Journal-based Block Images for Flash Memory Storage Systems

Flash memory has been widely used in various embedded systems as a novel nonvolatile storage media. There are currently two different approaches to store data on flash memory. One is to build a FTL (Flash Translation Layer) on flash memory and use traditional disk file systems on top of it; the other is to build dedicated flash file systems directly on flash memory. In order to address the common flash handling mechanisms redundantly implemented in FTL and flash file systems, BIL (Block Images Layer) has been developed. At present, the most common BIL is UBI (Unsorted Block Images), which still have some drawbacks making it inappropriate for high capacity flash chips. In this paper, we propose JBI (Journal-based Block Images), a novel BIL based on the journal system. The mapping management of JBI is completely based on the proposed journal system. Our performance evaluation demonstrates that JBI outperforms UBI significantly.