Abstract: A computer includes a processor including a plurality of registers, a memory, and a storage medium. A processor of a computer is configured to execute an encryption process of generating encrypted user data including a plurality of encrypted data blocks using the plurality of registers, and add a DIF including CRC to the encrypted data blocks and store the result in a storage medium. The encryption process includes repeatedly executing a first process of reading partial data from a predetermined number of the data blocks and storing the partial data in a first register, a second process of storing encrypted partial data obtained by encrypting the partial data stored in the first register in a second register, and a third process of executing an operation for calculating CRC using the encrypted partial data stored in the second register and storing a result of the operation in a third register.

Abstract: A storage system includes an interface and a data compression system configured to compress reception data from the interface before the data is stored in a storage device. The data compression system is configured to compress the reception data using a first compression algorithm to generate first compressed data, use the number of appearances of each of predetermined code categories included in the first compressed data to estimate a decompression time when a second compression algorithm is used, select a second compression method including compression using the second compression algorithm when the decompression time is equal to or less than a threshold value, and select a first compression method that does not include the compression using the second compression algorithm when the decompression time is greater than the threshold value.

Abstract: To speed up decoding of a range code. A decompression circuit calculates a plurality of candidate bit values for each bit of the N-bit string based on a plurality of possible bit histories of a bit before a K-th bit in parallel for a plurality of bits, and repeatedly selects a correct bit value of the K-th bit from the plurality of candidate bit values based on a correct bit history of the bit before the K-th bit to decode the N-bit string.

Abstract: The storage device includes a first memory, a process device that stores data in the first memory and reads the data from the first memory, and an accelerator that includes a second memory different from the first memory. The accelerator stores compressed data stored in one or more storage drives storing data, in the second memory, decompresses the compressed data stored in the second memory to generate plaintext data, extracts data designated in the process device from the plaintext data, and transmits the extracted designated data to the first memory.

Abstract: Deterioration of compression throughput including a decompression check after data compression is suppressed. Provided is a storage system including an interface and a controller. The controller includes a compression circuit configured to generate compressed data by compressing received data received via the interface; and a decompression circuit configured to decompress the compressed data before storing the compressed data in a storage drive to confirm data consistency. The compression circuit sequentially executes a compression task of the received data, sequentially generates packets of the compressed data, and transfers the packets to the decompression circuit. The decompression circuit decompresses the received packet in parallel with the compression task.

Abstract: To speed up decoding of a range code. A decompression circuit calculates a plurality of candidate bit values for each bit of the N-bit string based on a plurality of possible bit histories of a bit before a K-th bit in parallel for a plurality of bits, and repeatedly selects a correct bit value of the K-th bit from the plurality of candidate bit values based on a correct bit history of the bit before the K-th bit to decode the N-bit string.

Abstract: A storage system includes an interface and a data compression system configured to compress reception data from the interface before the data is stored in a storage device. The data compression system is configured to compress the reception data using a first compression algorithm to generate first compressed data, use the number of appearances of each of predetermined code categories included in the first compressed data to estimate a decompression time when a second compression algorithm is used, select a second compression method including compression using the second compression algorithm when the decompression time is equal to or less than a threshold value, and select a first compression method that does not include the compression using the second compression algorithm when the decompression time is greater than the threshold value.

Abstract: The storage device includes a first memory, a process device that stores data in the first memory and reads the data from the first memory, and an accelerator that includes a second memory different from the first memory. The accelerator stores compressed data stored in one or more storage drives storing data, in the second memory, decompresses the compressed data stored in the second memory to generate plaintext data, extracts data designated in the process device from the plaintext data, and transmits the extracted designated data to the first memory.

Abstract: A storage apparatus includes: a flash memory that provides a storage area; a controller that controls writing and reading of data to and from the storage area; and a buffer memory that temporarily stores data to be written in the storage area, in which the controller selects one compression method from a first reversible compression method and a second reversible compression method based on access performance to the flash memory, and determines to compress data based on the selected one compression method and to write the compressed data to the storage area, and the first reversible compression method has a lower compression ratio and a slower compression speed than the second reversible compression method.

Abstract: Provided is a storage system in which a compression rate of randomly written data can be increased and access performance can be improved. A storage controller 22A includes a cache area 203A configured to store data to be read out of or written into a drive 29. The controller 22A groups a plurality of pieces of data stored in the cache area 203A and input into the drive 29 based on a similarity degree among the pieces of data, selects a group, compresses data of the selected group in group units, and stores the compressed data in the drive 29.

