Abstract: According to an embodiment, a controller is connected to an external storage device and controls access to a semiconductor storage device including blocks each including memory cell groups each having memory cells. The block includes pages associated with each memory cell group. A writing process for each memory cell group includes writing stages. The controller includes a determining unit configured to determine data to be transferred to the page required in the writing process for a first memory cell group before the writing stage first starts when the writing stage is performed; a reading unit configured to read the determined data from the semiconductor storage device and to store the read data in the external storage device before the writing stage starts; and a writing unit configured to perform the writing process using the data stored in the external storage device when the writing stage is performed.

Abstract: According to an embodiment of a controller, a bit string manipulating unit manipulates a bit string of manipulation target data based on a predetermined rule. A special data setting unit generates a magic number based on a special data setting request from a host interface, obtains an error detecting code for the magic number, and sends the magic number and the error detecting code as manipulation target data to the bit string manipulating unit to obtain a manipulated manipulation target data. The special data setting unit also extracts logical block address information from the special data setting request, and instructs an access unit to write the magic number in the manipulated manipulation target data to a user data storage area and to write the error detecting code in the manipulated manipulation target data to a redundant area in a storage area located by the logical block address information.

Abstract: According to one embodiment, a semiconductor memory device includes semiconductor memory chips in which data requested to be written. The data has one or more pieces of first data in a predetermined unit. The device includes a write controller that writes the first data and redundancy information calculated by using a predetermined number of pieces of the first data and used for correcting an error in the predetermined number of pieces of the first data into different semiconductor memory chips; and a storage unit that stores identification information and region specifying information so as to be associated with each other. The identification information associates the first data and the redundancy information, and the region specifying information specifies a plurality of storage regions in the semiconductor memory chips to which the pieces of the first data and the redundancy information associated with each other are written.

Abstract: According to one embodiment, a write instructing unit instructs a data access unit to write, in a storage area of a data storage unit indicated by a first physical address, write object data, instructs a management information access unit to update address conversion information, and instructs a first access unit to update the first physical address. A compaction unit extracts a physical address of compaction object data, instructs the data access unit to read the compaction object data stored in a storage area of the data storage unit indicated by the physical address, instructs the data access unit to write the compaction object data in a storage area of the data storage unit indicated by a second physical address, instructs the management information access unit to update the address conversion information, and instructs a second access unit to update the second physical address.

Abstract: According to one embodiment, a semiconductor memory device includes semiconductor memory chips having writable storage regions in which data is written. The data has one or more pieces of first data, and one or more pieces of the first data includes second data. The device includes a determining unit that determines a prescribed number or fewer of semiconductor memory chips to which the first data is written; a write controller that writes the the first data and redundant information calculated from the second data and used for correcting an error in the second data into the writable storage regions in the determined semiconductor memory chips; and a storage unit that stores identification information and region specifying information associated with each other.

Abstract: According to one embodiment, a semiconductor memory device includes semiconductor memory chips in which data requested to be written. The data has one or more pieces of first data in a predetermined unit. The device includes a write controller that writes the first data and redundancy information calculated by using a predetermined number of pieces of the first data and used for correcting an error in the predetermined number of pieces of the first data into different semiconductor memory chips; and a storage unit that stores identification information and region specifying information so as to be associated with each other. The identification information associates the first data and the redundancy information, and the region specifying information specifies a plurality of storage regions in the semiconductor memory chips to which the pieces of the first data and the redundancy information associated with each other are written.

Abstract: A controller stores therein a sector address set indicating logical storage positions within a nonvolatile-memory storage area; page addresses indicating, in units of pages, physical storage positions within the nonvolatile-memory storage area; and pieces of management information each indicating whether one or more special sectors each being either a bad sector or a trimmed sector trimmed by a TRIM command are present in the corresponding page, while associating them with each other. When an access to a specified sector address is requested, the device refers to the piece of management information and judges whether any special sector is present in the page identified by the page address corresponding to the sector address. The device generates predetermined response data if the page contains one or more special sectors and accesses the nonvolatile-memory storage position corresponding to the sector address if the page contains no special sector.

Abstract: A volatile management memory stores management information for managing a use state of a storage medium. A management information storing unit divides the management information into plural division pieces and individually stores them in the storage medium. A main controller receives a command from a host device while the division pieces are being stored, performs data processing for the storage medium in response to the command between each division piece is stored, updates the management information divided into the division pieces according to the data processing content, and creates a log representing an update content of the management information. A log storing unit stores the log in the storage medium. A restoring unit reads the division pieces stored in the storage medium to the management memory as the management information, updates the management information according to the log stored in the storage medium, and restores the updated management information.

Abstract: According to one embodiment, a semiconductor memory device performs writing of data to a semiconductor memory element in response to a request to write the data with a specified logical block address from a host and performs writing of valid data to the semiconductor memory element for compaction according to a log-structured method. The semiconductor memory device adjusts a frequency of the writing response to a request from the host and a frequency of the writing for compaction according to a predetermined ratio.

Abstract: A semiconductor storage includes a receiver configured to receive a write request from a host device; a storage unit configured to hold redundancy data generation/non-generation information; a writing unit configured to write data in a semiconductor memory array and write redundancy data generation/non-generation information of the written data in the storage unit; a first data extracting unit configured to extract data whose redundancy data is not generated from among the data held by the semiconductor memory array; a first redundancy data generating unit configured to generate redundancy data; a first redundancy data writing unit configured to write the generated redundancy data in the semiconductor memory array; and a first redundancy data generation/non-generation information updating unit configured to update the redundancy data generation/non-generation information of the data whose redundancy data held by the storage unit is generated.

