Abstract: Methods and apparatus, including computer systems and program products, related to declarative synchronization of shared data. One method includes receiving one or more changes to data maintained by one of multiple computer programs having respective local copies of the data, identifying an event characterizing synchronization of the data maintained by the computer program with the other computer programs (e.g., with a local copy managed by the other computer program), and initiating synchronization of the changes with one of the other programs having respective local copies (e.g., with the local copy managed by the other program) in response to the event occurring. The event can be characterized by an annotation. Identifying an event can include reading a property of a data object (e.g., in a data object graph of shared data).

Abstract: According to one embodiment, a magnetic disk device includes a magnetic recording medium, a head including a recording magnetic pole, a spin torque oscillator provided near the recording magnetic pole, and a coil which excites the recording magnetic pole, a first current supply which supplies the coil with a first current corresponding to write data, a detector which detects a first signal corresponding to the write data, and outputs a second signal in accordance with the first signal, and a second power supply which varies, in accordance with the second signal, a second current supplied to the spin torque oscillator.

Abstract: A card reader is provided with a read head with a slot and is configured to be coupled to a mobile device and has a slot for swiping a magnetic stripe of a card. The read head reads data on the magnetic stripe and produces a raw magnetic signal indicative of data stored on the magnetic stripe. A power supply is coupled to wake-up electronics and a microcontroller. An output jack is adapted to be inserted in a port of the mobile device and deliver an output jack signal to the mobile device. The wake-up electronics is powered by a microphone bias of a mobile device.

Abstract: A slider of a magnetic recording head comprises a plurality of electrical bond pads coupled to bias sources and a ground pad. Each of a plurality of electrical components of the slider is coupled one or more of the electrical bond pads, wherein at least one of the electrical bond pads is a shared electrical bond pad coupled to at least a first electrical component and a second electrical component. A switching transistor is coupled to the first and second components and the ground pad. The switching transistor is arranged to control powering of the second component in response to biasing of the first component.

Abstract: A wide dynamic range trans-impedance amplifier includes a first trans-impedance amplifier configured to receive a first input current and produce a first voltage as a function of the first input current, and a second trans-impedance amplifier configured to receive a second input current and produce a second voltage as a function of the second input current. A current steering element causes a first portion of current from a current source to flow to the first trans-impedance amplifier until the first current portion reaches the first threshold current, and causes a second portion of current from the current source to flow to the second trans-impedance amplifier, until the second current portion reaches the second threshold current. The second current portion is current from the current source that exceeds the first threshold current. The wide dynamic range trans-impedance amplifier may receive, for example, ion collector current from a hot cathode ionization gauge (HCIG).

Abstract: The present invention relates to a transmitter, a receiver and to corresponding methods for transmitting and receiving data utilizing sequences of non-return-to-zero, inverted (NRZI) symbols and symbol rates higher than the Nyquist rate in data transmission systems, thus enabling an enlarged spectral efficiency while utilizing simple receivers only having sign information.

Abstract: A circuit may be configured to precompensate the storage of data on a storage device. The magnitude and polarity of the precompensated time adjustment can be determined by looking up data patterns of storage regions in a table. A boundary can include storage regions of the device used to determine the precompensation.

Abstract: A storage system includes a magnetic write head, a magnetic storage medium, a write data circuit having a write data output and a magnet length signal output, and a preamplifier that receives the write data and a magnet length signal from the write data circuit, and sets at least one write current characteristic through the magnetic write head based at least in part on the magnet length signal. The write data circuit processes write data to be recorded on the magnetic storage medium by the magnetic write head. The magnet length signal output communicates magnet lengths in the write data.

Abstract: The present invention provides methods and systems for narrow bandwidth digital processing of an input audio signal. Particularly, the present invention includes a high pass filter configured to filter the input audio signal. A first compressor then modulates the filtered signal in order to create a partially processed signal. In some embodiments, a clipping module further limits the gain of the partially processed signal. A splitter is configured to split the partially processed signal into a first signal and a second signal. A low pass filter is configured to filter the first signal. A pass through module is configured to adjust the gain of the second signal. A mixer then combines the filtered first signal and the gain-adjusted second signal in order to output a combined signal. In some embodiments, a tone control module further processes the combined signal, and a second compressor further modulates the processed signal.

Abstract: A storage system includes a magnetic write head, a magnetic storage medium, a channel circuit comprising a write data output, wherein the channel circuit is 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 from the channel circuit, wherein the preamplifier comprises a number of register pages configured to store pattern dependent write current characteristics for a variety of magnet lengths, and wherein the preamplifier is operable to retrieve the write current characteristics based on magnet lengths and to record data bits on the magnetic storage medium using the write current characteristics.

