Abstract: According to one embodiment, a memory system includes a controller controls writing data to a non-volatile memory and a volatile memory, a power supply circuit generates voltages with a first voltage externally supplied and supplies the voltages to the non-volatile memory, volatile memory, and controller, and a backup power supply circuit. The power supply circuit, when the first voltage drops irrespective of a shutdown command, generates the voltages with an output voltage of the backup power supply circuit. The controller changes a size of data storable in the volatile memory in accordance with a supply capability fed from the backup power supply circuit.

Abstract: According to one embodiment, a memory system includes a controller controls writing data to a non-volatile memory and a volatile memory, a power supply circuit generates voltages with a first voltage externally supplied and supplies the voltages to the non-volatile memory, volatile memory, and controller, and a backup power supply circuit. The power supply circuit, when the first voltage drops irrespective of a shutdown command, generates the voltages with an output voltage of the backup power supply circuit. The controller changes a size of data storable in the volatile memory in accordance with a supply capability fed from the backup power supply circuit.

Abstract: A memory system includes a nonvolatile memory and a controller that performs first, second, and third processes on memory cells of the nonvolatile memory. The first process is performed on first memory cells to store a first value therein, such that a highest threshold voltage among the threshold voltages of the first memory cells is set as a first threshold voltage. The second process is performed on second memory cells to store a second value therein, such that a lowest threshold voltage among the threshold voltages of the second memory cells is set as a second threshold voltage higher than the first threshold voltage. The third process performed on third memory cells such that a lowest threshold voltage in the third memory cells is lower than the first threshold voltage, and a highest threshold voltage in the third memory cells is higher than the second threshold voltage.

Abstract: A memory system includes a nonvolatile memory and a controller that performs first, second, and third processes on memory cells of the nonvolatile memory. The first process is performed on first memory cells to store a first value therein, such that a highest threshold voltage among the threshold voltages of the first memory cells is set as a first threshold voltage. The second process is performed on second memory cells to store a second value therein, such that a lowest threshold voltage among the threshold voltages of the second memory cells is set as a second threshold voltage higher than the first threshold voltage. The third process performed on third memory cells such that a lowest threshold voltage in the third memory cells is lower than the first threshold voltage, and a highest threshold voltage in the third memory cells is higher than the second threshold voltage.