Method and system for compacting data in non-volatile memory

A non-volatile memory system comprising:

• a non-volatile memory having a plurality of memory blocks;
• and
• a controller in communication with the non-volatile memory, the controller configured to:
• select a fully programed block from the plurality of memory blocks as a source block;
• copy valid data from a particular offset location in the source block to a same particular offset location in a destination block in the plurality of blocks;
• and
• write new data to the destination block only at offset locations corresponding to offset locations of obsolete data in the source block, wherein the destination block contains all valid data from the source block in offset locations identical to original offset locations of the valid data in the source block upon completion of copying all valid data from the source block.

A non-volatile memory system comprising:

• a non-volatile memory having a plurality of memory blocks;
• a fine granularity mapping table containing mapping entries of logical addresses to virtual addresses;
• a coarse granularity mapping table containing mapping entries of the virtual addresses to physical addresses associated with the plurality of memory blocks;
• and
• a controller in communication with the non-volatile memory, the controller configured to:
• relocate valid data from a source block selected from the plurality of memory blocks to a relocation block in the plurality of memory blocks;
• write new data to the relocation block;
• update both the fine granularity mapping table and the coarse granularity mapping table to map the new data written to the relocation block;
• and
• update only the coarse granularity mapping table, without updating any fine granularity mapping table mapping entries, in response to relocating valid data from the source block to the relocation block.