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題 名 | 以區塊為基礎之反及閘快閃記憶體管理模式=The Nand Type Flash Memory Management Model Based on the Block Base |
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作 者 | 黃文增; 陳俊達; 陳彥勝; 劉倉吉; | 書刊名 | 臺北科技大學學報 |
卷 期 | 37:2 2004.09[民93.09] |
頁 次 | 頁63-78 |
分類號 | 471.6511 |
關鍵詞 | 嵌入式計算系統; 快閃記憶體; 反及閘快閃記憶體; 抹除策略; 動態均勻抹除; 分配政策; Embedded computing system; Flash memory; NAND flash memory; Cleaning strategy; Dynamically cycle-leveling; Allocation strategy; |
語 文 | 中文(Chinese) |
中文摘要 | 反及閘快閃記憶體(NAND Type Flash,簡稱NandFlash),是嵌入式計算系統中記憶體的應用主流之一,主要因為NandFlash具有體積小、省電、非揮發性和耐震等特性。由於快閃記憶體具有特殊半導體特性,不僅限制其運用而且導致管理方法複雜化,所以如何有效率管理快閃記憶體,已經成為一項重要研究議題。特別當所管理的記憶體容量愈大時,有效管理機制的重要性將愈被彰顯。在探討文獻中,以Kim和Lee所提出的快閃記憶體管理方式最具其代表性,簡稱為KimLee演算法[10]。 本論文主要以NandFlash為基礎,提出一管理方法,並對KimLee文中未探討之處加以補充。我們所提方法中,是以區塊為研究基礎,因區塊為NandFlash中抹除的基本單位,以區塊作為探討基礎最為貼切。文中探討損壞區塊、均勻抹除、減少抹除頻率及無效資料頁回收之管理。然而,NandFlash管理中的「單元抹除成本」與「均勻抹除」兩者間的關係是相互衝突的;因此如何取得系統管理平衡點是一重點。 藉由動態方式分析資料屬性,分離成冷資料屬性與熱資料屬性,並將其資料寫至不同屬性區塊中,以降低無意義的搬移動作。動態均勻抹除策略可提昇可靠度,而此方法最大效益是只需要犧牲少量成本,可達到延長使用壽命與提高可靠度。再經由本文所提出的分配政策指標與抹除策略互相搭配,成效亦可彰顯。 |
英文摘要 | The NAND type flash, denoted by NandFlash, is on of the major applications in the embedded computing system, since it owns some advantages, the small size, great capacity, light power consummation, not volatility, and enduring vibration. For the special characteristic of the semi-conductor in NandFlash, its applications will be limitation and its manager method will also be complication. It is a major study topic to effectually manage this NandFlash. Especially, when a file system manages the huge size NandFlash, the performance of management mechanism will be more importance. Among the variously effective managements of the flash memory, the major representative method is proposed by Kim and Lee[10], whose method is denoted by KimLee algorithm in this paper. Based on the KimLee algorithm, we propose a more effective management than that of KimLee algorithm. In our proposal, since the basic erasing unit is a block in NandFlash, we use a block as the study basis with the meaning. We discuss the bad block management, the wear-leveling algorithm, the reduction of the erasing frequency, and the management of the invalid page data recovery. For conflicting between the unit cost of erasing cost and wear-leaving algorithm, it is another important issue to get the balance between the clearance and to do the cycle-leveling action. By dynamically analyzing the state of the data attribution, the data is divided into cold or hot data attribution and then re-written into the different block for reducing the nonsensical actions. Further, we can reduce the cost and promote the performance of the system. It only needs to sacrifice a jot cost for extending the life of flash memory and promoting the high usage. The performance will be more explicit with the allocation strategy index and the cycle-leveling strategy of our proposal model. |
本系統中英文摘要資訊取自各篇刊載內容。