СПОСОБ МАГНИТНОЙ ЗАПИСИ АНАЛОГОВЫХ СИГНАЛОВ С ПОДМАГНИЧИВАНИЕМ

Использование: магнитная запись информации на движущийся магнитоноситель, где предъявляются повышенные требования к качеству записи. Сущность изобретения: с целью ослабления размагничивающего действия тока подмагничивания на уровень остаточной намагниченности сигналом магнитоносителя, расширения на этой базе диапазона записывающих частот при одновременном снижении нелинейных искажений ток подмагничивания частотой 130 - 180 кГц, вырабатываемый генератором, модулируется колебаниями с заранее заданными постоянными параметрами: частота, глубина модуляции, форма модулирующих колебаний. Параметры модуляции выбираются такими, чтобы максимально оптимизировать характеристики записи. Глубина модуляции 30 - 70%, форма модуляции - синусоида или прямоугольные импульсы, частота модуляции синхронизируется с движением магнитоносителя. 1 ил., 1 табл.

Устройство для магнитной записи

Способ снижения шумов паузы при магнитной записи фонограммы

Изобретение относится к приборостроению, а именно к технике магнитной записи, и может быть использовано при записи и перезаписи фонограмм. Цель изобретения - расширение динамического диапазона фонограммы путем снижения высокочастотных шумов паузы. В моменты паузы между фрагментами звуковой фонограммы от источника 3 входного аналогового сигнала вырабатываемый генератором 5 ток высокочастотного подмагничивания увеличивают относительно номинального уровня с помощью регулирующего элемента 6, управление которым осуществляют от детектора 7 паузы. Время, за которое увеличивают ток высокочастотного подмагничивания, не должно превышать постоянной времени слухового восприятия, при этом в записываемую фонограмму не вносятся дополнительные помехи в виде "шумового хвоста". Увеличение тока высокочастотного подмагничивания сверх номинального уровня осуществляют до получения спада амплитудно-частотной характеристики канала записи (для данного типа носителя магнитной записи), численно равного величине высокочастотных ...

Устройство магнитной записи аналоговых сигналов

Изобретение относится к технике магнитной записи и позволяет расширить диапазон записьгоаемых частот за счет дина.мического регулирования тока подмагничивания. Дпя этого с выхода усилителя записи 1 часть сигнала записываемой рабочей частоты, через конденсатор 4 проходит на затвор транзистора 7, который регулирует степень модуляции сигналов рабочей частоты токами высокой частоты подмагничивания, что обеспечивает при выборе сопротивлений резисторов 5 и 8 расширение диапазона записываемых рабочих частот до 18 кГц при использовании бытовых магнитофонов с ферритовой универсальной головкой. 1 нл. 4J-L r22::rJ ш (Л ю 00 1C ...

Способ многодорожечной магнитной записи информации, представленной в виде импульсов

Устройство для воспроизведения цифровых данных с носителя магнитной записи

УСТРОЙСТВО ДЛЯ ВОСПРОИЗ; ВЕДЕНИЯ ЦИФРОВЫХ ДАННЫХ С НОСИТЕЛЯ МАГНИТНОЙ ЗАПИСИ, содержащее воспроизводящую магнитную головку, выполненную с магниторезистивньгми- тонкопленочными элементами, первые выводы которых подсоединены к шине питания , а вторые выводы - к входам дифференциального усилителя, резисторы, конденсатор и общую шину, отличающееся тем, что, с целью повышения чувствительности и уменьшения теплорассеяния, в него введе- ны гираторы, выпблненные на операционных усилителях, первые входы которых подсоединены к вторым выводам магниторезистивных тонкопленочных элементов, а выходы соединены через резисторы с входами дифференциального усилит.еля, выполненного i в виде биполярного операционного усилителя, причем вторые входы опеСО рационных усилителей гираторов подключены к общей шине, а управляклцие входы соединены непосредственно с разными выводами конденсатора. ел со со ...

Anordnung zur Amplitudenstabilisierung der hochfrequenten Loesch- oder Vormagnetisierungs-spannung in einem Magnetbandgeraet

DIGITALLY CONTROLLED AUTOMATIC BIAS CIRCUIT FOR MAGNETIC RECORDING

Einrichtung und Verfahren bei einem Schreibekreis mit Vorverstärker und verminderter Ausstiegs- und Abfallzeit

Verfahren zum Aufzeichnen von Magnetogrammen

Improvements in or relating to bias oscillators

... 966,209. Automatic voltage control. AMPEX CORPORATION. Oct. 31, 1962 [Dec. 19, 1961], No. 41248/62. Heading G3R. A circuit arrangement for maintaining constant the amplitude of the output signal of an oscillator 10 connected to a load 12 comprises a feedback loop having an integrating and rectifying network 16, 18 and 20 for deriving a unidirectional signal which is representative of the oscillator output and which is applied over an amplifier 22, e.g. a transistor, and a Zener diode 24 to a light bulb 26 arranged to illuminate a photo-electric cell 28 shunting the input to the oscillator 10. When the output amplitude varies in excess of a predetermined value set by the breakdown voltage of the Zener diode 24, the light radiation emitted by the bulb 26 varies correspondingly and the resistance of cell 28 is changed accordingly; this changing resistance controls the oscillator gain in a corrective manner to maintain the output amplitude constant. An application of the circuit arrangement ...

Magnetic recording and reproducing

... 676,766. Magnetic sound recording and reproducing apparatus. BRUSH DEVELOPMENT CO. Feb. 13, 1948. [Dec. 5, 1946] No. 4259/48. Class 40 (ii). In a magnetic recording and reproducing system, the recording head is energized by a constant frequency alternating current during recording and gradually de-energized at the end of a recording period. In one embodiment, a supply reel 21 feeds the record track 31 past an erasing head 32 and recording/reproducing head 33,. capstan 23 and limit switch 25 to a take-up reel 22. Felt pads 40 urge the record track 31 into contact with the heads 32, 33 and separate driving motors 41, 42, 43 are associated with the supply reel 21, take-up reel 22 and capstan 23 respectively. The switch assembly 35 controls the various functions of the apparatus being provided with pushbuttons 50 ... 55. The inward action of one push-button causes all the others to be released to the outward position. In the playback outward position of push-button 55, reproducing head 33 is ...

MAGNETIC ERASING HEADS

... 1476154 Magnetic erasing heads SONY CORP 30 Sept 1974 [2 Oct 1973] 42286/74 Heading G5R A recording track t to be erased encounters in turn a first magnetic pole P1 extending across the whole track, a second magnetic pole P2 of opposite polarity engaging one half of the track, and a third magnetic pole P3 of the same polarity as the first engaging the other half of the track.

AS INTEGRATED CIRCUIT DEVELOPED MECHANISM FOR THE CONTROLLING OF A LOESCH AND A BIAS POWER SOURCE GENERATOR

EQUIPMENT FOR A SYSTEM FOR THE RECORDING OF CLAY-FREQUENT SIGNALS ON A MAGNETIC RECORDING CARRIER

MECHANISM FOR THE PRODUCTION OF A SOUND RECORDING

EINRICHTUNG ZUR HERSTELLUNG EINER TONAUFZEICHNUNG

SWITCHING CONFIGURATION FUER MAGNETIC SOUND EQUIPMENT

EQUIPMENT FOR A SYSTEM FOR THE RECORDING OF CLAY-FREQUENT SIGNALS ON A MAGNETIC RECORDING CARRIER

PROCEDURE AND DEVICE AS A CHECK OF THE BIAS DURING MAGNETIC RECORDING.

PROCEDURE FOR THE REALIZATION OF A LINEAR STANDARDISED MAGNETIC VOLUME.

MAGNETORESISTIVE TRANSDUCERS AND METHODS OF MANUFACTURE

MAGNETIC RECORDING CONTROL CIRCUIT

DIGITALLY CONTROLLED AUTOMATIC BIAS CIRCUIT FOR MAGNETIC RECORDING

MULTI-TRACK MAGNETIC HEAD

MAGNETIC TRANSDUCER HEAD UTILIZING MAGNETORESISTANCE EFFECT

A magnetoresistance effect type magnetic head apparatus has a magnetoresistance effect sensing element, means for applying a bias magnetic field to the sensing element, a detecting circuit for obtaining a detecting signal, a low pass filter for deriving an unwanted signal component from the detecting signal, and means for applying a cancelling magnetic field to the sensing element so as to eliminate the unwanted signal component. An additional sensing element may also be provided to detect an external magnetic field, and a corresponding signal is generated which is applied to a first sensing element so as to cancel the effects of the external magnetic field.

PCM SIGNAL RECORDING APPARATUS

In an apparatus for recording data on a magnetic recording medium by means of a magnetic head, a recording current supplied to such head, for example, from a recording amplifier, is varied in accordance with the recording density of the data being recorded so as to reduce the bit error rate upon playback or reproducing of the recorded data. For each recording density, the recording current supplied to the magnetic head is a predetermined amount greater than the optimal value of the recording current at a Nyquist frequency of the digital data being recorded.

STABILIZED BIAS SYSTEM FOR MAGNETIC TAPE READ AND WRITE HEADS

Säuglingsunterlage für Kinderwagen oder dergleichen.

Schallträger für magnetische Aufzeichnung.

Verfahren zur Kennzeichnung von Magnetogrammträgern.

Putzeinrichtung für die Zylinderstreckwerke von Spinnmaschinen.

Verfahren zur magnetischen Schallaufzeichnung bei Diktiergeräten.

Verfahren zur Erzeugung von Mirkoorganismen, insbesondere Hefe.

Verfahren und Einrichtung zur Verarbeitung von Dungmaterial jeder Konsistenz mit Gülle oder Wasser zu einem flüssigen Dünger.

Hartmetalldrehstahl.

Magnettonverfahren.

Verfahren zur stereophonischen Schallübertragung unter Zwischenschaltung einer magnetischen Mehrkanalaufzeichnung.

Tonaufzeichnungsverfahren.

Verfahren zur magnetischen Schallaufzeichnung.

Magnettongerät mit einem ein- bzw. ausschaltbaren Generator für ultraschallfrequente elektrische Schwingungen, zur magnetischen Beeinflussung des Tonträgers.

Procédé d'enregistrement magnétique d'énergie électrique fluctuante sur un corps paramagnétique et dispositif pour la mise en oeuvre de ce procédé.

Gerät mit Magnettoneinrichtung.

Procédé d'enregistrement magnétique de fluctuations d'énergie électrique sur un corps ferromagnétique et dispositif pour la mise en oeuvre de ce procédé.

Magnetton-Aufzeichnungs- und -Wiedergabekopf für einen band- oder drahtförmigen Tonträger und Verfahren zur Herstellung desselben.

Tonfrequenzverstärker für Stahltongeräte mit Hochfrequenzlöschung.

Einrichtung zur Aufnahme und Wiedergabe von Magnettonaufzeichnungen mit einem Hochfrequenzgenerator

Appareil enregistreur magnétique.

Schaltung zum Zuführen und Verstärken der für den Tonkopf eines Magnettongerätes bestimmten Ströme

Verfahren zur Herstellung von Unterbrecherkontakten.

Magnettonverfahren.

Verfahren zur Herstellung von Stahldrähten oder Stahlbändern für magnetische Schallaufzeichnungen.

Verfahren zur Löschung einer magnetischen Schallaufzeichnung.

Richtantennenanordnung für Ultrakurzwellenbetrieb innerhalb eines breiten Frequenzbandes.

Kopiermaschine, insbesondere Kopierfräsmaschine.

Elektrisch beheizte Weiche.

Verfahren zur Herstellung von 1.5-Dichlornaphtalin-4.8-dicarbonsäure.

Bauchiges Sperrholzfass.

Fahrgerät für Granatwerfer.

Lautsprecher.

Verfahren zur Schallaufzeichnung auf einen magnetisierbaren Schallträger.

Verfahren zur Herstellung magnetischer Aufzeichnungen

Vorrichtung zur Aufzeichnung und Wiedergabe von Magnetogrammen mit einem Hochfrequenzoszillator

Zweispurlöschkopf

Magnetkopfanordnung für die Aufzeichnung von Signalen nach dem Magnettonverfahren

Dispositif d'enregistrement et de reproduction magnétiques du son.

Gerät für longitudinale Magnettonaufzeichnungen.

Stahlton-Aufnahme- und -Wiedergabegerät.

Röhrenschaltung für den Lösch- und Vormagnetisierungsgenerator in Geräten zur magnetischen Schallaufzeichnung.

Enregistreur magnétique

Vorrichtung zur magnetischen Schallaufzeichnung mit Hochfrequenzmagnetisierung

Löschkopf

Verfahren und Vorrichtung zur magnetischen Aufzeichnung und Wiedergabe von Signalen

Einrichtung zum allmählichen Ein- und Ausblenden von Schallaufzeichnungen auf Magnetogrammträgern

Verfahren und Vorrichtung zur Schall- oder Bildimpulsaufzeichnung durch Hochfrequenzvormagnetisierung

Magnetband-Aufnahme- und -Wiedergabegerät

Halbleiteranordnung zum Schalten von Wechselströmen für Vormagnetisierungs- und Löschzwecke in Magnetbandgeräten

Mehrspurlöschkopf

Oscillateur-amplificateur pour enregistrement magnétique

Verfahren und Tonfilmgerät zum Vertonen von Filmen

Anordnung zur Aufzeichnung von Signalen unter Verwendung eines Magnetkopfes

Einrichtung zur Wiedergabe aufgezeichneter elektrischer Signale

Dispositivo per la cancellazione totale di un filo o di un nastro magnetico negli apparecchi di registrazione sonora

УСТРОЙСТВО МАГНИТНОЙ ЗАПИСИ С АДАПТИВНЫМ ПОДМАГНИЧИВАНИЕМ

Изобретение относится к магнитной записи, а именно к устройствам магнитной записи аналоговых сигналов с подмагничиванием переменным полем. Устройство содержит усилитель записи, вход которого подключен к входной шине, а выход соединен с магнитной головкой записи и с входом фильтра нижних частот, операционный усилитель.

INTERNALLY BIASED MAGNETORESISTIVE MAGNETIC TRANSDUCER

Method for realization of magnetograms

Apparatus of recording and reproduction of the sounds using a ribbon of tape recording

HALL EFFECT MAGNETIC HEAD

DEVICES Of WRITING AND OBLITERATION FOR NUMERICAL TAPE RECORDERS HAS ROTARY HEAD

Order for machines to be reproduced, in particular for copying milling machines

Device of recording, and possibly of magnetic restitution

System transducer

Magnetic process of sound recording

Magnetic fitting of system for the tape recording of the sound and the reproduction and the obliteration of the recordings

PROCESS AND MEASURING DEVICE FOR THE DETERMINATION OF THE CHARACTERISTICS ELECTROACOUSTICS OF THE MAGNETIC BANDS

Process improved for the tape recording of a fluctuating electrical energy, and tape recorder for the implementation of this process

Device for the orientation of the magnetic particles of a magnetic band

Acid 1.5-dichloro-naphthalene-4.8-dicarboxylique, acid 1.5-dichloro-4.8-di- (omega-chloracétyle) - naphthalene and method of preparation of these products

Device recorder-reproducer of sounds and signals of remote control, intended especially, but not exclusively, with the lanterns with projection

Device of antennas directed for broad wavebands

Equalizer and equalization method

A linear equalizer unit sequentially subjects a signal to be processed to linear equalization. A temporary decision unit sequentially subjects a signal subjected to linear equalization by the linear equalizer unit to temporary decision. A nonlinear equalizer unit derives a plurality of coefficients using a signal subjected to temporary decision as a teacher signal and sequentially subject a signal subjected to linear equalization by the linear equalizer unit to nonlinear equalization based on the plurality of coefficients.

Disk drive with variable incremented counting of writes to the data tracks for minimizing the effect of far track erasure

A hard disk drive (HDD) minimizes the effects of far track erasure (FTE) by counting the number of writes to the data tracks and incrementing counters based on the known effect of FTE on each track. The extent of the FTE effect is determined for each track within a range of tracks of the track being written, and based on the relative FTE effect for all the tracks in the range a count increment (CI) is determined for each track within the range. A counter is maintained for each track. For every writing to a track, a count for each track within a range of the track being written is increased by the CI value associated with the track number within the range. When the count value for a track reaches a predetermined threshold the data is read from that track and rewritten, preferably to the same track.

Systems and Methods for Sequence Detection in Data Processing

Various embodiments of the present invention provide systems and methods for sequence detection. As an example, a method for data detection is disclosed that includes: receiving a series of data samples at a detector circuit; multiplying a portion of the series of data samples by a first correlator value corresponding to a first binary transition to yield a first value; multiplying the portion of the series of data samples by a second correlator value corresponding to a second binary transition to yield a second value; adding the first value to a prior state value to yield a first interim value; adding the second value to the prior state value to yield a second interim value; and selecting the larger of the first interim value and the second interim value to yield a surviving interim value.

Gain control with multiple integrators

A method according to one embodiment includes receiving an increment signal at a first integrator when a second integrator overflows; receiving a decrement signal at the first integrator when the second integrator underflows; and incrementing or decrementing a gain applied to an analog signal based on receipt of the increment or decrement signal. A system according to one embodiment includes a first integrator configured to cause incrementing of a gain applied to an analog signal based on receipt of an increment signal when a second integrator overflows, the first integrator being configured to cause decrementing of the gain applied to the analog signal based on receipt of a decrement signal when the second integrator underflows; and the second integrator.

