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US 7,890,550 B2Granted
Flash memory system and garbage collection method thereof
AssigneeSamsung Electronics Co., Ltd.
InventorsMyung-Jin Jung, Jang-Hwan Kim, Dong-Hyun Song, Shea-Yun Lee, Yeon-Jin Mo, Jae-Hyun Hwang
Life of this patent
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Abstract
Example embodiments provide a garbage collection method which includes applying a weight to each of at least two or more factors to calculate garbage collection costs. A hash table is configured using the calculated garbage collection costs. The method further includes searching a block having the lowest garbage collection cost from the hash table and performing garbage collection on the searched block.
Claims23
A garbage collection method of a memory system including an interface device, the method comprising:
- applying, by the interface device, a weight to a first factor and a second factor to calculate garbage collection costs, the weight for the first factor being higher than the weight for the second factor;
- configuring, by the interface device, a hash table using the calculated garbage collection costs;
- searching, by the interface device, a block having the lowest garbage collection cost from the hash table;
- and
- performing, by the interface device, garbage collection on the searched block,
- wherein the first factor is wear level information and the second factor is information of a valid page number per block or the second factor is wear level information and the first factor is information of a valid page number per block, and
- the garbage collection costs are calculated by adding at least a product of the first factor and the first weight and a product of the second factor and the second weight, with respect to each physical block.
4 more elements
A storage device comprising:
- a flash memory;
- and
- an interface device configured to operate responsive to a write request of the flash memory from a host, the interface device including,
- a host interface configured to interface with the host,
- a control processing unit configured to control an overall operation of the storage device,
- a work memory configured to store software for performing flash translation layer functions and to store mapping information of the flash memory, and
- a buffer memory configured to temporarily store data when storing data in the flash memory or when reading data form the flash memory,
- wherein upon the write request, the interface device is configured to apply a weight to a first factor and a second factor to calculate garbage collection costs and to configure a hash table using the calculated garbage collection cost, the weight for the first factor being higher than the weight for the second factor;
- and
- wherein the interface device is configured to search a block having the lowest garbage collection cost from the hash table and to perform garbage collection on the searched block, and
- the first factor is wear level information and the second factor is information of a valid page number per block or the second factor is wear level information and the first factor is information of a valid page number per block, and
- the garbage collection costs are calculated by adding at least a product of the first factor and the first weight and a product of the second factor and the second weight, with respect to each physical block.
9 more elements
Dependencies are inferred from the claim text.