UBI with Logging

Flash memory is widely adopted as a novel nonvolatile storage medium because of its characteristics: fastaccess speed, shock resistance, and low power consumption. UBI Unsorted Block Images, uses mechanisms like wear leveling and bad block management to overcome flash limitations such as “erase before write”. This simplifies file systems like UBIFS, which depend on UBI for flash management. However, UBI design imposes mount time to scale linearly with respect to flash size. With increasing flash sizes, it is very important to ensure that UBI mount time is not a linear function of flash size. This paper presents the design of UBIL: a UBI layer with logging. UBIL is designed to solve UBI issues namely mount time scalability & efficient user data mapping. UBIL achieves more than 50% mount time reduction for 1GB NAND flash. With optimizations, we expect attach time to reduce up to 70%. The read-write performance of UBIL introduces no degradation; a more elaborate comparison of results and merits of UBIL with respect to UBI are outlined in the conclusion of the paper.