Signal reception apparatus and signal reception method

One embodiment provides a signal reception apparatus including: a reception module configured to receive a signal; a storing module configured to store information regarding a characteristic of the received signal; a determination module configured to read out the stored information and to determine a parameter value corresponding to the read-out information; a discrimination module configured to discriminate a noise contained in the signal, based on the signal and the determined parameter value; and an identification module configured to identify the noise contained in the signal, based on a discrimination result by the discrimination module.

Efficient connection management in a sas target

A method includes pre-configuring a hardware-implemented front-end of a storage device with multiple contexts of respective connections conducted between one or more hosts and the storage device. Storage commands, which are received in the storage device and are associated with the connections having the pre-configured contexts, are executed in a memory of the storage device using the hardware-implemented front-end. Upon identifying a storage command associated with a context that is not pre-configured in the hardware-implemented front-end, software of the storage device is triggered to configure the context in the hardware-implemented front-end, and the storage command is then executed using the hardware-implemented front-end in accordance with the context configured by the software.

Channel circuit and seek method

A channel circuit includes a reader, a decoder, a prediction module, and a seek module. The reader reads data written in a medium. The decoder performs iterative decoding of the read data. The prediction module predicts whether an early read is possible or not without waiting for arrival of the read data. The seek module continuously initiates a seek when the prediction module predicts that the read is possible.

Disk drive calibrating a laser write power for heat assisted magnetic recording

A disk drive is disclosed comprising a head actuated over a disk, wherein the head comprises a laser for heating the disk while writing data to the disk. The disk drive receives write commands, and increases a power of the laser to a write power for heating the disk while writing data to the disk. A calibration interval is adjusted based on the power applied to the laser over time, and the write power is calibrated at the calibration interval.

Methods and Apparatus for Map Detection with Reduced Complexity

Methods and apparatus are provided for high-speed, low-power, high-performance channel detection. A soft-output detector is provided for processing a received signal, comprising: a forward detector for calculating forward state metrics; a backward detector for calculating backward state metrics; and a current branch detector for calculating a current branch metric, wherein at least two of the forward detector, the backward detector and the current branch detector employ trellis structures with a different number of states. A method is provided for processing a received signal using a soft-output detector, comprising: calculating forward state metrics using a forward detector; calculating backward state metrics using a backward detector; and calculating a current branch metric using a current branch detector, wherein at least two of the forward detector, the backward detector and the current branch detector employ trellis structures with a different number of states. 1. A soft-output detector for processing a received signal , comprising:a forward detector for calculating forward state metrics;a backward detector for calculating backward state metrics; andcurrent branch detector for calculating a current branch metric, wherein at least two of said forward detector, said backward detector and said current branch detector employ trellis structures with a different number of states.2. The soft-output detector of claim 1 , wherein said forward detector uses a four state claim 1 , radix 2trellis with or without feedback claim 1 , with N≧2 claim 1 , where N is a number of received samples.3. The soft-output detector of claim 1 , wherein said backward state metrics are unraveled by setting initial backward state metrics to 0 and calculating a best path leaving each current backward state in a forward direction.4. The soft-output detector of claim 1 , wherein forward branch metrics are used by said forward detector to calculate said forward state metrics and also used by ...

Perpendicular magnetic recording write head with ladder network compensation circuitry on slider body for write current overshoot at write current switching

Write enhancement circuitry on the head carrier of a magnetic recording disk drive provides additional write current overshoot beyond that provided by the write driver circuitry. The write enhancement circuitry is formed on the head carrier as ladder network blocks. A first ladder network block is a first capacitor C 1 located in parallel with the write coil. The second ladder network block includes a second capacitor C 2 having substantially the same inductance L 2 . The compensation circuitry is referred to as a ladder network because additional ladder blocks, like the second block but with different values of capacitance and inductance, may be located on the head carrier.

Implementing spin-torque oscillator sensing with enhanced delay control feedback circuit for hard disk drives

A method, apparatus, and system for implementing spin-torque oscillator (STO) sensing with an enhanced delay control feedback circuit for hard disk drives. A detector receives an input signal from a STO read sensor having an oscillation frequency related to the strength of the detected magnetic signal field. The received input signal is mixed with a time delayed input signal for providing a detector output signal. A low frequency component signal of the detector output signal is monitored and a delay control feedback is applied to an adjustable time delay to bias the DC signal of the detector output signal.

Systems and Methods for Combined Binary and Non-Binary Data Processing

Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing system is disclosed that includes a combination data decoder circuit. The combination data decoder circuit includes: a non-binary data decoder circuit and a binary data decoder circuit.

MAGNETIC DISK CONTROL DEVICE, MAGNETIC DISK APPARATUS, MAGNETIC DISK CONTROL METHOD AND COMPUTER PROGRAM

A magnetic disk control device according to an exemplary of the invention includes a write controller to control, in a magnetic disk having tracks, the track being a storage area made by concentrically dividing a magnetic recording layer formed onto a disk into a plurality of areas, the track being divided into a plurality of areas in a rotative direction as sectors, writing information into the each sector; and a substitution controller to make, by detecting the sector or the track written at a frequency higher than a writing frequency based on a number of times of writing by the write controller to the sector or the track and by moving information recorded in an adjacent track adjacent to a high-writing-frequency track including the detected high writing frequency sector or to a high-writing-frequency track which is detected as a high writing frequency track to a track of a substitution area. 1. A magnetic disk control device , comprising:a write controller to control, in a magnetic disk having tracks, the each track being a storage area made by concentrically dividing a magnetic recording layer formed onto a disk into a plurality of areas, the each track being further divided into a plurality of areas in a rotative direction as sectors, writing information into the each sector; anda substitution controller to make, by detecting the sector or the track written at a frequency higher than a prescribed writing frequency based on a number of times of writing by the write controller to the sector or the track per prescribed unit time and by moving information recorded in an adjacent track adjacent to a high-writing-frequency track including the detected high writing frequency sector or to a high-writing-frequency track which is detected as a high writing frequency track to a track of a substitution area set in advance, the adjacent track be in an idle status, the idle status being a status of not being used.2. The magnetic disk control device according to claim 1 , ...

SPIN CONDUCTION ELEMENT AND MAGNETIC SENSOR AND MAGNETIC HEAD USING SPIN CONDUCTION

A spin conduction element includes a main channel layer having a first electrode, a second electrode, a third electrode, a fourth electrode, a fifth electrode, and a sixth electrode, and extending in a first direction. Spins are injected into the main channel layer from a second ferromagnetic layer constituting the second electrode and a fourth ferromagnetic layer constituting the fourth electrode, and a spin current is detected as a voltage in a third ferromagnetic layer constituting the third electrode. 1. A spin conduction element comprising:a first region, a second region, a third region, a fourth region, and a fifth region provided on a main channel layer extending in a first direction, the regions being arranged in order from one of the sides in the first direction;a first electrode mounted on the first region;a second electrode mounted on the second region;a third electrode mounted on the third region;a fourth electrode mounted on the fourth region; anda fifth electrode mounted on the fifth region,wherein the second electrode includes a second ferromagnetic layer composed of a ferromagnetic material;the third electrode includes a third ferromagnetic layer composed of a ferromagnetic material;the fourth electrode includes a fourth ferromagnetic layer composed of a ferromagnetic material; andthe magnetization directions of the second ferromagnetic layer, the third ferromagnetic layer, and the fourth ferromagnetic layer are the same.2. The spin conduction element according to claim 1 , further comprising:a second channel layer provided in the third region of the channel layer to extend in a second direction different from the first direction on the same plane as the first direction;a sixth region extending in the second direction; anda sixth electrode mounted on the sixth region.3. The spin conduction element according to claim 1 ,wherein the first electrode and the fifth electrode include a first ferromagnetic layer and a fifth magnetic layer, respectively, ...

PRESENTATION OF SHINGLED MAGNETIC RECORDING DEVICE TO A HOST DEVICE RESOURCE MANAGER

A shingled magnetic recording hard drive is presented to a resource manager of a host device as an emulated device such as one or more optical media, an array of sequential access media, and/or write-once, read-many device. Data targeted for the emulated device is written to the shingled magnetic recording hard drive.

DISK-DRIVE PULSE DURATION CONTROL SYSTEM

One embodiment includes a pulse duration control system for a magnetic disk-drive system. A rise delay system generates first control voltages in response to a write data input signal changing between a first state and a second state. A fall delay system generates second control voltages in response to the write data input signal changing between the first and second states. A comparator system generates a rising-edge overshoot signal and a falling-edge overshoot signal based on a comparison of the first and second control voltages. The rising-edge overshoot signal can set a duration of a positive overshoot current pulse for a write current at a transition of the write data input signal from the first state to the second state, and the falling-edge overshoot signal can set a duration of a negative overshoot current pulse for the write current at a transition from the second state to the first state. 1. A pulse duration control system for a magnetic disk-drive system , the system comprising:a rise delay system configured to generate a first plurality of control voltages in response to a write data input signal changing between a first state and a second state;a fall delay system configured to generate a second plurality of control voltages in response to the write data input signal changing between the first state and the second state; anda comparator system configured to generate a rising-edge overshoot signal and a falling-edge overshoot signal based on a comparison of the first and second pluralities of control voltages, the rising-edge overshoot signal being associated with a duration of a positive overshoot current pulse for a write current at a transition of the write data input signal from the first state to the second state, and the falling-edge overshoot signal being associated with a duration of a negative overshoot current pulse for the write current at a transition of the write data input signal from the second state to the first state.2. The system of ...

Over-the-Rail Write Driver for Magnetic Storage Systems

A write driver circuit for generating a write current pulse for use by a magnetic write head includes an output stage adapted for connection with the magnetic write head and a charge storage circuit connected with the output stage. The charge storage circuit is operative in a first mode to store a prescribed charge and is operative in a second mode to transfer at least a portion of the charge stored therein to the output stage to thereby enable an output voltage level of the output stage to extend beyond a voltage supply rail of the write driver circuit. A control circuit in the write driver circuit is operative to generate at least one control signal for selectively controlling a mode of operation of the charge storage circuit.

Method and Apparatus for Reading a Non-Volatile Memory Using a Spin Torque Oscillator

A method and apparatus for reading electronic memory comprising a current source, a spin transfer oscillator, an external field source, coupled to the current source, for generating an RF signal, the spin torque oscillator positioned proximate a magnetic media comprising a plurality of bit regions of varying magnetic permeability, wherein a frequency of the RF signal varies in response to the permeability of a bit region in the plurality of bit regions being proximate the spin torque oscillator. 1. An apparatus for reading electronic memory comprising:a current source;an external magnetic field source;a spin transfer oscillator, coupled to the current source, for generating an RF signal;the spin torque oscillator positioned proximate a magnetic media comprising a plurality of bit regions of varying magnetic permeability, wherein a frequency of the RF signal varies in response to the permeability of a bit region in the plurality of bit regions being proximate the spin torque oscillator.2. The apparatus of claim 1 , further comprising a spectrum analyzer connected to the spin transfer oscillator for measuring the frequency and/or amplitude of the RF signal.3. The apparatus of claim 2 , wherein the spectrum analyzer measures changes in the RF signal to indicate a permeability of the region.4. The apparatus of claim 1 , further comprising a superheterodyne receiver to determine a frequency shift in the RF signal indicating a permeability of the bit region.5. The apparatus of claim 1 , further comprising multilevel signaling of n-level bits based on permeability of the bit region.6. The apparatus of claim 1 , further comprising an external magnetic field source for generating a magnetic field proximate the STO.7. The apparatus of claim 6 , wherein the external magnetic field modifies a precession frequency of the spin torque oscillator.8. The apparatus of claim 1 , wherein the spin torque oscillator generates a magnetic field that can be modified by the media and the ...

METHOD AND SYSTEM FOR READING FROM OR WRITING TO MULTIPLE SURFACES OF A DISK

A system includes a management module transferring sectors between an interface or a memory and ports. The management module transfers a first portion of a first sector to or from a first port while transferring to or from a second port a second portion of the first sector or a first portion of a second sector. A first channel module reads from or writes to a first surface of a disk via a first head by transferring the first portion of the first sector to or from a first amplifier module. A second channel module, while the first channel module transfers the first portion of the first sector to or from the first amplifier module, reads from or writes to a second surface of the disk via a second head by transferring to or from a second amplifier module the second portion or the first portion of the second sector. 1. A system comprising:a management module configured to transfer a first sector of data and a second sector of data between (i) an interface or a memory and (ii) a plurality of ports, wherein the interface is connected to a host, wherein the plurality of ports comprise a first port and a second port, and wherein the management module is configured to transfer a first portion of the first sector of data to or from the first port while transferring to or from the second port either (i) a second portion of the first sector of data, or (ii) a first portion of the second sector of data;a first channel module configured to read from or write to a first surface of a disk via a first head by transferring the first portion of the first sector of data to or from a first amplifier module; anda second channel module configured to, while the first channel module transfers the first portion of the first sector of data to or from the first amplifier module, read from or write to a second surface of the disk via a second head by transferring to or from a second amplifier module either (i) the second portion of the first sector of data, or (ii) the first portion of the ...

PRE-AMPLIFIER OUTPUT STAGE WITH INTEGRATED TEST BUFFER

Disk drive pre-amplifier output stage circuitry is presented including a high pass input filter for removing DC offsets from differential read data signals and providing an input to AB drivers of the output stage, in which an offset test circuit selectively drives the high pass filter output nodes according to the offset at the filter input to facilitate measurement of the preceding circuit offset at the driver output terminals, and a common mode regulator circuit regulates common mode voltages at the first and second driver output nodes to a predetermined value in read and write modes. 1. A pre-amplifier output stage for a pre-amplifier of a disk drive system , the output stage comprising: a first capacitor connected between the first filter input and the first filter output node,', 'a first filter resistance connected between the first filter output node and a filter rail node,', 'a second capacitor connected between the second filter input and the second filter output node, and', 'a second filter resistance connected between the second filter output node and the filter rail node;, 'a high pass filter circuit with first and second filter inputs that receive a differential input from a pre-amplifier gain stage, the high pass filter circuit providing a differential filter output to first and second filter output nodes, the high pass filter circuit comprisinga driver circuit, comprising first and second driver inputs connected to the first and second filter output nodes and providing a differential driver output at first and second driver output nodes;a reference generator circuit providing a reference voltage; a transconductance amplifier with a first input connected to the reference voltage, a second input, and an output connected to the filter rail node,', 'a first feedback resistor connected between the second input of the transconductance amplifier and the first driver output node, and', 'a second feedback resistor connected between the second input of the ...

PARTIAL WRITE SYSTEM

A method and system can be implemented to perform a read-modify-write operation on data recorded in a shingled media format. In one embodiment, a write operation on a band of data stored on a magnetic recording medium is initiated at an intermediate position within the band of data. This is particularly well-suited for data written by a shingled media write operation. 1. A method comprising:initiating a write operation on a band of data stored on a magnetic recording medium at an intermediate position within the band of data.2. The method as claimed in wherein the write operation comprises:utilizing shingled write operations.3. The method as claimed in and further comprising:reading less than the entire band of data from the magnetic recording medium; and then writing over less than the entire band of data on the recording medium.4. The method as claimed in and further comprising:receiving new data for insertion in the band of data;receiving position indication information indicating a target location in the band of data the new data is to be positioned.5. The method as claimed in and further comprising:reading less than the entire band of data from the magnetic recording medium as read data;storing the read data in temporary memory;replacing a portion of the read data in temporary memory with new data so as to form revised data; andwherein the initiating the write operation on the band of data stored on the magnetic recording medium at the intermediate position within the band of data comprises:writing the revised data into the band of data.6. The method as claimed in and further comprising:receiving new data for insertion in the band of data;determining that the new data is to be inserted in the last sector of the band of data;writing the new data over the last sector of the band of data without storing the last sector of data in temporary memory.7. The method as claimed in and further comprising:reading less than the entire band of data from the magnetic ...

DATA MANAGEMENT FOR A DATA STORAGE DEVICE WITH ZONE RELOCATION

Managing data stored on media of a Data Storage Device (DSD) using zone relocation. At least a portion of the media is logically divided into a plurality of zones and zones are identified with access counts greater than or equal to a threshold. The access count for each of the identified zones indicates a number of times data in the zone has been read or written. Data is relocated from at least one zone of the identified zones to at least one destination zone on the media to reduce a data access time between the identified zones. 1. A Data Storage Device (DSD) , comprising:at least one media for storing data; and logically divide at least a portion of the media into a plurality of zones;', 'identify zones of the plurality of zones with access counts greater than or equal to a threshold, wherein the access count for each of the identified zones indicates a number of times data in the zone has been read or written; and', 'relocate data from at least one of the identified zones to at least one destination zone on the media to reduce a data access time between the identified zones., 'a controller configured to2. The DSD of claim 1 , wherein the access count is a random access count indicating a number of times data in the zone has been non-sequentially read or written.3. The DSD of claim 1 , wherein the access count is a sequential access count indicating a number of times data in the zone has been sequentially read or written.4. The DSD of claim 1 , wherein the controller is further configured to update a mapping indicating physical locations for data stored on the media by offsetting physical addresses in the mapping for the relocated data.5. The DSD of claim 1 , wherein the controller is further configured to:logically divide the media into a plurality of blocks with each block having a larger data capacity than individual zones of the plurality of zones;identify a block of the plurality of blocks with a high access count relative to other blocks, wherein the access ...

