A Cross Layer Optimization Technique for Improving Performance of MLC NAND Flash-Based Storages

????????? ????????? ?????? ?????? ????????? ????????? ???????????? ????????? ????????? ?????? ???????????? ?????? ?????? ????????? ???????????? ???????????? ?????? ??????????????????, ??? ??????????????? MLC ?????? ????????? ???????????? ?????? ?????? ????????? SLC ?????? ????????? ????????? ?????? ??? ??? ?????? ???????????????. ??? ??????????????? MLC ?????? ????????? ?????? ??????????????? ?????? ????????? ?????? ??????????????? ????????? ?????? ????????? ????????? ???????????? ????????????, ??? ????????? ?????? ???????????? ???????????? ?????? ???????????? ???????????? ???????????? ????????? ?????? ????????? ????????????. MLC ?????? ????????? ??????????????? ???????????? ?????? ??????????????? ????????? ?????? ?????? ???????????? ????????? ??????????????????, ???????????? ????????? ???????????? ????????? ?????? ????????? SLC ?????? ????????? ??????????????? ???????????? ???????????? ??????????????? ?????? ????????? ????????????. ?????? ??????, ???????????? ????????? ?????? ?????? ?????? ?????? 39%??? ?????? ????????? ????????? ??? ????????? ???????????????????????? ????????? ?????? ?????? ????????? ????????? ???????????? ????????? ????????? ?????? ???????????? ?????? ?????? ????????? ???????????? ???????????? ?????? ??????????????????, ??? ??????????????? MLC ?????? ????????? ???????????? ?????? ?????? ????????? SLC ?????? ????????? ????????? ?????? ??? ??? ?????? ???????????????. ??? ??????????????? MLC ?????? ????????? ?????? ??????????????? ?????? ????????? ?????? ??????????????? ????????? ?????? ????????? ????????? ???????????? ????????????, ??? ????????? ?????? ???????????? ???????????? ?????? ???????????? ???????????? ???????????? ????????? ?????? ????????? ????????????. MLC ?????? ????????? ??????????????? ???????????? ?????? ??????????????? ????????? ?????? ?????? ???????????? ????????? ??????????????????, ???????????? ????????? ???????????? ????????? ?????? ????????? SLC ?????? ????????? ??????????????? ???????????? ???????????? ??????????????? ?????? ????????? ????????????. ?????? ??????, ???????????? ????????? ?????? ?????? ?????? ?????? 39%??? ?????? ????????? ????????? ??? ????????? ???????????????.The multi-leveling technique that stores multiple bits in a single memory cell has significantly improved the density of NAND flash memory along with shrinking processes. However, because of the side effects of the multi-leveling technique, the average write performance of MLC NAND flash memory is degraded more than twice that of SLC NAND flash memory. In this paper, we introduce existing cross-layer optimization techniques proposed to improve the performance of MLC NAND flash-based storages, and propose a new integration technique that overcomes the limitations of existing techniques by exploiting their complementarity. By fully exploiting the performance asymmetry in MLC NAND flash devices at the flash translation layer, the proposed technique can handle many write requests with the performance of SLC NAND flash devices, thus significantly improving the performance of NAND flash-based storages. Experimental results show that the proposed technique improves performance 39% on average over individual techniques