Abstract: A memory system includes a nonvolatile semiconductor memory having blocks, the block being data erasing unit; and a controller configured to execute; an update processing for; writing superseding data in a block, the superseding data being treated as valid data; and invalidating superseded data having the same logical address as the superseding data, the superseded data being treated as invalid data; and a compaction processing for; retrieving blocks having invalid data using a management table, the management table managing blocks in a linked list format for each number of valid data included in the block; selecting a compaction source block having at least one valid data from the retrieved blocks; copying a plurality of valid data included in the compaction source blocks into a compaction target block; invalidating the plurality of valid data in the compaction source blocks; and releasing the compaction source blocks in which all data are invalidated.

Abstract: A first normal bit and source lines are connected to a first memory cell. Second normal bit and source lines are connected to a second memory cell. A first column switch connects one of the first and second normal bit lines to a first global bit line. A second column switch connects one of the first and second normal source lines to a first global source line. A first reference bit and source lines are connected to a third memory cell. A third column switch connects the first reference bit line to a second global bit line. A fourth column switch connects the first reference source line to the first global source line. A sense amplifier is connected to the first and second global bit lines, and reads data stored in one of the first and second memory cells.

Abstract: A resistance change type memory includes a memory cell including a first resistance change element as a memory element; a reference cell including a second resistance change element and a first element having a resistance value which is not higher than a resistance range of the first and second resistance change elements; and a read circuit including a first input terminal connected to the memory cell, and a second input terminal connected to the reference cell.

Abstract: According to one embodiment, a semiconductor memory device includes a first bit line extending in a first direction, a first source line including a first portion that extends in the first direction, a second portion that extends in the first direction, and a third portion that connects one end of the first portion and one end of the second portion, a first memory cell having one terminal electrically connected to the first bit line and the other terminal electrically connected to the first portion of the first source line, a first sense amplifier arranged on the other end side of the first portion and the second portion of the first source line, and a first current sink arranged on a side of the first sense amplifier with respect to the first bit line and the first source line.

Abstract: According to one embodiment, a resistance change type memory includes a first and a second bit lines, a memory cell connected between the first and second bit lines and including a variable resistance element as a memory element and a first select element including a first control terminal connected to a word line, and an auxiliary circuit connected to the first bit line and including a second select element including a second control terminal connected to a control line. When data is read from the memory cell, a first current in a read current supplied to the first bit line is supplied to the memory element and the first select element, and a second current in the read current is supplied to the second select element.

Abstract: According to one embodiment, first normal bit and source lines are connected to a first memory cell. Second normal bit and source lines are connected to a second memory cell. A first column switch connects one of the first and second normal bit lines to a first global bit line. A second column switch connects one of the first and second normal source lines to a first global source line. A first reference bit and source lines are connected to a third memory cell. A third column switch connects the first reference bit line to a second global bit line. A fourth column switch connects the first reference source line to the first global source line. A sense amplifier is connected to the first and second global bit lines, and reads data stored in one of the first and second memory cells.

Abstract: A memory system includes a volatile first storing unit, a nonvolatile second storing unit in which data is managed in a predetermined unit, and a controller that writes data requested by a host apparatus in the second storing unit via the first storing unit and reads out data requested by the host apparatus from the second storing unit to the first storing unit and transfers the data to the host apparatus. The controller includes a management table for managing the number of failure areas in a predetermined unit that occur in the second storing unit and switches, according to the number of failure areas, an operation mode in writing data in the second storing unit from the host apparatus.

Abstract: A resistance change type memory device according to an embodiment includes a plurality of memory elements; a first to a fourth bit lines connected to the plurality of memory elements, respectively; a first to a fourth transistors connected at their one ends to the first to the fourth bit lines, respectively; a fifth transistor connected at its one end to the other ends of the first and second transistors; a sixth transistor connected at its one end to the other ends of the third and fourth transistors; and a fifth bit line connected to the other ends of the fifth and sixth transistors.

Abstract: A memory system according to an embodiment of the present invention comprises: speed of processing for searching through management tables is increased by providing a forward lookup table for searching for, respectively in track and cluster units, from a logical address, a storage device position where data corresponding to the logical address and a reverse lookup table for searching for, from a position of the storage device, a logical address stored in the position and linking these tables.

Abstract: A memory system includes a controlling unit that configured to control data transfer between the first and the second memory. The controlling unit executes copy processing for, after reading out data stored in a first page of the second memory to the first memory, writing the data in a second page of the second memory, determines, when executing the copy processing, whether the error correction processing for the data read out from the first page is successful, stores, when the error correction processing is successful, corrected data in the first memory and writes the corrected data in the second page, and reads out, when the error correction processing is unsuccessful, the data from the first page to the first memory and writes the data not subjected to the error correction processing in the second page.