MAGNETIC RECORDING MEDIUM PROCESSING DEVICE AND METHOD OF GENERATING INTERFERENCE FIELD

A magnetic recording medium processing device may include a magnetic recording medium insertion slot; a medium pathway connected to the magnetic recording medium insertion slot; a magnetic head arranged to face the medium pathway; and an interference magnetic field generating device structured to generate interference magnetic fields outside the magnetic recording medium insertion slot. The interference magnetic field generating device may include a coil, a capacitor, a first power line, a second power line to which a voltage different from that to the first power line is applied, multiple switches structured to switch the connections between the first power line and the second power line of the coil and the capacitor, and a switch control unit structured to control the multiple switches. 1. A magnetic recording medium processing device , comprising:a magnetic recording medium insertion slot;a medium pathway connected to said magnetic recording medium insertion slot;a magnetic head arranged to face said medium pathway; andan interference magnetic field generating device structured to generate interference magnetic fields outside said magnetic recording medium insertion slot; a coil,', 'a capacitor,', 'a first power line,, 'wherein said interference magnetic field generating device comprisesa second power line to which a voltage different from that to said first power line is applied, multiple switches structured to switch the connections between said first power line and said second power line of said coil and said capacitor, anda switch control unit structured to control said multiple switches to first implement a first interference magnetic field generating mode for which said coil and said capacitor are electrically connected in series between said first power line and said second power line and then to implement a second interference magnetic field generating mode for which said coil is oscillated by the charge stored in said capacitor during said first ...

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. 110-. (canceled)11. A recording system , comprising:a first recording head and a second recording head;a medium comprising a data recording layer and a servo layer, wherein the data recording layer is arranged between the recording head and the servo layer;an external energy source;wherein the first recording head and the external energy source are configured to respectively provide a first magnetic field of a first magnetic field strength and external energy for writing on the data recording layer;wherein the second recording head is configured to provide a second magnetic field of a second magnetic field strength for writing on the servo layer;wherein the first magnetic field strength is weaker than the second magnetic field strength.12. The recording system of claim 11 ,wherein the external energy source comprises any one of a group consisting of laser, infrared heating, electrical Joule heating, and injection of hot air.13. The recording system of claim 11 ,wherein the second recording head has a larger dimension than the first recording head.14. The recording system of claim 11 ,wherein the second recording head is configured to write servo information on the servo layer using a shingled writing scheme.15. The recording system of claim 14 ,wherein the second recording head is configured to provide the second magnetic field of the second magnetic field strength for writing on the servo layer.16. The recording system of claim 11 ,wherein the second recording head is configured to write servo information on the servo layer using an energy assisted magnetic recording scheme.17. The recording system of claim 16 ,wherein the second recording head and the external energy source are configured to respectively provide the second magnetic field of the second magnetic field strength and the external energy for ...

SERIAL PORT COMMUNICATION FOR STORAGE DEVICE USING SINGLE BIDIRECTIONAL SERIAL DATA LINE

A method is provided to enable communication between a controller and a preamplifier in a storage device. For example, the method includes implementing a serial port which is configured to transmit digital signals between the controller and the preamplifier over a single bidirectional serial data line. The serial port is controlled to selectively transmit digital signals over the bidirectional serial data line in either a first direction from the controller to the preamplifier or a second direction from the preamplifier to the controller. 1. A method to provide communication between a controller and a preamplifier in a storage device , comprising:implementing a serial port that is configured to transmit digital signals between the controller and the preamplifier over a single bidirectional serial data line; andcontrolling the serial port to selectively transmit digital signals over the bidirectional serial data line in either a first direction from the controller to the preamplifier or a second direction from the preamplifier to the controller.2. The method of claim 1 , wherein controlling the serial port comprises:transmitting a serial bit stream over the bidirectional serial data line from the controller to the preamplifier;generating a clock signal in the preamplifier using a phase-locked loop circuit, wherein the clock signal is generated based on a bit rate of the serial bit stream received by the preamplifier; andusing the clock signal to receive and deserialize the serial bit stream received by the preamplifier.3. The method of claim 2 , wherein controlling the serial port further comprises:transmitting a direction switch control signal over the bidirectional serial data line to the preamplifier; and generating a control signal to suspend phase and frequency adjustments of the phase-locked loop circuit of the preamplifier and maintain a static clock signal output from the phase-locked loop circuit of the preamplifier;', 'assuming control of the bidirectional ...

MANAGING FAR AND NEAR TRACK ERASURE BY DYNAMIC CONTROL OF A WRITE CURRENT PARAMETER OF A MAGNETIC DISK DRIVE

A method may include causing a write head of a magnetic data storage drive to write a first portion of data to a magnetic data storage device of the magnetic data storage drive based at least in part on a first value of at least one parameter of a write current. The method may include updating a value of a write counter and determining whether the value of the write counter is greater than or equal to a threshold write count. The method may also include adjusting the at least one parameter of the write current to a second, different value. The method may further include causing the write head to write a second portion of data to the magnetic data storage device based at least in part on the second value of the at least one parameter of the write current. 1. A method comprising:causing, by a controller of a magnetic data storage drive, a write head of the magnetic data storage drive to write a first portion of data to a magnetic data storage device of the magnetic data storage drive based at least in part on a first value of at least one parameter of a write current;in response to writing the first portion, updating, by the controller, a value of a write counter;determining, by the controller, whether the value of the write counter is greater than or equal to a threshold write count;in response to determining that the value of the write counter is greater than or equal the threshold write count, adjusting, by the controller, the at least one parameter of the write current to a second, different value; andcausing, by the controller, the write head to write a second portion of data to the magnetic data storage device based at least in part on the second value of the at least one parameter of the write current.2. The method of claim 1 , wherein adjusting the at least one parameter of the write current to the second claim 1 , different value comprises adjusting claim 1 , by the controller claim 1 , a rise time from a first duration to a second claim 1 , different ...

DETERMINING BIT ASPECT RATIOS FOR PARTIALLY-OVERLAPPING MAGNETIC RECORDING TRACKS

A method involves determining bit aspect ratios for interlaced tracks written to a magnetic recording medium. The interlaced tracks include top tracks that are written partially overlapping with bottom tracks. Isolated test tracks are written at first different bit aspect ratios to determine a top bit aspect ratio that achieves a first target areal density for the isolated test tracks. Test tracks are written at second different bit aspect ratios to determine a bottom bit aspect ratio that achieves a second target areal density for the test tracks. Top test tracks of the test tracks are written at the top bit aspect ratio. The top and bottom bit aspect ratios are selected to subsequently write partially-overlapping tracks on the magnetic recording medium. 1. A method , comprising:writing isolated test tracks to determine a first areal density function for top tracks of a magnetic recording medium, the first areal density function based on write-plus-erase track widths obtained using different first laser powers and first linear bit densities that achieve a first target bit error rate for the isolated test tracks;{'sub': top', 'top, 'selecting a value LDIof the first laser powers and a value BPIof the first linear bit densities that result in a first target value of the areal density function;'}{'sub': top', 'top, 'writing partially-overlapping test tracks to determine a second areal density function of bottom tracks based on squeezed track widths written using different second laser powers and second linear bit densities that achieve a second target bit error rate for bottom test tracks of the partially-overlapping test tracks, top test tracks of the partially-overlapping test tracks being written at LDIand BPI; and'}{'sub': bottom', 'bottom', 'top', 'top', 'bottom', 'bottom, 'selecting a value LDIof the second laser powers and a value BPIof the second linear bit densities that result in a second target value of the second areal density function, the LDI, BPI, LDI, ...

Storage Media Inter-Track interference Cancellation

Described embodiments provide a method of cancelling inter-track interference (ITI) from one or more sectors read from a desired track of a storage medium. A read channel reads sectors in a desired track of the storage medium. A decoder of the read channel decodes the read sectors, and if the read sectors are incorrectly recovered from the storage medium, selected sectors of a first adjacent track and a second adjacent track are read. An ITI canceller of the read channel estimates ITI in the read sectors of the desired track corresponding to the selected sectors of each adjacent track and subtracts the estimated ITI of each adjacent track from the data for the sectors of the desired track, providing updated sector data. The ITI cancelled data is replayed to the decoder, Which decodes the ITT cancelled data and provides the decoded ITI cancelled data as output of the read channel. 1. A storage media controller for cancelling inter-track interference (ITI) in one or more sectors read from a desired track of a storage medium , the media controller comprising:a read channel configured to read one or more sectors in a desired track of the storage medium;an iterative decoder circuit operable to apply a data decoding algorithm to one or more read sectors derived from a desired track of the storage medium to yield a decoded output; the read channel is configured to read selected sectors of a first adjacent track and a second adjacent track;', 'an ITI canceller of the read channel configured to (i) estimate ITI in the one or more read sectors of the desired track corresponding to the selected sectors of the first adjacent track and the second adjacent track, (ii) subtract the estimated ITI of the first adjacent track and the second adjacent track from the data for the one or more sectors of the desired track to provide updated sector data, and (iii) replay the ITI cancelled data to the iterative decoder;', 'the iterative decoder circuit is configured to (i) decode the ITI ...

DYNAMIC GAIN CONTROL FOR USE WITH ADAPTIVE EQUALIZERS

According to one embodiment, a system for processing data includes a controller configured to: receive data read from a magnetic storage medium, apply a finite impulse response (FIR) filter to the data to obtain equalized data, and direct the equalized data through either a first FIR gain module or a second FIR gain module to control FIR gain of the equalized data, wherein the first FIR gain module is utilized when reading data in an asynchronous mode, and wherein the second FIR gain module is utilized when reading data in a synchronous mode and a FIR gain value of the second FIR gain module is automatically controlled. Other systems and methods for processing data using dynamic gain control with adaptive equalizers are presented according to more embodiments. 1. A system for processing data , the system comprising a controller configured to:receive data read from a magnetic storage medium;apply a finite impulse response (FIR) filter to the data to obtain equalized data; anddirect the equalized data through either a first FIR gain module or a second FIR gain module to control FIR gain of the equalized data,wherein the first FIR gain module is utilized when reading data in an asynchronous mode, andwherein the second FIR gain module is utilized when reading data in a synchronous mode and a FIR gain value of the second FIR gain module is automatically controlled.2. The system as recited in claim 1 , wherein the controller is further configured to automatically control the FIR gain value in the second FIR gain module using an automated FIR gain control module based on a FIR output from the equalizer and variations in an amplitude of a waveform of the data.3. The system as recited in claim 2 , wherein the automated FIR gain control module comprises logic configured to:receive the FIR output from the equalizer;select at least one error source from a plurality of error sources available to the automated FIR gain control module;calculate the FIR gain value based on error ...

METHOD AND APPARATUS FOR JOINT ADAPTATION OF TWO-/MULTI- DIMENSIONAL EQUALIZER AND PARTIAL RESPONSE TARGET

The present disclosure relates to a method and apparatus for processing of multi-dimensional readback signal from magnetic recording or optical, physical data recording so as to reduce/control Inter Symbol Interference (ISI) and noise within acceptable limits. The method is based on Partial Response Maximum Likelihood (PRML) detection and takes care of time varying channel conditions. In an embodiment, the filter coefficients of both the equalizer and the partial response (PR) target are jointly adapted to account for the channel condition for both separable and non-separable targets thus reducing signal detection complexity. In an aspect, the disclosure provides an apparatus that incorporates an adaptation engine along with the equalizer and the PR target that updates filter coefficients of both the equalizer and the PR target following the formulated mathematical equations. 1. A method for processing of multi-dimensional readback signal to reduce Inter Symbol Interference (ISI) and noise , said method comprising the step of:equalizing the readback signal using a linear equalizer that adapts to varying channel conditions; anddesigning a Partial Response (PR) target for signal detection based on Partial Response Maximum Likelihood (PRML) and the equalizer output, wherein the equalizer and the PR target are jointly adapted.2. The method of claim 1 , wherein the step of equalizing enables handling of channel conditions accounting for one or more time varying factors selected from any or a combination of wear and tear claim 1 , media and temperature variations.3. The method of claim 1 , wherein one or more filter coefficients for the linear equalizer and the PR target are jointly adapted to account for channel condition to help mitigate effects of SNR variations along with ISI reduction/control.4. The method of claim 3 , wherein output of the equalizer is compared with target response to obtain an error that is used to update the one or more filter coefficients.5. The ...

Device and Method for Decoding Magnetic Patterns

A device for decoding magnetic patterns printed on documents comprising a reading head ( 12 ) having: a reader ( 20 ) arranged to read first magnetic signals belonging to the magnetic patterns and to electromagnetic noise due to sources internal and/or external to the device. The device further comprises: a further reader ( 40 ), arranged to read second magnetic signals belonging to the electromagnetic noise, an adder component ( 25 ) arranged to algebraically subtract the amplified second magnetic signals from the amplified first magnetic signals, and a converter ( 16 ) arranged to convert the resulting signal into a digital signal representing the read magnetic patterns. A method for decoding magnetic patterns is also disclosed.

Phase error recovery circuitry and method for a magnetic recording device

A recording head is configured to write and read data sectors to and from a recording medium, such as a heat-assisted recording medium. A read channel is coupled to the recording head. Phase-locked loop (PLL) circuitry of the read channel is configured to detect a change in a phase error at a location of the data sector. The phase error change may be indicative of a mode-hop that occurred while writing the data sector to the medium. The PLL circuitry is configured to determine a phase offset using the phase error. A controller is configured to effect re-reading of the data sector location using the phase offset to recover the data sector location.

Dual Pass Perpendicular Magnetic Recording

Dual Pass Perpendicular Magnetic Recording is an invention to increase the storage capacity of disk drives and provides faster data transfer when reading data from a disk drive operating in this mode. By using two passes of the recording head to write a data track, more magnetic states are created than in conventional or shingled magnetic recording. This allows a higher storage capacity to be achieved.

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 ...

DETECTION OF OPEN WRITE HEADS AND/OR CABLES IN TAPE DRIVES

A computer-implemented method, according to one embodiment, includes: receiving a first output signal from a write driver, the write driver having an operating voltage applied thereto, receiving a second output signal from a comparator circuit, the comparator circuit having a reference voltage applied thereto, comparing a voltage of the first output signal with a voltage of the second output signal, and detecting a high resistance condition in response to determining that the voltage of the first output signal is less than the voltage of the second output signal. According to the present embodiment, the high resistance condition indicates open and/or partially open circuitry in the write driver. Moreover, the operating voltage is equal to the reference voltage. Other systems, methods, and computer program products are described in additional embodiments. 1. A computer-implemented method , comprising:receiving a first output signal from a write driver, the write driver having an operating voltage applied thereto;receiving a second output signal from a comparator circuit, the comparator circuit having a reference voltage applied thereto;comparing a voltage of the first output signal with a voltage of the second output signal; anddetecting a high resistance condition in response to determining that the voltage of the first output signal is less than the voltage of the second output signal,wherein the high resistance condition indicates open and/or partially open circuitry in the write driver,wherein the operating voltage is equal to the reference voltage.2. The method as recited in claim 1 , wherein the write driver and the comparator circuit are formed on a common chip.3. The method as recited in claim 1 , wherein the comparing of the first and second output voltages is not performed while a magnetic tape is adjacent a write head coupled to the write driver.4. The method as recited in claim 1 , wherein the comparing is performed by a comparator circuit configured to ...

READING NARROW DATA TRACKS WITH MULTIPLE WIDE READERS

Technologies are described herein for utilizing multiple, wide readers to read narrow data tracks on a magnetic recording media in a storage device. A system for reading a data track on a magnetic recording media comprises a plurality of reader elements, the width of each reader element being an integer greater than 1 multiple of a width of the data tracks on the recording media. The system further comprises a multi-reader decoder module operably connected to the plurality of reader elements. Each of the reader elements is configured to read a magnetic signal from the magnetic recording media. The multi-reader decoder module is configured to receive a read signal from each of the reader elements, and decode the data on the data track based on the read signals from the reader elements. 1. A system for reading a data track on magnetic recording media , the system comprising:{'b': '1', 'a read/write head comprising a plurality of reader elements configured to read a magnetic signal from the magnetic recording media, a width of each of the plurality of reader elements being an integer greater than multiple of a width of the data track on the recording media; and'}a multi-reader decoder module operably connected to the read/write head and configured toreceive a read signal from each of the plurality of reader elements, anddecode the data on the data track based on the read signals from the plurality of reader elements.2. The system of claim 1 , wherein the read signals indicate a summation of data on the data track and one or more adjacent tracks.3. The system of claim 1 , wherein each of the plurality of reader elements has a different alignment over the data track.4. The system of claim 1 , wherein the multi-reader decoder module comprises:a plurality of multi-level detectors, each of the multi-level detectors configured to detect multiple levels in the read signals and generate an associated multi-level value; anda mapper configured to convert the multi-level values ...

Method and apparatus for speed control of voice coil motor retract operation dependent upon available power

The back EMF (B EMF ) of a motor is sensed and compared to a target back EMF (B EMF ) to generate an error control signal. The circuit supply voltage is also sensed. A PWM motor control signal is generated in response to a comparison of the error control signal to a ramp signal having a variable slope. The variable slope is selected in response to the sensed circuit supply voltage. The motor is then driven in response to the PWM control signal. The sign of the error control signal is used to selectively short one of motor terminals to a reference voltage supply node while the other motor terminal is driven in response to the PWM control signal.

