Kioxia Corporation

Kabushiki Kaisha Toshiba

Toshiba Memory Corporation

Keiri Nakanishi

Sho Kodama

Masato Sumiyoshi

Youhei Fukazawa

Kohei Oikawa

Daisuke Yashima

Takashi Miura

Zheye Wang

Yasuki Tanabe

Takashi Miyamori

Ryuji Hada

Kojiro Suzuki

Shunichi Ishiwata

Katsuyuki Kimura

Kazuki Inoue

Takahisa Wada

Tokumasa Hara

Takashi Takemoto

Masashi Jobashi

Kejen Lin

Hironori Uchikawa

Wataru Asano

Kensaku Yamaguchi

Daisuke Iwai

Akira Yamaga

Kazuhiro Hiwada

Konosuke Watanabe

Katsuyuki Nomura

Juan Shi

Harutaka Goto

According to one embodiment, a conversion device includes a demultiplexer, first to Nth extractors and a deinterleave unit. The demultiplexer extracts first to Nth substreams from a first compressed stream. The first to Nth substreams are placed in order in the first compressed stream and include first variable-length codes to Nth variable-length codes into which first symbols to Nth symbols of a symbol string have been converted. The first to Nth extractors extract the first variable-length codes to the Nth variable-length codes from the first to Nth substreams. The deinterleave unit reorders the first variable-length codes to the Nth variable-length codes in accordance with the symbol string and outputs a second compressed stream.

Conversion device, memory system, decompression device, and method

According to one embodiment, a compression device includes a substring generator and a match information generator. The substring generator receives generates substrings which are stored in a memory. Byte positions of the substrings are different from each other. The match information generator determines a first string, at least part thereof matching at least part of one of the substrings, and outputs match information. The match information includes a position of the memory storing the first string and a length of the at least part of the first string matching the at least part of one of the substrings.

Compression device and compression method

According to one embodiment, a dictionary compressor for compressing input first data includes a buffer and a search unit. The buffer stores data input to the dictionary compressor prior to the first data. The search unit acquires, from the first data, partial data strings each having a first data length and having head positions in the first data, respectively, that are sequentially shifted by a second data length shorter than the first data length. The search unit performs search processes in parallel and acquires search results respectively corresponding to the search processes, the search processes searching the buffer to acquire respective match data strings that at least partially match the partial data strings, respectively.

Dictionary compressor, data compression device, and memory system

According to one embodiment, an information processing apparatus includes a processor. The processor divides teacher data into character strings, calculates a score of each of the character strings based on at least an appearance frequency of each character string in the character strings, an appearance position of each of the character string in the character strings, and a length of each of the character strings, and determines a position of each of the character strings in a preset dictionary based on the score.

Information processing apparatus and preset dictionary generating method

According to one embodiment, a memory system includes a frequency value update unit, a first intra-group rearranging unit, a second intra-group rearranging unit, and a routing unit. The frequency value update unit adds a first value to each of one or more first frequency values that are associated with one or more first symbols, respectively, in one or more entries in a table. The first intra-group rearranging unit rearranges first entries, which belong to a first group, using frequency values in the first entries. The second intra-group rearranging unit rearranges second entries, which belong to a second group lower than the first group, using frequency values. The routing unit rearranges at least one of the first entries and at least one of the second entries.

Memory system

According to one embodiment, a data decompression device decodes a code included in compressed data into a symbol. The data decompression device includes a first code length generation unit and a second code length generation unit. The first code length generation unit generates a first code length of a first code included in the compressed data by arithmetic calculation. The second code length generation unit generates a second code length of a second code by using a table. The second code is included in the compressed data. The second code is subsequent to the first code. The table indicates at least the first code and the second code length that is associated with the first code.

