Method and system for wear leveling in a solid state drive
First Claim
1. A method comprising:
- determining erase counts of physical regions of a storage device, wherein the erase count indicates a number of times the physical region associated with the erase count has been subject to an erase operation;
determining whether a logical region stored in the physical region having the lowest erase count has static content, wherein logical regions having static content have a lower rate of host writes than logical regions having dynamic content;
mapping the logical region determined to have the static content in the physical region having the lowest erase count into a respective one of the physical regions of the storage device having a higher erase count than the physical region having the lowest erase count.
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Accused Products
Abstract
A method and system for wear leveling in a solid state drive by mapping the logical regions of the solid state drive that hold static content or information into the physical regions of the solid state drive that have erase counts more than an average erase count of all of the physical regions. By doing so, it allows the solid state drive to wear level itself naturally through continued usage. In one embodiment of the invention, the erase count of each physical region is incremented with every erasing operation of each physical region. The physical regions that have a high count of erase count operations are mapped with content of the logical regions with static content so that the possibility of future erase operations of these physical regions is reduced.
26 Citations
23 Claims
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1. A method comprising:
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determining erase counts of physical regions of a storage device, wherein the erase count indicates a number of times the physical region associated with the erase count has been subject to an erase operation; determining whether a logical region stored in the physical region having the lowest erase count has static content, wherein logical regions having static content have a lower rate of host writes than logical regions having dynamic content; mapping the logical region determined to have the static content in the physical region having the lowest erase count into a respective one of the physical regions of the storage device having a higher erase count than the physical region having the lowest erase count. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus comprising:
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one or more NAND flash memories, wherein the one or more NAND flash memories are to be partitioned into one or more logical bands and one or more physical bands; and logic coupled with the one or more NAND flash memories to perform; determining erase counts of physical bands, wherein the erase count indicates a number of times the physical band associated with the erase count has been subject to an erase operation; determining at least one logical band stored in the physical band having a lowest erase count of physical bands and having static content, wherein logical bands having static content have a lower rate of host writes than logical bands having dynamic content; relocating static content in the at least one logical band determined to have the static content in the at least one physical band having the lowest erase count of the physical bands into at least one physical band having an erase count exceeding the average erase count of the physical bands. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A system comprising:
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a solid state drive, the solid state drive comprising; a NAND flash memory; and a controller to; determine erase counts of physical regions of a storage device, wherein the erase count indicates a number of times the physical region associated with the erase count has been subject to an erase operation; determine whether information in one of a plurality of logical areas of the NAND flash memory is static, wherein logical regions having static content have a lower rate of host writes than logical regions having dynamic content, wherein the one logical area is associated with a first physical area of a plurality of physical areas having a lowest erase count of the physical areas; and relocate the information in the one logical area in the first physical area having the lowest erase count to a second physical area of the plurality of physical areas responsive to the determination that the information in the one logical area is not static, wherein the second physical area has an erase count lower than the average erase count and higher than the lowest erase count. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification