A Novel Independent Channel Addressing Flash Translation Layer Scheme

Address mapping algorithm plays a key role on the performance of Solid State Drives. Demand-based flash translation layer is one of the best address mapping algorithm up to now, but it has a fatal problem-cached mapping table missing. In order to reduce cached mapping table missing, higher cache hit ratio is needed. However, higher cache hit ratio means higher cache space occupation, and that is unacceptable in large capacity SSDs. To solve this problem, we designed a novel scheme named independent channel addressing flash translation layer. In this scheme, the whole mapping table is kept in an independent channel. Due to the parallelism of channels, addressing and data access can be executed at the same time. In this paper, we tested this scheme through Flashsim, and the simulation result showed that our new scheme can effectively reduce the burden of data channels and average response time especially when cache hit ratio is low. Compared with DFTL, our algorithm can improve the performance of SSD up to 23.6%.