Data decompression device, memory system, and data decompression method

According to one embodiment, a dictionary buffer stores dictionary data including a first substring and data before the first substring. A substring generator generates, from second input data, second substrings. A transformer transforms each of the second substrings into a hash value. A read processor reads the dictionary data, using a hash value transformed from a third substring among the second substrings. An acquisition unit compares a data string including the third substring and data before the third substring with the read dictionary data, and acquire first and second match lengths of the third and fourth substrings. A coded data generator generates coded data based on the acquired first and second match lengths.

Dictionary compression device and memory system

According to one embodiment, a controller of a memory system manages a first table maintaining a relationship between a logical address and a physical address, compresses first data corresponding to a first address of a write command, specifies a size of second data obtained by compressing the first data, determines allocation of the second data on a memory based on the size of the second data, stores a second address corresponding to a physical area where a head of the second data is stored and a physical area number used to store the second data in an entry of the first logical address in the first table, and stores the first address, offset of a position of a leader of the second data in the physical area, and the size of the second data in the physical area.

Memory system and method

According to one embodiment, a compression circuit generates substrings from input data for (3+M) cycles, the input data being N bytes per cycle, a byte length of each substring being greater than or equal to (N×(1+M)+1); obtains a set of matches, each of the matches including at least one past input data which input past and corresponds to at least a part of each of the substrings; selects a subset of matches from the set of matches including the input data of one cycle; and outputs the subset of matches. M is zero or a natural number. N is a positive integer which is two or more.

Compression circuit, storage system, and compression method

A compression device includes an analyzer circuit, a control circuit, a compressor circuit, and a selector circuit. The analyzer circuit is configured to analyze first data that is input thereto and generate one or more parameter values regarding data compression and/or decompression. The control circuit is configured to generate at least one compression mode information indicating whether or not compression is to be performed, based on the one or more parameter values. The compressor circuit is configured to compress the first data into second data according to the compression mode information. The selector circuit is configured to output the first data if not compressed or the second data if the first data is compressed, together with the compression mode information.

Compression device, compression and decompression device, and memory system

According to one embodiment, a compression device includes a first storage unit, a second storage unit, a calculation unit, and a comparison unit. The first storage unit stores addresses associated with hash values, respectively. The second storage unit includes storage areas specified by the addresses, respectively. The calculation unit determines a hash function to be used for first data in accordance with at least a part of the first data, and calculates a hash value using the hash function and at least a part of second data included in the first data. The comparison unit acquires third data from a storage area in the second storage unit specified by a first address, and compares the second data with the third data. The first address is stored in the first storage unit and is associated with the hash value.

Compression device and control method

According to one embodiment, a data decompression device includes: a detection circuit configured to detect a boundary between a header and a payload in a compressed stream, based on boundary information in the header; a separation circuit configured to separate the header and the payload; a first decompression circuit configured to decompress a compressed coding table in the header; and a second decompression circuit configured to decompress the payload, based on an output of the first decompression circuit.

Data decompression device, data compression device, and memory system

According to one embodiment, a data compression device includes a dictionary match determination unit, an extended matching generator, a match selector and a match connector. The dictionary match determination unit searches for first past input data matching first new input data. The extended matching generator compares second past input data subsequent to the first past input data with second new input data subsequent to the first new input data. The match selector generates compressed data by replacing a part of the input data with match information output from the dictionary match determination unit or the extended matching generator. The match connector replaces a plurality of match information in the compressed data with single match information.

Data compression device, memory system and method

According to one embodiment, a compression device includes a coding information generation unit. The unit determines code lengths that are respectively associated with a plurality of symbols, based on a frequency of occurrence of each of the plurality of symbols. When the plurality of symbols include one or more first symbols that are respectively associated with one or more first code lengths exceeding an upper limit, the unit changes the first code lengths to the upper limit, selects, from one or more second symbols of the plurality of symbols that are respectively associated with one or more second code lengths shorter than the upper limit, at least one symbol in descending associated code length order, changes at least one code length associated with the symbol to the upper limit.

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Kawasaki, Japan

Keiri Nakanishi