Abstract: A plurality of partially-decoded codewords that have been processed at least once by a first and a second error correction decoder is stored. A plurality of metrics associated with how close a corresponding partially-decoded codeword is to being successfully decoded is stored. From the plurality of partially-decoded codewords, a codeword having a metric indicating that that codeword is the closest to being successfully decoded by the first error correction decoder and the second error correction decoder is selected. The selected codeword is output to the first error correction decoder.

Abstract: A starting read threshold is received. A first offset and a second offset is determined. A first read is performed at the starting read threshold offset by the first offset to obtain a first hard read value and a second read is performed at the starting read threshold offset by the second offset to obtain a second hard read value. A soft read value is generated based at least in part on the first hard read value and the second hard read value.

Abstract: A first bit position of a cell in solid state storage is read where a sorting bit is obtained using the read of the first bit position. A second bit position of the cell is read for a first time, including by setting a first read threshold associated with the second bit position to a first value and setting a second read threshold associated with the second bit position to a second value. The second bit position of the cell is read for a second time, including by setting the first read threshold to a third value and setting the second read threshold to a fourth value. A new value for the first read threshold and for the second read threshold is generated using the sorting bit, the first read, and the second read.

Abstract: A system and method for determining soft read data for a group of cells in a nonvolatile flash memory are disclosed. An expected value representative of a plurality of stored values in a group of cells is obtained. A measured value representative of the plurality of stored values in the group of cells is obtained, based on a single read to the group of cells. A soft read data for the group of cells is determined based at least in part on the expected value and the measured value. The expected and measured values may include at least one of a number of 0s, a number of 1s, a ratio of 0s to 1s or a ratio of 1s to 0s. A reliability for a bit i may be obtained using a one-step majority logic decoder, and a threshold reliability may be used when determining the soft read data.

Abstract: An indication is received that a word line has been read. The word line is part of a plurality of word lines (in solid state storage) which is divided into a plurality of groups. It is determined which group is associated with the read. A count of consecutive, at least potentially uninformative reads is updated based at least in part on the group associated with the read and a group associated with a prior read. It is determining if the count is greater than a threshold and in the event it is determined the count is greater than the threshold, a read disturb check is triggered.

Abstract: An access instruction which includes a logical block address (LBA) is received. A first-level table is accessed to obtain a first-level table entry associated with the LBA. From the first-level table entry, a location associated with a second-level table on solid state storage media is determined. The second-level table is accessed at the determined location to obtain a second-level table entry associated with the LBA. From the second-level table entry, a physical block address corresponding to the logical block address is determined.

Abstract: A plurality of write data is received and combined to obtain backup write data. The plurality of write data is stored in storage. On a storage controller, the plurality of write data is released without waiting for a confirmation associated with writing the plurality of write data to the storage. The backup write data is stored.

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: A method of writing data to non-volatile computer storage is disclosed. A logical page of data is received and stored in an intermediate storage. A first portion of the logical page is read from the intermediate storage and written to a first physical page in the non-volatile computer storage. A second portion of the logical page is read from the intermediate storage and written to a second physical page in the non-volatile computer storage. A method of reading data from non-volatile computer storage is disclosed. A first portion of a logical page is read from a first physical page in the non-volatile computer storage and written in an intermediate storage. A second portion of the logical page is read from a second physical page and written in the intermediate storage. The first portion and the second portion of the logical page are concatenated to form the logical page.

Abstract: A victim group of one or more cells is read using a first read threshold to obtain a first raw read which includes one or more values. The victim group of cells is read using a second read threshold to obtain a second raw read which includes one or more values. A neighboring read, corresponding to a neighboring group of one or more cells associated with the victim group of cells, is obtained. A composite read is generated, including by selecting from at least the first raw read and the second raw read based at least in part on the neighboring read.

Abstract: A method for correcting a cell voltage driftage in a NAND flash device is disclosed. An indicator indicating a cell voltage driftage in a memory unit of a NAND flash device is monitored by a processor. A cell voltage driftage in the NAND flash device is detected based at least in part on the indicator. One or more NAND commands correcting the cell voltage driftage are generated. The one or more NAND commands include a NAND command associated with changing a configuration setting of the NAND flash device.

Abstract: Turbo equalization is performing by using a soft output detector to perform decoding. At least a portion of a local iteration of decoding is performed using a soft output decoder. A metric associated with decoding progress is generated and it is determined whether to perform another local iteration of decoding based at least in part on the metric.

Abstract: An instruction to write to a location in the Flash memory is received. It is determining if the Flash memory exposes a level placement setting associated with defining what voltage range corresponds to what level. In the event it is determined that the Flash memory exposes a level placement setting, an accurate coarse write is performed on the location, including by configuring the level placement setting to be a first value, and after the accurate coarse write is performed on the location, a fine write is performed on the location, including by configuring the level placement setting to be a second value, in response to receiving the instruction.

Abstract: A read back bit sequence and charge constraint information are obtained. A lower bound on a number of bit errors associated with the read back bit sequence is determined based at least in part on the read back bit sequence and the charge constraint information. The lower bound and an error correction capability threshold associated with an error correction decoder are compared. In the event the lower bound is greater than or equal to the error correction capability threshold, an error correction decoding failure is predicted and in response to the prediction a component is configured to save power.

Abstract: A set of branch metrics for a trellis associated with a Viterbi detector is generated. A set of path metrics associated with the trellis is generated based at least in part on the set of branch metrics, including by obtaining a pruned trellis by removing at least some portion of the trellis that is associated with an invalid bit sequence not permitted by a constrained code. A surviving path associated with the pruned trellis is selected based at least in part on the set of path metrics. A sequence of decisions associated with the surviving path is output.

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: An array f(n) is received for n=1, . . . , N where N is a length of a codeword. An array g(n) is received for n=1, . . . , N where N is a length of a codeword. Input data is encoded to satisfy an MTR constraint and a RLL constraint using the array f(n) and the array g(n).

Abstract: A first read threshold associated with a first page in a block and a second read threshold associated with a second page in the block are received, where the first page has a first page number and the second page has a second page number. A slope and a y intercept are determined based at least in part on the first read threshold, the second read threshold, the first page number, and the second page number. The slope and the y intercept are stored with a block identifier associated with the block.

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: It is decided whether to adjust data associated with a decoder. In the event it is decided to adjust the data associated with the decoder, the data is adjusted to obtain adjusted data and decoding is performed on the adjusted data. In the event it is decided to not adjust the data associated with the decoder, decoding is performed on the data associated with the decoder.