An Efficient and Non-Time-Sensitive File-Aware Garbage Collection Algorithm for NAND Flash-Based Consumer Electronics

Abstract

NAND flash memory has been widely used in consumer electronics, such as tablet personal computers and smart phones. However, unlike traditional hard disk, a garbage collection is required to reclaim memory space during data updates. A garbage collection includes a series of extra read, write and erase operations. Both write and erase operations are time consuming process, which affect the effectiveness and efficiency of the NAND flash memory system. Moreover, flash memory blocks are challenged by the limitation of the erase count. Thus, considerable efforts have been paid to reduce the garbage collection overhead and improve wear leveling. In this paper, an efficient and non-time-sensitive file-aware garbage collection algorithm, called FaGC+, is proposed. The FaGC+ algorithm involves a novel update frequency calculation method and a novel cold-hot logical page categorization scheme. The experimental results demonstrate that the proposed algorithm outperforms existing garbage collection algorithms in terms of garbage collection overhead and time-sensitivity in wear leveling control.