METHOD AND SYSTEM FOR PREVENTING UNRELIABLE DATA OPERATIONS AT COLD TEMPERATURES

Systems and methods for reducing problems and disadvantages associated with protecting data during cold excursions are provided. A method for preventing unreliable data operations at cold temperatures may include determining whether a first internal temperature of a hard disk drive (HDD) is below a threshold temperature. The method may also include initiating an artificial seek operation if the first internal temperature is below the threshold temperature. 1. A method for preventing unreliable data operations at cold temperatures comprising:determining whether a first internal temperature of a hard disk drive (HDD) is below a threshold temperature; andinitiating an artificial seek operation if the first internal temperature is below the threshold temperature.2. The method of claim 1 , further comprising sampling a second internal temperature of the HDD following a pre-defined time interval.3. The method of claim 2 , further comprising pausing a read/write operation if the second internal temperature of the HDD is below the threshold temperature.4. The method of claim 3 , further comprising proceeding with the read/write operation if the second internal temperature of the HDD is above the threshold temperature.5. The method of claim 1 , further comprising spinning the HDD up to a target revolutions per minute (RPM).6. The method of claim 1 , wherein the artificial seek operation comprises one of a random seek claim 1 , a butterfly seek claim 1 , a ⅓ stroke seek claim 1 , and a sequential seek.7. The method of claim 1 , wherein the threshold temperature is provided by a user.8. The method of claim 2 , wherein the pre-defined time interval is substantially based on an event.9. The method of claim 2 , wherein the pre-defined time interval is provided by a user.10. A hard disk drive (HDD) comprising:a temperature sensor configured to transmit a signal corresponding to a first internal temperature; anda component configured to perform an artificial seek operation if the ...

Encoding, distribution and reproduction of audio media using mechanical image digitization

The system and corresponding process includes a system for producing a mechanical image of original audio source media and a system for encoding the mechanical image information into a digital file. A processing system recovers the mechanical image information from the digital file at a receiving end. Audio processing is used to produce the original audio source material without the standard losses associated with digital encoding of audio material

RAID Storage System with Logical Data Group Priority

Example redundant array of independent disks (RAID) storage systems and methods provide rebuild of logical data groups in priority order. Storage devices are configured as a storage array for storing logical data groups distributed among the storage devices. The logical data groups are written in a configuration of RAID stripes in the storage devices. A logical group index includes a logical group map for each logical data group and identifies corresponding logical blocks. When a storage device fails, the rebuild queue is ordered based on the priority of the logical data groups and rebuild to the replacement storage device is completed in the priority order. 1. A storage system , comprising:a plurality of storage devices configured as a storage array for storing a plurality of logical data groups distributed among the plurality of storage devices; a rebuild module configured to rebuild a failed storage device from the plurality of storage devices based on the configuration of RAID stripes; and', 'a rebuild queue defining a rebuild order for the logical blocks of the failed storage device;, 'a redundant array of independent disks (RAID) controller configured to write the plurality of logical data groups in a configuration of RAID stripes across at least one RAID group in the plurality of storage devices, the RAID controller comprisinga logical group index comprising a logical group map for each of the plurality of logical data groups, wherein the logical group map identifies logical blocks corresponding to each of the plurality of logical data groups; anda logical group accelerator module configured to order the rebuild queue based on the plurality of logical data groups, wherein a first priority set of logical blocks corresponding to at least one of the plurality of logical data groups are ordered ahead of logical blocks not in the first priority set in the rebuild queue;wherein, the rebuild module is further configured to rebuild the first priority set before ...

MAGNETIC HEAD AND MAGNETIC RECORDING DEVICE

According to one embodiment, a magnetic head includes first and second magnetic poles, and a stacked body provided between the first and second magnetic poles. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic pole and the first magnetic layer, a third magnetic layer provided between the first magnetic pole and the second magnetic layer, a first nonmagnetic layer provided between the second and first magnetic layers, a second nonmagnetic layer provided between the third and second magnetic layers, and a third nonmagnetic layer provided between the first magnetic pole and the third magnetic layer. The second magnetic layer includes first and second magnetic regions. The second magnetic region is between the second nonmagnetic layer and the first magnetic region. The first magnetic region includes a first element. The second magnetic region includes the first element, and a second element.

METHOD AND SYSTEM FOR ESTIMATING THE POSITION ERROR SIGNAL (PES) METRIC FOR A MAGNETIC STORAGE SYSTEM

A method and system for estimating the position error signal (PES) metric for a magnetic storage system. The method comprises the steps of reading multiple readback tracks from a storage medium of the magnetic storage system using respective readers of a multiple reader head positioned at or near a data track of interest; employing an adaptive SMR equalizer to equalize the signals from the multiple read head; and extracting information from the adaptive SMR equalizer sub-filters as an estimate of the PES metric. 1. A method of estimating the position error signal (PES) metric for a magnetic storage system , the method comprising the steps of:reading multiple readback tracks from a storage medium of the magnetic storage system using respective readers of a multiple reader head positioned at or near a data track of interest;employing an adaptive SMR equalizer to equalize the signals from the multiple read head; andextracting information from the adaptive SMR equalizer sub-filters as an estimate of the PES metric.2. The method as claimed in claim 1 , wherein extracting the information comprises calculating energies of the respective equalizer sub-filters.3. The method as claimed in claim 2 , further comprising calculating differences in the energies of the respective equalizer sub-filters.4. The method as claimed in claim 3 , further comprising normalizing the calculated differences in the energies of the respective equalizer sub-filters.5. The method as claimed in claim 4 , wherein the normalizing comprises dividing the calculated differences in the energies of the respective equalizer sub-filters by the sum of the energies.6. The method as claimed in claim 1 , wherein the adaptive SMR equalizer is based on any of a group of adaptive filtering algorithms including claim 1 , but not limited to the least mean square algorithm (LMS) claim 1 , the variable step-size least mean square (VSLMS) algorithm claim 1 , the frequency based LMS algorithm claim 1 , and the ...

MAGNETIC DISK DEVICE AND RECORDING HEAD CONTROL METHOD

According to one embodiment, a magnetic disk device conforming to perpendicular magnetic recording includes a magnetic disk, a recording head, and a controller. The head includes a main magnetic pole, a return magnetic pole, a recording coil, and a conductive member in which end surfaces are connected to opposed surfaces of a write gap which is opposed to a distal portion of the main magnetic pole and a distal portion of the return magnetic pole, and a resistance value varies. The controller applies a current to the recording coil to excite the magnetic flux in the recording operation, and applies a current at a constant voltage to the magnetic circuit via the comductive member. 1. A magnetic disk device comprising:a magnetic disk having a recording layer conforming to perpendicular magnetic recording;a recording head which generates a perpendicular recording magnetic field to be applied to the recording layer; anda controller which controls a recording operation and a non-recording operation of the recording head, whereinthe recording head includes:a main magnetic pole which generates the perpendicular recording magnetic field;a return magnetic pole which returns a magnetic flux from the main magnetic pole and forms a magnetic circuit in cooperation with the main magnetic pole;a recording coil which excites the magnetic flux in the magnetic circuit formed of the main magnetic pole and the return magnetic pole; anda conductive member in which end surfaces are connected to opposed surfaces of a write gap which is opposed to a distal portion of the main magnetic pole and a distal portion of the return magnetic pole, and a resistance value varies between the recording operation and the non-recording operation, andthe controller includes:a constant voltage supply source which applies a current at a constant voltage to the magnetic circuit formed in the main magnetic pole and the return magnetic pole via the conductive member; anda current supply source which applies a ...

Systems and Methods for Multi-Level Encoding and Decoding

A storage system includes a storage medium operable to maintain a data set, a read/write head assembly operable to write the data set to the storage medium and to read the data set from the storage medium, a multi-level encoder operable to encode the data set at a plurality of different code rates before it is written to the storage medium, and a multi-level decoder operable to decode the data set retrieved from the storage medium and to apply decoded values encoded at a lower code rate when decoding values encoded at a higher code rate. 1. A storage system comprising:a storage medium operable to maintain a data set;a read/write head assembly operable to write the data set to the storage medium and to read the data set from the storage medium;a multi-level encoder operable to encode the data set at a plurality of different code rates before it is written to the storage medium; anda multi-level decoder operable to decode the data set retrieved from the storage medium and to apply decoded values encoded at a lower code rate when decoding values encoded at a higher code rate, wherein the multi-level encoder is operable to encode the data set at a plurality of different code rates such that symbols encoded at different code rates in the data set are interleaved on the storage medium.2. (canceled)3. The storage system of claim 1 , wherein each symbol in the data set maintained on the storage medium is recorded adjacent at least one other symbol in the data set encoded at a different one of the plurality of code rates.4. The storage system of claim 1 , wherein applying decoded values encoded at a lower code rate when decoding values encoded at a higher code rate reduces inter-track interference.5. The storage system of claim 1 , wherein the multi-level encoder comprises a serial to parallel converter operable to divide the data set into a plurality of data segments to be encoded at the different code rates.6. The storage system of claim 1 , wherein the multi-level encoder ...

Adaptive Pattern Detection for Pattern-Dependent Write Current Control in a Magnetic Recording System

The disclosure is directed to a system and method of a system and method for determining fundamental bit cell duration of a data record, which can be used for pattern-dependent write (PDW) current control. According to various embodiments of the disclosure, at least a first portion of a data record is fed through a plurality of delay units. A binary output of each delay unit is stored in at least one register when the delay units have received the first portion of the data record. The register contents are then decoded to determine fundamental bit cell duration of the data record based upon the stored binary outputs. 1. A system for determining fundamental bit cell duration of a data record , comprising:a plurality of delay units configured to receive at least a first portion of a data record;at least one register configured to store a binary output of each delay unit of the plurality of delay units when the plurality of delay units have received the first portion of the data record; anda decoder configured to determine a fundamental bit cell duration based upon the stored binary outputs of the plurality of delay units.2. The system of claim 1 , wherein the first portion of the data record includes at least a portion of a preamble of the data record.3. The system of claim 2 , wherein the preamble of the data record includes bit cells with uniform durations.4. The system of claim 1 , wherein the first portion of the data record includes a bit cell with a duration that is a multiple of the fundamental bit cell duration.5. The system of claim 4 , wherein the fundamental bit cell duration is half of the duration of the bit cell of the first portion of the data record.6. The system of claim 1 , wherein each delay unit of the plurality of delay units is configured to provide a delay of approximately t claim 1 , where t is a substantially fixed duration.7. The system of claim 6 , wherein the decoder is configured to determine the fundamental bit duration as a function of t ...

DATA MIGRATION FOR DATA STORAGE DEVICE

Migration of data in a data storage device (DSD). A spindle motor of the DSD is controlled to rotate a disk of the DSD to perform at least one operation on the disk and an operational activity level is determined for performing the at least one operation. It is determined whether the operational activity level is greater than a target level, and if it is determined that the operational activity level is not greater than the target level, data is transferred between a solid state memory of the DSD and the disk while the disk rotates. 1. A data storage device (DSD) , comprising:a disk for storing data;a spindle motor for rotating the disk;a solid state memory for storing data; and control the spindle motor to rotate the disk to perform at least one operation on the disk;', 'determine an operational activity level for performing the at least one operation;', 'determine whether the operational activity level is greater than a target level; and', 'if it is determined that the operational activity level is not greater than the target level, transfer data between the solid state memory and the disk while the disk rotates., 'a controller configured to2. The DSD of claim 1 , wherein the operational activity level represents a number of commands queued for performance on the disk.3. The DSD of claim 1 , wherein the controller is further configured to set the target level based on a performance limit for performing operations on the disk.4. The DSD of claim 1 , wherein the data transferred between the solid state memory and the disk includes dirty data transferred from the solid state memory to the disk claim 1 , the dirty data including data that is most recently written for a logical address and that can be used to update the disk by writing the dirty data to the disk for the logical address.5. The DSD of claim 1 , wherein the data transferred between the solid state memory and the disk includes at least one of frequently accessed data and high priority data transferred from ...

High Frequency Data Writer Field Generator Device

A data writing device may be constructed and operated with at least a data writer that has at least a write pole and a magnetic feature. A controller may selectively activate the magnetic feature to magnetically oscillate and produce a radio frequency signal proximal the write pole on an air bearing surface (ABS). 1. An apparatus comprising a data writer comprising a write pole separated from a magnetic feature by a magnetic shield on an air bearing surface (ABS) , a controller configured to heat and cool the magnetic feature to magnetically oscillate the magnetic shield to produce a radio frequency signal proximal the write pole on the ABS.2. The apparatus of claim 1 , wherein the magnetic feature comprises a conductive wire.3. The apparatus of claim 12 , wherein the second magnetic feature comprises a shunt.4. The apparatus of claim 3 , wherein the shunt comprises a ferromagnetic material doped with a non-magnetic metal.5. The apparatus of claim 3 , wherein the shunt comprises gadolinium.6. The apparatus of claim 1 , wherein the magnetic feature is positioned proximal a leading edge of the write pole on the ABS.7. The apparatus of claim 1 , wherein the magnetic shield is disposed between the magnetic feature and the ABS.8. The apparatus of claim 7 , wherein the magnetic feature is physically separated from the magnetic shield.9. The apparatus of claim 1 , wherein the magnetic feature is positioned proximal a trailing side of the write pole.10. The apparatus of claim 1 , wherein the radio frequency is a microwave frequency.11. The apparatus of claim 1 , wherein the magnetic shield comprises a material having a 2.4 T magnetic saturation.12. An apparatus comprising a data writer comprising a write pole claim 1 , first magnetic feature claim 1 , and second magnetic feature claim 1 , the first magnetic feature separated from the write pole by a first magnetic shield on an air bearing surface (ABS) claim 1 , the second magnetic feature separated from the write pole and ...

DETERMINING OSCILLATION CHARACTERISTIC FOR HIGH-FREQUENCY ASSISTED MAGNETIC RECORDING DEVICE

A magnetic disk device according to an embodiment includes a magnetic head including a write head with a high-frequency oscillator and a read head, a recording medium, a driving unit configured to moves the magnetic head on the recording medium, a measuring unit configured to obtain a first read signal with no current or a smaller current and a second read signal with a normal current supplied in the normal writing operation, a comparison unit configured to calculate comparative data indicating a comparison result between the first and second read signals, and a determination unit configured to determine an oscillation characteristic from the comparative data. 1. A magnetic disk device comprising:a magnetic head including a write head with a high-frequency oscillator and a read head;a recording medium to and from which data is written and read by the magnetic head;a driving unit configured to move the magnetic head on the recording medium;a measuring unit configured to obtain a first read signal and a second read signal, the first read signal being obtained by reading a first data pattern written when no current is supplied to the high-frequency oscillator or a smaller current than in a writing operation to the recording medium is supplied to the high-frequency oscillator, the second read signal being obtained by reading a second data pattern written when a current supplied in the normal writing operation to the recording medium is supplied to the high-frequency oscillator;a comparison unit configured to calculate comparative data indicative of a comparison result between the first and second read signals; anda determination unit configured to determine an oscillation characteristic of the high-frequency oscillator from the comparative data.2. The magnetic disk device of claim 1 , further comprising:a heater provided in the magnetic head, and to generate heat for changing floating amount of the magnetic head when a current is supplied thereto,wherein the measuring ...

APPARATUS WITH FIRST AND SECOND CLOSE POINTS ON MEDIA-FACING SURFACE OF MAGNETIC HEAD

A magnetic head includes a read transducer and a write transducer at a media-facing surface of the magnetic head. The magnetic head includes at least one heater that causes heat deformation at the media-facing surface in response to different first and second energizing currents. The first energizing current results in a first close point between the media-facing surface and a recording medium. The second energizing current results in a second close point between the media-facing surface and the recording medium. The second close point is at a different location in the media-facing surface than the first close point. 1. A method comprising:applying a first energizing current to a heater of a magnetic head responsive to entering a first operational mode of the magnetic head, the first energizing current resulting in a first close point between a media-facing surface of the magnetic head and a recording medium, the first close point proximate to a read transducer of the magnetic head; andapplying a different, second energizing current to the heater responsive to entering a second operational mode of the magnetic head, the second energizing current resulting in a second close point between the media-facing surface and the recording medium, the second close point proximate to a contact pad disposed at the media-facing surface between the read transducer and a write transducer of the magnetic head.2. The method of claim 1 , wherein the first and second operational modes comprise respective read and write modes during which the respective read and write transducers of the magnetic head are used for reading and writing to the recording medium.3. The method of claim 2 , further comprising energizing the write transducer during the write mode claim 2 , wherein the energized write transducer contributes to the heat deformation at the media-facing surface and influences the respective first and second close points.4. The method of claim 3 , further comprising energizing a ...

