Abstract: A memory system includes a nonvolatile memory, an interface circuit, and a controller configured to upon receipt of a plurality of write commands for storing write data in the nonvolatile memory via the interface circuit, acquire compression-ratio information about the write data associated with each write command, determine a compression ratio of each write data based on the acquired compression-ratio information, and determine an execution order of the write commands based on the determined compression ratio.

Abstract: A memory system including a storage device and a memory controller controlling the storage device and decoding an encoded data. The memory controller including: a history buffer storing a decoded data string; a history buffer read controller executing a read request to the history buffer; a decode executing section generating a first shaped data string based on the decoded data string read from the history buffer, generating a second shaped data string by refferring the first shaped data string before the first shaped data string being written back to the history buffer in response to the read request, and generating a decoded result using the first shaped data string and the second shaped data string.

Abstract: A memory system including a history buffer, a hash calculator, a read pointer table, a history buffer writing circuit, a read pointer writing circuit, a read pointer reading circuit, a history buffer reading circuit, a matching circuit replacing the input data string with a reference information referring the matching candidate data string in the case where at least a part of the input data string and a part of the matching candidate data string match. Reading of the read pointer by the read pointer reading circuit and reading of the stored input data string by the history buffer reading circuit are executed after writing of the read pointer by the read pointer writing circuit and writing of the input data string by the history buffer writing circuit are finished.

Abstract: 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.

Abstract: According to one embodiment, a compression device includes a dictionary based encoder, a second buffer, a comparator, and a compression data generator. The dictionary based encoder searches for second data at least partially matching first data from a first buffer, and acquires a first match position indicating a position of the second data in the first buffer and a match length indicating a matched length of the first and second data. The second buffer stores the previously acquired second match position with an index. The compression data generator generates first compressed data that includes the index assigned to the second match position in the second buffer and the match length when the first match position matches the second match position in the second buffer.

Abstract: A memory system includes a first memory that is nonvolatile, a second memory that is volatile, and a memory controller. The memory controller is configured to store first information in the second memory. The first information includes management information. The memory controller is further configured to compress the first information. The compressed first information is second information. The memory controller is configured to store the second information in the first memory.

Abstract: A memory system includes a nonvolatile memory, an interface circuit, and a controller configured to upon receipt of a plurality of write commands for storing write data in the nonvolatile memory via the interface circuit, acquire compression-ratio information about the write data associated with each write command, determine a compression ratio of each write data based on the acquired compression-ratio information, and determine an execution order of the write commands based on the determined compression ratio.

Abstract: A memory system includes a nonvolatile memory, an interface circuit, and a controller configured to upon receipt of a plurality of write commands for storing write data in the nonvolatile memory via the interface circuit, acquire compression-ratio information about the write data associated with each write command, determine a compression ratio of each write data based on the acquired compression-ratio information, and determine an execution order of the write commands based on the determined compression ratio.

Abstract: A memory system includes a nonvolatile memory, an interface circuit, and a controller configured to upon receipt of a plurality of write commands for storing write data in the nonvolatile memory via the interface circuit, acquire compression-ratio information about the write data associated with each write command, determine a compression ratio of each write data based on the acquired compression-ratio information, and determine an execution order of the write commands based on the determined compression ratio.

Abstract: According to one embodiment, a memory system includes an error mitigation encoder that executes error mitigation coding on write data to be stored in a processing target page of a non-volatile memory, a memory interface that writes the write data which has undergone the error mitigation coding in the processing target page of the non-volatile memory and reads the write data which has undergone the error mitigation coding from the processing target page as read data, an error mitigation decoder that performs error mitigation decoding on the read data read from the processing target page of the non-volatile memory, and an error mitigation coding rate deciding unit that decides an error mitigation coding rate of the error mitigation encoder and the error mitigation decoder on the basis of at least one of information indicating the processing target page and information indicating a device characteristic of the processing target page.