Abstract: According to an embodiment, a resistance change memory device includes memory cells each including a resistance change element, reference cells each including a resistance change element, and a control circuit configured to control the memory cells and the reference cells, wherein, if an error is detected about data of a memory cell, the control circuit performs write back to data of the memory cell associated with the error detected and data of a reference cell in parallel with one another.

Abstract: A memory system includes a management-information restoring unit. The management-information restoring unit determines whether a short break has occurred referring to a pre-log or a post-log in a NAND memory. The management-information restoring unit determines that a short break has occurred when the pre-log or the post-log is present in the NAND memory. In that case, the management-information restoring unit determines timing of occurrence of the short break, and, after selecting a pre-log or a post-log used for restoration, performs restoration of the management information reflecting these logs on a snapshot. Thereafter, the management-information restoring unit applies recovery processing to all write-once blocks in the NAND memory, takes the snapshot again, and opens the snapshot and the logs in the past.

Abstract: A memory system according to an embodiment of the present invention comprises: speed of processing for searching through management tables is increased by providing a forward lookup table for searching for, respectively in track and cluster units, from a logical address, a storage device position where data corresponding to the logical address and a reverse lookup table for searching for, from a position of the storage device, a logical address stored in the position and linking these tables.

Abstract: A resistance change type memory includes a memory cell including a first resistance change element as a memory element; a reference cell including a second resistance change element and a first element having a resistance value which is not higher than a resistance range of the first and second resistance change elements; and a read circuit including a first input terminal connected to the memory cell, and a second input terminal connected to the reference cell.

Abstract: A memory system includes a volatile first storing unit, a nonvolatile second storing unit in which data is managed in a predetermined unit, and a controller that writes data requested by a host apparatus in the second storing unit via the first storing unit and reads out data requested by the host apparatus from the second storing unit to the first storing unit and transfers the data to the host apparatus. The controller includes a management table for managing the number of failure areas in a predetermined unit that occur in the second storing unit and switches, according to the number of failure areas, an operation mode in writing data in the second storing unit from the host apparatus.

Abstract: A memory system includes a controlling unit that configured to control data transfer between the first and the second memory. The controlling unit executes copy processing for, after reading out data stored in a first page of the second memory to the first memory, writing the data in a second page of the second memory, determines, when executing the copy processing, whether the error correction processing for the data read out from the first page is successful, stores, when the error correction processing is successful, corrected data in the first memory and writes the corrected data in the second page, and reads out, when the error correction processing is unsuccessful, the data from the first page to the first memory and writes the data not subjected to the error correction processing in the second page.

Abstract: A memory system includes a nonvolatile semiconductor memory having blocks, the block being data erasing unit; and a controller configured to execute; an update processing for; writing superseding data in a block, the superseding data being treated as valid data; and invalidating superseded data having the same logical address as the superseding data, the superseded data being treated as invalid data; and a compaction processing for; retrieving blocks having invalid data using a management table, the management table managing blocks in a linked list format for each number of valid data included in the block; selecting a compaction source block having at least one valid data from the retrieved blocks; copying a plurality of valid data included in the compaction source blocks into a compaction target block; invalidating the plurality of valid data in the compaction source blocks; and releasing the compaction source blocks in which all data are invalidated.

Abstract: A memory system includes a management-information restoring unit. The management-information restoring unit determines whether a short break has occurred referring to a pre-log or a post-log in a NAND memory. The management-information restoring unit determines that a short break has occurred when the pre-log or the post-log is present in the NAND memory. In that case, the management-information restoring unit determines timing of occurrence of the short break, and, after selecting a pre-log or a post-log used for restoration, performs restoration of the management information reflecting these logs on a snapshot. Thereafter, the management-information restoring unit applies recovery processing to all write-once blocks in the NAND memory, takes the snapshot again, and opens the snapshot and the logs in the past.

Abstract: According to one embodiment, a resistance change type memory includes a first and a second bit lines, a memory cell connected between the first and second bit lines and including a variable resistance element as a memory element and a first select element including a first control terminal connected to a word line, and an auxiliary circuit connected to the first bit line and including a second select element including a second control terminal connected to a control line. When data is read from the memory cell, a first current in a read current supplied to the first bit line is supplied to the memory element and the first select element, and a second current in the read current is supplied to the second select element.

Abstract: According to one embodiment, a resistance change type memory includes a memory cell including a first resistance change element as a memory element; a reference cell including a second resistance change element and a first element having a resistance value which is not higher than a resistance range of the first and second resistance change elements; and a read circuit including a first input terminal connected to the memory cell, and a second input terminal connected to the reference cell.