUCER SETS

A slider includes an array of two or more transducer sets offset from one another in a cross-track direction. Each transducer set includes at least one writer and at least one reader. All of the transducer sets are configured to operate simultaneously to perform any combination of reading and writing on two or more tracks of a recording medium. At least one actuator is included between two the transducer sets. The actuator is configured to adjust a cross-track spacing between the two transducer sets in response to a control current. 1. A method comprising:positioning a slider over a disk via a positioning mechanism, the slider comprising first and second transducer sets, the first and second transducer sets offset from one another in a cross-track direction, each transducer set comprising at least one reader, an actuator located between the first and second transducer sets and configured to change a crosstrack spacing between the first and second transducer sets;reading first position data from the disk via a first reader of the first transducer set;reading second position data from the disk via a second reader of the second transducer set;using the first position data to position the first transducer set over a first track via the positioning mechanism; andusing the second position data to position the second transducer set over a second track via the actuator.2. The method of claim 1 , wherein the positioning mechanism comprises a voice coil and a microactuator claim 1 ,3. The method of claim 1 , wherein the actuator comprises a heater that changes the crosstrack spacing between the first and second transducer sets via thermal expansion.4. The method of claim 1 , wherein the slider further comprises a third transducer set and a second actuator configured to change a second crosstrack spacing between the third transducer set and the first and second transducer sets claim 1 , the method further comprising:reading third position data from the disk via a third reader ...

Dual Stage Actuated Suspension Having Shear-Mode PZT Actuators for Rotating Gimbal Tongue

A dual stage actuated (DSA) suspension uses two shear-mode PZT microactuators to finely position the head slider. The bottom surfaces of the PZTs are affixed to the flexure, and the PZT top surfaces move forward and backward, respectively, in push-pull fashion when the PZTs are activated. Flexible connector arms attach the tops surfaces of the PZTs to the gimbal tongue such that activating the PZTs causes the gimbal tongue to rotate, with the connector arms acting as levers to magnify the motion such that a relatively small shear movement of the PZTs results in a significantly larger lateral movement of the head slider across the data disk. 1. A dual stage actuated suspension for a disk drive , comprising:a beam portion; first and second flexible outrigger arms extending on respective lateral sides of the flexure from a relatively fixed portion of the flexure; and', 'a gimbal tongue;, 'a flexure mounted to the beam portion, the flexure includinga head slider mounted to the gimbal tongue for writing data to, and reading data from, a moving data medium containing a plurality of data tracks thereon;a first shear-mode piezoelectric device mounted at a distal end of the first flexible outrigger arm, the first shear-mode piezoelectric device having a top surface, a bottom surface, and two electrodes, the top surface moving in a linear shear direction relative to the bottom surface when an actuation voltage is applied across the electrodes; anda mechanical coupling that, in response to the piezoelectric device being activated, couples the shear movement of the piezoelectric device to rotational movement of the head slider.2. The suspension of further comprising:a second shear-mode piezoelectric device mounted at a distal end of the second flexible outrigger arm, the second shear-mode piezoelectric device having a top surface and a bottom surface;wherein when the first and second piezoelectric devices are actuated, the top surface of the first piezoelectric devices moves in ...

SCISSOR MAGNETIC READ SENSOR WITH NOVEL MULTI-LAYER BIAS STRUCTURE FOR UNIFORM FREE LAYER BIASING

A scissor type magnetic sensor having a back edge bias structure that has a non-uniform magnetic moment to compensate for differences in magnetic spacing between the bias structure and a first magnetic free layer as compared with the magnetic spacing between the bias structure and a second magnetic free layer. The magnetic bias structure can include a first magnetic layer and a second magnetic layer formed over the first magnetic layer, with the first magnetic layer having a higher magnetic moment than the second magnetic layer. 1. A magnetic sensor , comprising:a sensor stack; anda magnetic bias structure formed adjacent to the sensor stack, the bias structure having a magnetic moment that varies with location within the bias structure;wherein the magnetic bias structure comprises a first magnetic layer and a second magnetic layer formed over the first magnetic layer and wherein, the first magnetic layer having a greater magnetic moment than the second magnetic layer and wherein the difference between the magnetic moment of the first and second magnetic layers is not greater than 2.2 Tesla:wherein the magnetic bias structure is separated from the back edge of the sensor stack by a non-magnetic, electrically insulating layer; andwherein the first magnetic layer extends up along the non-magnetic, electrically insulating layer so as to separate the second magnetic layer from the non-magnetic, electrically insulating layer.2. The magnetic sensor as in claim 1 , wherein the bias structure includes a first magnetic layer and a second magnetic layer formed over the first magnetic layer claim 1 , the first magnetic layer having a higher magnetic moment than the second magnetic layer.3. The magnetic sensor as in wherein the magnetic bias structure includes a plurality of magnetic layers having differing magnetic moments.4. (canceled)5. (canceled)6. The magnetic sensor as in wherein the magnetic bias structure further comprises a first magnetic layer having a magnetic moment ...

INFORMATION DEVICE

An information device includes a slider () including a first metal antenna (), a second metal antenna (), and a heater () configured to vary the distance between the first metal antenna () and the second metal antenna () in a direction orthogonal to a track direction on the surface of a disk (), and an arm motor () configured to move the slider () in parallel to the surface of the disk (). The arm motor () and the heater () cause the first metal antenna () and the second metal antenna () to respectively follow corresponding target tracks. 1. An information device comprising:a head including a first element, a second element, and an inter-element distance varying unit configured to vary a distance between the first element and the second element in a direction orthogonal to a track direction on a surface of an information carrier, anda head moving unit configured to move the head in parallel to the surface of the information carrier, whereinthe head moving unit and the inter-element distance varying unit cause the first element and the second element to respectively follow corresponding target tracks.2. The information device according to claim 1 , wherein the head moving unit and the inter-element distance varying unit cause the first element and the second element to follow tracks in different radial positions.3. The information device according to claim 2 , wherein the head moving unit and the inter-element distance varying unit cause the first element and the second element to follow tracks adjacent to each other in the direction orthogonal to the track direction.4. The information device according to claim 1 , wherein the head moving unit and the inter-element distance varying unit cause the first element and the second element to follow a same track.5. The information device according to claim 1 , whereinthe first element includes a recording element for recording information on the information carrier, andthe second element includes a reproducing element for ...