Abstract: According to one embodiment, for first data, which is read from a nonvolatile memory, for which a first data translation is performed, a second data translation that is a reverse translation of the first data translation is performed. Next, for the first data for which the second data translation is performed, the first data translation is performed. In addition, the read first data is compared with the first data for which the first data translation is performed, and check information is generated based on a result of the comparison.

Abstract: According to one embodiment, a memory system includes an error mitigation encoder that executes error mitigation coding on write data to be stored in a processing target page of a non-volatile memory, a memory interface that writes the write data which has undergone the error mitigation coding in the processing target page of the non-volatile memory and reads the write data which has undergone the error mitigation coding from the processing target page as read data, an error mitigation decoder that performs error mitigation decoding on the read data read from the processing target page of the non-volatile memory, and an error mitigation coding rate deciding unit that decides an error mitigation coding rate of the error mitigation encoder and the error mitigation decoder on the basis of at least one of information indicating the processing target page and information indicating a device characteristic of the processing target page.

Abstract: An image compression apparatus according to an embodiment includes a slope determiner and a compressor. The slope determiner determines slopes of linear lines calculated from a reference component and non-reference components. The reference component is one of a plurality of image components forming pixels included in an input image data. The non-reference components are other image components. The compressor generates a compressed image data in which a value of the reference component of each of the pixels in the input image data, the slopes, and representative values of the non-reference components are compressed.

Abstract: According to one embodiment, a control unit determines a first physical sector in which first data is to be written among a plurality of physical sectors based on first information that is based on a result of the first data translation and the device characteristics of the plurality of physical sectors. A write unit writes data for which a first data translation is performed into the first physical sector of a nonvolatile memory.

Abstract: According to one embodiment, a memory controller includes a compression unit and a padding processing unit. The compression unit generates first compressed data and second compressed data by compressing first data and second data. The padding processing unit pads first padding data for the first compressed data in accordance with a first padding pattern and pads second padding data for the second compressed data in accordance with a second padding pattern.

Abstract: According to an embodiment, a storage control device includes a controller, a compression condition determiner, a compressor, and an error correction encoder. The controller receives a write request for a data item and determines whether or not the wear degree of a target region in a storage device to which the data item is to be written is less than a threshold value. The compression condition determiner determines, based on the wear degree, an optimal compression condition out of compression conditions that include lossy compression. The compressor generates, based on the compression condition, compressed data. The error correction encoder subjects the data item to error correction and generates encoded data.

Abstract: A data compressing device according to an embodiment includes a data cutting unit configured to divide continuously inputted data into W-bit data blocks and to output the data blocks in segments such that each of the segments is composed of N data blocks, and a compression-method determining unit configured to select, as a compression portion for each of the segments, a run length system, a flag system, or no compression, according to a ratio of data blocks of specific data in any of the segments. The data compressing device further includes an RL compression unit configured to execute, on any of the segments, a run length system of storing a consecutive amount of the specific data into compressed data, and a flag compression unit configured to execute, on any of the segments, a flag system of storing positional information of the specific data into compressed data.

Abstract: According to one embodiment, for first data, which is read from a nonvolatile memory, for which a first data translation is performed, a second data translation that is a reverse translation of the first data translation is performed. Next, for the first data for which the second data translation is performed, the first data translation is performed. In addition, the read first data is compared with the first data for which the first data translation is performed, and check information is generated based on a result of the comparison.

Abstract: According to one embodiment, a controller writes first processed data acquired by a first process into a nonvolatile memory during a first period. The controller writes second processed data acquired by a second process into the nonvolatile memory during a second period. The first process is for the purpose of improving the endurance of memory cells. The second process is for the purpose of decreasing inter-cell interferences between adjacent cells.

Abstract: According to one embodiment, a memory controller includes a compression unit and a padding processing unit. The compression unit compresses first data to be written into a first page and second data to be written into a second page. The padding processing unit performs a padding processing such that the compressed first data is written into first memory cells, first padding data is written into second memory cells, the compressed second data is written into third memory cells, and second padding data is written into fourth memory cells.