Abstract: According to one embodiment, a memory system includes a semiconductor memory and a controller. The semiconductor memory is configured to execute a first to third read operations. In the first read operation, a first voltage is applied to a selected word line. In the second read operation, a second voltage different from the first voltage and a third voltage are applied to the selected word line. In the third read operation, a fourth voltage different from the first to third voltages and a fifth voltage are applied to the selected word line. An absolute value of a difference between the second voltage and the fourth voltage is different from an absolute value of a difference between the third voltage and the fifth voltage.

Abstract: According to one embodiment, a memory system includes a semiconductor memory and a controller. The semiconductor memory is configured to execute a first to third read operations. In the first read operation, a first voltage is applied to a selected word line. In the second read operation, a second voltage different from the first voltage and a third voltage are applied to the selected word line. In the third read operation, a fourth voltage different from the first to third voltages and a fifth voltage are applied to the selected word line. An absolute value of a difference between the second voltage and the fourth voltage is different from an absolute value of a difference between the third voltage and the fifth voltage.

Abstract: According to an embodiment, a semiconductor memory, on receiving a first command, applies a voltage within a first range and a voltage within a second range to a word line and reads a first bit from a memory cell, and, on receiving a second command, applies a voltage within a third range to the word line and reads a second bit from the memory cell. The controller issues the first command a plurality of times and changes the voltages to be applied to the word line within the first range and the second range in accordance with the plurality of first commands, specifies a first and second voltage within the first and the second range, respectively, and estimates a third voltage within the third range. The voltage applied to read the second bit is the estimated third voltage.

Abstract: According to an embodiment, a control circuitry performing: a first operation of reading data out of a memory cell with a first voltage applied to a word line while changing the first voltage by a first shift amount within a first range, and a second operation of reading data out of the memory cell with a second voltage applied to the word line while changing the second voltage by a second shift amount within a second range, wherein the second shift amount is smaller than the first shift amount, and wherein the control circuitry performs the second operation to apply the second voltage to the word line subsequently to application of the first voltage to the word line in the first operation.