Abstract: According to one embodiment, a memory device includes a nonvolatile memory and a command storage module in which a command is stored. The memory device further comprises a memory module in which a type of a background process and an order of priority of the background process are set, in which information of a necessary background process is set, and in which permission or refusal of the background process is set by a host device.

Abstract: According to one embodiment, a memory system includes a memory and a controller. The memory includes NAND strings. Each of the NAND strings includes memory cells. The memory cells capable of holding data. The memory writing and reading data in units of a page corresponding to a set of the memory cells and erasing data in units of a block corresponding to a set of the NAND strings. The controller controls the memory. The controller includes a holding unit and a control unit. The holding unit holds a table in which information on a check page is recorded, for each zone corresponding to a set of the blocks. The control unit references the table to calculate a read error and instructs the memory to write the data in the block including the check page to another block in the memory, if the occurrence rate exceeds a preset threshold.