(Flash Translation Layer) Software that lets an operating system read and write flash-based storage modules as if they were rotating disk drives. It translates the block level calls to the disk from the operating system's file system to the internal addressing scheme of the flash drive. Without a flash translation layer (FTL), the file system in the host computer, smartphone or other device must be written to address the flash architecture. Mapping and Wear Leveling The two primary functions of an FTL are to map disk storage to flash storage and to manage wear. The mapping translates disk block addresses into flash block addresses. Because flash memory has a shorter rewritable lifespan than disks, wear leveling moves data around the flash cells to evenly distribute the writes. See flash file system and flash memory.