Abstract: A dynamic dictionary-based data symbol encoder. A dynamic dictionary data structure is populated with evictable dictionary entries. The evictable dictionary entries are encoded with a dictionary index that is shorter than an original representation of the input symbols. A reference count evicts dictionary indices when eligible for eviction. Through building a dynamic symbol dictionary which is much smaller than (global) alphabet size, locally repetitive symbols can be effectively compressed using dictionary. The dictionary is also dynamically built along with the compression/decompression process and therefore does not carry overhead. However, tables/trees might be appended to enable entropy decoding. The method is also readily combined with the popular LZ77 and its variant encoding methods into composite one-pass encoding algorithms to achieve superior performance.

Abstract: Apparatuses and methods for performing an error correction code (ECC) operation are provided. One example method can include generating a codeword based on a number of low density parity check (LDPC) codewords failing a LDPC decoding operation and performing a BCH decoding operation on the codeword.

Abstract: An input file is processed according to hash algorithm that references sets of literals to preceding sets of literals to facilitate copy-offset command generation. Preceding instances are identified by generating a hash of the literal set and looking up a corresponding entry in a hash table. The hash table may be accessed by placing look-up requests in a FIFO buffer. When the FIFO buffer is full, generation of the hash chain is suspended until it is no longer full. When repeated literals are found, generation of the hash chain is likewise suspended. The hash chain is used to generate a command file, such as according to the LZ algorithm. Runs of consecutive literals are replaced by a run-length command. The command file may then be encoded using Huffman encoding.

Abstract: A saturation metric that represents a degree of saturation in a low-density parity-check (LDPC) decoding system that uses a fixed-point number representation is determined. The saturation metric is compared against a saturation threshold. In the event the saturation metric exceeds the saturation threshold, at the end of a decoding iteration, a message is more aggressively attenuated compared to when the saturation metric does not exceed the saturation threshold in order to produce an attenuated message. In the event the saturation metric does not exceed the saturation threshold, at the end of the decoding iteration, the message is less aggressively attenuated compared to when the saturation metric does exceed the saturation threshold in order to produce the attenuated message.

Abstract: A chunk-based data deduplication system and method. Incoming data chunk is partitioned into head and tail portions for fingerprinting and mapping into respective head SHA (secure hash algorithm) and tail SHA tables. Head or tail fingerprints are used to locate predecessor data chunks almost identical to incoming data chunks and to determine data bursts to deduplicate the incoming data chunks.

Abstract: A data block may be identified. A first decoding operation may be performed on the data block. An unsuccessful correction of an error of the data block associated with the first decoding operation may be determined. A set of bits of the data block that caused the unsuccessful correction of the error of the data block may be identified. In response to identifying the set of bits of the data block that is associated with the unsuccessful correction of the error, a second decoding operation on the set of bits of the data block may be performed. The second decoding operation may be different than the first decoding operation.

Abstract: A dynamic dictionary-based data symbol encoder. A dynamic dictionary data structure is populated with evictable dictionary entries. The evictable dictionary entries are encoded with a dictionary index that is shorter than an original representation of the input symbols. A reference count evicts dictionary indices when eligible for eviction. Through building a dynamic symbol dictionary which is much smaller than (global) alphabet size, locally repetitive symbols can be effectively compressed using dictionary. The dictionary is also dynamically built along with the compression/decompression process and therefore does not carry overhead. However, tables/trees might be appended to enable entropy decoding. The method is also readily combined with the popular LZ77 and its variant encoding methods into composite one-pass encoding algorithms to achieve superior performance.

Abstract: A chunk-based data deduplication system and method. Incoming data chunk is partitioned into head and tail portions for fingerprinting and mapping into respective head SHA (secure hash algorithm) and tail SHA tables. Head or tail fingerprints are used to locate predecessor data chunks almost identical to incoming data chunks and to determine data bursts to deduplicate the incoming data chunks.

Abstract: A method for augmenting a dictionary of a data compression scheme. For each input string, the result of a sliding window search is compared to the result of a dictionary search. The dictionary is augmented with the sliding window search result if the sliding window search result is longer than the dictionary search result. An embodiment of the disclosure implements multiple sliding windows, each sliding window having an associated size, the size of sliding window dependent on a corresponding match length. For one embodiment, each sliding window has a corresponding hash function based upon the match length.

Abstract: An example methods for interleaved BCH codes can include encoding a plurality of portions of data using a first generator polynomial to obtain a plurality of respective BCH codewords. The method can include encoding an additional BCH codeword based at least in part on a second plurality of portions of data and the plurality of BCH codewords using a second generator polynomial. The method can include outputting the plurality of respective BCH codewords and the additional BCH codeword.

Abstract: One example of integrated interleaved Reed-Solomon decoding can include computing a number of syndromes for each of a number of interleaves and correcting a number of erasures in each of the number of interleaves.

Abstract: A data block may be identified. A first decoding operation may be performed on the data block. An unsuccessful correction of an error of the data block associated with the first decoding operation may be determined. A set of bits of the data block that caused the unsuccessful correction of the error of the data block may be identified. In response to identifying the set of bits of the data black that is associated with the unsuccessful correction of the error, a second decoding operation on the set of bits of the data block may be performed. The second decoding operation may be different than the first decoding operation.

Abstract: A set of bits of a data block that is associated with an unsuccessful first decoding operation may be identified. A second decoding operation to simulate switching at least one bit of the set of bits may be performed. At least one bit of the set of bits switched during the performance of the second decoding operation may be determined to correspond to an error. The error from the at least one bit of the set of bits may be corrected by changing a value of the at least one bit.

Abstract: An example methods for interleaved BCH codes can include encoding a plurality of portions of data using a first generator polynomial to obtain a plurality of respective BCH codewords. The method can include encoding an additional BCH codeword based at least in part on a second plurality of portions of data and the plurality of BCH codewords using a second generator polynomial. The method can include outputting the plurality of respective BCH codewords and the additional BCH codeword.

Abstract: Apparatuses and methods for performing an error correction code (ECC) operation are provided. One example method can include generating a codeword based on a number of low density parity check (LDPC) codewords failing a LDPC decoding operation and performing a BCH decoding operation on the codeword.

Abstract: A compression algorithm based on Huffman coding is disclosed that is adapted to be readily implemented using VLSI design. A data file may be processed to replace duplicate data with a copy commands including an offset and length, such as according to the LV algorithm. A Huffman code may then be generated for parts of the file. The Huffman code may be generated according to a novel method that generates Huffman code lengths for literals in a data file without first sorting the literal statistics. The Huffman code lengths may be constrained to be no longer than a maximum length and the Huffman code may be modified to provide an acceptable overflow probability and be in canonical order. Literals, offsets, and lengths may be separately encoded. The different values for these data sets may be assigned to a limited number of bins for purpose of generating usage statistics used for generating Huffman codes.

Abstract: A system implements adaptive desaturation for the min-sum decoding of LDPC codes. Specifically, when an-above threshold proportion of messages from check nodes to variable nodes (CN-to-VN messages) are saturated to a maximum fixed-precision value, all CN-to-VN messages are halved. This facilitates the saturation of correct messages and boosts error correction over small trapping sets. The adaptive desaturation approach reduces the error floor by orders of magnitudes with negligible add-on circuits.

Abstract: Apparatuses and methods for performing an error correction code (ECC) operation are provided. One example method can include generating a codeword based on a number of low density parity check (LDPC) codewords failing a LDPC decoding operation and performing a BCH decoding operation on the codeword.

Abstract: A method is disclosed for performing LDPC soft decoding of data stored in a flash storage device. Upon occurrence of a hard read failure, one or more retries with soft decoding after each retry are performed until soft decoding is successful or a maximum iteration count is reached. For each retry thresholds for sensing a level of a cell are adjusted according to a specific sequence. Likewise, the LLR table for each retry is selected from pre-determined LLR tables each corresponding to a retry attempt and the thresholds used for the retry attempt. The LLR table is not adjusted between retries or based on outcomes of any retries. A step size by which thresholds adjusted may be tuned to improve performance.

Abstract: An input file is processed according to hash algorithm that references sets of literals to preceding sets of literals to facilitate copy-offset command generation. Preceding instances are identified by generating a hash of the literal set and looking up a corresponding entry in a hash table. The hash table may be accessed by placing look-up requests in a FIFO buffer. When the FIFO buffer is full, generation of the hash chain is suspended until it is no longer full. When repeated literals are found, generation of the hash chain is likewise suspended. The hash chain is used to generate a command file, such as according to the LZ algorithm. Runs of consecutive literals are replaced by a run-length command. The command file may then be encoded using Huffman encoding.