臺灣博碩士論文加值系統

在儲存裝置的領域中，非揮發性記憶體是近年相當受到注目的技術之一，非揮發性記憶體具有體積小，省電及資料不受斷電影響等優勢，其中目前最主流的應用為NAND Flash，我們可在固態硬碟或是隨身碟等裝置中見其身影。然而，許多快閃記憶體之應用目前僅限於儲存端，若要延伸到記憶體的層級，我們勢必須需要讀寫速度更快速的方案，其中相變化記憶體(Phase Change Memory, PCM)是目前相當具潛力的選項之一，被視作有望取代DRAM的一種新型態記憶體，相比DRAM有非揮發性，及更好的擴展性(儲存密度高)之優點。
由於PCM具有高密度存取的特性，使用MLC PCM可充分利用到這項優點，然而，若要再儲存空間以及存取速度中做權衡，需要對寫入及讀取做適當的調整，本論文針對此議題對PCM空間的使用加以探討，並提出一套可在MLC-SLC之間轉換的架構，使得PCM更加適合作為新世代的主記憶體。

In storage systems, non-volatile memory has become a popular technique in these years. The properties of non-volatile memory contain small size, low-power consumption and non-volatility. There are many types of non-volatile memory now. Phase change memory (PCM) is one of the most potential one among them. PCM is also considered as a candidate to replace DRAM in main memory. Compared to DRAM, it has the advantages of non-volatility and higher storage density. We can take advantage from the property of higher storage density by applying PCM in MLC format. However, MLC PCM has longer access time than SLC PCM. We need to have a trade-off method between capacity and speed. To make PCM a better candidate for main memory, we propose a dynamic MLC/SLC configuration for PCM in main memory system. According to the experimental results, we can show the performance and endurance improvement of the proposed method.

第一章 緒論 1
1.1 前言 1
1.2 論文架構 3
第二章 環境背景和研究動機 4
2.1 PCM的運作原理 4
2.2 Process Variation 及寫入次數限制 6
2.3 Array Architecture 7
2.4 MLC SLC Density 9
2.5 Cache替換機制 9
2.6 虛擬記憶體 10
2.7 研究動機 12
2.8 相關研究 13
第三章 研究方法 14
3.1 系統架構(System Overview) 14
3.2 可使用儲存空間之討論 15
3.3 MLC-SLC地址存取方式 16
3.4 資料寫入步驟 18
3.5 轉換區塊挑選策略 20
3.6 PCM主記憶體的虛擬記憶體機制 23
第四章 實驗與效能分析 27
4.1 實驗環境 27
4.2 比較議題 29
4.3 實驗效能結果分析 31
4.3.1 使用不同挑選策略的系統效能 32
4.3.2 使用不同SLC比例的系統效能 34
4.4 耐寫程度分析 36
4.4.1 Normalized Endurance分析 36
4.4.2 不同SLC比例的使用壽命 37
第五章 結論 40
參考文獻 41

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