Abstract: Various embodiments of the present invention that include arranging a first storage device and second storage device to store data in a mirrored configuration. Upon receiving a message indicating that the first storage device is in an error recovery mode, the host processor can convey a second request to read the data from the second storage device. The storage device is selected from a list comprising a hard disk drive and a solid state disk drive, and the hard disk drive comprises a disk head having a magnetoresistive (MR) element configured to read and write data to and from the storage media, and coupled to an analog/digital (A/D) converter, and wherein the error recovery operation is selected from a list comprising changing an automatic gain control of the A/D converter, positioning the disk head off-track in order to read the data, and adjusting a bias value of the MR element.

Abstract: A sensor system or a sensor bus comprises a plurality of sensors coupled together by a bus to a controller for sensing physical parameters and responding to changes of the physical parameters. The bus comprises a two wire bus, with a first wire and a second wire, configured to communicate supply signals to the plurality of sensors and data communication signals generated by current modulate signals from the plurality of sensors or the controller. The plurality of sensors and the controller comprise variable current sources. The variable current sources of the sensors generate data communication signals in a first frequency range, while the variable currents sources of the controller and sensors regulate the supply signals from the bus in a different frequency range. A termination network having termination, dividers at both ends of the bus, match the load impedances and the line impedances of the bus within the first frequency range, which is about five to ten times larger than the second frequency range.

Abstract: 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.

Abstract: 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.

Abstract: A method and an apparatus for controlling a threshold voltage are provided. The method includes receiving noise event signals from a sensing core, the sensing core sensing a portion of a moving object, and generating an event signal. The method further includes determining a type of the noise event signals, determining a number of the noise event signals based on the type of the noise event signals, determining whether the number of the noise event signals satisfies a condition, and controlling a threshold voltage value corresponding to the noise event signals in response to the determining that the number of the noise event signals does not satisfy the condition.

Abstract: Systems and methods relating generally to data storage, and more particularly to systems and methods for accessing and storing information using multiple sensors.

Abstract: The input samples transmitted by the base station are decimated and the decimated samples are correlated with the three reference PSS sequences to obtain the correlation results. The correlation results are differentially combined to obtain the hypotheses. The hypotheses are grouped into windows. The peaks across windows of multiple half frames are selected and obtained peaks are averaged over the multiple half frames to detect the half frame boundary window. Reference PSS versions are generated for ICFO estimation. The hypotheses are generated in the HFBW. The highest averaged hypothesis is selected to estimate ICFO. The ICFO error is corrected by adjusting a reference clock signal. The decimated samples are correlated and differentially combined around the HFB to determine a HFB and a FCFO from the peak value of the hypotheses. The received samples are correlated and differentially combined around the half frame boundary to further refine HFB and FCFO estimations.

Abstract: A computer program product for monitoring head wear includes reading from a cartridge a high frequency pattern and a low frequency pattern, determining a first read amplitude corresponding to the high frequency pattern and a second read amplitude corresponding to the low frequency pattern, and determining a head wear metric according to the first read amplitude and the second read amplitude.

Abstract: A hard disk drive write drive method and integrated circuit that provide a configurable overshoot current based on the length of the pattern in the write current signal that is being written to the hard disk by the write driver. The hard disk write driver adds a first overshoot current to all patterns in the write current signal and adds an additional second overshoot current to patterns in the write current signal shorter than a first duration. The hard disk drive write driver utilizes an H-bridge circuit configured to add the first overshoot current and the additional second overshoot current to the write current signal. The H-bridge circuit is comprised of four switching elements that are configured to generate a first overshoot current for all pattern transitions of the write current signal and generate a second overshoot current for pattern transitions shorter than the first duration.

Abstract: A decoder includes variable-node circuitry, check-node circuitry and a Message Passing (MP) module, which includes multiple configurable partial cyclic shifters that each supports only a partial subset of shift values out of a full range of shift values 0 . . . L?1. The variable-node circuitry and check-node circuitry are configured to exchange messages with one another in accordance with a parity check matrix that represents a respective Quasi-Cyclic (QC)-Low Density Parity Check (LDPC) Error Correcting Code (ECC) and that includes L-by-L sub-matrices, and to process the exchanged messages to decode a given code word that was encoded using the QC-LDPC ECC. The MP module is configured to schedule the variable-node circuitry and check-node circuitry that are interconnected in accordance with a respective sub-matrix to exchange L messages simultaneously by assigning a given partial cyclic shifter to shift the L messages cyclically a number of positions that depends on a structure of the respective sub-matrix.

