Adaptive Paired Page Prebackup Scheme for MLC NAND Flash Memory

Multilevel cell (MLC) NAND flash memory is more cost effective compared with single-level cell NAND flash memory as it can store two or more bits in a memory cell. However, in MLC flash memory, a programming operation can corrupt the paired page under abnormal termination. In order to solve the paired page problem, a backup scheme is generally used, which inevitably causes performance degradation and shortens the lifespan of flash memory. In this paper, we propose a more efficient paired page prebackup scheme for MLC flash memory. It adaptively exploits interleaving, copyback operations, and parity data to reduce the prebackup overhead. In experiments, the proposed scheme reduced the backup overhead by up to 78%.