| CPC G06F 3/064 (2013.01) [G06F 3/0608 (2013.01); G06F 3/061 (2013.01); G06F 3/0643 (2013.01); G06F 3/0659 (2013.01); G06F 3/0688 (2013.01); G06F 12/0253 (2013.01); G06F 16/00 (2019.01); G06F 16/1847 (2019.01)] | 8 Claims |

|
1. A memory system connectable to a host, comprising:
a nonvolatile semiconductor memory device including a plurality of blocks, each of the blocks including a plurality of memory cells; and
a memory controller configured to:
set a writing method applied to each of the blocks to one of a plurality of writing methods that are different in a number of data bits stored in each memory cell in the block;
receive a first command from the host, the first command including first information indicating an identifier of a logical address space and second information identifying one of the plurality of writing methods to be applied to the logical address space identified with the identifier;
set the one of the plurality of writing methods identified with the second information to the logical address space identified with the identifier of the first information;
receive data associated with the identifier and to be written into the nonvolatile semiconductor memory device from the host;
after receiving the first command and the data, write the received data into a first block among the plurality of blocks for which the one of the writing methods identified with the second information has been set, in accordance with the one of the writing methods identified with the second information; and
after the data is erased from the first block, change the writing method set for the first block to a different one of the plurality of writing methods.
|