Abstract: A method, apparatus and a data storage device are provided for implementing track following and data recovery with readback of shingled data written in overlapping shingled data tracks on a recordable surface of a storage device. Positional information is identified with data readback of shingled data written in overlapping shingled data tracks. The identified positional information is used to selectively modify at least one predefined channel parameter, for example, to provide enhanced track following and enhanced data recovery.

Abstract: A method, apparatus, and system are provided for implementing magnetic defect location detection on-the-fly for hard disk drives. A magnetic media readback signal of a hard disk drive is demodulated to generate phase modulation (PM) and amplitude modulation (AM) signals. A new coordinate plane defined by a combined phase modulation (PM) and amplitude modulation (AM) phasor-defect detector calculation function used to locate magnetic defects on-the-fly.

Abstract: Embodiments of the present invention relate to the detection of synchronization marks in data storage and retrieval. According to one embodiment, synchronization marks are detected from the output of a matched filter, upstream of the Viterbi detector. This approach avoids the delay associated with the latency of the Viterbi output, thereby allowing time to align parity framing and to properly start the time-varying trellis. Certain embodiments disclose 34- and 20-bit primary synchronization marks located at the beginning of a data region. Other embodiments disclose 16-, 20-, and 24-bit embedded synchronization marks located within a data region.

Abstract: A Flash memory system and a method for data management using the system's sensitivity to charge-disturbing operations and the history of charge-disturbing operations executed by the system are described. In an embodiment of the invention, the sensitivity to charge-disturbing operations is embodied in a disturb-strength matrix in which selected operations have an associated numerical value that is an estimate of the relative strength of that operation to cause disturbances in charge that result in data errors. The disturb-strength matrix should also include the direction of the error which indicates either a gain or loss of charge. The disturb-strength matrix can be determined by the device conducting a self-test in which changes in the measured dispersion value are provoked by executing a selected operation until a detectable change occurs. In alternative embodiments the disturb-strength matrix is determined by testing selected units from a homogeneous population.

Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator sensing with an enhanced integrated demodulator for hard disk drives. The demodulator receives an input signal from a STO read sensor having an oscillation frequency ? related to the strength of the detected magnetic signal field. The demodulator includes a pair of mixers coupled to a quadrature reference oscillator with respective quadrature components cos(?0t), and sin(?0t) of the quadrature reference oscillator being mixed with a received input signal to form signals at the sum and difference frequencies, ?±?0. Each of these mixer products is lowpass filtered by a respective a lowpass filter to remove the sum frequency components for providing a demodulator output signal that is directly proportional the STO oscillation frequency ?. The demodulator output signal is used for processing by data detection electronics.

Abstract: 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.

Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator sensing with an enhanced integrated demodulator for hard disk drives. The demodulator receives an input signal from a STO read sensor having an oscillation frequency ? related to the strength of the detected magnetic signal field. The demodulator includes a pair of mixers coupled to a quadrature reference oscillator with respective quadrature components cos(?0t), and sin(?0t) of the quadrature reference oscillator being mixed with a received input signal to form signals at the sum and difference frequencies, ?±?0. Each of these mixer products is lowpass filtered by a respective a lowpass filter to remove the sum frequency components for providing a demodulator output signal that is directly proportional the STO oscillation frequency ?. The demodulator output signal is used for processing by data detection electronics.

Abstract: 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.

Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator (STO) sensing with a demodulator for hard disk drives. The demodulator measures an instantaneous phase of the readback signal from a STO sensor and converts the readback signal into a signal that is proportional to the magnetic field affecting the STO frequency during a bit time. The converted signal is used for processing by conventional data detection electronics.

Abstract: A method, apparatus, and system are provided for implementing magnetic defect classification using phase modulation for hard disk drives. A magnetic media readback signal of a hard disk drive is processed to identify predefined phase modulation (PM) characteristics to implement magnetic defect classification of magnetic media bump and pit defects.

Abstract: Techniques for early detection of degradation in NAND Flash memories by measuring the dispersion of the threshold voltages (VT's), of a set (e.g. page) of NAND Flash memory cells during read operations are described. In an embodiment of the invention the time-to-completion (TTC) values for the read operation for the memory cells are used as a proxy for dispersion of the threshold voltages (VT's). A Dispersion Analyzer determines the dispersion of the set of TTC values. In one embodiment the delta between the maximum and minimum TTC values is used as the dispersion measurement. If the measured TTC dispersion differs by more than a selected amount from a reference dispersion value, a warning signal is provided to indicate that the page of memory has degraded. The warning signal can be used to take appropriate action such as moving the data to a new page.

Abstract: Two levels of error correction decoding are performed using first and second level decoders. A composite code formed by combining an inner component code and an outer component code can be used to decode the data and correct any errors. Performing two level decoding using a composite code allows the size of the inner parity block to be reduced to a single Reed-Solomon symbol while keeping a good code rate. The first level decoder generates soft information. The soft information can indicate a most likely error event for each possible syndrome value of the inner component code. The soft information can also include error metric values for each of the most likely error events. The second level decoder generates corrected syndrome values based on the soft information using the outer component code. The most likely trellis path that corresponds to the corrected syndrome values is then selected.

