Abstract: A memory system includes a semiconductor memory that includes a cell unit having a plurality of memory cells, and a control circuit for controlling the plurality of memory cells, and a memory controller configured to control the semiconductor memory. The control circuit is configured to execute a data read operation on the cell unit by using one or more read voltages, acquire first data by the data read operation, generate second data with a data size smaller than the first data, based on the first data, and transmit the second data to the memory controller. The memory controller is configured to determine, based on the second data, whether or not to rewrite the page data written in the cell unit.

Abstract: A memory system according to an embodiment includes a nonvolatile memory and a memory controller. The nonvolatile memory includes a plurality of memory cells. The memory controller is configured to control the nonvolatile memory. In read operation for the memory cells, the memory controller is configured to: perform tracking including a plurality of reads in which a read voltage is shifted; determine a hard bit read voltage based on results of the tracking; calculate a soft bit read voltage based on the determined hard bit read voltage; perform soft bit read using the calculated soft bit read voltage; and perform a soft bit decoding process using a result of the soft bit read and a log-likelihood ratio table associated with the calculated soft bit read voltage.

Abstract: According to one embodiment, a memory system includes a non-volatile memory, a memory interface that reads data recorded in the non-volatile memory as a received value, a converting unit that converts the received value to first likelihood information by using a first conversion table, a decoder that decodes the first likelihood information, a control unit that outputs an estimated value with respect to the received value, which is a decoding result obtained by the decoding, when decoding by the decoder has succeeded, and a generating unit that generates a second conversion table based on a decoding result obtained by the decoding, when decoding of the first likelihood information by the decoder has failed. When the generating unit generates the second conversion table, the converting unit converts the received value to the second likelihood information by using the second conversion table, and the decoder decodes the second likelihood information.

Abstract: A memory system according to an embodiment includes a nonvolatile memory and a memory controller. The nonvolatile memory includes a plurality of memory cells. The memory controller is configured to control the nonvolatile memory. In read operation for the memory cells, the memory controller is configured to: perform tracking including a plurality of reads in which a read voltage is shifted; determine a hard bit read voltage based on results of the tracking; calculate a soft bit read voltage based on the determined hard bit read voltage; perform soft bit read using the calculated soft bit read voltage; and perform a soft bit decoding process using a result of the soft bit read and a log-likelihood ratio table associated with the calculated soft bit read voltage.

Abstract: According to one embodiment, a memory system includes a non-volatile memory, a memory interface that reads data recorded in the non-volatile memory as a received value, a converting unit that converts the received value to first likelihood information by using a first conversion table, a decoder that decodes the first likelihood information, a control unit that outputs an estimated value with respect to the received value, which is a decoding result obtained by the decoding, when decoding by the decoder has succeeded, and a generating unit that generates a second conversion table based on a decoding result obtained by the decoding, when decoding of the first likelihood information by the decoder has failed. When the generating unit generates the second conversion table, the converting unit converts the received value to the second likelihood information by using the second conversion table, and the decoder decodes the second likelihood information.

Abstract: According to one embodiment, a memory system includes a non-volatile memory, a memory interface that reads data recorded in the non-volatile memory as a received value, a converting unit that converts the received value to first likelihood information by using a first conversion table, a decoder that decodes the first likelihood information, a control unit that outputs an estimated value with respect to the received value, which is a decoding result obtained by the decoding, when decoding by the decoder has succeeded, and a generating unit that generates a second conversion table based on a decoding result obtained by the decoding, when decoding of the first likelihood information by the decoder has failed. When the generating unit generates the second conversion table, the converting unit converts the received value to the second likelihood information by using the second conversion table, and the decoder decodes the second likelihood information.

Abstract: According to one embodiment, a memory system comprising includes a semiconductor memory and a memory controller. The memory controller is configured to obtain first data read from the semiconductor memory using a first voltage, obtain second data read from the semiconductor memory using a second voltage, calculate a first value for a first section of the first data using the first data and the second data, calculate a second value for a second section of the first data using the first data and the second data, calculate a third value for a third section of the first data using the first data and the second data, and correct an error of the first data using the first to third values.

Abstract: According to one embodiment, a memory system includes a non-volatile memory, a memory interface that reads data recorded in the non-volatile memory as a received value, a converting unit that converts the received value to first likelihood information by using a first conversion table, a decoder that decodes the first likelihood information, a control unit that outputs an estimated value with respect to the received value, which is a decoding result obtained by the decoding, when decoding by the decoder has succeeded, and a generating unit that generates a second conversion table based on a decoding result obtained by the decoding, when decoding of the first likelihood information by the decoder has failed. When the generating unit generates the second conversion table, the converting unit converts the received value to the second likelihood information by using the second conversion table, and the decoder decodes the second likelihood information.

Abstract: According to one embodiment, a memory system comprising includes a semiconductor memory and a memory controller. The memory controller is configured to obtain first data read from the semiconductor memory using a first voltage, obtain second data read from the semiconductor memory using a second voltage, calculate a first value for a first section of the first data using the first data and the second data, calculate a second value for a second section of the first data using the first data and the second data, calculate a third value for a third section of the first data using the first data and the second data, and correct an error of the first data using the first to third values.

Abstract: According to one embodiment, a memory system includes a non-volatile memory, a memory interface that reads data recorded in the non-volatile memory as a received value, a converting unit that converts the received value read from the non-volatile memory to first likelihood information by using a first conversion table, a decoder that decodes the first likelihood information, a control unit that outputs an estimated value with respect to the received value, which is a decoding result obtained by the decoding, when decoding by the decoder has succeeded, and a generating unit that generates a second conversion table based on a decoding result obtained by the decoding, when decoding of the first likelihood information by the decoder has failed. When the generating unit generates the second conversion table, the converting unit converts the received value to the second likelihood information by using the second conversion table, and the decoder decodes the second likelihood information.

Abstract: According to one embodiment, a storage device includes a plurality of nonvolatile semiconductor memories, a sensor and a controller. The sensor is configured to measure a temperature of the nonvolatile semiconductor memories. The controller is configured to receive data from a host, determine a rewriting interval of the data and write the data to, of the nonvolatile semiconductor memories, a nonvolatile semiconductor memory having a temperature corresponding to the rewriting interval.

Abstract: According to one embodiment, a storage device includes a plurality of nonvolatile semiconductor memories, a sensor and a controller. The sensor is configured to measure a temperature of the nonvolatile semiconductor memories. The controller is configured to receive data from a host, determine a rewriting interval of the data and write the data to, of the nonvolatile semiconductor memories, a nonvolatile semiconductor memory having a temperature corresponding to the rewriting interval.