Locality Competent Flash Translation Layer (LC-FTL) for NAND Flash Memory
- 발행기관 아주대학교
- 지도교수 Tae-Sun Chung
- 발행년도 2012
- 학위수여년월 2012. 2
- 학위명 석사
- 학과 및 전공 일반대학원 컴퓨터공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000012132
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Flash memory based memory devices are getting more and more admired. It has many advantages compared with traditional hard disk drives. It is well established fact that, random access pattern of different workload influences on the performance of flash memory. However, design of Flash Translation Layer (FTL) which performs logical to physical address translation, should be changed into a new paradigm. Present trend on FTL design is locality based FTL. In this thesis. a FTL, called Locality Competent FTL or LC-FTL is proposed, where both type of locality- temporal locality and spatial locality are considered.LC-FTL divides file system requests in two kinds- single page and multiple page request according to size, for using locality properly. To utilize both of locality some small active mappings are temporally stored in SRAM . However, total three small tables and a buffer is maintained in cache. Buffer is used to divide requests, whereas two tables store active mappings. Existing FTL involve a lot of overhead accesses because of uncached data.LC-FTL use maximum benefit from aforementioned localities to improve performance. Proposed FTL is based on page level mapping scheme. The experimental result shows that, proposed FTL outperforms less read, write and most importantly erase operation than other existing FTLs.
more목차
LIST OF FIGURES 5
LIST OF TABLES 7
CHAPTER 1. Introduction 8
CHAPTER 2. Background Knowledge 9
2.1 Flash Memory 9
2.2 Overview of Flash Translation Layer (FTL) 13
2.2.1 Page Level Mapping 14
2.2.2 Block Level Mapping 16
2.2.3 Hybrid Mapping 17
CHAPTER 3.Related Works 18
CHAPTER 4.Design Principle 20
4.1Locality Competent Flash Translation Layer (LC-FTL) 21
4.2 Overall Architecture 22
4.2.1 Temporal Cache Mapping Table (TCM) 23
4.2.2 Spatial Cache Mapping Table (SCM) 23
4.2.3 Global Translation Directory (GTD) 24
4.2.4 Update table 24
4.2.5 LC-Buffer 25
4.3 Locality Behavior of Single Page and Multiple Page Request 26
CHAPTER 5. Functionality of LC-FTL 27
5.1 Address Translation 27
5.1.1 Single Page Requests Address Translation 27
5.1.2 Multiple Page request Address Translation 28
5.2 Read and Write Operation Handling 29
5.3 Evict Entry Handling Policy 32
5.4 Garbage Collection Mechanism 33
5.4.1 Data Block as a Victim 33
5.4.2 Translation Block as a Victim 35
5.5 Power Off Recovery 36
CHAPTER 6. Experimental Evaluation 37
6.1 Experimental Setup 37
6.2 Performance Metrics 38
6.3 Performance Analysis 38
6.3.1 Read Performance 38
6.3.2 Write Performance 40
6.3.3 Erase Performance 41
6.3.4 Total Elapsed Time 42
CHAPTER 7. Conclusion and Future Work 44
References: 44
