Usually, flash memory controllers also include the "flash translation layer'''" (FTL), a layer below the file system that maps host side or file system logical block addresses (LBAs) to the physical address of the flash memory (logical-to-physical mapping). The LBAs refer to sector numbers and to a mapping unit of 512 bytes. All LBAs that represent the logical size visible to and managed by the file system are mapped to a physical ___location (block ID, page ID and sector ID) of the Flash. As part of the [[wear leveling]] and other flash management algorithms (bad block management, read disturb management, safe flash handling etc.), the physical ___location of an LBA might dynamically change frequently. The mapping units of an FTL can differ so that LBAs are mapped block-, page- or even sub-page-based. Depending on the usage pattern, a finer mapping granularity can significantly reduce the flash wear out and maximize the endurance of a flash based storage media.<ref>http://drona.csa.iisc.ernet.in/~gopi/west10/goodson.pdf</ref><ref>http://flashdba.com/2014/09/17/understanding-flash-the-flash-translation-layer/</ref><ref>http://files.iccmedia.com/magazines/basfeb15/basfeb15-p25.pdf</ref>
