一种基于功能表的高效FTL算法

FTL用于将闪存模拟成标准的块设备以屏蔽其写前进行擦除的特性。传统的FTL算法采用扫描冗余区的方式建立映射表，初始化速度慢，并通过单纯的映射表实现地址转换，只能部分改善空间利用率，有的甚至提高了块回收代价，使运行效率变得低效。本文提出了功能表的思想，通过状态表寻址直接建立块映射表和块信息来提高启动速度，降低空间复杂度。通过将映射表与块信息相结合来实现读写操作中地址的查找，均衡了空间利用率和回收代价。

An Efficient FTL Algorithm Based on Function Tables

FTL is used to emulate a flash memory as a standard block device via hiding the erase before write characteristics of the NAND flash. As conventional FTLs slow the initialization by scanning the spare area of blocks to build mapping tables, and implement address translation with a single mapping table, they can only improve space utilization partially, some of which even increase the block recycling cost and debase the operating efficiency.In this paper, an idea of funtion table is proposed to build the block mapping table and block information by the status table, which accelerates the mounting speed, and decreases the space complexity as well.Meanwhile, the mapping table is combined with the block information to achieve fast addressing in reading and writing, and also balances the space utilization and the recycling cost.