Abstract: According to an embodiment, a memory system includes semiconductor memories each having a plurality of blocks; a first table; a receiving unit; a generating unit; a second table; and a writing unit. The first table includes a plurality of memory areas each associated with each block and in each of which defect information is stored. The generating unit generates a set of blocks by selecting one block to which data are to be written in each semiconductor memory based on an index number indicating one of a plurality of rows in the first table and the first table. In the second table, an index number and a channel number are stored for each logical block address in association with one another. When a write command is received by the receiving unit, the writing unit writes data to a block associated with a selected channel number among blocks constituting the set.

Abstract: According to an embodiment of a controller, a bit string manipulating unit manipulates a bit string of manipulation target data based on a predetermined rule. A special data setting unit generates a magic number based on a special data setting request from a host interface, obtains an error detecting code for the magic number, and sends the magic number and the error detecting code as manipulation target data to the bit string manipulating unit to obtain a manipulated manipulation target data. The special data setting unit also extracts logical block address information from the special data setting request, and instructs an access unit to write the magic number in the manipulated manipulation target data to a user data storage area and to write the error detecting code in the manipulated manipulation target data to a redundant area in a storage area located by the logical block address information.

Abstract: According to one embodiment, a memory system includes a non-volatile semiconductor memory, a block management unit, and a transcription unit. The semiconductor memory includes a plurality of blocks to which data can be written in both the first mode and the second mode. The block management unit manages a block that stores therein no valid data as a free block. When the number of free blocks managed by the block management unit is smaller than or equal to a predetermined threshold value, the transcription unit selects one or more used blocks that stores therein valid data as transcription source blocks and transcribes valid data stored in the transcription source blocks to free blocks in the second mode.

Abstract: According to one embodiment, a controller controls writing into and reading from a storage apparatus that includes a first data-storage unit and a second data-storage unit. The second data-storage unit stores user data and parity data of the user data. The first data-storage unit stores the parity data. The controller includes a parity updating unit and a parity writing unit. When parity data is updated, the parity updating unit writes the updated parity data into the first data-storage unit. When a certain requirement is satisfied, the parity writing unit reads the parity data written in the first data-storage unit, and writes the parity data thus read into the second data-storage unit.

Abstract: A data control apparatus includes a mapping-table managing unit that manages a mapping table that is associated with a corrupted-data recovery function of recording data and error correcting code data as redundant data that is given separately from the data, distributed and stored in units of stripe blocks in the plural nonvolatile semiconductor memory devices, the mapping table containing arrangement information of the data and the error correcting code data; a determining unit that determines whether to differentiate frequencies of writing the data into the semiconductor memory devices; and a changing unit that changes the arrangement information by switching the data stored in units of the stripe blocks managed using the mapping table to differentiate the frequencies of writing the data into the semiconductor memory devices, when the determining unit determines that the frequencies of writing the data into the semiconductor memory devices are to be differentiated.

Abstract: A size storage unit stores therein a block size of a memory element. A buffering unit executes buffer processing configured to store data received from a RAID (Redundant Arrays of Inexpensive/Independent Disks) controller into a buffer, and to write the data stored in the buffer into the memory element. A stripe-size receiving unit receives a stripe size that indicates a size of a unit of access at time of access to the memory element by the RAID controller. Writing processing is configured to write data received from the RAID controller into the memory element without executing the buffer processing by the buffering unit, when the stripe size is n times of the block size (n is a positive integer).

Abstract: According to one embodiment, a write instructing unit instructs a data access unit to write, in a storage area of a data storage unit indicated by a first physical address, write object data, instructs a management information access unit to update address conversion information, and instructs a first access unit to update the first physical address. A compaction unit extracts a physical address of compaction object data, instructs the data access unit to read the compaction object data stored in a storage area of the data storage unit indicated by the physical address, instructs the data access unit to write the compaction object data in a storage area of the data storage unit indicated by a second physical address, instructs the management information access unit to update the address conversion information, and instructs a second access unit to update the second physical address.

Abstract: According to one embodiment, a semiconductor memory device includes semiconductor memory chips having writable storage regions in which data is written. The data has one or more pieces of first data, and one or more pieces of the first data includes second data. The device includes a determining unit that determines a prescribed number or fewer of semiconductor memory chips to which the first data is written; a write controller that writes the the first data and redundant information calculated from the second data and used for correcting an error in the second data into the writable storage regions in the determined semiconductor memory chips; and a storage unit that stores identification information and region specifying information associated with each other.

Abstract: According to one embodiment, a semiconductor memory device performs writing of data to a semiconductor memory element in response to a request to write the data with a specified logical block address from a host and performs writing of valid data to the semiconductor memory element for compaction according to a log-structured method. The semiconductor memory device adjusts a frequency of the writing response to a request from the host and a frequency of the writing for compaction according to a predetermined ratio.

Abstract: According to one embodiment, a semiconductor memory device includes semiconductor memory chips in which data requested to be written. The data has one or more pieces of first data in a predetermined unit. The device includes a write controller that writes the first data and redundancy information calculated by using a predetermined number of pieces of the first data and used for correcting an error in the predetermined number of pieces of the first data into different semiconductor memory chips; and a storage unit that stores identification information and region specifying information so as to be associated with each other. The identification information associates the first data and the redundancy information, and the region specifying information specifies a plurality of storage regions in the semiconductor memory chips to which the pieces of the first data and the redundancy information associated with each other are written.