Flash memory has been widely used in storage systems because of its nonvolatile nature,its small size,shock resistance and fast access speed. The traditional scheduler over flash memory storage systems is NOOP scheduler. There is much room for improving the I/O performance, especially over multi-bank flash memory storage systems. Because several banks can operate simultaneously, we proposed a new scheduler called Multi-Bank flash memory Scheduler (MBS) based on the native file system YAFFS to take advantage of the parallelism o{ multiple banks by considering the high read speed. A flexible bank assignment policy was proposed to assign proper banks for write requests according to the attributes(hot or cold) of requests, which were identified by an AVL-based-tree mechanism. MBS scheduler reorders read and write requests and gives higher priority to reads. The experimental results show that the I/O throughputs and average response time are improved significantly compared with the NOOP scheduler. An even erasable count and capacity utilization were obtained between different banks in the multi-bank storage system.%闪存以其体积小、抗震性强、能耗低、读取速度快等特点,被广泛应用于存储系统中.NOOP是闪存上传统的调度方法,但是NOOP的I/O性能较低,不能满足很多应用程序的要求.根据闪存读取速度快、多个banks(chips)可以并行运行等特点,提出了一种基于闪存文件系统YAFFS的Multi-bank闪存调度方法(简称MBS).MBS并行地执行请求,且给予读请求更高的优先级.MBS根据AVL-based-tree机制识别出的写请求属性动态地将其分配到合适的bank中.实验结果表明,相比NOOP,MBS调度具有更高的I/O吞吐率、更短的请求响应时间并具有均匀的bank擦除次数和利用率.
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