METHODS FOR READING DATA FROM A STORAGE MEDIUM USING A READER AND STORAGE DEVICES

According to various embodiments, a method for reading data from a storage medium using a reader may be provided. The method may include: reading a first signal with a reader head of the reader at a first position of the storage medium; reading a second signal with a reader head of the reader at a second position of the storage medium; and determining data stored at a pre-determined position of the storage medium based on the first signal and based on the second signal. 1. A method for reading data from a storage medium using a reader , the method comprising:reading a first signal with a reader head of the reader at a first position of the storage medium;reading a second signal with a reader head of the reader at a second position of the storage medium; anddetermining data stored at a pre-determined position of the storage medium based on the first signal and based on the second signal.2. The method of claim 1 ,wherein the storage medium comprises a plurality of tracks, each track having a width smaller than a width of a reader head of the reader.3. The method of claim 1 ,wherein for at least one of the first position or the second position a reader head of the reader covers a first track and a second track.4. The method of claim 3 ,wherein the pre-determined position comprises one of a pre-determined position on the first track or a pre-determined position on the second track.5. The method of claim 3 ,wherein the first track and the second track are adjacent.6. The method of claim 1 , further comprising:reading a plurality of signals, wherein for each signal a reader head of the reader is at a different position of the storage medium; anddetermining data stored at the pre-determined position of the storage medium based on the plurality of signals.7. The method of claim 1 , further comprising:reading a frequency burst signal with a reader head of the reader at a position of the storage medium comprising a frequency burst provided before a data drack on the storage ...

PREAMPLIFIER OUTPUT CURRENT CONTROL

One embodiment includes a preamplifier system. The system includes a reference stage configured to set a magnitude of a clamping voltage for a reference node based on a reference current generated in an adjustable reference current path. The system also includes an output stage comprising an adjustable slew current source that is configured to provide an activation current to the reference node in response to at least one activation signal, the output stage to generate an output current at an output of the output stage with a magnitude that is based on the clamping voltage. 1. A preamplifier system comprising:a reference stage configured to set a magnitude of a clamping voltage for a reference node based on a reference current generated in an adjustable reference current path; andan output stage comprising an adjustable slew current source that is configured to provide an activation current to the reference node in response to at least one activation signal, the output stage to generate an output current at an output of the output stage with a magnitude that is based on the clamping voltage.2. The system of claim 1 , wherein the adjustable slew current source is configured to provide the activation current to the reference node to provide the output current with a slew-rate that is based on a magnitude of the activation current.3. The system of claim 2 , wherein the adjustable slew current source is a first adjustable slew current source claim 2 , wherein the output stage comprises a second adjustable slew current source that is configured to generate a deactivation current that is provided from the reference node to provide the output current with a deactivation slew-rate that is based on a magnitude of the deactivation current.4. The system of claim 1 , wherein the adjustable slew current source comprises:a first adjustable slew current source that is activated in response to a first activation signal to provide the activation current to the reference node to ...

SWITCHING PERIOD CONTROL OF MICROWAVE ASSISTED MAGNETIC RECORDING FOR POLE ERASURE SUPPRESSION

A magnetic recording system for preventing data loss resulting magnetic oscillator current. The magnetic recording system includes a magnetic write head with a magnetic write pole, a magnetic oscillator near the magnetic write pole, and a write coil for magnetizing the write pole. Circuitry is connected with the magnetic write coil to supply a current to the write coil and connected with the magnetic oscillator to supply a current to the magnetic oscillator. The circuitry is configured to ensure that the current to the magnetic oscillator does not inadvertently magnetize the write pole after the magnetic write pole has demagnetized. 1. A magnetic recording system , comprising:a magnetic write pole;a magnetic oscillator adjacent to the magnetic write pole, wherein the magnetic oscillator is configured to generate an oscillating magnetic field; andcircuitry connected to the magnetic oscillator to induce a direct current through the magnetic oscillator during operation of the magnetic oscillator and an alternating current through the magnetic oscillator for a predetermined period upon deactivation of the magnetic oscillator.2. The magnetic recording system of claim 1 , wherein the circuitry comprises:a first transistor and second transistor connected to a first input; anda third transistor and fourth transistor connected to a second input;wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are selectively activated and deactivated by a control signal to output either the direct current or the alternating current.3. The magnetic recording system of claim 2 , wherein the control signal comprises a first control signal connected to the first transistor and the fourth transistor and a second control signal connected to the second transistor and the third transistor.4. The magnetic recording system of claim 3 , wherein the first control signal is connected to a base terminal of the first transistor and a base terminal of the ...

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 ...

MAGNETIC DISK DEVICE

According to one embodiment, a magnetic disk device includes a magnetic disk, a write head which includes an assist unit configured to assist in writing data to the magnetic disk, a read head configured to read data from the magnetic disk, and a control unit configured to control writing data to the magnetic disk by the write head and reading data from the magnetic disk by the read head. The magnetic disk includes a first region in which reading/writing data is performed by a first processing method and a second region in which reading/writing data is performed by a second processing method different from the first processing method. The control unit is operable to change assist power of the assist unit between the first region and the second region when writing data to the magnetic disk by the write head. 1. A magnetic disk device comprising:a magnetic disk;a write head which includes an assist unit configured to assist in writing data to the magnetic disk;a read head configured to read data from the magnetic disk; anda control unit configured to control writing data to the magnetic disk by the write head and reading data from the magnetic disk by the read head;wherein the magnetic disk includes a first region in which reading/writing data is performed by a first method and a second region in which reading/writing data is performed by a second method different from the first method, andthe control unit is operable to change assist power of the assist unit between the first region and the second region when writing data to the magnetic disk by the write head.2. The magnetic disk device according to claim 1 , whereinthe assist unit includes a high-frequency element, andthe control unit is operable to change the assist power by applying different bias voltages to the high-frequency element, in the first region and the second region.3. The magnetic disk device according to claim 2 , whereinthe magnetic disk device has a plurality of pairs of the write head and the read ...

DISK DEVICE

According to one embodiment, a disk device includes a recording medium, a first magnetic head, a first wiring member, a flexible printed circuit board, and a wire. The first wiring member is electrically connected to the first magnetic head. The flexible printed circuit board includes a surface, a first fixed part fixed to a first component, and a second fixed part fixed to a second component, and is electrically connected to the first magnetic head through the first wiring member. The wire on the flexible printed circuit board extends along the surface such that the wire extends between the first fixed part and the second fixed part in a direction intersecting at an angle of lager than 45 degrees and not larger than 90 degrees with an extending direction of a virtual shortest line that connects the first fixed part to the second fixed part along the surface. 1. A disk device comprising:a recording medium of a disk form including a recording layer;a first magnetic head configured to read and write information from and to the recording medium;a first wiring member electrically connected to the first magnetic head;a flexible printed circuit board comprising a surface, a first fixed part fixed to a first component, and a second fixed part fixed to a second component, the flexible printed circuit board electrically connected to the first magnetic head through the first wiring member; anda wire installed on the flexible printed circuit board, extending along the surface, the wire extending between the first fixed part and the second fixed part in a direction intersecting at an angle of lager than 45 degrees and not larger than 90 degrees with an extending direction of a virtual line that connects a shortest distance between the first fixed part and the second fixed part along the surface.2. The disk device according claim 1 , whereinthe first component comprises a rotary actuator configured to rotate to move the first magnetic head, and a preamplifier mounted on the ...

SELECTABLE READ MODES FOR A TWO DIMENSIONAL MAGNETIC RECORDING SYSTEM

Two or more read modes of a data storage system and device are defined. The data storage device is capable of concurrently reading from two or more tracks using two or more read transducers. The read modes utilize different numbers of the two or more read transducers while reading data. The tread modes are selected based on an operating condition of the data storage system or device. 1. A system comprising:a plurality of data storage devices each comprising two or more transducers capable of concurrently reading from tracks of a recording medium in a two-dimensional magnetic recording configuration; anda system controller coupled to the data storage devices and configured to define two or more read modes affecting at least a subset of the data storage devices, the read modes utilizing different numbers of the two or more read transducers while reading data, and configured to select from the read modes based on an operating condition of the system.2. The system of claim 1 , wherein the system controller selects from the read modes via a command descriptor block of a host interface protocol used for communicating with the data storage devices.3. The system of claim 1 , wherein the operating condition comprises a target power consumption of the system or a target operating temperature of the system.4. The system of claim 1 , wherein the operating condition comprises a RAID rebuild or drive replication of the system such that maximum performance is desired and the read mode with a greater number of activated read transducers is utilized.5. The system of ; wherein a first of the read modes comprises using one of the transducers claim 1 , and a second of the read modes comprises using at least two of the transducers.6. The system of claim 5 , wherein the first mode utilizes one-dimensional detection claim 5 , and the second mode utilizes two-dimensional detection.7. The system of claim 5 , wherein the tracks comprise shingled tracks claim 5 , and the second mode comprises ...

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 ...

DISK APPARATUS AND HEAD APPARATUS

A disk apparatus includes a disk, a head, a circuit board, and an abnormality detection circuit. The head includes a plurality of loads, including at least a first load and a second load, associated with writing or reading of data to or from the disk, and a plurality of head terminals corresponding to and connected to the plurality of loads, respectively. The circuit board includes board terminals corresponding to and connected to the plurality of head terminals, respectively, and a preamplifier that applies a voltage to the loads via the plurality of board terminals during writing or reading of the data to or from the disk. The abnormality detection circuit detects a short-circuit between a first board terminal, which is the board terminal connected to the head terminal of the first load, and a second board terminal, which is the board terminal connected to the head terminal of the second load. 1. A disk apparatus comprising:a disk;a magnetic head including a plurality of loads, including at least a first load and a second load, and a plurality of head terminals corresponding to and connected to the plurality of loads, respectively;a circuit board including a plurality of board terminals corresponding to and connected to the plurality of head terminals, respectively, and a preamplifier configured to apply a voltage to the loads via the plurality of board terminals, the plurality of board terminals including a first board terminal and a second board terminal that are connected to the first load via at least part of the head terminals, and a third board terminal that is connected to the second load via at least part of the head terminals and not connected to the first load;a first abnormality detection circuit configured to detect a short-circuit between the first board terminal and the second board terminal; anda second abnormality detection circuit configured to detect a short-circuit between the second board terminal and the third board terminal.2. The disk ...

DISK STORAGE APPARATUS AND METHOD FOR SERVO CONTROLLING

According to one embodiment, a disk storage apparatus includes an interrupt controller and a servo controller. The interrupt controller determines whether or not to carry out servo interrupt processing and holds a number of negative results of the determination. The servo controller includes an internal model configured to calculate an estimated current position of the head. The servo controller corrects a state of the internal model based on the number of negative results of the determination and performs head positioning control based on a result of a calculation of the internal model, if the result of the determination by the interrupt controller is affirmative. 1. A disk storage apparatus comprising:an interrupt controller configured to determine whether or not to carry out servo interrupt processing and to hold a number of negative results of the determination; anda servo controller comprising an internal model configured to follow a detected position of a head to calculate an estimated current position which is a position error with respect to a target position of the head,wherein the servo controller is configured to correct a state of the internal model based on the number of negative results of the determination and perform head positioning control based on a result of a calculation of the internal model, if the result of the determination by the interrupt controller is affirmative.2. The disk storage apparatus of claim 1 , further comprising:a command processor configured to inhibit the servo interrupt processing and to preferentially carry out command processing,wherein the interrupt controller is configured to determine whether or not to carry out the servo interrupt processing based on a state of execution of the command processing in response to a servo interrupt request at each sampling point of time, and count and hold the number of negative results of the determination corresponding to an elapsed time of execution of the command processing in ...

DETECTING TRACK INFORMATION FROM OVERLAPPING SIGNALS READ FROM A DATA STORAGE MEDIUM

Detecting track information involves receiving first and second overlapping track signals from first and second read elements that read first and second tracks from a data storage medium. Information of the first and second tracks is estimated using the respective first and second track signals. An improved information estimate of the first track is obtained using the first track signal and the estimated information of the second track, and an improved information estimate of the second track is obtained using the second track signal and the estimated information of the first track. First and second track data are decoded using the respective improved information estimates of the first and second tracks. 1. A method comprising:receiving first and second overlapping track signals from first and second read elements that read first and second tracks from a data storage medium;estimating information of the first and second tracks using the respective first and second track signals;obtaining an improved information estimate of the first track using the first track signal and the estimated information of the second track;obtaining an improved information estimate of the second track using the second track signal and the estimated information of the first track; anddecoding first and second track data using the respective improved information estimates of the first and second tracks.2. The method of claim 1 , wherein the first and second read elements concurrently read first and second tracks from the data storage medium.3. The method of claim 1 , wherein the operations of obtaining the improved information estimates of the first and second tracks are performed in parallel.4. The method of claim 1 , wherein the operations of obtaining the improved information estimate of the first and second tracks are iteratively repeated claim 1 , wherein the improved information estimate of the first and second tracks from one iteration are used as the respective estimated information ...

Systems and Methods for X-Sample Based Data Processor Marginalization

Systems, methods, devices, circuits for data processing, and more particularly to data processing including operational marginalization capability. 1. A data processing system , the data processing system comprising:an analog to digital converter circuit operable to convert an input signal into a series of corresponding digital samples; generate a noise component based at least in part on the series of digital samples;', 'add the noise component to the series of digital samples to yield a noise injected output; and', 'select one of the series of digital samples and the noise injected output as a processing input; and, 'a sample based noise injection circuit operable toan equalizer circuit operable to equalize the processing input to yield an equalized output.2. The data processing system of claim 1 , the data processing system further comprising:a processing circuit operable to apply a data processing algorithm to the processing input to yield a data output.3. The data processing system of claim 2 , wherein the processing circuit comprises:a data detector circuit operable to apply a data detection algorithm to the equalized output to yield a detected output; anda data decoder circuit operable to apply a data decoding algorithm to a decoder input derived from the detected output to yield the data output.4. The data processing system of claim 3 , wherein the data decoder circuit is a low density parity check decoder circuit.5. The data processing system of claim 3 , wherein the data detector circuit is selected from a group consisting of: a maximum a posteriori data detector circuit claim 3 , and a Viterbi algorithm data detector circuit.6. The data processing system of claim 1 , wherein the sample based noise injection circuit comprises:a summation circuit operable to subtract an ideal output derived from the digital samples input to yield a sum; anda multiplier circuit operable to multiply the sum by a scalar value to yield the noise component.7. The data processing ...

Non-Binary Layered Low Density Parity Check Decoder

A non-binary layered low density parity check decoder includes a variable node processor operable to generate variable node to check node messages and to calculate perceived values based on normalized check node to variable node messages and on normalized decoder inputs, and to output normalized decoded values, and a check node processor operable to generate the check node to variable node messages based on normalized variable node to check node messages. 1. A low density parity check decoder comprising:a variable node processor operable to generate variable node to check node messages and to calculate perceived values based on normalized check node to variable node messages and on normalized decoder inputs, and to output normalized decoded values; anda check node processor operable to generate the check node to variable node messages based on normalized variable node to check node messages, wherein the variable node processor and check node processor are operable to perform layered multi-level decoding.2. The decoder of claim 1 , wherein the normalized decoder inputs and normalized decoded values comprise hard decisions and soft data claim 1 , wherein the soft data is normalized to a likelihood of the corresponding hard decision.3. The decoder of claim 1 , wherein the variable node processor comprises a format conversion circuit operable to convert the normalized decoder inputs to a non-normalized format.4. The decoder of claim 3 , wherein the non-normalized format of a likelihood value for a symbol comprises probabilities for each element of a Galois Field that the symbol has a value of the corresponding element.5. The decoder of claim 1 , wherein the variable node processor comprises a format conversion circuit operable to convert the check node to variable node messages for a previous layer to a non-normalized format.6. The decoder of claim 1 , wherein the variable node processor comprises a first part and a second part claim 1 , the decoder further comprising a ...

MAGNETIC TAPE REWIND OVERWRITE DATA PROTECTION

A computer-implemented method for preventing overwriting of data, e.g., on a magnetic medium, includes receiving a write command to write to a magnetic tape. The current location of the magnetic tape is determined. A determination is also made as to whether data corresponding to the write command is at least one of: a size and type specified for a block at the current location. Execution of the write command is disallowed in response to determining that the data corresponding to the write command is not of the specified size and/or type. 1. A computer-implemented method , comprising:receiving a write command to write to a magnetic tape;determining a current location of the magnetic tape;determining whether data corresponding to the write command is at least one of: a size and type specified for a block at the current location; anddisallowing execution of the write command in response to determining that the data corresponding to the write command is not of the specified size and/or type.2. A computer-implemented method as recited in claim 1 , wherein the type of the data corresponds to a volume identifier.3. A computer-implemented method as recited in claim 1 , wherein the size specified for the block is different than a size specified for a user data block.4. A computer-implemented method as recited in claim 1 , wherein the block is a first block on the tape.5. A computer-implemented method as recited in claim 1 , wherein execution of the write command is disallowed in response to determining that the data corresponding to the write command is not of the specified size and type.6. A computer-implemented method as recited in claim 1 , wherein the method is performed in a tape drive.7. A computer-implemented method as recited in claim 6 , wherein the write command is received from a first host claim 6 , wherein the current location of the magnetic tape is at the block at a beginning of tape because of a rewind command received from a second host.8. A system claim 6 , ...

Dynamic gain control for use with adaptive equalizers

According to one embodiment, a magnetic tape drive includes a controller configured to direct first data through a first finite impulse response (FIR) gain module in response to a determination that the first data is being read from a magnetic tape medium in an asynchronous mode to control FIR gain of the first data. The controller is also configured to direct second data through a second FIR gain module in response to a determination that the second data is being read from the magnetic tape medium in a synchronous mode to control FIR gain of the second data. A FIR gain value of the second FIR gain module is automatically controlled. Other systems for dynamic gain control with adaptive equalizers are described according to more embodiments.

