An Improved Analytical Expression for Write Amplification in NAND Flash

Agarwal et al. gave an closed-form expression for write amplification in NAND flash memory by finding the probability of a page being valid over the whole flash memory. This paper gives an improved analytic expression for write amplification in NAND flash memory by finding the probability of a page...

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Bibliographic Details
Published in:arXiv.org 2011-10
Main Authors: Luojie Xiang, Kurkoski, Brian
Format: Article
Language:English
Subjects:
Amplification
Computer simulation
Flash memory (computers)
Garbage
Garbage collection
Online Access:Get full text
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Summary:Agarwal et al. gave an closed-form expression for write amplification in NAND flash memory by finding the probability of a page being valid over the whole flash memory. This paper gives an improved analytic expression for write amplification in NAND flash memory by finding the probability of a page being invalid over the block selected for garbage collection. The improved expression uses Lambert W function. Through asymptotic analysis, write amplification is shown to depend on overprovisioning factor only, consistent with the previous work. Comparison with numerical simulations shows that the improved expression achieves a more accurate prediction of write amplification. For example, when the overprovisioning factor is 0.3, the expression proposed by this paper gives a write amplification of 2.36 whereas that of the previous work gives 2.17, when the actual value is 2.35.
ISSN:2331-8422