Abstract: A shifter that can avoid utilizing a partial pulse, comprising: at least one shifting stage, for receiving an external clock signal or a command triggering clock signal to generate sampling signals according a command signal; and a command triggering clock signal generating circuit, for generating the command triggering clock signal according to the command signal. The shifting stage utilizes the external clock signal to generate the sampling signal but does not utilize the command triggering clock signal to generate the sampling signal, if the command triggering clock signal may have a partial pulse for a cycle that the shifting stage generates the sampling signal.

Abstract: According to at least one embodiment, a signal processor apparatus includes a Viterbi decoder, a processor, and an adjustment module. The Viterbi decoder calculates a branch metric based on an input signal. The processor outputs a processing result correlated with a processing result of the Viterbi decoder. A latency of the processor for the input signal is lower than a latency of the Viterbi decoder. The adjustment module adjusts a first parameter for calculating the branch metric based on the processing result of the processor.

Abstract: Disclosed is a technique of providing a large-capacity magnetic storage device at high device manufacturing yield while keeping the reliability, the magnetic storage device enabling recording on a perpendicular magnetic recording medium having distribution of characteristics in the circumferential direction as well at high track density of 500 kTPI or more that would be expected from the average characteristics of the medium. A recording condition from is selected for each sector from a parameter table that stores a set of at least two types of recording conditions by a microwave assisted magnetic recording head including a magnetic recording pole and a high-frequency magnetic field oscillator in the magnetic storage device, and information is recorded for each sector based on the condition.

Abstract: Technologies are described herein for writing servo reference patterns in a storage device implementing heat-assisted magnetic recording. A recording signal for the servo reference patterns is generated through a read/write channel to a read/write head of the storage device. The read/write head is moved across a recording surface of a disk in the storage device as the disk is rotated and an intermittent signal is applied to a write gate interposed between the read/write channel and the read/write head so that a maximum continuous writing time of the recording signal does not exceed a continuous write time limit of the storage device.

Abstract: Various approaches, methods, systems, circuits and devices for channel bit density estimation.

Abstract: An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.

Abstract: Methods and architecture for monitoring hard disk drive operation is provided. The hard disk drive system provided includes a spindle, a head and a disk with a disk medium including a buried servo layer having a first frequency of data on a first track and a second frequency of data on a second track, the second track adjacent to the first track. The method includes the steps of writing a wide track pattern having a predetermined frequency on a track of a hard disk drive medium, generating a readback signal by reading the pattern from the track, processing the readback signal by mixing the readback signal with a reference signal to obtain a mixed signal having a summed signal and a difference signal, and filtering the mixed signal by a filter centered around the difference signal to generate a measurement signal corresponding to a relative speed change of the spindle and a head-to-disk motion.

Abstract: In a disk drive apparatus, there is provided with a controller which determines a demodulated positioning error from a demodulated position and a target position, wherein the demodulated position is obtained by demodulating a servo signal readout from the disk. The controller estimates a demodulation noise amount which is included in the demodulated position on the basis of a signal quality of the servo signal, and corrects a predetermined off-track threshold with a correction value which is obtained from the estimated demodulation noise amount. A write operation of writing data on the disk is inhibited, if the demodulated positioning error exceeds the corrected off-track threshold.

Abstract: A low-power-mode unit connected in parallel with a low-dropout regulator to provide a low-power mode includes a power P-MOS transistor, a differential amplifier, and an analog synchronization loop. The analog synchronization loop is configured to add a variable voltage offset depending on a total current at the output such that, in a high-power mode, the low-power unit current flowing through the P-MOS transistor is not zero, while being substantially smaller than the low-dropout regulator current flowing through the low-dropout regulator, and smaller than a predetermined value.

Abstract: A disk drive slider is disclosed comprising a first read element for generating a first read signal, and a first sense amplifier comprising a first input terminal coupled to the first read element, a first output terminal coupled to a first output line, and a first supply terminal coupled to a supply line. The first sense amplifier is for amplifying the first read signal to generate a first amplified read signal, the first output line is for transmitting the first amplified read signal to a preamp, and the supply line is for coupling to the preamp in order to supply power to the first sense amplifier and supply a first bias to the first read element.

