Memory system

A memory system, comprising:

• a nonvolatile memory including a plurality of blocks each including a plurality of layers functioning as a plurality of stages of a shift register, and configured to perform write and read of data for each block by a last-in first-out method by shifting, in a unit of a layer, data stored in individual layers in a first direction from a layer corresponding to a first stage to a layer corresponding to a last stage or in a second direction opposite to the first direction;
• and
• a controller configured to control the nonvolatile memory, wherein
• the layers of each block are logically partitioned into a plurality of pages each including a set of adjacent layers, and
• the controller is configured to:
• when a read target data portion designated by a read request received from a host is stored in a first page of a first block,
• read the read target data portion stored in the first page and one or more data portions stored in all of one or more other pages positioned closer to a layer corresponding to the first stage than the first page, return, to the host, the read target data portion that is read;
• write back the read one or more other data portions to the first block;
• and
• write back the read target data portion that is read to the first block at last so that the read target data portion is written to a beginning page corresponding to a set of layers including a layer of the first stage of the first block, or to another block different from the first block so that the read target data portion that is read is written to a beginning page of the other block.

A memory system, comprising:

• a nonvolatile memory including a plurality of blocks each including a plurality of layers functioning as a plurality of stages of a shift register, and configured to perform write and read of data for each block by a last-in first-out method by shifting, in a unit of a layer, data stored in individual layers in a first direction from a layer corresponding to a first stage to a layer corresponding to a last stage or in a second direction opposite to the first direction;
• and
• a controller configured to control the nonvolatile memory, wherein
• the layers of each block are logically partitioned into a plurality of pages each including a set of adjacent layers, and
• the controller is configured to:
• manage, for each of the blocks, the number of data portions currently written;
• manage, when writing a write data portion associated with a write request received from a host to a first write destination block in the blocks, a corresponding relationship between a logical address designated by the write request, a block identifier of the first write destination block, and data number information indicating the number of data portions which have been written to the first write destination block before the write data portion is written, by using an address translation table;
• and
• acquire, when receiving a read request designating a logical address of a read target data portion from the host, a block identifier and data number information corresponding to a logical address of the read target data portion from the address translation table, identify a block corresponding to the acquired block identifier as a block where the read target data portion is stored, and identify a page in the identified block storing the read target data portion based on the number of data portions currently written to the block corresponding to the block identifier and the number of data portions indicated by the acquired data number information.

A memory system, comprising:

• a nonvolatile memory including a plurality of blocks each including a plurality of layers functioning as a plurality of stages of a shift register, and configured to perform write and read of data for each block by a last-in first-out method by shifting, in a unit of a layer, data stored in individual layers in a first direction from a layer corresponding to a first stage to a layer corresponding to a last stage or in a second direction opposite to the first direction;
• and
• a controller configured to control the nonvolatile memory,
• wherein the layers of each block are logically partitioned into a plurality of pages each including a set of adjacent layers, and
• the controller is configured to:
• manage, for each of the blocks, a counter value indicating a cumulative value of the number of times operation of shifting data is performed;
• and
• copy data portions stored in pages of a first block having a counter value exceeding a reference value determined based on counter values of the blocks to another block having a smaller counter value than the first block.

A memory system, comprising:

• a nonvolatile memory including a plurality of blocks each including a plurality of layers functioning as a plurality of stages of a shift register and configured to perform write and read of data for each block by a last-in first-out method by shifting, in a unit of a layer, data stored in individual layers in a first direction from a layer corresponding to a first stage to a layer corresponding to a last stage or in a second direction opposite to the first direction;
• and
• a controller configured to control the nonvolatile memory, wherein
• the layers of each block are logically partitioned into a plurality of pages each including a set of adjacent layers, and
• the controller is configured to:
• manage, for each of the blocks, a counter value indicating the number of times an oldest data portion in a block is shifted;
• and
• read, when a counter value corresponding to a first block in the blocks exceeds a threshold value, data portions written to pages of the first block and write back data portions obtained by correcting an error of the read data portions to the first block or another block different from the first block.