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US 2021/0278974 A1Published application
Memory system and method for controlling nonvolatile memory
AssigneeToshiba Memory Corporation
InventorsShinichi Kanno, Hideki Yoshida
Life of this patent
Estimating the term…
Abstract
According to one embodiment, a memory system manages wear of each of a plurality of blocks in a nonvolatile memory. The memory system receives, from a host, a write request including a parameter specifying a data retention term required for first data to be written. The memory system selects, from the blocks, a first block in which a data retention term estimated from the wear of the first block is longer than or equal to the specified data retention term. The memory system writes the first data to the first block.
Claims20
A memory system comprising:
- a nonvolatile memory that includes a plurality of blocks;
- and
- a controller configured to control the nonvolatile memory and including a wear reduction processing unit,
- the controller is configured to:
- classify the blocks into a plurality of block groups corresponding to a plurality of data retention terms based on wear of each of the blocks, the wear relating to an erase operation;
- receive a write command including one of a first parameter specifying a first retention term required for first data to be written and a second parameter specifying a second retention term required for second data to be written, the second retention term being shorter than the first retention term;
- in response to receiving the write command including the first parameter, select, when a block classified into a first block group having a data retention term which is equal to the first retention term specified by the first parameter in the received write command is present, the block classified into the first block group as a first block, and select, when no block classified into the first block group is present, a block classified into a second block group having a data retention term longer than the first retention term as the first block;
- write the first data to the first block;
- in response to receiving the write command including the second parameter, select, when a block classified into a third block group having a data retention term which is equal to the second retention term specified by the second parameter in the received write command is present, the block classified into the third block group as a second block, and select, when no block classified into the third block group is present, a block classified into a fourth block group having a data retention term longer than the second retention term as the second block;
- and
- write the second data to the second block.
8 more elements
A method for controlling a nonvolatile memory that includes a plurality of blocks, the method comprising:
- classifying the blocks into a plurality of block groups corresponding to a plurality of data retention terms based on wear of each of the blocks, the wear relating to an erase operation;
- receiving a write command including one of a first parameter specifying a first retention term required for first data to be written and a second parameter specifying a second retention term required for second data to be written, the second retention term being shorter than the first retention term;
- in response to receiving the write command including the first parameter, selecting, when a block classified into a first block group having a data retention term which is equal to the first retention term specified by the first parameter in the received write command is present, the block classified into the first block group as a first block, and selecting, when no block classified into the first block group is present, a block classified into a second block group having a data retention term longer than the first retention term as the first block;
- writing the first data to the first block;
- in response to receiving the write command including the second parameter, selecting, when a block classified into a third block group having a data retention term which is equal to the second retention term specified by the second parameter in the received write command is present, the block classified into the third block group as a second block, and selecting, when no block classified into the third block group is present, a block classified into a fourth block group having a data retention term longer than the second retention term as the second block;
- and
- writing the second data to the second block.
4 more elements
Dependencies are inferred from the claim text.