Abstract: A sensor arrangement for position sensing comprises a magnetic field source and a magnetoresistive element arranged in a magnetic field generated by the magnetic field source, which magnetoresistive element provides an output signal (R) dependent on a position (x) of the magnetoresistive element relative to the magnetic field source. A feedback controller is configured to receive the output signal (R) of the magnetoresistive element and is configured to adjust one or more of the position (x) of the magnetoresistive element relative to the magnetic field source and a strength of the magnetic field generated by the magnetic field source acting on the magnetoresistive element dependent on the output signal (R) of the magnetoresistive element.

Abstract: A method, executed by a computer, for monitoring head wear includes reading from a cartridge a high frequency pattern and a low frequency pattern, determining a first read amplitude corresponding to the high frequency pattern and a second read amplitude corresponding to the low frequency pattern, and determining a head wear metric according to the first read amplitude and the second read amplitude. A computer program product and computer system corresponding to the above method are also disclosed herein.

Abstract: Systems and methods are provided for decoding low density parity check (LDPC) codes with different circulant sizes using common decoding circuitry. The systems and methods include receiving a plurality of codewords corresponding to an LDPC code and determining a circulant size associated with the plurality of received codewords. In response to determining the circulant size associated with the plurality of received codewords, the systems and methods partition processing resources of the common decoding circuitry into a plurality of cells based on the determined circulant size and processing the plurality of received codewords simultaneously using the plurality of cells.

Abstract: Some methods provide an electronic design file, which includes an integrated circuit (IC) component that is operably coupled to a package component. The IC component and package component collectively form a resistor inductor capacitor (RLC) resonant circuit. The method also provides a damping component in the electronic design file. This damping component is configured to reduce a pre-resonant time during which energy exchanged in the RLC resonant circuit approaches a steady-state, and thereby speeds simulation time.

Abstract: A magnetization controlling element includes a ferromagnetic material layer, an exchange coupling adjustment layer, an antiferromagnetic material layer, an electrode layer, a magnetic field applying mechanism which applies a magnetic field to the antiferromagnetic material layer, and an electric field applying mechanism which applies an electric field to the antiferromagnetic material layer. The antiferromagnetic material layer contains an antiferromagnetic material or ferrimagnetic material having a magnetoelectric effect, the ferromagnetic material layer includes a perpendicular magnetization film having a magnetization component perpendicular to the film surface, the ferromagnetic material layer includes a ferromagnetic material layer that is magnetically connected, through exchange coupling, to the antiferromagnetic material layer. The exchange coupling adjustment layer has a function of adjusting exchange coupling between the ferromagnetic material layer and the antiferromagnetic material layer.

Abstract: Systems and methods are disclosed for binding shingled recording bands in data storage devices, particularly devices employing shingled magnetic recording. In one embodiment, an apparatus may comprise a controller configured to define boundaries of an area of a data storage medium based on a constraint and a list of defective sectors. In another embodiment, an apparatus may comprise a data storage device including a memory configured to store data in a shingled manner where one track partially overlaps an adjacent track, and a controller configured to define boundaries of a plurality of bands, each band including a plurality of tracks of the memory, based on the results of an error discovery scan for defective sectors of the memory.

Abstract: A semiconductor apparatus includes a transmission block and a reception block. The transmission block may convert an input signal into two or more synchronization signals, some bits of which have longer data valid windows than the other bits, and output the two or more synchronization signals. The reception block may generate the output signal by capturing bits having longer data valid windows between the two or more synchronization signals.

Abstract: An apparatus for two-dimensional magnetic recording includes an array reader with a number of magnetoresistive read sensors configured to read data from a storage medium. The magnetoresistive read sensors have a number of connection terminals, with at least one of the connection terminals being shared by more than one of the magnetoresistive read sensors. The apparatus also includes a number of low-noise amplifiers connected to the connection terminals, each configured to amplify a differential signal from a different one of the magnetoresistive read sensors. The apparatus also includes a number of impedance balancing networks connected to a subset of the connection terminals.

Abstract: Systems and methods relating generally to data processing, and more particularly to adjusting gain parameters in relation to data processing.