Abstract: A Flash memory system and a method for data management using the embodiments of the invention use special test cells with Early Degradation Detection (EDD) circuitry instead of using the actual user-data storage cells are described. The Flash memory test cells can be made to serve as a “canary in a coal mine” by being made more sensitive than the standard cells by using experimentally determined sensitive write VT and variable read VT. Techniques for early degradation detection (EDD) in Flash memories measure the dispersion of the threshold voltages (VT's), of a set (e.g. page) of NAND Flash memory cells during read operations. In an embodiment of the invention the time-to-completion (TTC) values for the read operation for the memory cells are used as a proxy for dispersion of the threshold voltages (VT's). A Dispersion Analyzer determines the dispersion of the set of TTC values.

Abstract: The embodiments of the invention in this disclosure describe techniques for early warning of degradation in NOR Flash memories by estimating the dispersion of the threshold voltages (VT's), of a set of NOR Flash memory cells during read operations. In an embodiment invention the time-to-completion (TTC) values for the read operation for the memory cells are used as a proxy for dispersion of the threshold voltages (VT's). If the measured TTC dispersion differs by more than a selected amount from the reference dispersion value, a warning signal is provided to indicate that the page of memory has degraded significantly. Higher level components in the system can use the warning signal to take appropriate action. Since every cell's VT position in an ideal distribution can be estimated, the data from each cell can have a confidence level assigned based on deviation from the mean of an ideal distribution.

Abstract: Techniques are provided for iteratively decoding data recorded on a data storage device. An iterative decoder decodes the data using multiple decoding iterations to correct errors. In multiple iterations of the iterative decoder, a post processing block generates soft information, and a decoder applies a minimum sum decoding algorithm to a low density parity check (LDPC) code to generate extrinsic information based on the soft information and updated soft information.

Abstract: Embodiments of the present invention relate to the detection of synchronization marks in data storage and retrieval. To detect a synchronization mark, embodiments of the present invention require both pattern matching and proper phase alignment, following a repeating synchronization field. According to one particular embodiment, proper phase alignment following a repeated four bit synchronization field, is utilized in conjunction with pattern matching, to identify a synchronization mark. By allowing a synchronization mark to be identified only with proper phase alignment at the earliest possible occurrence of the synchronization mark, accuracy of synchronization mark detection may be improved.

Abstract: The embodiments of the invention in this disclosure describe techniques for early warning of degradation in NOR Flash memories by estimating the dispersion of the threshold voltages (VT's), of a set of NOR Flash memory cells during read operations. In an embodiment invention the time-to-completion (TTC) values for the read operation for the memory cells are used as a proxy for dispersion of the threshold voltages (VT's). If the measured TTC dispersion differs by more than a selected amount from the reference dispersion value, a warning signal is provided to indicate that the page of memory has degraded significantly. Higher level components in the system can use the warning signal to take appropriate action. Since every cell's VT position in an ideal distribution can be estimated, the data from each cell can have a confidence level assigned based on deviation from the mean of an ideal distribution.

Abstract: A Flash memory system and a method for data management using the system's sensitivity to charge-disturbing operations and the history of charge-disturbing operations executed by the system are described. In an embodiment of the invention, the sensitivity to charge-disturbing operations is embodied in a disturb-strength matrix in which selected operations have an associated numerical value that is an estimate of the relative strength of that operation to cause disturbances in charge that result in data errors. The disturb-strength matrix can also include the direction of the error which indicates either a gain or loss of charge. The disturb-strength matrix can be determined by the device conducting a self-test in which charge-disturb errors are provoked by executing a selected operation until a detectable error occurs. In alternative embodiments the disturb-strength matrix is determined by testing selected units from a homogeneous population.

Abstract: A Flash memory system and a method for data management using the system's sensitivity to charge-disturbing operations and the history of charge-disturbing operations executed by the system are described. In an embodiment of the invention, the sensitivity to charge-disturbing operations is embodied in a disturb-strength matrix in which selected operations have an associated numerical value that is an estimate of the relative strength of that operation to cause disturbances in charge that result in data errors. The disturb-strength matrix should also include the direction of the error which indicates either a gain or loss of charge. The disturb-strength matrix can be determined by the device conducting a self-test in which changes in the measured dispersion value are provoked by executing a selected operation until a detectable change occurs. In alternative embodiments the disturb-strength matrix is determined by testing selected units from a homogeneous population.

Abstract: Techniques for early detection of degradation in NAND Flash memories by measuring the dispersion of the threshold voltages (VT's), of a set (e.g. page) of NAND Flash memory cells during read operations are described. In an embodiment of the invention the time-to-completion (TTC) values for the read operation for the memory cells are used as a proxy for dispersion of the threshold voltages (VT's). A Dispersion Analyzer determines the dispersion of the set of TTC values. In one embodiment the delta between the maximum and minimum TTC values is used as the dispersion measurement. If the measured TTC dispersion differs by more than a selected amount from a reference dispersion value, a warning signal is provided to indicate that the page of memory has degraded. The warning signal can be used to take appropriate action such as moving the data to a new page.