An Efficient Parallel Executing Command Scheduler for NAND Flash Storage Systems

Flash memory storage device has received tremendous attention due to its superior performances. The command scheduling algorithm between Flash Translation Layer (FTL) and Flash Controller (FC) is a critical part for the system performance. However, conventional first-in-first-out command scheduling scheme may not fully utilize the full bandwidth due to the different timing budgets for NAND flash operations. In this paper, an efficient out-of-order executing command scheduler is proposed to maximize the parallelism of instructions among channels, targets, dies, planes and even pages. The experimental results demonstrate that the bandwidth can be 45.1 % to 250% higher for different data patterns as compared to regular scheduling.