Abstract: A system including a storage medium, a demodulator, and a decoder. The demodulator is configured to receive an input signal from the storage medium and demodulate the input signal. The decoder is configured to estimate data stored in the storage medium by decoding the demodulated input signal to provide an output signal. The decoder includes a filter and first and second processors. The filter is configured to generate a first equalized signal based on the output signal. The first processor is configured to, based on the first equalized signal and a first Viterbi algorithm, generate a first estimate of the data and an estimate of noise. The second processor is configured to generate a second estimate of the data based on the first estimate of the data, the estimate of the noise, and a second Viterbi algorithm. The output signal includes the second estimate of the data.

Abstract: Devices, systems, methods, and other embodiments associated with accessing memory using fractional reference voltage are described. In one embodiment, an apparatus includes comparison logic. The comparison logic compares a threshold voltage of a memory cell to at least one pair of reference voltages that are near an integral reference voltage to generate comparison results. The apparatus includes read logic to determine a bit value of the memory cell based, at least in part, on the comparison results.

Abstract: Apparatus having corresponding methods and storage devices comprise: an iterative decoder configured to generate codewords based on input samples, wherein the iterative decoder is further configured to perform a number of decoding iterations for each codeword, wherein the number of decoding iterations is an integer greater than zero, and wherein the number of decoding iterations does not exceed a limit number; and a sensor configured to generate one or more measurements of a physical variable, wherein the limit number is set in accordance with the one or more measurements generated by the sensor.

Abstract: A controller for a nonvolatile memory includes an encoder and a decoder. The memory includes memory cells that each store data using more than two levels. The encoder generates first data for storage in first memory cells. For first and second subsets of cells of the first memory cells, the first data is stored at first and second levels, respectively. Measurable values of the first subset of cells are characterized by a first probability density function having a first width. Measurable values of the second subset of cells are characterized by a second probability density function having a second width. The first width is greater than the second width. The encoder generates the first data such that a size of the first subset of cells is less than a size of the second subset of cells. The decoder decodes encoded data from the memory.

Abstract: A memory control module includes a read module configured to receive a first signal read from a first storage region of a memory cell, and receive a second signal read from a second storage region of the memory cell. A data detection module is configured to, based on a noiseless signal, detect respective data in each of the first storage region and the second storage region. The noiseless signal includes an ideal signal and an interference signal associated with at least one of the first signal and the second signal.

Abstract: Methods, systems and computer program products for performing hybrid defect detection are disclosed. In some implementations, an apparatus includes a signal module to process data signals corresponding to data on a storage medium to generate signal samples. The apparatus includes a first defect detector to identify a first portion of the signal samples, determine a number of the signal samples in the first portion that are associated with abnormal signal characteristics, and generate a first output based on the number of the signal samples in the first portion that are associated with abnormal signal characteristics. The apparatus includes a second defect detector to identify a second portion of the signal samples different from the first portion, and generate a second output based on a correlation between data bits and signal samples in the second portion.

Abstract: Systems, methods, and other embodiments associated with a data detector that processes signals read from a storage device are described. According to one embodiment, a detector for detecting a data signal embedded in a read signal from a storage device includes a signal estimator configured to generate an estimate of the control signal from the read signal by sampling the read signal to determine characteristics of the control signal. The read signal includes the data signal and the control signal. The signal estimator uses the characteristics to calculate the estimate of the control signal. The detector also includes a cancellation unit configured to produce the data signal by cancelling the estimate of the control signal from the read signal.

Abstract: Systems, methods and computer program products for minimizing floating gate coupling interference and threshold voltage drift associated with flash memory cells are described. In some implementations, the memory cells can be programmed in a predetermined sequence that allows pages with the most-significant bit (MSB) and central significant bit (CSB) to be programmed first prior to programming pages with the least-significant bit (LSB). This sequence allows neighboring cells (e.g., cells neighboring a target cell) to be programmed first so as to reduce the floating gate coupling interference and threshold voltage drift on the target cell that is to be programmed in the subsequent stage. To accommodate the programming sequence (e.g., at the device level), additional buffer memories can be added.

Abstract: A system including a reconstruction module and a correlation module. The reconstruction module is configured to reconstruct data bits detected from first signals, and to generate second signals based on the reconstruction of the data bits detected from the first signals. The correlation module is configured to generate first correlation values by correlating (i) the first signals and (ii) the second signals, and to generate second correlation values by self-correlating the second signals. In response to one or more of (i) the first signals and (ii) the second signals including a floating number having (i) a plurality of bits and (ii) a sign bit, the correlation module is configured to generate one or more of (i) the first correlation values and (ii) the second correlation values based on (i) a plurality of most significant bits of the floating number and (ii) the sign bit of the floating number.

Abstract: The present disclosure includes apparatus, systems and techniques relating to iterative decoder memory arrangement. A described apparatus includes R banks; Q banks; circuitry configured to store R data for a current codeword in a first R bank of the R banks and store R data for a previous codeword in a second R bank of the R banks; circuitry configured to alternate among the R banks for storing current codeword R data; circuitry configured to store Q data for the current codeword in a first Q bank of the Q banks and store Q data for the previous codeword in a second Q bank of the Q banks; and circuitry configured to alternate among the Q banks for storing current codeword Q data. The apparatus can include circuitry configured to interleave read accesses among the R banks.

