A New FTL-based Flash Memory Management Scheme with Fast Cleaning Mechanism

Due to the advantages of non-volatility, lightweight, low power consumption, and shock resistance, flash memory has been widely used as the storage of embedded systems and mobile devices. However, unlike hard disk, flash memory does not support update-in-place operation, and each block on flash memory has the limited erasure cycles. Therefore, flash memory needs a different storage management scheme designed specifically for flash memory characteristics. Many researches adopt the log-based approach which needs an efficient cleaning mechanism to reclaim the storage space occupied by obsolete data. In this paper, we have designed and implemented a new flash translation layer for flash memory management and proposed a fast cleaning mechanism for space reclamation. It is based on the DAC technique to separately cluster hot and cold data in flash memory. For the NAND-type flash memory with large capacity, it maintains multiple LRU lists to reduce the time of selecting blocks for erasure in cleaning activity. Moreover, we modify the cost-benefit policy with different weight that considers the attribute of each block on flash memory in selecting a block for cleaning. Simulation results show that our proposed flash memory management scheme with the proposed fast cleaning mechanism could efficiently decrease the number of erase operations, speed up the cleaning activity, and enhance system performance.