| 摘要 |
<p>[Problem] Since JFFS, which is used as an existing method of storing data in a flash memory, stores all data sequentially according to a generated order, pure data of a file system and metadata for managing the pure data must be sequentially stored. Thus, when a PC is turned on and mounts the file system, since all metadata must be read to RAM, the entire space of the flash memory must be read, and thus a long time is taken to mount the file system. An increase in the capacity of the flash memory causes an increase in the mounting time. Thus, a booting time taken to turn on and use an embedded system significantly increases. Accordingly, JFFS is not suitable for embedded systems requiring quick access. [Solution] A data storage space is secured by dividing a free list of segments that are used as a data storage space of a flash memory into a front journaling free list and a rear journaling free list by setting a central point of the segment free list, determining whether enough free segments are secured in the front journaling free list, and if it is determined that not enough free segments are guarantied, collecting garbage data from among stored data with reference to a wear-leveling threshold and a valid data threshold which are set in segments in which data is stored.</p> |
