Rethink the Design of Flash Translation Layers in a Component-Based View

NAND flash memory is a popular memory device that has many advantages such as high-density, lightweight, shock-resistance, non-volatile, and low-power features. Although NAND flash memory has many attractive features, it still has several limitations due to its architectural characteristics, such as out-of-place update, erase-before-write feature, and limit of erase count. Therefore, various flash translation layers (FTLs) have been proposed to handle the characteristics. An FTL consists of three main functions, such as address translation, garbage collection, and wear-leveling effect. In order to facilitate developers to realize and design the main functions of FTLs, we propose a component-based view to rethink the design of FTLs. With the component-based view, developers can replace inappropriate components to form a new FTL and dynamically replace the present FTL. Therefore, we also propose the transformation of FTLs to adaptively transform a present FTL to a suitable one. In the experiments, we can demonstrate that the revised FTL (by replacing some components) can improve its original performance and the transformed FTL can also improve the performance under the current workload.