Magnetic recording and reproducing device and method of controlling magnetic recording and reproducing device

According to one embodiment, a magnetic recording and reproducing device which has a magnetic recording medium, a magnetic head, and a recording current output unit. Magnetic data is recorded on the magnetic recording medium. The magnetic head records the magnetic data on the magnetic recording medium. The recording current output unit supplies a recording current to the magnetic head so as to magnetize the magnetic head. A waveform of the recording current has a first slope for a first period to record data of first information continuously and a second slope for a following second period to switch the data to data of second information and to record the data of the second information. The first slope and the second slope are different from each other.

DATA RECORDING APPARATUS AND DATA RECORDING METHOD

A data recording apparatus includes a disk, a read/write head, and a control circuit configured to control the head to perform reading of first data on the disk according to a first format and writing of second data to the disk according to a second format, wherein the second data is generated by compressing at least a part of the first data, and the second format is determined according to a data size of the second data. 1. A data recording apparatus , comprising:a disk;a read/write head; anda control circuit configured to control the head to perform reading of first data on the disk according to a first format and writing of second data to the disk according to a second format, whereinthe second data is generated by compressing at least a part of the first data, andthe second format is determined according to a data size of the second data.2. The data recording apparatus according to claim 1 , wherein the second data is written to the disk by using a shingled magnetic recording method.3. The data recording apparatus according to claim 2 , wherein the first data is data of a first band and the second data is written to a second band.4. The data recording apparatus according to claim 1 , wherein the first and second formats each correspond to a data recording density claim 1 , the data recording density specified by the first format being greater than that of the second format.5. The data recording apparatus according to claim 4 , wherein the data recording density is either track density or bit density.6. The data recording apparatus according to claim 1 , wherein the control circuit is configured to control the head to read third data claim 1 , and combine the first and third data prior to compressing.7. The data recording apparatus according to claim 1 , wherein the first data is data of a single track.8. The data recording apparatus according to claim 1 , wherein information of the second format is written to the disk along with the second data.9. A data ...

PSEUDO-DIFFERENTIAL MAGNETIC RECORDING SYSTEM AND METHOD INCORPORATING A DUMMY READ ELEMENT AND A DUMMY TRANSMISSION LINE

A system including a first transmission line, a second transmission line, a first element, a second element and a differential amplifier. The first element is configured to read a storage media to generate a read signal, where the first element is connected to the first transmission line. The second element is configured to detect interference and generate an interference signal, where the second element is connected to the second transmission line. The differential amplifier includes a first input and a second input, where the first input of the differential amplifier is connected to a the first transmission line and receives the read signal, and where the second input of the differential amplifier is connected to the second transmission line and receives the interference signal. 1. A system comprising:a first transmission line;a second transmission line;a first element configured to read a storage media to generate a read signal, wherein the first element is connected to the first transmission line;a second element configured to detect interference and generate an interference signal, wherein the second element is connected to the second transmission line; anda differential amplifier comprising a first input and a second input, wherein the first input of the differential amplifier is connected to a the first transmission line and receives the read signal, and wherein the second input of the differential amplifier is connected to the second transmission line and receives the interference signal.2. The system of claim 1 , wherein the second element is not configured to read data or information from a track.3. The system of claim 1 , comprising:a plurality of transmission lines comprising the first transmission line and not the second transmission line,wherein the read signal is a first read signal;a plurality of elements comprising the first element, wherein the plurality of elements are configured to read one or more tracks on the storage media to generate a ...

TWO-DIMENSIONAL MAGNETIC RECORDING SYSTEMS AND METHODS FOR MINIMIZING AND ACCOUNTING FOR INTER-MODULATION OF SIGNALS INDUCED IN ADJACENT READ ELEMENTS

A system including transmission lines, read elements, and differential amplifiers. The read elements are connected in series. Each of the read elements is connected to a respective pair of the transmission lines. The differential amplifiers are connected respectively to the read elements via the transmission lines. The differential amplifiers are configured to amplify differential signals received from the respective pairs of the transmission lines. 1. A system comprising:a plurality of transmission lines;a plurality of read elements connected in series, wherein each of the plurality of read elements is connected to a respective pair of the plurality of transmission lines; anda plurality of differential amplifiers connected respectively to the plurality of read elements via the plurality of transmission lines, wherein the plurality of differential amplifiers are configured to amplify differential signals received from the respective pairs of the plurality of transmission lines.2. The system of claim 1 , wherein a number of the plurality of transmission lines is twice a number of the plurality of read elements.3. The system of claim 1 , wherein a number of the plurality of read elements is equal to a number of the plurality of differential amplifiers.4. The system of claim 1 , wherein a number of the plurality of transmission lines is twice a number of the plurality of differential amplifiers.5. The system of claim 1 , wherein:the plurality of transmission lines comprises a first transmission line, a second transmission line, and a third transmission line;the plurality of read elements comprise a first element and a second element;the plurality of differential amplifiers comprise a first differential amplifier and a second differential amplifier;the first element is connected to the first transmission line;the second element is connected to the second transmission line and the third transmission line;the first transmission line is connected to a first input terminal ...

INDEPENDENTLY DRIVEN WRITE COILS

A writer assembly having two separately driven write coils allows a combined write field generated by the writer assembly to be fine turned and optimized for a particular application. Two preamplifiers may be incorporated into a printed circuit board in order to separately drive the write coils. In other implementations, there may be more than two write coils and corresponding preamplifiers. 1. A method comprising:independently driving at least two write coils within a writer assembly using separate preamplifiers.2. The method of claim 1 , wherein the separate preamplifiers drive the at least two write coils using one or more of different current magnitudes claim 1 , phases claim 1 , and polarities.3. The method of claim 1 , wherein the at least two write coils generate individual write fields that yield a combined write field.4. The method of claim 3 , wherein the combined write field is directed to a storage media via a write pole and a return pole to write data to the storage media.5. The method of claim 4 , wherein the at least two write coils are oriented on opposite sides of the write pole.6. The method of claim 1 , wherein each of the at least two write coils have one of a substantially planar orientation and a substantially helical orientation.7. The method of claim 1 , wherein at least one of the write coils utilizes at least three bond pads located on different turns of the write coil.8. A writer assembly comprising:a first write coil independently driven by a first preamplifier; anda second write coil independently driven by a second preamplifier.9. The writer assembly of claim 8 , wherein the first preamplifier drives the first write coil and the second preamplifier drives the second write coil using one or more of different current magnitudes claim 8 , phases claim 8 , and polarities.10. The writer assembly of claim 8 , wherein the first write coil and the second write coil generate individual write fields that yield a combined write field.11. The ...

MAGNETIC RECORDING AND REPRODUCING DEVICE

According to one embodiment, a magnetic recording and reproducing device includes a magnetic flux control layer provided between a main magnetic pole and an auxiliary magnetic pole, and a protective layer provided on an ABS of the auxiliary magnetic pole. The magnetic flux control layer includes an adjustment layer formed of a magnetic material includes one of Fe, Co or Ni and provided between a first conductive layer and a second conductive layer, and generates a spin torque and inverts a direction of magnetization in the adjustment layer, when current is supplied. A voltage Vb applied to the magnetic flux control layer is lower than a voltage Vba represented by an expression (1). 2. The magnetic recording and reproducing device of claim 1 , wherein the protective layer has a thickness of 1.0 to 2.5 nm.3. The magnetic recording and reproducing device of claim 1 , wherein the protective layer includes a surface layer formed of diamond-like carbon.4. The magnetic recording and reproducing device of claim 1 , wherein the voltage Vb applied to the magnetic flux control layer is 100 to 300 mV.5. The magnetic recording and reproducing device of claim 1 , wherein a temperature of the magnetic flux control layer in operation is 5 to 150° C.6. The magnetic recording and reproducing device of claim 1 , wherein an ambient atmosphere of the magnetic recording head has a humidity of 80% or less when the magnetic recording head operates.7. The magnetic recording and reproducing device of one of to claim 1 , wherein an ambient atmosphere of the magnetic recording head has an oxygen partial pressure of 20% or less when a pressure of whole air in the recording and reproducing device is 100%.8. The magnetic recording and reproducing device of claim 1 , further comprising a voltage controller connected to the magnetic recording head claim 1 , whereinthe voltage controller controls the voltage Vb applied to the magnetic flux control layer to be lower than the voltage Vba represented ...

COLOR STORAGE AND TRANSMISSION SYSTEMS AND METHODS

A system comprises a writer to form a plurality of color mits on a base material, wherein at least one of the color mits may represent computer-readable instructions comprising data other than pixel-image data. The plurality of color mits may include a first color mit and a second color mit, wherein the first color mit represents information data, and the second color mit represents that the first color mit contains a particular type of information data. The system also may include a reader to read colors of the plurality of color mits on the base material. The system may comprise a device to map at least one of the color mits to computer-readable instructios. The system may further comprise a processor configured to transmit signals using a colored light. 136-. (canceled)37. A device comprising a processor having a photodiode , wherein the processor is processor is configured to receive signals including colored light signals , each color corresponding to unique computer-readable instructions.381. The device of claim wherein the colored light signal includes light transmitted from a light emitting diode.391. The device of claim wherein the colored light is configured to be manipulated , wherein manipulating the light includes bending light through a prism , halving a frequency of the light by passing through crystal , combining two or more colors to give a different color , or subtracting a color from a light beam by passing it through a filter or multilayer coating.403. The device of claim wherein the manipulation of light includes similar functions to current processors , wherein functions include move , add , subtract , multiply , divide and basic logical , and input/output operations of a system.411. The device of claim further comprising a driver configured to map the color signals to the computer-readable instructions.421. The device of claim , wherein the colored light signal includes light transmitted from a laser.431. The device of claim , wherein the ...

Iterative data storage read channel architecture having dropout mitigation

According to one embodiment, a computer program product for dropout detection in a read channel includes a computer readable storage medium having program code embodied therewith, the embedded program code being readable and/or executable by a processor to execute dropout detection on a block of signal samples to detect one or more dropout events employing a set of decisions provided by a detector executing a detection algorithm, determine an approximate location for each of the one or more detected dropout events, statistically characterize the one or more detected dropout events to calculate one or more dropout profiles, and selectively filter the block of signal samples during a duration of each of the detected dropout events. Other computer program products, systems, and methods for detecting dropouts are presented in more embodiments.

METHOD AND SYSTEM FOR PRESERVING DATA OF A STORAGE DEVICE

A method and system for preserving data of a storage device are disclosed. In one embodiment, the method includes determining a number of times data is written to a first track in a first region of a storage medium, and rewriting data from a second track that is adjacent to the first track in the first region if the number of times data is written to the first track in the first region exceeds a first predetermined threshold. The method further includes determining a number of times data is rewritten to the second track in the first region, and relocating data from the second track in the first region to a second region of the storage medium if the number of times data is rewritten to the second track in the first region exceeds a second predetermined threshold. 1. A method comprising:determining a number of times data is written to a first track in a first region of a storage medium;rewriting data from a second track that is adjacent to the first track in the first region if the number of times data is written to the first track in the first region exceeds a first predetermined threshold;determining a number of times data is rewritten to the second track in the first region; andrelocating data from the second track in the first region to a second region of the storage medium if the number of times data is rewritten to the second track in the first region exceeds a second predetermined threshold.2. The method of claim 1 , further comprising rewriting data from a third track that is adjacent to the first track in the first region if the number of times data is written to the first track in the first region exceeds a third predetermined threshold claim 1 , and the first track is positioned between the second track and the third track.3. The method of claim 2 , further comprising relocating data from the third track in the first region to the second region of the storage medium if a number of times data is rewritten to the third track in the first region exceeds a ...

INTER-TRACK INTERFERENCE CANCELATION FOR SHINGLED MAGNETIC RECORDING

Inter-track interference cancelation is disclosed, including: receiving an input sequence of samples associated with a track on magnetic storage; using a processor to generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track. 1. A method , comprising:receiving an input sequence of samples associated with a track on magnetic storage; andusing a processor to generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track.2. The method of claim 1 , further comprising removing the ITI data associated with the first side track from the input sequence of samples.3. The method of claim 1 , wherein generating ITI data includes generating a set of correlation coefficients and selecting a subset of the set of correlation coefficients.4. The method of claim 3 , wherein the selected subset of correlation coefficients is used to determine one or more of the following: (1) a relative phase offset between the track and the first side track or (2) a side track pulse-shape associated with the first side track.5. The method of claim 3 , wherein selecting a subset of the set of correlation coefficients is based at least in part on one or more of the following: a peak value associated with the set of correlation coefficients claim 3 , a maximum power value associated with the set of correlation coefficients claim 3 , or a maximum absolute sum value associated with the set of correlation coefficients.6. The method of claim 1 , further comprising determining whether a function associated with the set of correlation coefficients exceeds a set threshold claim 1 , and in the event that the function exceeds the set threshold claim 1 , removing the ITI data from the input sequence of ...

MOTOR AND DISK DRIVE

A motor for a disk drive includes a stationary unit, a bearing mechanism attached to the stationary unit, and a rotation unit supported on the stationary unit rotatably around a central axis via the bearing mechanism. The stationary unit includes a base portion that is a part of a housing defining an internal space sealed in the disk drive and includes a recess portion recessed from a side of the internal space toward an outside of the housing and not penetrated. The bearing mechanism includes a shaft extending in a direction of the central axis and a sleeve surrounding at least a portion of an outer circumferential surface of the shaft. A lower end portion of the shaft is press-fit and glued into the recess portion, and a lower surface of the base portion including a base step portion extending toward an axially upper side. 1. A motor for a disk drive , the motor comprising:a stationary unit;a bearing mechanism attached to the stationary unit; anda rotation unit supported on the stationary unit rotatably around a central axis via the bearing mechanism; whereinthe stationary unit includes a base portion;the base portion is a portion of a housing defining an internal space sealed in the disk drive and includes a recess portion that is recessed from a side of the internal space toward an outside of the housing and that is not penetrated;the bearing mechanism includes a shaft extending in a direction of the central axis and a sleeve surrounding at least a portion of an outer circumferential surface of the shaft;the shaft has a cylindrical shape including a hollow portion extending along the central axis;an inner circumferential surface of the shaft includes a shaft step portion that extends directly radially outward from the central axis, the shaft step portion being provided at an axially upper end of the hollow portion;a fixed step portion is provided at an axially lower side of the shaft step portion, the fixed step portion extending directly radially outward from ...

Systems and Methods for Loop Processing With Variance Adaptation

Systems and methods for data processing, and more particularly systems and methods for loop processing with variance adaptation. 1. A data processing system comprising:a filter circuit operable to equalize a series of digital samples;a variance adaptation circuit operable to generate a plurality of scaling factors for the series of digital samples; anda data detector circuit operable to scale the series of digital samples by the plurality of scaling factors to yield scaled digital samples and to apply a data detection algorithm to the scaled digital samples to yield a detected output, wherein a variance of a distribution for each data pattern in the series of digital samples is normalized by the plurality of scaling factors.2. The data processing system of claim 1 , wherein the plurality of scaling factors comprises one scaling factor for each of the data patterns in the series of digital samples.3. The data processing system of claim 1 , wherein the variance adaptation circuit is operable to generate the plurality of scaling factors based at least in part on the series of digital samples claim 1 , on ideal values of the series of digital samples claim 1 , and on a target variance.4. The data processing system of claim 3 , wherein the ideal values are programmable.5. The data processing system of claim 3 , further comprising:a second data detector circuit operable to apply a data detection algorithm to a signal derived from the series of digital samples to yield a second detected output; anda data decoder circuit operable to apply a data decoding algorithm to a decoder input derived from the second detected output to yield a decoder output, wherein the ideal values are derived from the decoder output.6. The data processing system of claim 1 , wherein the variance adaptation circuit is operable to generate the scaling factor for a lowest and a highest one of the data patterns based on only a portion of the digital samples falling to one side of a corresponding ideal ...

VIDEO REPRODUCTION DEVICE AND VIDEO REPRODUCTION METHOD

A video reproduction device () reproduces expanded video data (D) whose brightness dynamic range is wider than a standard video. The video reproduction device () includes a brightness information adjustment unit (). The brightness information adjustment unit () changes first output brightness levels of the expanded video data (D) to second output brightness levels. When the expanded video data (D) is reproduced at a second reproduction speed faster than a first reproduction speed which is a normal speed, the brightness information adjustment unit () reduces the first output brightness levels to the second output brightness levels. 116-. (canceled)17. A video reproduction device to reproduce expanded video data whose brightness dynamic range is wider than that of a standard video , the device comprising a brightness information adjuster to change first output brightness levels of the expanded video data to respective second output brightness levels , wherein , when the expanded video data is reproduced at a second reproduction speed faster than a first reproduction speed which is a normal speed , the brightness information adjuster reduces the first output brightness levels to the second output brightness levels.18. The video reproduction device according to claim 17 , wherein in a case where a third reproduction speed and a fourth reproduction speed are faster reproduction speeds than the first reproduction speed and the third reproduction speed is faster than the fourth reproduction speed claim 17 , the brightness information adjuster gives larger reduction amounts to the first output brightness levels when reproduced at the third reproduction speed claim 17 , than reduction amounts to the first output brightness levels when reproduced at the fourth reproduction speed.19. The video reproduction device according to claim 17 , wherein in a case where a third reproduction speed and a fourth reproduction speed are faster reproduction speeds than the first reproduction ...

