AB-FTL: An alternative block Flash Translation Layer using locality-aware technique

Since flash memory has useful characteristics, it has been used in a variety of areas recently. However, it has a critical weakness known as “erase-before-write”, which means that whenever receiving a write request to the preoccupied place from a file system, an erase operation must be preceded. If such a frequent request is generated in succession, this policy makes systems have experienced serious performance degradation. Many efforts have been actively made to solve this problem, and the activities are moved to utilize Flash Translation Layers (FTL). The software layer also manages garbage collection and wear leveling strategies to extend the life span and prevent malfunction. In this paper, we propose a novel flash memory management scheme named AB-FTL using an alternative block which plays a role to collect the data with the same LBN (Logical Block Number) and the new operation named split operation to decrease many erase operations created by a number of full merge operations. Moreover, alternative blocks depend on the characteristics of locality to manage update requests more efficiently. Our experimental results show that AB-FTL is an outstanding FTL algorithm of reducing the full merge cost generated by full merge operations over the implemented FTLs.