Abstract: According to an embodiment, a memory interface that includes n number of channels and writes data subjected to an error correction encoding process having capable of correcting t symbols, n number of first error correction decoding units that perform an error correction decoding process of correcting s (s<t) symbols on read data, and a second error correction decoding units that perform an error correction decoding process of correcting t symbols on read data from which an error is detected after the error correction decoding process of correcting s symbols.

Abstract: According to one embodiment, a memory system includes a nonvolatile memory including first blocks configured to store an address indicating a data storage position, and second blocks configured to store the data, a first table configured to store a first address including first information and second information, the second information indicating a data storage position in the first block, and a second table configured to convert the first information into third information, the first information having a first data size by which one entry of the second table can be identified, the third information having a second data size which is larger than the first data size and by which one of the first blocks and the second blocks can be identified.

Abstract: According to one embodiment, a controller switches modes including a normal operating mode in which power resources of a volatile memory, a data storage unit, and a power control unit are all ON, a first mode in which the power resource of the volatile memory is OFF, and the power resources of the data storage unit and the power control unit are both ON, and a second mode in which the power resources of the volatile memory and the data storage unit are both OFF, and the power resource of the power control unit is ON. Upon receiving a low power consumption instruction command from a host, the controller stores management information to return to the normal operating mode into the volatile storage unit, and shifts the state of the memory system from the normal operating mode to the first mode.

Abstract: A semiconductor storage device includes a first memory area configured in a volatile semiconductor memory, second and third memory areas configured in a nonvolatile semiconductor memory, and a controller which executes following processing. The controller executes a first processing for storing a plurality of data by the first unit in the first memory area, a second processing for storing data outputted from the first memory area by a first management unit in the second memory area, and a third processing for storing data outputted from the first memory area by a second management unit in the third memory area.

Abstract: According to one embodiment, a memory controller includes a writing destination management unit which determines a writing destination of user data, an encoding unit which generates a parity of the user data, and an ECC management unit which measures a fatigue degree of each certain memory area of a nonvolatile memory, selects an encoding method to instruct the encoding unit to be performed according to the encoding method, and changes the encoding method to an encoding method having a high error correction capability in a case where the fatigue degree corresponding to the writing destination is equal to or higher than a threshold and a total sum of parities is equal to or less than a predetermined amount.

Abstract: According to one embodiment, a memory controller includes a controller that is configured to, when notified of an error by one of memory chips at a time of power supply startup, transmit a first command including an address to the memory chip by which the error was notified, when notified of a normal end by the memory chip in which the first command was received, transmit a second command including an address to the memory chip by which the normal end was notified.

Abstract: According to one embodiment, a memory system includes a non-volatile first storage unit, a second storage unit, a third storage unit, and a controller. The controller is configured to selectively execute, following transition to a first mode, either a procedure of writing data of the second storage unit in the third storage unit, or a procedure of writing data of the third storage unit in the first storage unit while reducing power feed to the first and third storage units.

Abstract: A memory system includes a nonvolatile memory including a plurality of blocks as data erase units, a measuring unit which measures an erase time at which data of each block is erased, and a block controller which writes data supplied from at least an exterior into a first block which is set in a free state and whose erase time is oldest.

Abstract: According to one embodiment, a storage device performs error correction processing of a code of which the maximum correction performance is T bits, the decoding device including an error correction processor for performing error correction processing using calculating devices capable of handling errors of J bits (J is an integer equal to or more than one and less than T), wherein an initial value of an error number expectation value is set to I (I is an integer equal to or more than one and less than T), and execution of increment of the error number expectation value and execution of the error correction processing is repeated until no error is detected or the error number expectation value becomes T bits.

Abstract: According to one embodiment, a memory controller includes an encoding unit that executes an error correction coding process on input-data and generates a code word, a calculation control unit that controls whether to execute a multiplication calculation of a multiplication circuit, and a memory interface unit that controls writing of the code word to the memory and reading of the code word from the memory, and the encoding unit includes a remainder circuit that performs a remainder calculation on the input-data using a first generator polynomial and generates a first code word having a first error correction capability and a first multiplication circuit that performs a multiplication calculation on the first code word using a second generator polynomial and performs a multiplication calculation of generating a second code word having a second error correction capability.

