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星期一, 3月 16, 2009

Wear-Leveling(Advance intro)

Dynamic wear leveling employs wear levels over the dynamic Flash array areas. Embedded Designs using
dynamic wear leveling do not touch static data. In a Flash use model where 75% of storage is for code or
static data, only 25% is available for wear leveling. This model offers higher level of Flash endurance
compared to no wear leveling. Note that only one-fourth of the Flash cell array employs wear leveling.


A static wear-leveling algorithm evenly distributes data over an entire Flash cell array and searches for the
least used physical blocks. The identified low cycled sectors are used to write the data to those locations. If
blocks are empty, the write occurs normally. If blocks contain static data, it moves that data to a more heavily
used location before it moves the newly written data. The static wear leveling maximizes effective endurance
Flash array compared to no wear leveling or dynamic wear leveling.


New comer- Global Wear-leveling(A.K.A Universal wear-leveling)
Incorprate the benefit of Dynamic and Static wear-leveling.
Which treat the SSD as a whole block.