Abstract: A disk drive slider is disclosed comprising a first read element for generating a first read signal, and a first sense amplifier comprising a first input terminal coupled to the first read element, a first output terminal coupled to a first output line, and a first supply terminal coupled to a supply line. The first sense amplifier is for amplifying the first read signal to generate a first amplified read signal, the first output line is for transmitting the first amplified read signal to a preamp, and the supply line is for coupling to the preamp in order to supply power to the first sense amplifier and supply a first bias to the first read element.

Abstract: 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.

Abstract: According to one embodiment, there is provided an FPC (Flexible Printed Circuits) assembly including an FPC and a reinforcing plate The reinforcing plate reinforces a part of the FPC. The reinforcing plate has a first part and a second part. The first part is disposed in a part of the reinforcing plate and formed of a material whose main component is resin. The second part is disposed in a part other than the part of the reinforcing plate and formed of a material whose main component is metal.

Abstract: A Dynamic Wave-Shaping (DWS) write driver for use in a preamp in a disk drive is described. The DWS write driver includes a Dynamic Current Booster (DCB) that adds a current component (WDCB) to the standard write driver signal (including overshoot) that is a function of the bit spacing in the write data input waveform supplied to the write driver. The invention allows dynamic control of the bit-pattern dependent overshoot amplitude without requiring significant preamp overhead. Embodiments of the Dynamic Current Booster include a programmable analog feed-forward timer at the preamp level. The boost current amplitude is a function of the time between the transitions that represent bits. In embodiments, the polarity of the boost current WDCB can be programmed to be positive or negative.

Abstract: A semiconductor integrated circuit device has a p-type substrate to which a ground voltage is applied and a floating-type NMOSFET which is integrated on the p-type substrate and to which a negative voltage lower than the ground voltage is applied. The floating-type NMOSFET includes an n-type buried layer buried in the p-type substrate, a high voltage n-type well formed on the n-type buried layer and floats electrically, a p-type drift region formed in the n-type well, an n-type drain region and an-type source region formed in the p-type drift region, and a gate electrode formed on a channel region interposed between the n-type drain region and the n-type source region. The high voltage n-type well includes an n-type tunnel region, with a higher impurity concentration than that of the high voltage n-type well, inside a peripheral region formed so as to surround the p-type drift region.

Abstract: Devices and methods for reducing thermal stress within a head of a storage device are disclosed. In one or more embodiments, a method includes writing a selected pattern to a storage medium of a storage device using a head of the storage device; reading the selected pattern from the storage medium using the head to provide a data signal; and calculating an instability value of the head based on the data signal. The method can further include reconfiguring the storage device if the instability value is greater than an instability threshold by performing at least one of: deactivating a heater if the head includes two or more heaters; and increasing a fly height between the head and the storage medium.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Individual magneto-resistive read elements are connected to the pre-amplifier through a multi-conductor transmission line; one side of each magneto-resistive read element is taken to a single common lead which is also received in the read pre-amplifier. Amplification and bias control are performed by the read pre-amplifier. A low-noise input stage amplifier configuration accommodates a shared common lead in a multi-head environment. Means for independently biasing the magneto-resistive read elements are also provided. Feedback loops are employed to regulate the operating points of the input stages, and to set the potential of the common head terminal. Two-dimensional magnetic recording system testability is enhanced by ability to multiplex any head to a single system output.

Abstract: Systems and techniques relating to storage devices, such as storage devices that employ Shingled Magnetic Recording (SMR), can include a device, which includes: circuitry configured to write stored data and parity data to discrete portions of a Shingled Magnetic Recording (SMR) track in a SMR storage device; and circuitry configured to recover stored data for one of the discrete portions of the SMR track using the parity data and the stored data read from remaining ones of the discrete portions of the SMR track.