Abstract: An analog signal processing device for equalizing a low pass filter to create a Nyquist filter in accordance with the present invention includes a low pass filter for passing a predetermined bandwidth, and a tapped delay filter connected with the low pass filter to create the Nyquist filter. In more detail, the tapped delay filter is used to sample an input analog signal having a predetermined symbol rate. The samples from the input signal are then respectively weighted to establish a system transfer function for the Nyquist filter. The purpose here is to minimize both inter-symbol interference and transmission bandwidth. A decision circuit can be provided to convert the input signal into a desired data format for creation of an output signal to be transmitted by the data transmission system. Also, the Nyquist filter can be selectively evaluated as an “eye diagram” and the system transfer function appropriately adjusted accordingly.

Abstract: A method, executed by a computer, for monitoring head wear includes reading from a cartridge a high frequency pattern and a low frequency pattern, determining a first read amplitude corresponding to the high frequency pattern and a second read amplitude corresponding to the low frequency pattern, and determining a head wear metric according to the first read amplitude and the second read amplitude.

Abstract: Embodiments are related to systems and methods for data processing, and more particularly to systems and methods for data encoding and decoding.

Abstract: A data storage device is disclosed comprising a head actuated over a disk. A first control circuit comprises a pattern detector configured to detect at least one pattern in write data and generate a corresponding multi-state signal, and a transmitter configured to transmit a first differential signal representing the write data and a second differential signal representing the multi-state signal. A second control circuit comprises a receiver configured to receive the first differential signal and the second differential signal, and a write driver configured to generate a write current applied to the head based on the first differential signal and configured to adjust at least one property of the write current based on the second differential signal.

Abstract: A write driver is configured to determine a magnitude and an application time of a pre-emphasis current pulse in response to control codes generated according to parasitic components on a path from a write driver to a program target cell and a resistance value of the program target cell, and supply a preset program current to a memory circuit block by adding a pre-emphasis current to the preset program current in a program mode.

Abstract: An apparatus, according to one embodiment, includes a controller having a write driver, and a comparator circuit configured to detect a high resistance condition by comparing a first output voltage of the write driver with a second output voltage of the comparator circuit. A high resistance condition is detected in response to determining that the second output voltage of the comparator circuit is greater than the first output voltage of the write driver. Other systems, methods, and computer program products are described in additional embodiments.

Abstract: Systems and methods for high speed communications are described herein. In certain aspects, the systems and methods include innovative transceiver architectures and techniques for re-timing, multiplexing, de-multiplexing and transmitting data. The systems and methods can be used to achieve reliable high-speed point-to-point communication between different electronic devices, computing devices, storage devices and peripheral devices.

Abstract: A data storage device is disclosed comprising a head actuated over a disk. The head is positioned at a first radial location over the disk and at least part of a codeword on the disk is read to generate first signal samples. A first quality metric is generated for the first signal samples. The head is positioned at a second radial location over the disk different from the first radial location and at least part of the codeword is read to generate second signal samples. A second quality metric is generated for the second signal samples. A first subset of the first signal samples is combined with a second subset of the second signal samples based on the first and second quality metrics to generate a combined set of signal samples. An attempt is made to decode the codeword based on the combined set of signal samples.

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: Various embodiments of the present invention provide systems and methods for data filter tuning. As an example, a method for filter tuning is disclosed that includes: providing a tunable filter having an operation filter and a calibration filter; applying a low frequency test input to the operation filter in place of an input signal to yield a first filter output; calculating a low frequency magnitude value corresponding to the first filter output; applying a high frequency test input to the operation filter in place of an input signal to yield a second filter output; calculating a high frequency magnitude value corresponding to the second filter output; modifying a tuning factor of the calibration filter when a ratio of the high frequency magnitude value and the low frequency magnitude value is outside of a defined range; and storing the tuning factor of the calibration filter when the ratio of the high frequency magnitude value and the low frequency magnitude value is within the defined range.

Abstract: An apparatus having a circuit is disclosed. The circuit may be configured to (i) receive an input signal from a communication channel and (ii) generate an intermediate signal by amplifying the input signal (a) by a low-frequency gain in response to an amplitude control signal and (b) by a high-frequency gain in response to a boost control signal.

Abstract: Systems and methods are included for determining a presence of an upcoming reading field during a write mode of a storage device, and initiating a read-while write RWW) mode of the storage device in response to the sensed reading field. Initiating the RWW mode comprises warming up the reader circuitry, generating a signal in response to an end to the write operation, and activating reader bias current in response to the generated signal.

