Memory system and control method thereof
First Claim
Patent Images
1. A memory system comprising:
- a nonvolatile memory including a plurality of blocks as data erase units;
a measuring unit which measures an erase time at which data of each block is erased;
a block controller which writes data supplied from at least an exterior into a first block which is set in a free state and whose erase time is oldest, wherein the block controller has a block table indicating a correspondence relation between a status value indicating one of a free state and an in-use state and the erase time for each block; and
a first selector which selects the first block based on information of the block table.
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Abstract
A memory system includes a nonvolatile memory including a plurality of blocks as data erase units, a measuring unit which measures an erase time at which data of each block is erased, and a block controller which writes data supplied from at least an exterior into a first block which is set in a free state and whose erase time is oldest.
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Citations
21 Claims
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1. A memory system comprising:
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a nonvolatile memory including a plurality of blocks as data erase units; a measuring unit which measures an erase time at which data of each block is erased; a block controller which writes data supplied from at least an exterior into a first block which is set in a free state and whose erase time is oldest, wherein the block controller has a block table indicating a correspondence relation between a status value indicating one of a free state and an in-use state and the erase time for each block; and a first selector which selects the first block based on information of the block table. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A memory system comprising:
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a nonvolatile memory including a plurality of blocks as data erase units; a measuring unit which measures an erase time at which data of each block is erased; a block controller which counts an erase count of each block, and has a block table indicating a correspondence relation between a status value indicating one of a free state and an in-use state, the erase time and the erase count for each block; and a first selector which selects a first block whose erase count is minimum among a preset number of blocks set in the free state starting from a block whose erase time is oldest based on information of the block table, wherein the block controller writes data supplied from at least an exterior into the first block. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification