基于逻辑页冷热分离的NAND闪存磨损均衡算法

Wear-leveling algorithm for NAND flash memory based on separation of hot and cold logic pages

针对现有的NAND闪存垃圾回收算法对磨损均衡考虑不足的问题,提出了一种基于逻辑页冷热分离的NAND闪存磨损均衡算法。算法同时考虑了无效页的年龄、物理块的擦除次数以及物理块更新的频率,采用混合模式选择回收符合条件的物理块。同时,推导了一种新的逻辑页热度计算方法,并将回收块上有效页数据按照逻辑页的热度进行了冷热分离。实验结果表明,与GR算法、CB算法、CAT算法以及Fa GC算法相比,该算法不仅在磨损均衡上取得了很好的效果,而且总的擦除次数与拷贝次数也有了明显减少。

According to the problem of the existing garbage collection algorithm for NAND flash memory,an efficient algorithm,called AWGC（ Age With Garbage Collection）,was presented to improve wear leveling of NAND flash memory. A hybrid policy with the age of invalid page,erase count of physical blocks and the update frequency of physical blocks were redefined to select the returnable block. Meanwhile,a new heat calculation method logic pages was deduced,and cold-hot separating of valid pages in returnable block was conducted. Compared with the GReedy（ GR） algorithm,Cost-Benefit（ CB）algorithm,Cost-Age-Time（ CAT） algorithm and File-aware Garbage Collection（ Fa GC） algorithm,not only some good results in wear leveling have been got,but also the total numbers of erase and copy operations have significantly been reduced.