Abstract: The storage device includes a first memory, a process device that stores data in the first memory and reads the data from the first memory, and an accelerator that includes a second memory different from the first memory. The accelerator stores compressed data stored in one or more storage drives storing data, in the second memory, decompresses the compressed data stored in the second memory to generate plaintext data, extracts data designated in the process device from the plaintext data, and transmits the extracted designated data to the first memory.

Abstract: To speed up decoding of a range code. A decompression circuit calculates a plurality of candidate bit values for each bit of the N-bit string based on a plurality of possible bit histories of a bit before a K-th bit in parallel for a plurality of bits, and repeatedly selects a correct bit value of the K-th bit from the plurality of candidate bit values based on a correct bit history of the bit before the K-th bit to decode the N-bit string.

Abstract: The storage device includes a first memory, a process device that stores data in the first memory and reads the data from the first memory, and an accelerator that includes a second memory different from the first memory. The accelerator stores compressed data stored in one or more storage drives storing data, in the second memory, decompresses the compressed data stored in the second memory to generate plaintext data, extracts data designated in the process device from the plaintext data, and transmits the extracted designated data to the first memory.

Abstract: A data compression system in a storage system compresses data with a first compression method to generate compressed data, determines whether a compression rate of the compressed data is better than a predetermined reference, outputs data obtained by compressing the data by the compression method having a better compression rate than that of the other compression method of the first compression method and a second compression method when it is determined that the compression rate is better than the reference, and outputs data obtained by compressing the data by the compression method having a worse compression rate than that of the other compression method of the first compression method and the second compression method when it is determined that the compression rate is equal to or worse than the reference.

Abstract: It is assumed that at least one of the plurality of nonvolatile semiconductor memory devices is a nonvolatile semiconductor memory device (hereinafter, referred to as a first memory device) in a low power consumption state in which error check processing and refresh processing cannot be performed. A storage apparatus releases a low power consumption state of a first memory device at a timing according to a lapsed time after the first memory device is in the low power consumption state and an estimated ambient temperature of the first memory device at the lapsed time. When the low power consumption state is released, the first memory device executes the error check processing and the refresh processing.

Abstract: A data compression system in a storage system compresses data with a first compression method to generate compressed data, determines whether a compression rate of the compressed data is better than a predetermined reference, outputs data obtained by compressing the data by the compression method having a better compression rate than that of the other compression method of the first compression method and a second compression method when it is determined that the compression rate is better than the reference, and outputs data obtained by compressing the data by the compression method having a worse compression rate than that of the other compression method of the first compression method and the second compression method when it is determined that the compression rate is equal to or worse than the reference.

Abstract: The storage device includes a first memory, a process device that stores data in the first memory and reads the data from the first memory, and an accelerator that includes a second memory different from the first memory. The accelerator stores compressed data stored in one or more storage drives storing data, in the second memory, decompresses the compressed data stored in the second memory to generate plaintext data, extracts data designated in the process device from the plaintext data, and transmits the extracted designated data to the first memory.

Abstract: To speed up decoding of a range code. A decompression circuit calculates a plurality of candidate bit values for each bit of the N-bit string based on a plurality of possible bit histories of a bit before a K-th bit in parallel for a plurality of bits, and repeatedly selects a correct bit value of the K-th bit from the plurality of candidate bit values based on a correct bit history of the bit before the K-th bit to decode the N-bit string.

Abstract: t is assumed that at least one of the plurality of nonvolatile semiconductor memory devices is a nonvolatile semiconductor memory device (hereinafter, referred to as a first memory device) in a low power consumption state in which error check processing and refresh processing cannot be performed. A storage apparatus releases a low power consumption state of a first memory device at a timing according to a lapsed time after the first memory device is in the low power consumption state and an estimated ambient temperature of the first memory device at the lapsed time. When the low power consumption state is released, the first memory device executes the error check processing and the refresh processing.

Abstract: Provided is a storage system in which a compression rate of randomly written data can be increased and access performance can be improved. A storage controller 22A includes a cache area 203A configured to store data to be read out of or written into a drive 29. The controller 22A groups a plurality of pieces of data stored in the cache area 203A and input into the drive 29 based on a similarity degree among the pieces of data, selects a group, compresses data of the selected group in group units, and stores the compressed data in the drive 29.