STORAGE DEVICE SYSTEM PERFORMANCE MANAGEMENT

The technology disclosed herein pertains to a method for determining expected command completion time (CCT), the method including receiving a plurality of position error signals (PESs) for an HDD over a predetermined time period, determining sigma of the plurality of PESs, retrieving upper off-track limits (UOL) for one or more data sectors of the HDD, calculating average number of retrieved sectors (A) between two consecutive occurrences of the |PES|>UOL for the HDD, and determining required number of revolutions (CCT) to collect data based on the average number of retrieved data sectors (A) and a total number of requested data sectors (N). 1. A method , comprising:receiving a plurality of position error signals (PESs) for an HDD over a predetermined time period;calculating average number of retrieved sectors (A) between two consecutive occurrences of the |PES|>UOL for the HDD, wherein the UOL being upper off-track limit for one or more data sectors of the HDD; andin response to determining that a required number of revolution (CCT) to collect data is above a threshold, collecting data from a mirrored HDD.2. The method of claim 1 , further comprising formulating a data request based on the determined required number of revolutions.3. The method of claim 2 , wherein formulating a data request based on the determined required number of revolutions further comprising requesting data from an alternative storage device configured to provide data redundancy to the HDD.4. The method of claim 1 , further comprising determining a probability of the PES being above the UOL based on the sigma of the plurality of PESs claim 1 , wherein the average number of retrieved data sectors (A) is calculated using the probability of the PES being above the UOL based on the sigma of the plurality of PESs.5. The method of claim 1 , further comprising comparing the required CCT to a threshold and communicating the CCT to a host in response to determining that the CCT is above the threshold. ...

Ratio-Adjustable Sync Mark Detection System

Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for detecting a sync mark with a ratio-adjustable detection system.

APPARATUS, SYSTEMS AND PROCESSES FOR REDUCING A HARD DISK DRIVE'S ACCESS TIME AND CONCOMITANT POWER OPTIMIZATION

Rotational latency is reduced in a standard conventional form factor HDD system by replacing, for example, the prior art rotary arm actuator of a conventional HDD, with one or more belts and pulleys and one or more read/write heads mounted on, or otherwise associated with the belts. Multiple scaled iterations facilitate energy savings and power optimized systems, without compromise to data access performance. 1. An apparatus comprising a belt , a pulley , a read/write head , and a data recording medium , the belt and the pulley configured to suspend the read/write head over a surface of the data recording medium and to move the read/write head linearly across and above the surface upon movement of the pulley.2. The apparatus of further comprising a slider claim 1 , the read/write head being coupled to the slider.3. The apparatus of further comprising a head gimbal assembly (HGA) attached to the belt claim 2 , the HGA comprising the slider.4. The apparatus of further comprising a chassis claim 1 , a voice coil claim 1 , and a controller claim 1 , the pulley rotatably mounted to the chassis and rotated by action of the voice coil claim 1 , the voice coil controlled by the controller.5. The apparatus of wherein the chassis is configured to fit within a form factor of a conventional hard disk drive (HDD).6. The apparatus of further comprising a plurality of belts claim 1 , pulleys claim 1 , read/write heads claim 1 , and data recording mediums.7. The apparatus of further comprising a plurality of data recording mediums.8. The apparatus of further comprising a plurality of read/write heads claim 7 , at least one of the read/write heads for each of the data recording mediums.9. The apparatus of wherein each of the plurality of read/write heads is configured to read simultaneously from its respective data recording medium.10. A mounting and moving system for read/write heads in a data storage device claim 8 , the system comprising a hard disk drive (HDD) claim 8 , the HDD ...

MAGNETIC DISK DEVICE AND METHOD OF WRITE PROCESSING OF POSTCODE

According to one embodiment, a magnetic disk device includes a disk including a first region with a first format efficiency and a second region with a second format efficiency lower than the first format efficiency, a head that writes data to the disk and reads data from the disk, and a controller that selects a first postcode to be written to the first region from a plurality of postcodes with different lengths and writes the first postcode to the first region, and selects a second postcode to be written to the second region from a plurality of postcodes with different lengths and writes the second postcode to the second region. 1. A magnetic disk device comprising:a disk including a first region with a first format efficiency and a second region with a second format efficiency lower than the first format efficiency;a head that writes data to the disk and reads data from the disk; anda controller that selects a first postcode to be written to the first region from a plurality of postcodes with different lengths and writes the first postcode to the first region, and selects a second postcode to be written to the second region from a plurality of postcodes with different lengths and writes the second postcode to the second region.2. The magnetic disk device according to claim 1 , wherein the controller selects the second postcode having a second length shorter than a first length of the first postcode and writes the second postcode to the second region.3. The magnetic disk device according to claim 2 , wherein in the second region claim 2 , a first servo sector in a first servo region including servo data extending in a radial direction of the disk claim 2 , a gap claim 2 , and a second servo sector in a second servo region including servo data extending in the radial direction are arranged in this order in a first direction of a circumferential direction of the disk.4. The magnetic disk device according to claim 3 , wherein the controller writes the second postcode ...