EFFICIENT RECOVERY OF THE CODEWORD INTERLEAVE ADDRESS

In one embodiment, a system includes a data processing unit configured to read encoded data from a magnetic tape medium. The data processing unit is also configured to decode a plurality of codeword interleaves (CWIs) from the encoded data, each CWI being a row in a sub data set logically organized into a two-dimensional array. The array includes a predetermined number of rows and columns of predetermined lengths. The data processing unit is also configured to determine an address for a first-written CWI without successfully decoding a corresponding codeword interleave designation (CWID) from the encoded data, each CWID specifying an address for a corresponding CWI. Also, each CWID is calculated as a function of a logical track number and a CWI set number. 1. A system , comprising: read encoded data from a magnetic tape medium;', 'decode a plurality of codeword interleaves (CWIs) from the encoded data, each CWI being a row in a sub data set logically organized into a two-dimensional array, wherein the array comprises a predetermined number of rows and columns of predetermined lengths; and', 'determine an address for a first-written CWI without successfully decoding a corresponding codeword interleave designation (CWID) from the encoded data, each CWID specifying an address for a corresponding CWI,', 'wherein each CWID is calculated as a function of a logical track number and a CWI set number., 'a data processing unit configured to2. The system as recited in claim 1 , wherein each CWI comprises four interleaved codewords (a CWI-4) claim 1 , and wherein the CWIs are read from the magnetic tape in CWI sets comprising a plurality of CWIs belonging to a data set.3. The system as recited in claim 2 , wherein the data processing unit is configured to store a CWI set number associated with a CWI set to which the first-written CWI belongs based on successfully decoding a CWI header of at least one first-written CWI from the data set to which the first-written CWI belongs ...

Efficient connection management in a sas target

A method includes pre-configuring a hardware-implemented front-end of a storage device with multiple contexts of respective connections conducted between one or more hosts and the storage device. Storage commands, which are received in the storage device and are associated with the connections having the pre-configured contexts, are executed in a memory of the storage device using the hardware-implemented front-end. Upon identifying a storage command associated with a context that is not pre-configured in the hardware-implemented front-end, software of the storage device is triggered to configure the context in the hardware-implemented front-end, and the storage command is then executed using the hardware-implemented front-end in accordance with the context configured by the software.

SIGNAL PROCESSING DEVICE, MAGNETIC INFORMATION PLAYBACK DEVICE, AND SIGNAL PROCESSING METHOD

The invention provides a signal processing device, including: an extraction section that extracts, from an input digital signal, a decoding target signal at an extraction timing that has been determined as a timing for extracting the decoding target signal; a decoding section that decodes the decoding target signal by estimating, by a maximum likelihood decoding, a candidate for a decoding result of the decoding target signal extracted by the extraction section and detecting a maximum likelihood decoding result; and an adjustment section that adjusts the extraction timing using a likelihood of the candidate for the decoding result estimated by the decoding section. 1. A signal processing device , comprising:an extraction section that extracts, from an input digital signal, a decoding target signal at an extraction timing that has been determined as a timing for extracting the decoding target signal;a decoding section that decodes the decoding target signal by estimating, by a maximum likelihood decoding, a candidate for a decoding result of the decoding target signal extracted by the extraction section and by detecting a maximum likelihood decoding result; andan adjustment section that adjusts the extraction timing using a likelihood of the candidate for the decoding result estimated by the decoding section.2. The signal processing device of claim 1 , wherein the decoding section comprises:a detection section that estimates the candidate by the maximum likelihood decoding and detects the maximum likelihood decoding result; anda correction section that corrects errors in the maximum likelihood decoding result detected by the detection section.3. The signal processing device of claim 1 , wherein adjustment of the extraction timing by the adjustment section is initiated on a condition that a predetermined time claim 1 , which is an upper limit time in which deviations in the extraction timing are permissible claim 1 , has elapsed from initiation of extraction of the ...

COMPENSATING FOR LOSS OF CURRENT THROUGH SHORTED TUNNELING MAGNETORESISTANCE SENSORS

Embodiments of the present invention provide methods, systems, and computer program products for compensating for loss of current through shorted tunneling magnetoresistance (TMR) sensors. In one embodiment, for a magnetic head having multiple TMR read sensors, a first voltage limit is set for most parts and a second voltage limit is set for all of the parts. A number of TMR read sensors which are allowed to function between the first and the second voltage limits is determined using a probability algorithm, which determines the probability that the application of the second voltage limit will result in a dielectric breakdown within an expected lifetime of a drive is below a threshold value. For the number of TMR read sensors which are allowed to function at voltages between the first and second voltage limits, a determined subset of those sensors are then allowed to function at the second voltage limit. 1one or more computer processors;one or more non-transitory computer readable storage media; and program instructions to, for a magnetic head having multiple TMR read sensors, set a first voltage limit for a plurality of parts and a second voltage limit for all of the parts;', 'program instructions to determine a number of TMR read sensors which are allowed to function between the first and the second voltage limits using a probability algorithm, wherein the probability algorithm is configured to determine the probability that one or more defective tracks are selected when a number of tracks are selected and limits the number of tracks selected for the second voltage limit based on a statistical algorithm of selecting one or more defective tracks, and wherein the probability that application of the second voltage limit will result in a dielectric breakdown within an expected lifetime of a drive is below a threshold value;', 'program instructions to, responsive to determining a number of TMR read sensors which are allowed to function at voltages between the first and ...

AUTOMATIC GAIN CONTROL LOOP ADAPTATION FOR ENHANCED NYQUIST DATA PATTERN DETECTION

Techniques are provided for automatic gain control loop adaptation in circuitry for processing such data signals. In one example, an apparatus comprises read channel circuitry and signal processing circuitry associated with the read channel circuitry. The signal processing circuitry comprises an amplifier, a detector operatively coupled to the amplifier, and a feedback path operatively coupled between the detector and the amplifier. The amplifier is configured to receive and amplify an input signal received by the read channel circuitry. The detector is configured to detect a data pattern from the amplified input signal. The feedback path is configured to provide a feedback signal to the amplifier to adjust a gain of the amplifier, and to generate the feedback signal in accordance with a value selected to improve detection of the data pattern by increasing an amplitude of the data pattern around a given frequency. 1. An apparatus , comprising:read channel circuitry; and an amplifier, the amplifier being configured to receive and amplify an input signal received by the read channel circuitry;', 'a detector operatively coupled to the amplifier, the detector being configured to detect a data pattern from the amplified input signal and to generate a detected digital signal representing the data pattern; and', 'a feedback path operatively coupled between the detector and the amplifier, the feedback path being configured to provide a feedback signal to the amplifier to adjust a gain of the amplifier, wherein the feedback path generates the feedback signal in accordance with a value selected to improve detection of the data pattern by increasing an amplitude of the data pattern around a given frequency;, 'signal processing circuitry associated with the read channel circuitry, the signal processing circuitry comprisingwherein the feedback path further comprises a multiplier operatively coupled to the detector and configured to multiply the value with the detected digital ...

MAGNETIC RECORDING DISK DRIVE WITH WRITE DRIVER TO WRITE HEAD TRANSMISSION LINE WITH MULTIPLE SEGMENTS HAVING DIFFERENT NUMBERS OF CONDUCTIVE TRACES

A multiple-segment transmission line in a hard disk drive enables a wider optimization range of the slope, duration and amplitude of the transmission line overshoot (TLO) wave shape. There is a first segment with two traces for connection to the write driver circuitry, an end segment with two traces for connection to the write head and at least two intermediate segments. The number of traces in a segment is different from the number of traces in the segments to which the segment is immediately connected. There is an even number of traces in each segment and the traces in each segment are interleaved. The number of segments and the number of traces in each segment can be selected to achieve the desired impedance levels for the different segments to achieve the desired wave shape for the TLO. All of the traces on the transmission line are preferably coplanar. 1. In a magnetic recording disk drive having write driver circuitry and an inductive write head , a transmission line between the write driver circuitry and the write head comprising:multiple connected transmission line segments, each segment comprising a number of electrically conductive +W traces for positive write signals and an equal number of electrically conductive traces −W traces for negative write signals interleaved with the +W traces, the transmission line including a first segment with two traces for connection to the write driver circuitry, an end segment with two traces for connection to the write head, and at least two intermediate segments, wherein the number of traces in each intermediate segment is greater than two and different from the number of traces in the segments to which it is immediately connected.2. The transmission line of further comprising a substrate and an insulator layer on the substrate claim 1 , wherein the electrically conductive traces are formed on the insulator layer.3. The transmission line of further comprising segment interconnects between the segments claim 2 , each ...

SELF-CONTROLLED LASER PULSING FOR THERMALLY ASSISTED RECORDING

A method of storing data includes providing a write signal for a write head of a hard disk drive, generating a transition pulse signal derived from the write signal using a transition pulse generator, and generating a logic signal to drive a thermal source associated with the write head of the hard disk drive. The logic signal includes the logical summation of a cyclical base pulse signal and the transition pulse signal. 1. A method of storing data , the method comprising:providing a write signal for a write head of a hard disk drive;generating a transition pulse signal derived from the write signal using a transition pulse generator;configuring a pulse shaping register to store the characteristics of a cyclical base pulse signal, comprising the frequency, pulse width and pulse interval; andgenerating a logic signal to drive a thermal source associated with the write head of the hard disk drive, the logic signal comprising the logical summation of the cyclical base pulse signal and the transition pulse signal; wherein the characteristics of the base pulse signal are controlled by the pulse shaping register.2. The method of claim 1 , wherein the write signal is provided to a preamplifier of the hard disk drive system and wherein the preamplifier of the hard disk drive system includes the transition pulse generator; and wherein a preamplifier of the hard disk drive includes a base pulse generator claim 1 , configured to generate a base pulse signal in the absence of an external pulse signal and in accordance with a pulse shaping register.3. The method of claim 1 , further comprising generating the base pulse signal with a base pulse generator.4. The method of claim 3 , wherein a preamplifier of a hard drive system includes the base pulse generator.5. The method of claim 3 , wherein generating the base pulse signal includes generating the base pulse signal in the absence of an external pulse signal.6. (canceled)7. (canceled)8. The method of claim 1 , further comprising ...

READ HEAD CHARACTERISTIC PRE-DETECTION

Implementations disclosed herein provide a method comprising applying voltage to a read head during an unload state, detecting characteristic read head data, and storing the detected characteristic read head data in a buffer. In another implementation, the method further comprises performing a read retry operation in response to a read failure, reading the detected characteristic read head data from the buffer, determining if the detected characteristic read head data meets a threshold for a first predetermined criterion, performing a correction operation if the threshold for the first the first predetermined criterion is met, determining whether a media sector is read successfully, and ending the read retry operation if the media sector is read successfully. 1. A method comprising:applying voltage to a read head during an unload state; anddetecting characteristic read head data responsive to the applied voltage.2. The method of claim 1 , further comprising:storing the detected characteristic read head data in a buffer.3. The method of claim 2 , further comprising:performing a read retry operation in response to a read failure;reading the detected characteristic read head data from the buffer; anddetermining if the detected characteristic read head data meets a threshold for a first predetermined criterion.4. The method of claim 3 , further comprising:performing a correction operation responsive to meeting the threshold for the first predetermined criterion.5. The method of claim 4 , further comprising:determining whether a media sector is read successfully; andending the read retry operation based on a determination of a successful media sector read.6. The method of claim 3 , further comprising performing another read retry operation responsive to not meeting the first predetermined criterion.7. The method of claim 3 , further comprising performing another read retry operation if the media sector is not read successfully.8. A storage device claim 3 , comprising:a ...

DETERMINING INSTABILITY ZONES OF A LASER OF A HEAT-ASSISTED MAGNETIC RECORDING HEAD

Stability or instability zones are determined for ambient temperatures and one or more operational parameters applied to a heat-assisted magnetic recording head. Operations within the stability or instability zones resulting in respective stable or unstable operation of a laser of the recording head. During operation of the recording head, it is determining that a current ambient temperature and currently applied values of the one or more operational parameters are at or near one of the instability zones, and a write operation of the recording head is modified in response. 1. A method , comprising:determining instability zones for ambient temperatures and one or more operational parameters applied to a heat-assisted magnetic recording head that writes to a recording medium, the one or more operational parameters including one or more of a laser input bias current and a laser input boost current, operations within the instability zones resulting in instability in operation of a laser of the recording head;during operation of the recording head, determining that a current ambient temperature and currently applied values of the one or more operational parameters are at or near one of the instability zones; andmodifying a write operation of the recording head in response thereto.2. (canceled)3. The method of claim 1 , wherein the one or more or more operation inputs include a read clearance heater input that is applied before the write operation.4. The method of claim 1 , wherein modifying the write operation comprises delaying the write operation.5. The method of claim 1 , wherein modifying the write operation comprises changing one or more of a clearance heater current claim 1 , a laser input bias current claim 1 , a laser input boost current claim 1 , and a write coil current.6. The method of claim 1 , wherein modifying the write operation comprises changing a current to a laser heater.7. The method of claim 1 , wherein modifying the write operation comprises using a ...

MEASUREMENT CIRCUIT FOR MICROWAVE ASSISTED MAGNETIC RECORDING

According to one embodiment, a disk device includes a disk includes a recording layer, a recording head includes a main pole configured to apply a recording magnetic field onto the recording layer, and a microwave oscillator adjacent to the main pole, configured to apply a microwave magnetic field to the recording layer, a current supply circuit configured to supply a current to the microwave oscillator, and a switching circuit configured to switch a direction of current flow to the microwave oscillator. 1. A disk device comprising:a disk comprising a recording layer;a recording head comprising a main pole configured to apply a recording magnetic field onto the recording layer, and a microwave oscillator adjacent to the main pole, configured to apply a microwave magnetic field to the recording layer;a current supply circuit configured to supply a current to the microwave oscillator;a switching circuit configured to switch a direction of current flow to the microwave oscillator; anda measurement circuit configured to measure first oscillation characteristics of the microwave oscillator when a current is supplied to the microwave oscillator in a first direction of current flow, to measure second oscillation characteristics of the microwave oscillator when a current is supplied to the microwave oscillator in a second direction of current flow, and to compare the measured first and second oscillation characteristics, andwherein the switching circuit is configured to select and switch to the first direction of current flow or the second direction of current flow, with which better oscillation characteristics of the microwave oscillator can be obtained.2. The disk device of claim 1 , whereinthe microwave oscillator comprises a first oscillatory layer, and a second oscillatory layer stacked on the first oscillatory layer via an intermediate layer.3. The disk device of claim 2 , whereinthe recording head comprises an air bearing surface opposing the recording layer, and the ...

SYSTEM AND METHOD FOR PROVIDING CONTROLLABLE STEADY STATE CURRENT WAVESHAPING IN A HARD DISK DRIVE (HDD) PREAMPLIFIER

Aspects of the disclosure pertain to a system and method for providing controllable steady state current waveshaping in a preamplifier of a data storage system (e.g., hard disk drive). The preamplifier provides an output including a write current waveform having a steady state current level that is controllable via the write block circuitry of the preamplifier. This enhances the ability of the waveform to promote improved on-track and off-track write performance. 1. A data storage system , comprising:a preamplifier, the preamplifier including write block circuitry, the write block circuitry including a steady state current level block, a first current overshoot block and a second current overshoot block, wherein the steady state current level block, the first current overshoot block and the second current overshoot block are configured for generating a plurality of signal outputs, the preamplifier configured for generating and transmitting an output derived from the plurality of signal outputs;write coils, the write coils being operationally coupled with the preamplifier;a write head, the write head being magnetically coupled with the write coils, the write coils configured for controlling magnetization of the write head, the write head being operationally coupled with the preamplifier, the write coils and write head configured for receiving the transmitted output from the preamplifier; anda recording medium, the recording medium being operationally coupled with the write head,wherein the write head is configured for writing data to the recording medium based upon the received preamplifier output, the preamplifier output including a write current waveform having a steady state current level that is controllable via the second current overshoot block.2. The data storage system as claimed in claim 1 , wherein the data storage system is a hard disk drive.3. The data storage system as claimed in claim 1 , wherein the write block circuitry includes a signal summer claim ...

ELECTROSTATIC DISCHARGE PROTECTION FOR A MAGNETORESISTIVE SENSOR

A magneto-resistive (MR) sensor protection circuit is disclosed, for the protection of an MR sensor. The MR sensor may have a safe operating voltage range, a normal operating voltage range within the safe operating voltage range, and two terminals coupled to a read channel circuit, including a positive terminal and a negative terminal. The MR sensor protection circuit may have positive and negative protection threshold voltage ranges. The MR sensor protection circuit may also have a plurality of N-channel field-effect transistors (NFETs) that are coupled to the positive terminal and to the negative terminal, and configured to, in response to a voltage between the two terminals being within either the positive or the negative protection threshold voltage range, limit the voltage between the terminals by shunting current between the positive terminal and the negative terminal. 1. A data storage device comprising:a magnetic recording medium configured to contain stored data;an MR sensor having a safe operating voltage range, a normal operating voltage range within the safe operating voltage range, and two terminals coupled to a read channel circuit, including a positive terminal and a negative terminal, the MR sensor configured to read the stored data from the magnetic recording medium; and a positive protection threshold voltage range outside of and above the normal operating voltage range and within the safe operating voltage range;', 'a negative protection threshold voltage range outside of and below the normal operating voltage range and within the safe operating voltage range;', 'a first N-channel field-effect transistor (NFET) that is coupled to the positive terminal and to the negative terminal, and configured to, in response to a voltage between the two terminals being within the positive protection threshold voltage range, limit the voltage between the terminals by shunting current between the positive terminal and the negative terminal, and;', 'a second NFET ...

