Performance improvement of block based NAND flash translation layer

With growing capacities of flash memories, an efficient layer to manage read and write access to flash is required. NFTL is a widely used block based flash translation layer designed to manage NAND flash memories. NFTL is designed to achieve fast write times at the expense of slower read times. While traditionally, it is assumed that the read traffic to secondary storage is insignificant, as reads are cached, we show that this need not be true for NAND flash based storage due to garbage collection and reclamation processes. In this work, we present two independent techniques that extend NFTL and improve the read throughput in particular. The techniques presented add a minimal amount of RAM overhead to a flash controller, while providing, on an average, a 22.9% improvement in page read times and a 2.6% improvements in page write times on a set of file system and rigorous synthetic benchmarks. The techniques presented are well suited for flash controllers that are typically space constrained and have minimal processing power.