Abstract: A system including a read module and a detector module. The read module is configured to generate a plurality of read signals by reading a plurality of memory cells located along a bit line or a word line. The detector module is configured to detect a sequence of data stored in the plurality of memory cells based on (i) the plurality of read signals, and (ii) a plurality of reference signals associated with the plurality of memory cells. One of the plurality of reference signals associated with a first memory cell of the plurality of memory cells includes one of a first signal and a second signal. The first signal is free of interference from a second memory cell adjacent to the first memory cell along the bit line or the word line. The second signal accounts for interference from the second memory cell.

Abstract: Systems and methods are provided for implementing various aspects of a Reed-Solomon (RS) error-correction system. A detector can provide a decision-codeword from a channel and can also provide soft-information for the decision-codeword. If the decision-codeword corresponds to an inner code and an RS code is the outer code, a soft-information map can process the soft-information for the decision-codeword to produce soft-information for a RS decision-codeword. A RS decoder can employ the Berlekamp-Massey algorithm (BMA), list decoding, and a Chien search, and can include a pipelined architecture. A threshold-based control circuit can be used to predict whether list decoding will be needed and can suspend the list decoding operation if it predicts that list decoding is not needed.

Abstract: A system including an input configured to receive data and an encoder module configured to perform an encoding operation on the data using an error correcting code. The data comprises one or more bits inserted at predetermined locations in the data. A number of the one or more bits inserted in the data corresponds to a number of inner-code parity bits to be inserted at the predetermined locations subsequent to the encoding operation being performed on the data. The encoder module is configured to use, subsequent to the encoding operation being performed on the data, an inner code to generate the inner-code parity bits based on the data, and at the predetermined locations in the data, replace the one or more bits inserted in the data with the inner-code parity bits generated based on use of the inner code.

Abstract: A controller for a nonvolatile memory includes an encoder and a decoder. The memory includes memory cells that each store data using more than two levels. The encoder generates first data for storage in first memory cells. For first and second subsets of cells of the first memory cells, the first data is stored at first and second levels, respectively. Measurable values of the first subset of cells are characterized by a first probability density function having a first width. Measurable values of the second subset of cells are characterized by a second probability density function having a second width. The first width is greater than the second width. The encoder generates the first data such that a size of the first subset of cells is less than a size of the second subset of cells. The decoder decodes encoded data from the memory.

Abstract: Embodiments provide a method for a method comprising causing data to be written on a first track located on a disk; while writing the data on the first track, buffering, in a buffer module, the data; determining that while writing the data on at least a portion of the first track, a portion of a write head was offset with respect to the first track, such that at least the portion of the write head infringed on a second track; determining a direction of movement of the write head; and based on determining that the portion of the write head was offset and determining the direction of movement of the write head, selectively performing one of (i) using the data buffered in the buffer module to recover data of the second track, or (ii) discarding the data buffered in the buffer module.

Abstract: The disclosed technology provides systems and methods for identifying potential error locations, patterns, and likelihood metrics in connection with trellis-based detection/decoding. In one aspect of the invention, the disclosed technology detects information that was previously encoded based on a trellis, and decodes the detected information based on the trellis to provide decoded information. The decoded information corresponds to a winning path through the trellis that ends at a winning state. The disclosed technology can identify one or more alternate paths through the trellis that also end at the winning state, and can generate a potential error pattern for each of the alternate paths.

Abstract: An apparatus includes a circuit configured to at least one of (i) encode first data to produce encoded data or (ii) decode second data to produce decoded data. The circuit is configured to operate according to a predetermined matrix. Each element of the predetermined matrix labeled with a hyphen corresponds to a zero matrix. Each element of the predetermined matrix labeled with a number corresponds to a respective cyclic-permutation matrix.

Abstract: A storage drive includes a first integrated circuit, a second integrated circuit, an interface, an encoder, and a write module. The first integrated circuit includes a first array of memory cells. The second integrated circuit includes a second array of memory cells. The interface is connected to a host. The interface is configured to receive a first block of data transmitted from the host to the storage drive. The encoder is configured to encode the first block of data. The write module is configured to write (i) a first portion of the encoded first block of data to a first row of the first array of memory cells, and (ii) a second portion of the encoded first block of data to a first row of the second array of memory cells.

Abstract: Systems and methods for adaptively operating a storage device are provided. A level of integrity of storing data in the storage device is determined. A coding scheme is selected based on the determined level of integrity of the storage device. An operation is performed on the storage device using the selected coding scheme.

Abstract: A system includes a read module, a statistical data generating module, and a storing module. The read module reads charge levels of nonvolatile memory cells and generates read signals. The statistical data generating module generates statistical data based on the read signals. The storing module stores the statistical data. The read module generates the read signals based on the charge levels of the nonvolatile memory cells and the statistical data.