Sub-block based storage device and management method thereof

A sub-block-based memory management method, comprising:

• selecting a garbage collection source block from among used sub-blocks storing valid data, the used sub-blocks being divided into used sub-block groups based on a size of each of the used sub-blocks;
• selecting candidate destination blocks from free sub-blocks based on a size of the valid data stored in the garbage collection source block;
• and
• selecting a garbage collection destination block from among the candidate destination blocks.

A sub-block-based storage device, comprising:

• a memory device configured to include a plurality of memory blocks, each block of the plurality of memory blocks comprising a plurality of sub-blocks having different capacities;
• a work memory storing instructions;
• and
• a memory controller communicatively coupled with the memory device and the work memory and configured to manage the plurality of memory blocks,
• wherein the memory controller is configured to execute instructions to:
• manage a used sub-block pool comprising used sub-block groups, each of the used sub-block groups comprising used sub-blocks storing valid data;
• manage a free sub-block pool comprising free sub-block groups, each of the free sub-block groups storing free sub-blocks that are empty;
• select a garbage collection source block from the used sub-blocks;
• select candidate destination blocks from the free sub-blocks;
• and
• select a garbage collection destination block from the candidate destination blocks.