Abstract: A technique for tamper protection of incoming data signal to an electronic device is disclosed. An intentional interference signal is generated and modulated onto the incoming data signal as one composite input signal, to prevent unauthorized acquisition of valid data from the incoming data signal. The magnitude of the interference signal is adjusted to correspond to the magnitude of the incoming data signal, thereby preventing an attacker from properly differentiating the two different signals and/or decoding the valid data from the composite input signal. Once the composite input signal is safely received within the device, the interference signal can be filtered out in either analog mode or digital mode.

Abstract: Data storage systems having barriers that may reduce erasure flux and increase write-ability are provided. Data storage systems include a writing element. The writing element has a write pole with a flare region. A magnetic flux barrier is located along the write pole flare region. The magnetic flux barrier is illustratively made from an in-plane magnetically anisotropic material that has an easy plane of magnetization. In another embodiment, a data storage system includes a writing element having an air bearing surface and a shield at the air bearing surface. The shield has a magnetic permeability of approximately zero. The shield illustratively includes alternating layers of positive and negative permeabilities. The shield optionally includes a plurality of shields that may include top, bottom, and side shields.

Abstract: A disk drive has multiple preamplifiers (preamps) connected to the system-on-a-chip (SOC) by a common transmission line with resistors between the preamps and the SOC. Each preamp includes a read resistor at the output of each read amplifier, and a write resistor at the input of each write driver. The resistors may be programmable resistors located in the preamps. The read resistors are at the source of the signal to the transmission line and the write resistors are at the termination of the signal from the transmission line. The read and write resistors provide impendence matching with the transmission line and the SOC when one of the preamps is selected as active, which enables the SOC to operate seamlessly with a common transmission line connected to all preamps.

Abstract: According to one embodiment, a system for processing data includes a processor and logic integrated with and/or executable by the processor, the logic being configured to read data from a magnetic data storage medium using a read channel, detect and track positive peak amplitudes and negative peak amplitudes of a readback waveform during the data reading using a tracking threshold module, and perform asymmetry compensation on the data using an asymmetry compensator based on input from the tracking threshold module in an asymmetry compensation loop, wherein the asymmetry compensator does not rely on an input from path metrics in order to perform the asymmetry compensation. Other systems, such as magnetic tape drives, and methods for processing data, and specifically for asynchronously providing asymmetry compensation for data read from a magnetic tape, are described in more embodiments.

Abstract: The present invention is an improved linearizer that implements more complex transfer functions to provide the necessary linearization performance with a reasonable amount of signal processing resources. Particularly, the linearizer operates on an analog-to-digital converter and comprises a distortion compensator and one or more factored Volterra compensators, which may include a second-order factored Volterra compensator, a third-order factored Volterra compensator, and additional higher-order factored Volterra compensators. Inclusion of factored Volterra distortion compensators improves linearization processing performance while significantly reducing the computational complexity compared to a traditional Volterra-based compensator.

Abstract: Disclosed herein is a data reproduction circuit including: a comparator configured to compare input data resulting from capacitive coupling with a comparison voltage as a threshold voltage and output a comparison result; and a comparison voltage variable section configured to change the comparison voltage along a mark rate of the input data and supply the changed comparison voltage to the comparator.

Abstract: A digital gain estimation loop and a gain smoothing method for burst demodulation in a servo channel are disclosed. The gain estimation is performed on digital samples obtained from a digital finite impulse response (DFIR) filter, wherein the digital samples include at least a portion of a servo address mark (SAM) and gray data in the servo sector. The gain estimation method includes the steps of: generating a reference signal based on the digital samples obtained from the DFIR filter; generating a comparison signal by delaying the digital samples obtained from the DFIR filter; determining a gain error gradient by comparing the reference signal and the comparison signal; and calculating the second gain adjustment based on the gain error gradient.

Abstract: A system for accessing a data from a storage device includes a gain value calculation circuit operable to calculate a first gain value based upon a data set, an early gain acquisition circuit operable to generate a second gain value in parallel to calculation of the first gain value by the gain value calculation circuit, and a gain combination circuit operable to combine the first gain value and the second gain value to yield a third gain value.

Abstract: A method for measuring a change in a spacing between a head and a storage medium of a data storage system. The method includes obtaining a first readback signal from the storage medium using the head at a first spacing between the head and the storage medium, determining a first power spectrum density over a frequency range from the obtained first readback signal, obtaining a second readback signal from the storage medium using the head at a second spacing between the head and the storage medium, determining a second power spectrum density over the frequency range from the obtained second readback signal, and providing a measurement indicative of the change in the spacing based on the determined first power spectrum density and the determined second power spectrum density. A data storage system is also provided.