Storage device and method of operating the same
A memory controller, for controlling a memory device including a plurality of memory blocks, includes a garbage collection controller configured to determine candidate blocks in which valid data is equal to or less than a predetermined ratio among the plurality of memory blocks, and configured to determine at least two or more memory blocks as victim blocks among the candidate blocks based on information on blocks that may be simultaneously erased among the plurality of memory blocks. The memory controller also includes an operation controller configured to control the memory device to copy valid data stored in the victim blocks to a different memory block.
1. A memory controller for controlling a memory device including a plurality of memory blocks, the memory controller comprising:
a garbage collection controller configured to determine candidate blocks in which a valid data ratio is equal to or less than a predetermined ratio among the plurality of memory blocks, and configured to determine two or more memory blocks as victim blocks among the candidate blocks based on information on memory blocks to be simultaneously erasable among the plurality of memory blocks; and
an operation controller configured to control the memory device to copy valid data stored in the victim blocks to a different memory block,
wherein the valid data ratio indicates a ratio of a number of valid pages to a number of total pages in a memory block,
wherein the victim blocks includes first, second, third, and fourth memory blocks,
wherein the first memory block is connected to a first global word line through a first path switch,
wherein the second memory block is connected to the first global word line through a second path switch,
wherein the third memory block is connected to a second global word line through a third path switch,
wherein the fourth memory block is connected to the second global word line through a fourth path switch,
wherein a first block word line control signal is applied to the first and third path switches,
wherein a second block word line control signal is applied to the second and fourth path switches,
wherein the first and second memory blocks are simultaneously erased according to an operation voltage applied to the first global word line and the first and second block word line control signals, and
wherein the first and third memory blocks are simultaneously erased according to an operation voltage applied to the first and second global word lines and the first block word line control signal.
2. The memory controller of claim 1 , wherein the operation controller is configured to control the memory device to simultaneously erase the victim blocks after the valid data is copied to the different memory block.
3. The memory controller of claim 1 , wherein the garbage collection controller comprises:
a block manager configured to store block management information on the plurality of memory blocks; and
a victim block determiner configured to determine the victim blocks based on the block management information.
4. The memory controller of claim 3 , wherein the block management information includes:
information on the candidate blocks;
the information on the memory blocks to be simultaneously erasable; and
information on a free block among the plurality of memory blocks.
5. The memory controller of claim 3 , wherein the victim block determiner is configured to determine the victim blocks in a way that a number of memory blocks to be simultaneously erasable is maximized.
6. The memory controller of claim 5 , wherein the victim block determiner is configured to determine the victim blocks in a way that an amount of valid data stored in the memory blocks to be simultaneously erasable is minimized.
7. The memory controller of claim 3 , wherein the victim block determiner is configured to determine a number of the victim blocks according to a supply of a free block that is determined based on a number of free blocks among the plurality of memory blocks.
8. A memory controller, for controlling a memory device including a plurality of memory blocks, the memory controller comprising:
a garbage collection controller configured to determine a reference number of victim blocks based on a number of free blocks among the plurality of memory blocks, and configured to determine candidate blocks as the victim blocks based on a comparison between a number of the candidate blocks to be simultaneously erasable among the plurality of memory blocks and the reference number of the victim blocks; and
an operation controller configured to control the memory device to copy valid data stored in the victim blocks to a different memory block,
wherein the victim blocks includes first, second, third, and fourth memory blocks,
wherein the first memory block is connected to a first global word line through a first path switch,
wherein the second memory block is connected to the first global word line through a second path switch,
wherein the third memory block is connected to a second global word line through a third path switch,
wherein the fourth memory block is connected to the second global word line through a fourth path switch,
wherein a first block word line control signal is applied to the first and third path switches,
wherein a second block word line control signal is applied to the second and fourth path switches,
wherein the first and second memory blocks are simultaneously erased according to an operation voltage applied to the first global word line and the first and second block word line control signals, and
wherein the first and third memory blocks are simultaneously erased according to an operation voltage applied to the first and second global word lines and the first block word line control signal.
9. The memory controller of claim 8 , wherein the operation controller is configured to control the memory device to simultaneously erase the victim blocks after the valid data is copied to the different memory block.
10. The memory controller of claim 8 , wherein the garbage collection controller comprises:
a block manager configured to store block management information on the plurality of memory blocks; and
a victim block determiner configured to determine the victim blocks based on the block management information.
11. The memory controller of claim 10 , wherein the block management information includes:
information on the candidate blocks among the plurality of memory blocks;
information on memory blocks to be simultaneously erasable among the plurality of memory blocks; and
information on the free blocks among the plurality of memory blocks.
12. The memory controller of claim 10 , wherein the victim block determiner is configured to determine the candidate blocks as the victim blocks when the number of the candidate blocks reaches the reference number of the victim blocks.
13. The memory controller of claim 8 , wherein the reference number of the victim blocks is determined based on the number of the free blocks.
14. The memory controller of claim 8 , wherein the candidate blocks comprise memory blocks for which a valid data ratio is equal to or less than a predetermined ratio, and
wherein the valid data ratio indicates a ratio of a number of valid pages to a number of total pages in a memory block.
15. A method of operating a storage device including a plurality of memory blocks, the method comprising:
determining candidate blocks in which a valid data ratio is equal to or less than a predetermined ratio among the plurality of memory blocks;
determining at least four memory blocks to be simultaneously erasable as victim blocks among the candidate blocks; and
copying valid data stored in the victim blocks to a different memory block,
wherein the valid data ratio indicates a ratio of a number of valid pages to a number of total pages in a memory block,
wherein the at least four memory blocks include first, second, third, and fourth memory blocks,
wherein the first memory block is connected to a first global word line through a first path switch,
wherein the second memory block is connected to the first global word line through a second path switch,
wherein the third memory block is connected to a second global word line through a third path switch,
wherein the fourth memory block is connected to the second global word line through a fourth path switch,
wherein a first block word line control signal is applied to the first and third path switches, and
a second block word line control signal is applied to the second and fourth path switches.
16. The method of claim 15 , further comprising: erasing the first and second memory blocks using an operation voltage applied to the first global word line and the first and second block word line control signals.
17. The method of claim 15 , wherein determining the at least four memory blocks as the victim blocks comprises determining the victim blocks so that a number of memory blocks to be simultaneously erasable is maximized.
18. The method of claim 17 , wherein the victim blocks are determined so that an amount of valid data stored in the memory blocks to be simultaneously erasable is minimized.
19. The method of claim 15 , wherein determining the at least four memory blocks as the victim blocks comprises:
determining a reference number of the victim blocks based on a number of free blocks among the plurality of memory blocks, and
determining the at least four memory blocks as the victim blocks when a number of the at least four memory blocks reaches the reference number.
20. The method of claim 15 , further comprising:
erasing the first and third memory blocks using an operation voltage applied to the first and second global word lines and the first block word line control signal.