Abstract: A memory system includes a volatile first storing unit, a nonvolatile second storing unit, and a controller. The controller performs data transfer, stores management information including a storage position of the data stored in the second storing unit into the first storing unit, and performs data management while updating the management information. The second storing unit has a management information storage area for storing management information storage information including management information in a latest state and a storage position of the management information. The storage position information is read by the controller during a startup operation of the memory system and includes a second pointer indicating a storage position of management information in a latest state in the management information storage area and a first pointer indicating a storage position of the second pointer.

Abstract: A method of controlling a nonvolatile semiconductor memory includes checking a first group at a first interval period, the first group including a plurality of blocks, and when a first block in the first group satisfies a first condition, assigning the first block to a second group. The method includes checking, at a second interval period, an error count of data stored in the second group, and when a second block in the second group satisfies a second condition, moving data stored in the second block to an erased block in which stored data is erased among the plurality of blocks.

Abstract: According to one embodiment, a semiconductor storage device includes a nonvolatile memory, memory controller storing control information, a switch between the nonvolatile memory/memory controller and a power supply terminal, a second memory, an interpreter interprets a command, a switch controller, and a third memory stores an address of the control information in the second memory. The memory controller instructs the switch controller to open the switch after writing the control information into the second memory and reads the control information from the second memory based on the address stored in the third memory when the memory controller is electrically connected to the first power supply terminal.

Abstract: A memory system includes a nonvolatile memory including a plurality of blocks as data erase units, a measuring unit which measures an erase time at which data of each block is erased, and a block controller which writes data supplied from at least an exterior into a first block which is set in a free state and whose erase time is oldest.

Abstract: A memory system includes a volatile first storing unit, a nonvolatile second storing unit, and a controller. The controller performs data transfer, stores management information including a storage position of the data stored in the second storing unit into the first storing unit, and performs data management while updating the management information. The second storing unit has a management information storage area for storing management information storage information including management information in a latest state and a storage position of the management information. The storage position information is read by the controller during a startup operation of the memory system and includes a second pointer indicating a storage position of management information in a latest state in the management information storage area and a first pointer indicating a storage position of the second pointer.

Abstract: According to an embodiment, an access controller refers to state information upon an erase operation, causes the erase operation to be performed on all the collection of physical blocks included in a first logical block, and causes the erase operation to be performed on a part of the collection of physical blocks included in a second logical block and does not causes the erase operation to be performed on rest of the collection of the physical blocks in the second logical block.

Abstract: According to one embodiment, a storage device includes a nonvolatile memory and a controller. The nonvolatile memory includes blocks which store data. Each of the blocks is an erase unit. The controller controls an operation of the nonvolatile memory. The controller executes writes and erases with respect to a first block of the blocks in the nonvolatile memory for the first number of times during a first period. The controller executes writes and erases with respect to other blocks for the second number of times smaller than the first number of times during the first period.

Abstract: According to one embodiment, a memory controller that controls non-volatile memory including a data area and a parity area in which parity for data of a fixed length to be stored in the data area is stored is provided, the memory controller including a coding unit configured to generate parity for each of two or more partial data, each of which has a length less than the fixed length, and the memory controller writing one of the parity generated by the coding unit onto the parity area as first parity, writing the partial data and second parity that is the parity, other than the first parity, generated by the coding unit, onto the data area as the data of the fixed length, and writing the second parity onto a position subsequent to the partial data corresponding to the second parity.

Abstract: According to one embodiment, a storage device has a plurality of memory modules and a memory controller. The memory controller has a first unit configured to receive data to be stored in the memory modules from a host device as a write data stream and transmit data read from the memory modules to the host device as a read data stream, a second unit having a plurality of subunits, each of which is configured to write data in one of the memory modules corresponding to the subunit and read data from one of the memory modules corresponding to the subunit, and a data stream converter configured to parallelize the write data stream into a plurality of data blocks each of which is to be stored in one of the memory modules and to serialize a plurality of data blocks read from the memory modules into the read data stream.

Abstract: An apparatus according to an embodiment comprises a first storage, a second storage, an input unit, a shift number determining unit, and an output unit. The first storage stores identification information of sectors and defective information indicating a presence of defect on the data line, while associating the identification information and the defective information. The second storage has storage regions in a number larger than the first number. The input unit inputs data to the second storage by the first number at a time. The shift number determining unit determines a shift number. The output unit outputs the data stored in the storage regions which is after a head storage region by the shift number, as the data is to be supplied to the data line having no defect sector based upon the defective information, and outputs information that differs from the data to the defective data line.