公开(公告)号：US20220294469A1

公开(公告)日：2022-09-15

申请号：US17304130

申请日：2021-06-15

Applicant: Kioxia Corporation

Inventor： Sho KODAMA ,  Masato SUMIYOSHI ,  Keiri NAKANISHI

IPC: H03M7/40 ,  G06F3/06

Abstract: 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.

公开(公告)号：US20220269416A1

公开(公告)日：2022-08-25

申请号：US17304025

申请日：2021-06-14

Applicant: Kioxia Corporation

Inventor： Sho KODAMA ,  Keiri NAKANISHI ,  Masato SUMIYOSHI ,  Zheye WANG ,  Kohei OIKAWA ,  Youhei FUKAZAWA ,  Daisuke YASHIMA ,  Takashi MIURA

IPC: G06F3/06 ,  H03M7/30

Abstract: According to one embodiment, a memory system includes a compressor configured to output second data obtained by compressing input first data and a non-volatile memory to which third data based on the second data output from the compressor is written. The compressor includes a dictionary coding unit configured to perform dictionary coding on the first data, an entropy coding unit configured to perform entropy coding on the result of the dictionary coding, a first calculation unit configured to calculate compression efficiencies of the dictionary coding and the entropy coding, and a first control unit configured to control an operation of at least one of the dictionary coding unit and the entropy coding unit based on the compression efficiencies and a power reduction level.

公开(公告)号：US20220187994A1

公开(公告)日：2022-06-16

申请号：US17471107

申请日：2021-09-09

Applicant: Kioxia Corporation

Inventor： Youhei FUKAZAWA ,  Kohei OIKAWA ,  Sho KODAMA ,  Keiri NAKANISHI ,  Takashi MIURA ,  Daisuke YASHIMA ,  Masato SUMIYOSHI ,  Zheye WANG

IPC: G06F3/06 ,  H03M7/30

Abstract: 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.