摘要
NAND Flash专用文件系统Yaffs2在磨损均衡算法方面仍存在缺陷,通过详细分析Yaffs2中磨损均衡算法的实现原理,综合考虑磨损均衡与垃圾回收的矛盾关系,提出了一种基于多阈值的磨损均衡机制(属于静态磨损均衡算法),利用三个关键技术:(1)改进回收块选择机制,选择公式(1)的计算结果落入目标区间中的所有块中擦除次数最大的块进行回收;(2)利用有序双向链表管理空闲块,分配当前链表中擦除次数最小的块给新写入的数据,而将擦除擦除次数最大的块分配给静态数据;(3)针对磨损均衡的两级分化引入冷热数据分离策略.实验结果表明,在仅付出4.05%的额外擦除代价下,将NAND Flash的寿命延长了近4倍.
Yaffs2, special to NAND Flash, still exits defect aiming at wear leveling. A static wear-leveling algorithm based on Yaffs2 is designed in this paper, considering the contradiction between wear-leveling and garbage collection. Firstly, Improve retrieve block selection mechanism., choose the block for recycle whose the value of benifit/cost falling to the target range according to the formula （1）, and its erasure number is biggest ;Secondly, allocation free page whose erasure number is smallest to new data and whose erasure number is biggest to cold data in line of orderly two-way linked list~ Last, introduce hot and cold data separation strategy orienting to hot and cold data coexists in a block. The experimental results show that the algorithm prolongs NAND lifetime nearly four times at the expense of 4. 05% additional erasure number.
出处
《微电子学与计算机》
CSCD
北大核心
2018年第1期6-9,共4页
Microelectronics & Computer