HEAT ASSISTED MAGNETIC RECORDING FOR BIT-PATTERNED MEDIA

A heat-assisted magnetic recording (HAMR) device includes a controller that selects a power for operating a heat source for a data write to a target data track. According to one implementation, the controller selects the power based on an assessment of whether the target data track is bounded by any data-storing tracks. A first power is selected when the data track is not bounded by any data-storing tracks and a second lower power is selected when the data track is bounded by one or more data-storing tracks. In another implementation, the controller writes to different partitioned regions of a storage media with different powers of the heat source. The controller selects a storage location for data based on an expected write error rate and environmental conditions within the HAMR device. 1. A storage device comprising:a heat-assisted magnetic recording (HAMR) head including a heat source; anda controller that selects a power for the heat source to write data to a target data track based on a whether the target data track is bounded by any data-storing tracks.2. The storage device of claim 1 , wherein the controller selects a first power if the target data track is not bounded by any data-storing tracks and selects a second power lower than the first power if the target data track is bounded by at least one data-storing track.3. The storage device of claim 2 , wherein the controller relaxes a positioning requirement of the HAMR head when writing data while operating the heat source at the first power and tightens the positioning requirement of the HAMR head while operating the heat source at the second power.4. The storage device of claim 2 , wherein the controller is configured to write data to a series of alternating data tracks at the first power until a capacity condition is satisfied.5. The storage device of claim 1 , wherein the storage media is a bit patterned media (BPM).6. One or more tangible computer-readable storage media encoding computer-executable ...

HYBRID TAPE HEAD ASSEMBLY AND DRIVE FOR ACCEPTING THE SAME

A head assembly according to one embodiment includes at least one module having magnetic transducers for reading and/or writing to a magnetic tape; electronics electrically coupled to the transducers, the electronics comprising at least one of amplifiers; bias circuitry; write drivers; write resistors; a memory device; and a chip with at least one of identification information about the head assembly, customization data, and firmware; and a connector for detachably interfacing to a drive having a head region for receiving the head assembly. A method according to one embodiment includes inserting a head assembly in a head region of a magnetic tape drive, the head assembly having one or more modules containing a plurality magnetic transducers and one of amplifiers, write drives, or bias circuitry; wherein upon receiving the head assembly the drive is at least one of a functional drive, an updated drive, and a legacy drive. 1. A head assembly , comprising:at least one module having magnetic transducers for reading and/or writing to a magnetic tape;electronics electrically coupled to the transducers, the electronics comprising at least one of amplifiers; bias circuitry; write drivers; write resistors; a memory device; and a chip with at least one of identification information about the head assembly, customization data, and firmware; anda connector for detachably interfacing to a drive having a head region for receiving the head assembly.2. The head assembly of having one or more datums for establishing a location of tape bearing surfaces and the transducers relative to the drive.3. The head assembly of claim 1 , wherein the electronics further comprise multiplexers for switching between multiple sets of readers and/or writers.4. The head assembly of claim 1 , wherein the electronics are positioned proximate to the at least one module.5. The head assembly of claim 1 , wherein the electronics are capable of wireless communication with the drive.6. The head assembly of ...

SWITCHING PERIOD CONTROL OF MICROWAVE ASSISTED MAGNETIC RECORDING FOR POLE ERASURE SUPPRESSION

A magnetic recording system for preventing data loss resulting magnetic oscillator current. The magnetic recording system includes a magnetic write head with a magnetic write pole, a magnetic oscillator near the magnetic write pole, and a write coil for magnetizing the write pole. Circuitry is connected with the magnetic write coil to supply a current to the write coil and connected with the magnetic oscillator to supply a current to the magnetic oscillator. The circuitry is configured to ensure that the current to the magnetic oscillator does not inadvertently magnetize the write pole after the magnetic write pole has demagnetized. 1. A magnetic recording system , comprising:a magnetic write pole;a write coil configured to magnetize the magnetic write pole;a magnetic oscillator formed adjacent to the magnetic write pole, the magnetic oscillator begin configured to cause an oscillating magnetic field; andcircuitry connected to the write coil and the magnetic oscillator, the circuitry being configured to ensure that current flow through the write coil terminates before the write pole has completely demagnetized upon termination of writing.2. The magnetic recording system as wherein the circuitry is configured to shorten a time in which current flow through the magnetic oscillator stops upon shut down of the magnetic oscillator.3. The magnetic recording system as in claim 1 , wherein the circuitry is configured to terminate current to the magnetic oscillator prior to terminating current to the write coil.4. The magnetic recording system as in claim 1 , wherein the circuitry is configured to extend the time to demagnetize the write pole to ensure that electrical current flow through the magnetic oscillator has terminated before the write pole has demagnetized.5. The magnetic recording system as in claim 1 , wherein the magnetic oscillator is a spin torque oscillator.6. A magnetic recording system claim 1 , comprising:a magnetic write pole;a write coil configured to ...

IMPEDANCE MATCHING FOR AN INTEGRATED CIRCUIT OF A MAGNETIC DISK DEVICE

An integrated circuit connectable to a signal transmission path of a storage device includes an impedance setting circuit including a plurality of switches, a detector configured to detect an input signal level, and a decoder. The decoder controls one or more switches of the impedance setting circuit based on the detected input signal level so as to match an impedance of the integrated circuit with an impedance of the signal transmission path. 1. An integrated circuit connectable to a signal transmission path of a storage device , comprising:an impedance setting circuit including a plurality of switches;a detector configured to detect an input signal level; anda decoder configured to control one or more of the switches of the impedance setting circuit based on the detected input signal level so as to match an impedance of the integrated circuit with an impedance of the signal transmission path.2. The integrated circuit according to claim 1 , wherein the detector is connected to a terminal and the input signal level is at a first level when the terminal is connected to a power line and at a second level when the terminal is connected to a ground line.3. The integrated circuit according to claim 1 , whereinthe signal transmission path includes an output signal transmission path and an input signal transmission path, andthe impedance setting circuit includes a first impedance setting circuit for the output signal transmission path and a second impedance setting circuit for the input signal transmission path.4. The integrated circuit according to claim 3 , whereineach of the first and second impedance setting circuits includes a first resistor and a second resistor having a higher resistance than the first resistor.5. The integrated circuit according to claim 4 , wherein the second resistor has twice the resistance of the first resistor.6. The integrated circuit according to claim 1 , wherein the storage device includes a magnetic recording disk claim 1 , and a read ...

Systems and Methods for Multi-Path Preamplifier Fault Processing

Systems and method relating generally to data processing, and more particularly to systems and methods for utilizing multiple data streams for data recovery from a storage device. 1. A preamplifier circuit , the circuit comprising: a first flaw scan detector circuit operable identify a first flaw on a first surface of a storage medium based upon a first information set corresponding to the first surface; and', 'a second flaw scan detector circuit operable identify a second flaw on a second surface of a storage medium based upon a second information set corresponding to the first surface., 'a single integrated circuit including2. The preamplifier circuit of claim 1 , wherein the single integrated circuit further includes:an amplifier circuit operable to amplify a third information set derived from a third sensor.3. The preamplifier circuit of claim 2 , wherein:the information corresponding to the first surface is derived from a first sensor disposed in relation to the first surface; andthe information corresponding to the second surface is derived from a second sensor disposed in relation to the second surface.4. The preamplifier circuit of claim 3 , wherein the preamplifier circuit is implemented as part of a storage system claim 3 , and wherein the storage system includes:a head disposed in relation to the first surface of the storage medium, wherein the head includes the first sensor and the third sensor.5. The preamplifier circuit of claim 4 , wherein the first sensor is a temperature sensor claim 4 , and the third sensor is a data sensor.6. The preamplifier circuit of claim 4 , wherein the storage system further includes:the storage medium.7. The preamplifier circuit of claim 6 , wherein the storage system is a hard disk drive.8. The preamplifier circuit of claim 1 , wherein the first flaw scan detector is a first thermal asperity based flaw scan detector circuit claim 1 , and wherein the second flaw scan detector is a second thermal asperity based flaw scan ...

FLEXIBLE BIASING STRATEGY FOR GROUND-SPLIT TCR SENSORS

A first biasing potential is sent to a first input end of a first temperature coefficient of resistance (TCR) sensor having a first ground end coupled to a ground potential. A second biasing potential is sent to a second input end of a second TCR sensor having a second ground end coupled to the ground potential. The first and the second biasing potentials are changed to operate in a plurality of modes. 1. A method , comprising:sending a first biasing potential to a first input end of a first temperature coefficient of resistance (TCR) sensor having a first ground end coupled to a ground potential; andsending a second biasing potential to a second input end of a second TCR sensor having a second ground end coupled to the ground potential;changing the first and second biasing potentials to operate in a plurality of modes, the plurality of modes comprising a differential mode wherein the first and second biasing potentials have the same polarity and a series mode wherein the first and second biasing potentials have opposite polarity.2. (canceled)3. The method of claim 2 , further comprising tuning the first and second biasing potentials to improve cancellation of common mode noise from the first and second TCR sensors.4. The method of claim 1 , wherein the first and second biasing potentials have the same biasing potential in the differential mode.5. (canceled)6. The method of claim 1 , wherein the plurality of modes comprise an individual channel mode such that first biasing potential comprises a non-zero biasing potential and the second biasing potential comprises the ground potential.7. The method of claim 6 , further comprising detecting a failure of the first TCR sensor and claim 6 , in response thereto claim 6 , setting the second biasing potential to the non-zero biasing potential and the first biasing potential comprises the ground potential.8. The method of claim 6 , wherein the first TCR sensor is closer to the recording medium than the second TCR sensor ...

MAGNETIC RECORDING HEAD, MAGNETIC HEAD ASSEMBLY, MAGNETIC RECORDING APPARATUS, AND MAGNETIC RECORDING METHOD

An example magnetic recording apparatus includes a magnetic recording medium, a magnetic recording head and a signal processor. The magnetic recording head includes a first magnetic pole; a second magnetic pole; a spin torque oscillator; a first coil to magnetize the first magnetic pole; and a second coil through which a current is passed independently of the first coil. The signal processor writes and reads a signal on the magnetic recording medium by using the magnetic recording head and includes a first current circuit to supply a recording current to the first coil and a second current circuit to supply a modulating current to the second coil. 1. A magnetic recording apparatus , comprising:a magnetic recording medium; a first magnetic pole to apply a recording magnetic field to the magnetic recording medium;', 'a second magnetic pole provided parallel to the first magnetic pole;', 'a spin torque oscillator at least a portion of which is provided between the first magnetic pole and the second magnetic pole;', 'a first coil to magnetize the first magnetic pole; and', 'a second coil through which a current is passed independently of the first coil; and, 'a magnetic recording head including a first current circuit to supply a recording current to the first coil, the recording current including a recording signal to be recorded on the magnetic recording medium; and', 'a second current circuit to supply a modulating current to the second coil, wherein, 'a signal processor to write and read a signal on the magnetic recording medium by using the magnetic recording head, the signal processor includingthe modulating current includes either one of a signal changing at a frequency higher than that of the recording signal and a signal having the same frequency as the recording signal and changing an absolute value thereof in one cycle.2. The apparatus according to claim 1 , whereinthe second current circuit includes a modulation signal current circuit and a controlling ...

STORAGE DEVICE HAVING DEGAUSS CIRCUITRY CONFIGURED FOR GENERATING DEGAUSS SIGNAL WITH ASYMMETRIC DECAY ENVELOPES

A hard disk drive or other storage device comprises a storage medium, a write head configured to write data to the storage medium, and control circuitry coupled to the write head. The control circuitry comprises degauss circuitry coupled to or otherwise associated with one or more write drivers. The degauss circuitry is configured to generate an asymmetric degauss signal to be applied to the write head. The asymmetric degauss signal has a waveform with upper and lower decay envelopes that are asymmetric about a specified degauss current level, such as a substantially zero current level. 1. An apparatus comprising:control circuitry adapted for coupling to a write head configured to write data to a storage medium;wherein the control circuitry comprises:a write driver; anddegauss circuitry associated with the write driver and configured to generate an asymmetric degauss signal to be applied to the write head, the asymmetric degauss signal having a waveform with upper and lower decay envelopes having respective different decay rates.2. The apparatus of wherein the upper and lower decay envelopes of the asymmetric degauss signal waveform comprise respective positive side and negative side decay envelopes.3. The apparatus of wherein the upper and lower decay envelopes are asymmetric about a substantially zero current level.4. The apparatus of wherein the degauss circuitry comprises:a first signal generator configured to generate a symmetric degauss signal having a waveform with upper and lower decay envelopes that are symmetric about a specified degauss current level;a second signal generator configured to generate a bias signal; anda signal combiner having first and second inputs coupled to respective outputs of the first and second signal generators and configured to combine the symmetric degauss signal and the bias signal to form the asymmetric degauss signal.5. The apparatus of wherein the degauss circuitry further comprises:a detector configured to detect a polarity ...

SKEW-AWARE DISK FORMAT FOR ARRAY READER BASED MAGNETIC RECORDING

A method of reading data in a multi-reader two-dimensional magnetic recording system includes determining a position of a multi-reader head, selecting a mode for reading the data of a magnetic recording medium as a function of the position of the multi-reader head, and reading the data of the magnetic recording medium in the selected mode. 1. A method of reading data in a multi-reader two-dimensional magnetic recording system , the method comprising:determining a position of a multi-reader head;selecting a mode for reading the data of a magnetic recording medium as a function of the position of the multi-reader head; andreading the data of the magnetic recording medium in the selected mode.2. The method of claim 1 , wherein the position is determined relative to a diameter of the magnetic recording medium.3. The method of claim 2 , the method further comprising determining a cross-track spacing between readers of the multi-reader head that corresponds to the position of the multi-reader head claim 2 , the step of selecting the mode further comprising reading a zone table to determine the mode corresponding to the cross-track spacing.4. The method of claim 1 , wherein the position is determined relative to a track of the magnetic recording medium.5. The method of claim 1 , further comprising providing a zone table comprising indications of a plurality of modes claim 1 , each mode corresponding to a different position of the multi-reader head.6. The method of claim 5 , wherein the step of selecting the mode further comprises reading the zone table to determine the mode corresponding to the position of the multi-reader head.7. The method of claim 1 , wherein the mode is a multiple input single output mode.8. The method of claim 7 , further comprising inputting the data read by one or more readers of the multi-reader head into one joint equalizer.9. The method of claim 1 , wherein the mode is a multiple input multiple output mode.10. The method of claim 9 , further ...

MAGNETIC RECORDING AND REPRODUCING APPARATUS

A magnetic recording and reproducing apparatus includes a magnetic recording medium including a recording layer in which at least two magnetic layers are layered on a non-magnetic substrate; and a magnetic head including a main magnetic pole for applying a recording magnetic field in a direction substantially perpendicular to a recording face of the magnetic recording medium and a microwave generating element that generates a microwave magnetic field. The relationship between a thickness Ts of a magnetic layer having a lowest magnetic anisotropy energy among the at least two magnetic layers composing the recording layer of the magnetic recording medium, and a thickness Tt of the recording layer is Ts/Tt≦0.2. The microwave generating element applies the microwave magnetic field having a width broader than the width of the recording magnetic field generated by the main magnetic pole of the magnetic head to the magnetic recording medium.

ESD Protection Surface Charge Control Recording Head

Electrostatic discharge protection can be afforded to a data recording head in accordance with various embodiments. A data recording head may consist of a circuit having a preamp ground connected to a ground substrate via a ground trace. The ground trace can consist of a first leg connected to the ground substrate and a second leg with an open connection extending from a dice line. 1. An apparatus comprising a circuit comprising a preamp ground connected to a ground substrate via a ground trace , the ground trace comprising a first leg connected to the ground substrate and a second leg with an open connection extending from a dice line.2. The apparatus of claim 1 , wherein the first leg has a greater resistance than the second leg.3. The apparatus of claim 1 , wherein the ground substrate comprises AlTiC.4. The apparatus of claim 1 , wherein the preamp ground is concurrently connected to the ground substrate claim 1 , a data reader claim 1 , and a data writer.5. The apparatus of claim 1 , wherein the second leg is positioned between a resistor of the first leg and the preamp ground.6. The apparatus of claim 5 , wherein the open connection comprises a conductive trace ending at an insulating location.7. The apparatus of claim 1 , wherein the ground substrate is positioned on an air bearings surface (ABS).8. The apparatus of claim 1 , wherein the circuit is positioned on a transducing head of a data storage system.9. The apparatus of claim 1 , wherein the circuit is positioned wholly on a single wafer.10. A system comprising a controller connected to a surface charge control circuit comprising a preamp ground connected to a ground substrate via a ground trace claim 1 , the first ground trace comprising a first leg connected to the ground substrate and a second leg with an open connection extending from a dice line and terminating at an insulated location.11. The system of claim 10 , wherein the preamp ground is concurrently connected to a reader heater and a writer ...