Abstract: A plurality of random bit sequences is generated. Each of the random bit sequences is different and is based at least in part on an input bit sequence. A plurality of metrics corresponding to the plurality of random bit sequences is generated. The plurality of metrics is associated with one or more transition run lengths. One of the random bit sequences is selected based at least in part on the metrics. An output bit sequence is generated that includes the selected random bit sequence and an index associated with demodulating the selected random bit sequence.

Abstract: A storage system includes a channel detector, an LDPC decoder, and an erasure block. The channel detector is configured to receive data corresponding to data read from a storage and output an LLR signal. The LDPC decoder is configured to receive the LLR signal and output a feedback signal to the channel detector. The erasure block is configured to erase at a portion of at least one of the LLR signal and the feedback signal. A method for testing includes generating an error rate function corresponding to an erasure pattern. The function is a function of a number of LDPC iterations. The method includes determining testing parameters at least in part based on the error rate function, wherein the testing parameters comprise a testing number of LDPC iterations, a passing error rate, and the erasure pattern. The method includes testing storage devices using the testing parameters.

Abstract: A set of decisions is determined based at last in part on a set of samples. For a given sample in the set of samples, a low frequency noise estimate is estimated based at least in part on (1) at least some samples from the set of samples and (2) at least some decisions from the set of decisions. A reduced noise sample is generated by removing the low frequency noise estimate from the given sample.

Abstract: A first set of one or more soft detector outputs is generated. It is determined if error correction decoding is successful using the first set of soft detector outputs. In the event it is determined error correction decoding is not successful, a second set of one or more soft detector outputs is generated where a largest likelihood associated with the first set is greater than a largest likelihood associated with the second set.

Abstract: For each of a plurality of locations in flash memory, a number of pulses required to change a value stored in that location is obtained. From the plurality of locations, a location to write to is selected using the obtained number of pulses. The selected location is written to.

Abstract: Data is processed by selecting one or more bits in a codeword to replace with an erasure. The selected bits in the codeword are replaced with the erasure and error correction decoding is performed on the codeword with the erasure in place for the selected bits.

Abstract: Determining a parameter associated with whether a portion of a storage device is defective is disclosed. Determining comprises: obtaining known data associated with the portion; reading back from the portion to produce a read-back waveform; decoding the read-back waveform, including producing statistical information; and determining a parameter associated with whether the portion is defective based at least in part on the statistical information.

Abstract: A first decoder performs decoding on each data set in a first plurality of data sets using a first code; each data set in the first plurality is stored on a different chip. It is determined if the first decoding is successful; if not, a second decoder performs a second decoding on each data set in a second plurality of data sets using a second code; each data set in the second plurality includes at least some data, after the first decoding using the first code, from each data set in the first plurality. The first decoder performs a third decoding on each data set in the first plurality using the first code, where each data set in the first plurality includes at least some data, after the second decoding using the second code, from each data set in the second plurality.

Abstract: Accessing data at a memory is described. A request associated with a read or write operation is received, wherein the request includes a logical address associated with the memory. A physical address is generated based at least in part on the logical address. A block of data at the memory that includes data associated with the physical address is determined. Data at the determined block of data and a corresponding set of ECC from the memory are accessed. Whether the accessed data can be decoded based at least in part on the corresponding set of ECC is determined.

Abstract: Inter-track-interference correlation and cancellation for disk drive application includes receiving an input sequence of samples; and simultaneously processing the input sequence in at least a detector over one or more iterations while processing the input sequence to produce inter-track-interference information during at least a portion of one of the one or more iterations.

Abstract: An indication to store a data value in Flash memory is received. An accurate coarse write is performed on the Flash memory, including by: storing a first voltage level in the Flash memory and setting a configuration setting of the Flash memory to a first setting. The first voltage level, when interpreted using the configuration setting at the first setting, corresponds to the data value. A fine write is performed on the Flash memory, including by: storing a second voltage level in the Flash memory and setting the configuration setting of the Flash memory to a second setting. The second voltage level, when interpreted using the configuration setting at the second setting, corresponds to the data value.

Abstract: A plurality of metrics associated with a plurality of partially decoded codewords is obtained. The plurality of partially decoded codewords has been processed at least once by a first soft output decoder and a second soft output decoder and the plurality of partially decoded codewords is stored in a memory. At least one of the plurality of partially decoded codewords is selected based at least in part on the plurality of metrics; the memory is instructed to vacate the at least one selected codeword.

Abstract: Encoded least significant bit (LSB) values are generated for a cell based at least in part on a readback value for the cell. The encoded LSB values is decoded in order to obtain one or more decoded LSB values. Encoded most significant bit (MSB) values are generated for the cell based at least in part on (1) the readback value for the cell and (2) the decoded LSB values. The encoded MSB values are decoded in order to obtain one or more decoded MSB values, wherein the bit positions of the decoded LSB values do not overlap with the bit positions of the decoded MSB values.

Abstract: A system for clocking a decoder is disclosed. The system includes: a channel front end configured to receive input data, a first clock configured to provide a first clock signal as input to the channel front end, a decoder configured to receive intermediate data associated with the output of the channel front end, and a second clock configured to provide a second clock signal as input to the decoder. In some embodiments, the second clock signal is not derived from the first clock signal.

Abstract: Old user data, old metadata, and old error correction parity information are received. New metadata corresponding to the old user data is generated. The old metadata and the new metadata are combined to obtain combined metadata. New error correction parity information is generated using the combined metadata. The old error correction parity information and new error correction parity information are combined to obtain combined error correction parity information. The old user data, new metadata, and combined error correction parity information are stored in solid state storage.

Abstract: An amount of time and an error rate function are received, where the error rate function defines a relationship between a number of iterations associated with iterative decoding and an error rate. A testing error rate is determined based at least in part on the amount of time. The number of iterations which corresponds to the testing error rate in the error rate function is selected to be a testing number of iterations; the testing error rate and the testing number of iterations are associated with testing storage media using iterative decoding.

Abstract: Calibrating a read channel is disclosed. Previously written user data is read from an auxiliary memory. The previously written user data is processed through a plurality of write channel stages. The output of at least one of the plurality of write channel stages is compared to the output of a corresponding read channel stage to generate an error signal.

Abstract: An indication to store a data value in Flash memory is received. An accurate coarse write is performed on the Flash memory, including by: storing a first voltage level in the Flash memory and setting a configuration setting of the Flash memory to a first setting. The first voltage level, when interpreted using the configuration setting at the first setting, corresponds to the data value. A fine write is performed on the Flash memory, including by: storing a second voltage level in the Flash memory and setting the configuration setting of the Flash memory to a second setting. The second voltage level, when interpreted using the configuration setting at the second setting, corresponds to the data value.

Abstract: A method for reducing a number of bits for representing a value is disclosed. A first value represented with a first number of bits is transformed to a second value represented with a second number of bits, wherein the first number of bits is greater than the second number of bits. The transformed second value is scaled by a scale factor to a third value. Transforming includes selecting a target window with a width of a third number of bits, wherein the third number of bits is smaller than the first number of bits. Transforming further includes saturating the first value to a most significant bit (MSB) within the selected target window and extracting bits within the selected target window from the saturated value.

Abstract: A second controller is communicated with from a first controller via an interface. Storage is also communicated with from the first controller via the interface. The first controller is configured to be a master on the interface and the second controller and the storage are configured to be targets on the interface.