NAND flash图像记录系统坏块管理关键技术

提出了NAND flash型高速大容量图像记录系统的高效坏块管理方案。针对坏块表的快速检索和可靠存储问题,提出了基于位索引的坏块信息快速检索结构;为解决坏块快速匹配问题,提出了基于滑动窗口的无效块预匹配机制;对于突发坏块造成写入速度下降问题,提出了滞后回写机制。系统架构全部用硬件方式在FPGA中实现,实验结果表明:检索8个物理块坏块信息仅耗时2个时钟周期;预匹配和正确物理地址生成耗时都为0个时钟周期;突发坏块发生时系统写入速度不受影响,滞后写回在最差情况下耗时也仅22.280 36 ms;系统持续写入速度最大为848.65 MB/s,读取速度为1 265.5 MB/s,擦除速度为9 120.245 MB/s,系统存储容量为160 GB,坏块管理保留容量为8 GB,纠错能力为1 bit/512 B。

Key technology of invalid block management in NAND flash-based image recorder system

A high-efficiency invalid block management scheme in high-speed and large-capacity image recorder system based on NAND flash was presented.In order to solve the problems of invalid block table′s fast search and reliable store,an invalid block information fast search architecture based on bit index was proposed.An invalid block pre-matching mechanism based on glide window was proposed to solve the problem of invalid block′s fast matching.In consideration of the disadvantage that burst invalid block would decrease write speed,a lag copy back mechanism was presented.All architectures were implemented in FPGA in form of hardware.The results show that it only takes 2 clock periods to search 8 invalid block information,pre-matching and generating right physical address operations are no clock delay,write speed is not affected by burst invalid block,copy back takes only 22.280 36 ms under extremity situation,consecutive write speed is up to 848.65 MB/s,consecutive read speed is up to 1 265.5 MB/s,and consecutive erase speed is up to 9 120.245 MB/s,the storage capacity is 160 GB,reserved capacity for invalid block management is 8 GB and ECC ability is 1 bit/ 512B.