Vector Read: Exploiting the Read Performance of Hybrid NAND Flash

OneNAND flash is a NAND based hybrid flash memory which offers much better read/write performance and other functionalities than standard NAND flash memory. Because of its superior read performance, OneNAND flash became the most promising storage solution for implementing high performance mobile device which adopts demand paging memory architecture. However, unfortunately, existing general purpose operating systems, such as Linux, fail to exploit the read performance of OneNAND flash because of a restriction imposed by their I/O architecture and device driver interface. This paper investigated the cause of such inability, and proposed the design of vectored read scheme for solving that problem. Implementation studies on Linux kernel shows that vectored read scheme reduces the block level read latency of OneNAND flash by up to 41% compared with commercial FTL device. It also proved its effectiveness in real-world applications by reducing page fault handling time by 28%.