Storage system using a flash memory partitioned with write-once and rewritable blocks
First Claim
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1. A storage system, comprising:
- a nonvolatile memory which erases data for respective blocks; and
a controller for inputting and outputting the data to and from the nonvolatile memory,wherein the controller assigns at least one of the blocks in the nonvolatile memory as a rewritable area where stored data can be erased, and assigns at least a portion of the rest of the blocks in the non-volatile memory as a write once area where the stored data cannot be erased;
wherein the controller determines a block belonging to the rewritable area based on an attribute of the block, and performs a wear leveling process and a reclamation process only on the block determined as belonging to the rewritable area,wherein the block stores retention period information of the stored data,wherein the storage system has a storage area including;
the rewritable area where the stored data can be erased;
the write-once area where the stored data cannot be erased; and
an unused area for which the attribute is not determined; and
wherein the controller erases data whose retention period expires from the block that stores the data, and changes the write-once area to the unused area by changing the attribute of the block.
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Abstract
Provided is a storage system including: a nonvolatile memory which stores and erases data for respective blocks; and a controller for inputting and outputting the data to and from the nonvolatile memory, wherein: the storage system has a storage area including: a rewritable area where a stored data can be erased; and a write-once area where the stored data cannot be erased; and the controller determines a block belonging to the rewritable area based on an attribute of the block, and performs a wear leveling process and a reclamation process only on the block determined as belonging to the rewritable area.
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Citations
10 Claims
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1. A storage system, comprising:
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a nonvolatile memory which erases data for respective blocks; and a controller for inputting and outputting the data to and from the nonvolatile memory, wherein the controller assigns at least one of the blocks in the nonvolatile memory as a rewritable area where stored data can be erased, and assigns at least a portion of the rest of the blocks in the non-volatile memory as a write once area where the stored data cannot be erased; wherein the controller determines a block belonging to the rewritable area based on an attribute of the block, and performs a wear leveling process and a reclamation process only on the block determined as belonging to the rewritable area, wherein the block stores retention period information of the stored data, wherein the storage system has a storage area including;
the rewritable area where the stored data can be erased;
the write-once area where the stored data cannot be erased; and
an unused area for which the attribute is not determined; andwherein the controller erases data whose retention period expires from the block that stores the data, and changes the write-once area to the unused area by changing the attribute of the block. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification