Abstract: An object is to reduce the number of writes of information managed by a controller to a non-volatile memory. A controller according to one aspect of the present invention includes: a first interface unit connected to a non-volatile memory including a plurality of blocks of memory cells that enter into both a first state and a second state and in which a plurality of addresses is allocated to the plurality of blocks; an information holding unit that holds first information; and a control unit that reads first data from a first block of the non-volatile memory via the first interface unit, specifies the memory cell in the second state among the memory cells in the first block and writes second data for causing the specified memory cell in the second state to transition to the first state, and selects one of the first information and the first data on the basis of the address of the first block and writes the selected first information or first data to the first block.

Abstract: A selector malfunction caused by a drift is prevented in a memory having a cross-point structure. A memory cell array is provided with a data area and a drift reference cell. An accumulated drift amount acquisition unit acquires an accumulated drift amount of the drift reference cell. A total drift amount reading unit reads a total drift amount stored in the data area. A refresh control unit adds the accumulated drift amount to the total drift amount to update the total drift amount as a new total drift amount. Further, the refresh control unit refreshes the data area of the memory cell array in a case where the new total drift amount exceeds a predetermined threshold value.

Abstract: To eliminate drift that is generated in a memory cell and continue use of the memory cell. A storage control device controls a memory cell array in which each bit is in any one of first or second states. The storage control device includes a detection unit and a control unit. The detection unit detects a transition bit that should be in the first state but is in the second state in the memory cell array. The control unit performs control to supply, to the transition bit, a drift refresh voltage higher than a read voltage required for reading from the memory cell array.

Abstract: An object is to suppress a process of evicting cached data so as to improve a throughput of an entire system. A storage controller includes an access request section and an operation management section. The access request section requests access to a first storage and to a second storage that is higher in response speed than the first storage, the second storage storing part of data stored in the first storage. The operation management section manages, based on a usage state of the second storage, whether or not to transfer from the first storage to the second storage data targeted for access but not stored in the second storage.

Abstract: Even data mapped to discrete physical addresses of a volatile memory is saved in a non-volatile memory. A memory management information registration unit registers, as an entry of memory management information, a physical address of a first memory that is volatile memory and an address of a second memory that is a non-volatile memory, in association for every management unit. A control unit saves data from the first memory into the second memory in accordance with the memory management information in response to a save request, and restores data from the second memory into the first memory in accordance with the memory management information in response to a restore request.

Abstract: Memory devices having different parallel accessible data sizes and different access speeds are caused to work efficiently as a cache memory. A memory access device accesses first and second memory devices that respectively include a plurality of parallel accessible memories and have different parallel accessible data sizes and different access speeds. The memory access device includes a management information storage unit and an access control unit. The management information storage unit stores management information as associating each corresponding management unit of the first and second memory devices. The access control unit accesses one of the first and second memory devices on the basis of the management information.

Abstract: An object is to suppress a process of evicting cached data so as to improve a throughput of an entire system. A storage controller includes an access request section and an operation management section. The access request section requests access to a first storage and to a second storage that is higher in response speed than the first storage, the second storage storing part of data stored in the first storage. The operation management section manages, based on a usage state of the second storage, whether or not to transfer from the first storage to the second storage data targeted for access but not stored in the second storage.

Abstract: [Object] To sufficiently reduce frequency of error occurrence in memory cells. [Solution] A reading unit reads read data from a memory cell, the read data including an information bit and reversal information for determining whether or not the information bit has been reversed. In addition, an error detection/correction unit detects the presence or absence of an error in the information bit and corrects the error. A data reversing unit reverses the information bit that has the error corrected and the reversal information. Furthermore, a writing unit writes the reversed information bit and the reversed reversal information in the memory cell.

Abstract: To secure flexibility of the memory extension area which is secured on the memory of the host computer and used by the memory controller. [Solution] A controller memory stores data corresponding to an area allocated to a memory in a memory controller configured to control the memory. An access control unit allocates a partial area of the controller memory to a host memory in a host computer and uses the areas as a memory extension area. The extension area managing unit performs management so that a size of the memory extension area in the host memory is changeable.

Abstract: A data holding characteristic of a memory cell is improved in a memory system in which data is encoded and written to a memory cell. A first candidate parity generation unit generates, as a first candidate parity, a parity for detecting an error in an information section in which a predetermined value is assigned in a predetermined variable area. A second candidate parity generation unit generates, as a second candidate parity, a parity for detecting an error in the information section in which a value different from the predetermined value is assigned in the predetermined variable area. A selection unit selects a parity that satisfies a predetermined condition from among the first and second candidate parities as a selection parity. An output unit outputs a codeword constituted by the information section corresponding to the selection parity and the selection parity.

Abstract: Detecting a defective cell in a memory in consideration of an error property difference depending on the storage state. A determination unit determines whether there is a possibility of defect for each of unit-of-storages on a memory cell formed with a non-volatile memory. The non-volatile memory undergoes either a reset operation that transitions a state from a low resistive state (LRS) to a high resistive state (HRS) or a set operation that transitions the state from the high resistive state to the low resistive state. The determination unit determines a unit-of-storage in which the number of errors in predetermined one of the reset operation and the set operation has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect.

Abstract: To perform both writing and reading at a high speed by utilizing a first memory and a second memory that has a lower writing speed and a higher reading speed than the first memory. A writing unit writes writing data related to a writing command in a first memory when the writing command is executed. A transfer unit transfers the writing data from the first memory to a second memory at a predetermined timing. A reading unit performs reading of reading data from the second memory with higher priority than from the first memory when a reading command is executed.

Abstract: To suppress the degradation of memory cells in a non-volatile memory. A read processing unit performs a read process for reading read data from each of a plurality of memory cells on the basis of a first threshold. An error detection unit detects presence or absence of an error in the read data and specifies memory cells in which the error is present among the plurality of memory cells. A re-read processing unit performs a re-read process for reading data, as re-read data, from the specified memory cells on the basis of a second threshold different from the first threshold. A refresh processing unit rewrites, for a memory cell of which the re-read data has a different value from the read data among the specified memory cells, data with the re-read data as a refresh process.

Abstract: A data holding characteristic of a memory cell is improved in a memory system in which data is encoded and written to a memory cell. A first candidate parity generation unit generates, as a first candidate parity, a parity for detecting an error in an information section in which a predetermined value is assigned in a predetermined variable area. A second candidate parity generation unit generates, as a second candidate parity, a parity for detecting an error in the information section in which a value different from the predetermined value is assigned in the predetermined variable area. A selection unit selects a parity that satisfies a predetermined condition from among the first and second candidate parities as a selection parity. An output unit outputs a codeword constituted by the information section corresponding to the selection parity and the selection parity.

Abstract: To secure flexibility of the memory extension area which is secured on the memory of the host computer and used by the memory controller. [Solution] A controller memory stores data corresponding to an area allocated to a memory in a memory controller configured to control the memory. An access control unit allocates a partial area of the controller memory to a host memory in a host computer and uses the areas as a memory extension area. The extension area managing unit performs management so that a size of the memory extension area in the host memory is changeable.

Abstract: A storage control apparatus includes: a pre-processing-execution determining block for determining whether or not either one of an erase operation and a program operation is to be executed as pre-processing in a write operation to be carried out on a predetermined data area to serve as a write-operation object; and a pre-read processing block for reading out pre-read data from the data area prior to the write operation if a result of the determination indicates that the pre-processing is to be executed. The apparatus further includes a bit operating block for carrying out: the pre-processing and one of the erase and program operations which is not the pre-processing as post-processing if a result of the determination indicates that the pre-processing is to be executed; and the post-processing without carrying out the pre-processing if a determination result indicates that the pre-processing is not to be executed.

Abstract: To suppress the degradation of memory cells in a non-volatile memory. A read processing unit performs a read process for reading read data from each of a plurality of memory cells on the basis of a first threshold. An error detection unit detects presence or absence of an error in the read data and specifies memory cells in which the error is present among the plurality of memory cells. A re-read processing unit performs a re-read process for reading data, as re-read data, from the specified memory cells on the basis of a second threshold different from the first threshold. A refresh processing unit rewrites, for a memory cell of which the re-read data has a different value from the read data among the specified memory cells, data with the re-read data as a refresh process.

Abstract: Reduction in deterioration of a memory cell in a non-volatile memory is achieved. A memory controller is configured to include a time measuring unit, an elapsed time determination unit, and a read unit. The time measuring unit measures time elapsed from predetermined timing on an address where data written. The elapsed time determination unit determines whether the elapsed time exceeds a fixed amount of time upon receiving an instruction to read out the data from the address. The read control unit causes reading-out of the data from the address to pause in a case where the elapsed time is determined not to exceed the fixed amount of time.

Abstract: [Object] To sufficiently reduce frequency of error occurrence in memory cells. [Solution] A reading unit reads read data from a memory cell, the read data including an information bit and reversal information for determining whether or not the information bit has been reversed. In addition, an error detection/correction unit detects the presence or absence of an error in the information bit and corrects the error. A data reversing unit reverses the information bit that has the error corrected and the reversal information. Furthermore, a writing unit writes the reversed information bit and the reversed reversal information in the memory cell.

Abstract: Detecting a defective cell in a memory in consideration of an error property difference depending on the storage state. A determination unit determines whether there is a possibility of defect for each of unit-of-storages on a memory cell formed with a non-volatile memory. The non-volatile memory undergoes either a reset operation that transitions a state from a low resistive state (LRS) to a high resistive state (HRS) or a set operation that transitions the state from the high resistive state to the low resistive state. The determination unit determines a unit-of-storage in which the number of errors in predetermined one of the reset operation and the set operation has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect.