Journaling File System Design And Implementation Of Embedded Storage Device

In embedded systems, unexpected power-off often occurs. For a normal kind of filesystem, unexpected power-off often causes the corruption of the file system and the lose ofdata. T fore, it is very important to design and implement a special kind of file system topreven such corruption. Journaling File System is just such kind file system we need.In this paper, we firstly compare several kinds of journaling file systems and point out thedefference between them. On the base of analysis above, we discuss the design and layout ofJFFS, a special journaling file system. In consideration of small size and special read-writecharacters of Flash devices, JFFS is designed as a simplified kind of log-structured jounaling filesystem, which have good performance to prevent corruption caused by unexpected power-off.At the last part of the paper, we put emphasis on JFFS' implementaion on DistOnChip, aspecial kind of embedded memory devcie. We successfully solve the problem that the dirver ofDiskOnChip support JFFS, bring forward and implement a memory plan in which JFFS andother normal file systems can exist on a DiskOnChip at the same time, and make JFFS turn intoa important part of Red Flag Embedded Memory Plan. In future, with its further devolopment,JFFS will be used far and wide.