臺灣博碩士論文加值系統

使用NAND flash為基礎的固態硬碟越來越廣泛且用來取代傳統硬。因為NAND flash的特性造成固態硬碟的一些缺點如效能下降。為了增加寫入效能，所以使用TRIM的命令。在論文裡探討TRIM是如何影響效能的，我們將影響效能的因素分為三種:1.主機的行為，2.接口的頻寬，3.設備內部行為。我們設計了一些實驗來觀察這些影響因素。然後觀察TRIM命令是如何影響根為什麼造成寫入效能的上升或下降。

NAND fash-based solid-state disks (SSDs) have become widely available and to replace HDDs. Because NAND fash characteristic cause the disadvantage of SSD to degradation of write performance. To improve the write performance, the TRIM command is used. In this paper we discuss how TRIM effect the performance, we sperate aecting factors into three
parts:1.Host behaviors, 2.Interface bandwidth and 3. Device internal behaviors. We design several experiments to observed the aecting factors. Discussed when and why TRIM
command is benefit for write performance or when can degradation write performance.

Table of Contents iii
List of Tables iv
List of Figures v
Abstract vii
Acknowledgements viii
1 Introduction 1
2 Related Work 3
3 Background 4
3.1 Performance-Aecting Factors . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2 TRIM Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Experiments Results 9
4.1 Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2 Host behaviors on TRIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.3 Experiment on real SSD . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3.1 Experiment2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3.2 Experiment3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.3.3 Experiment4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5 Conclusion 21
Bibliography 22

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