Garbage Collection Algorithms for NAND Flash Memory Devices -- An Overview

This paper highlights the necessary garbage collection algorithms which is needed in flash translation layer (FTL) for NAND Flash memory devices such as SATA SSD´s (Solid State Devices). Garbage collection is the process of freeing up partially filled blocks to make room for more data and the Garbage collection (GC) algorithms recommended here plays a key role in maintaining SSD´s Performance and structuring the Flash memory´s long term problems related to Reliability and early wearing out of cells due to repeated overwrites beyond the threshold program limit (P/E cycles). NAND Flash Memories require Garbage Collection (GC) and Wear Leveling (WL) operations to be carried out by Flash Translation Layers (FTLs) that oversee flash management. These Algorithms were implemented to reduce the number of read/write, erase cycles on the pages so that Wear Leveling, Write Amplification and Wear out of the Flash Pages can be reduced.