Flash memory controller: Difference between revisions

Revision as of 09:37, 17 December 2019

Revision as of 20:35, 29 December 2019

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==Flash Translation Layer (FTL) and Mapping==

{{main||Flash translation layer|Flash file system}}

{{merge from|Flash translation layer|date=August 2018|discuss=Talk:Flash translation layer#Merge|section=TRUE}}

Usually, Flash Memory Controller 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>

==Garbage collection==