Sub block based storage device and method for managing sub block thereof

A method performed by a storage device comprising a plurality of memory blocks, the method comprising:

• based on a predetermined sub-block attribute criteria, selecting at least one sub-block from a plurality of sub-blocks in the plurality of memory blocks;
• adding the selected at least one sub-block to a sub-block pool;
• and
• based on the predetermined sub-block attribute criteria, allocating the selected at least one sub-block in the sub-block pool to a virtual memory block,
• wherein at least two sub-blocks of the plurality of sub-blocks have different sizes, and
• wherein the predetermined sub-block attribute criteria includes at least one of an erase count or a data access frequency of at least one sub-block.

A method performed by a storage device, the method comprising:

• receiving, from a host, a virtual memory block allocation requirement;
• confirming the virtual memory block allocation requirement;
• based on the virtual memory block allocation requirement, selecting at least one sub-block;
• selecting a sub-block pool and adding the selected at least one sub-block to the selected sub-block pool;
• combining a virtual memory block using the selected at least one sub-block of the selected sub-block pool;
• comparing the combined virtual memory block and the virtual memory block allocation requirement and checking whether the virtual memory block allocation requirement is satisfied;
• and
• based on a determination that the virtual memory block allocation requirement is satisfied, allocating the virtual memory block.