Abstract: According to one embodiment, a magnetic disk apparatus includes a plurality of magnetic disks, a plurality of heads which execute recording or reading with respect to the magnetic disks, a plurality of sensors provided in each of the heads and output a signal in accordance with a flying height of the heads from the magnetic disks, a writing module which simultaneously writes servo data in the plurality of magnetic disks by using the plurality of heads, and a control module which simultaneously executes a process for detecting a crash of the heads into the magnetic disks for the plurality of heads based on each output signal of the plurality of sensors when the servo data is written.

Abstract: 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.

Abstract: Systems and method relating generally to data processing, and more particularly to systems and methods for tone reduction in relation to data transmission. In one case, a data processing system is disclosed that includes: a two stage tone reduction circuit including a first stage circuit and a second stage circuit; and a polarity change circuit operable to change a polarity of the second stage output to yield a tone reduction output.

Abstract: Implementations described and claimed herein provide a stacked dual reader with a bottom sensor stack and a top sensor stack wherein the bottom sensor stack and the top sensor stack are mirrored along a down-track direction.

Abstract: Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for reducing inter-track interference in relation to processing data retrieved from a storage medium.

Abstract: A system including a first filter module configured to receive an input signal including (i) a first shift in a DC level of the input signal and (ii) a second shift in the DC level of the input signal. The first shift has (i) a first magnitude and (ii) a first duration. The second shift has (i) a second magnitude and (ii) a second duration. The second magnitude is different than the first magnitude. The second duration is greater than the first duration. The first filter module is configured to pass the first shift. The second filter module is configured to detect one or more of (i) the first shift and (ii) the second shift, and in response to detecting one or more of (i) the first shift and (ii) the second shift, filter one or more of (i) the first shift and (ii) the second shift.

Abstract: Detecting surface irregularities on a disk of a data storage device (DSD) includes reading data from a first side of the disk using a first head of the DSD. A first set of variable gain amplifier (VGA) values is generated which is related to the reading of data from the first side using the first head. Data is read from a second side of the disk using a second head of the DSD and a second set of VGA values is generated which is related to the reading of data from the second side using the second head. A profile for the disk is determined using the first set of VGA values and the second set of VGA values. The profile is compared to at least one threshold to detect surface irregularities on the disk.

Abstract: Sliding-window based data processing includes receiving an analog signal, converting the analog signal to a series of digital samples synchronous to a sampling clock, performing a first discrete Fourier transform on a first portion of the series of digital samples, performing a second discrete Fourier transform on a second portion of the series of digital samples, performing a third discrete Fourier transform on a third portion of the series of digital samples, generating a first series of zero phase start values by calculating a zero phase start value based on the first discrete Fourier transform in a sliding-window at a series of time increments across the servo preamble, storing the zero phase start values, and averaging the stored zero phase start values at the end of the servo preamble.

Abstract: According to one embodiment, a magnetic disk apparatus includes a main magnetic pole configured to apply a recording magnetic field to a recording medium, a recording coil configured to magnetize the main magnetic pole, a spin-torque oscillator adjacent to the main magnetic pole, and configured to generate a high frequency magnetic field, a recording current control circuit configured to supply a recording current to the recording coil, a driving current control circuit configured to supply a fixed driving current to the spin-torque oscillator, and an overshoot control circuit configured to control overshoot current of the recording current in proportion to the magnitude of the driving current after the recording current has reversed.

Abstract: Interface circuitry of a storage device or other type of processing device comprises a digital input detector and an adaptive power supply. The digital input detector comprises an input transistor. The adaptive power supply provides a variable supply voltage to the digital input detector that varies with a threshold voltage of the input transistor. In one embodiment, the variable supply voltage provided to the digital input detector by the adaptive power supply varies with the threshold voltage of the input transistor about a set point value determined as a function of an expected logic level of an input signal. For example, the set point value may be determined as a function of a minimum expected logic high input signal level. In such an arrangement, the input transistor is biased at or close to the threshold voltage for an input signal having the minimum expected logic high input signal level.

Abstract: A method of enhancing read performance in array-reader hardware includes generating, by the array-reader hardware, a plurality of signals, according to data read from a magnetic disk, and canceling at least a portion of cross-talk in the plurality of signals to generate a plurality of corrected signals.

Abstract: A read channel of a storage device. The read channel includes a data generator configured to generate a test symbol. An encoding circuit in a write path of the read channel is configured to encode the test symbol as a write signal and provide the write signal to a preamplifier circuit to be amplified by the preamplifier circuit. A decoding circuit in a read path of the read channel is configured to receive the write signal as amplified by the preamplifier circuit and decode the write signal as amplified by the preamplifier circuit to determine a received symbol corresponding to the encoded test symbol. A comparator is configured to compare the received symbol to the test symbol and output, based on the comparison of the received symbol and the test symbol, an indication of whether the preamplifier circuit is operational.

Abstract: 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.

Abstract: A storage system with pattern dependent write includes a magnetic write head, a magnetic storage medium, a read channel operable to process write data to be recorded on the magnetic storage medium by the magnetic write head, and a preamplifier operable to receive the write data and an associated clock from the read channel, to generate a pattern dependent write control signal based on a pattern in the write data and on the clock, and to set a write current level through the magnetic write head to a number of different current levels based on the pattern dependent write control signal.

Abstract: The disclosure is directed to a low noise amplifier (LNA) configuration that compensates for DC offsets of incoming signals from a magnetoresistive head. According to various embodiments, the LNA includes a shunt-feedback differential pair of amplifiers adaptively biased according to a detected input DC voltage offset of the incoming signals from the magnetoresistive head. The LNA is thus enabled to amplify the AC signal component substantially unaffected by the DC offset. The DC component in the LNA output signal is then removable via offset compensating circuitry located between the LNA and subsequent stages without significant signal-to-noise ratio (SNR) penalty.

Abstract: A data signal comprising an even component and an odd component with differing amplitudes is received at a main automatic gain controller (AGC). The even component is adjusted by a first interleaved AGC and the odd component is adjusted by a second interleaved AGC such that even and odd component amplitudes are substantially equal. Amplitude adjusted even and odd components are recombined to define a data signal with components having substantially equal amplitudes. The even and odd components can be generated by a read transducer moving relative to a magnetic storage medium comprising tracks defined by discrete and spaced-apart recording bits arranged in an interspersed pattern. A read channel separates the data signal into even and odd samples such that a gain can be independently adjusted for each of the even and odd samples to compensate for asymmetry between the even and odd samples.

Abstract: A circuit includes an input that receives a current that increases as a tunneling current sensor moves closer to a media. A high gain path is operatively coupled to the input to amplify the received current as a first amplified output. The first amplified output increases until a saturation threshold is attained for the high gain path. Further increases in the received current beyond the saturation threshold are diverted from the input as an overflow current. A low gain path is operatively coupled to the input to amplify the overflow current as a second amplified output. The second amplified output increases with the overflow current as the tunneling current sensor continues to move closer to the media.

Abstract: A semiconductor integrated circuit device has a p-type substrate to which a ground voltage is applied and a floating-type NMOSFET which is integrated on the p-type substrate and to which a negative voltage lower than the ground voltage is applied. The floating-type NMOSFET includes an n-type buried layer buried in the p-type substrate, a high voltage n-type well formed on the n-type buried layer and floats electrically, a p-type drift region formed in the n-type well, an n-type drain region and an-type source region formed in the p-type drift region, and a gate electrode formed on a channel region interposed between the n-type drain region and the n-type source region. The high voltage n-type well includes an n-type tunnel region, with a higher impurity concentration than that of the high voltage n-type well, inside a peripheral region formed so as to surround the p-type drift region.

Abstract: The present invention is related to systems and methods for adaptive parameter modification in a data processing system.

Abstract: A circuit includes an input that receives a current that increases as a tunneling current sensor moves closer to a media. A high gain path is operatively coupled to the input to amplify the received current as a first amplified output. The first amplified output increases until a saturation threshold is attained for the high gain path. Further increases in the received current beyond the saturation threshold are diverted from the input as an overflow current. A low gain path is operatively coupled to the input to amplify the overflow current as a second amplified output. The second amplified output increases with the overflow current as the tunneling current sensor continues to move closer to the media.

Abstract: Disk drives with sliders including with an impedance compensation network in the signal path for the read sensor are described. The read signal bandwidth at the preamplifier is improved by the impedance compensation network to allow signals in the multi-GHz range from spin torque oscillators as well as tunnel magnetoresistance (TMR) sensors to be used. An embodiment of the invention achieves a signal layout balance by constructing two inductor-capacitor pair structures on the trailing edge of the slider that are integrated into the differential read signal traces. The differential balanced structure helps to suppress external signal interference pick-up from transferring from common-mode pick-up to differential mode.

Abstract: An electric field writing magnetic storage device including: a rotatable disk including a substrate and a magnetic recording film provided on a surface of the substrate, the magnetic recording film including at least one ferromagnetic and ferroelectric layer; a writing device writing information into the magnetic recording film by means of an electric field, the writing device including a writing electrode generating a dielectric flux between the writing electrode and the substrate by having electric potential to the substrate; and a writing circuit choosing one electric potential among plurality of electric potential level and applying the chosen one electric potential to the writing electrode in every operation of writing information, wherein the dielectric flux generated according to the electric potential applied to the writing electrode by the writing circuit magnetizes the ferromagnetic and ferroelectric layer in a specific direction.

Abstract: A drive signal for a motor-driven mechanical system has zero (or near zero) energy at an expected resonant frequency of the mechanical system. These techniques not only generate a drive signal with substantially no energy at the expected resonant frequency, they provide a zero-energy “notch” of sufficient width to tolerate systems in which the actual resonant frequency differs from the expected resonant frequencies.

Abstract: A method for performing parallel flaw scans of a plurality of tracks of a storage device. The storage device includes at least one disk, at least two read sensors, at least two analog front ends, and at least two independent timing loops. Each disk includes at least one surface, wherein each surface includes a plurality of tracks. The method includes writing flaw patterns to tracks of one or more surfaces of one or more disks. The method also includes positioning a first read sensor to read a first track. The method further includes positioning a second read sensor to read a second track. The method additionally includes simultaneously reading signals from the first track and the second track. The method also includes simultaneously performing flaw scans on read back signals from the first track and the second track. The method further includes outputting flaw scan results.

Abstract: An electric field writing magnetic storage device including: a rotatable disk including a substrate and a magnetic recording film provided on a surface of the substrate, the magnetic recording film including at least one ferromagnetic and ferroelectric layer; a writing device writing information into the magnetic recording film by means of an electric field, the writing device including a writing electrode generating a dielectric flux between the writing electrode and the substrate by having electric potential to the substrate; and a writing circuit choosing one electric potential among plurality of electric potential level and applying the chosen one electric potential to the writing electrode in every operation of writing information, wherein the dielectric flux generated according to the electric potential applied to the writing electrode by the writing circuit magnetizes the ferromagnetic and ferroelectric layer in a specific direction.

Abstract: 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.

Abstract: The present disclosure relates to a perpendicular pole head for creating a perpendicular magnetic moment in a concentrated pattern for writing the pattern on perpendicular magnetic media, such as BaFe based media. The pole head can have flux concentrators in the shape of the written pattern, which can be repeatedly applied to a moving magnetic medium to create a timing pattern on the media, e.g., a servo timing pattern.

Abstract: 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.

Abstract: A servo system includes a first equalizer circuit operable to filter digital servo data samples derived from a first read head to yield first equalized data, a second equalizer circuit operable to filter digital servo data samples derived from a second read head to yield second equalized data, a first interpolator operable to interpolate the first equalized data to yield a number of first interpolated outputs at different phases, a second interpolator operable to interpolate the second equalized data to yield a number of second interpolated outputs at different phases, and a phase tracking and signal combining circuit operable to select and combine most closely aligned signals from the first interpolated outputs and the second interpolated outputs to yield a combined servo data signal.