近年來NAND flash memory被迅速地廣泛應用於桌上型電腦、儲存系統以及其他嵌入式裝置，由於它非揮發性、體積小、耐震性、高I/O效能與低功耗等獨特的優點，但也因為一些NAND flash memory的硬體限制，各種方法被提出用來改善快閃記憶體內部軟體及硬體元件，尤其是在SSD內部的RAM緩衝區管理已成重要的議題；SSD內部的RAM緩衝區主要用於資料緩衝區(Data Buffer)及映射緩衝區(Mapping Buffer)，其中資料緩衝區可以處理頻繁的讀取和寫入請求，而映射緩衝區維持從邏輯位址到實體位址對應的映射資訊。我們還觀察到SSD的效能會隨著不同的工作負載特性而改變，因此我們提出了一個針對高性能快閃記憶體裝置之工作集導向的緩衝區管理設計，目的是分析工作負載特性並根據當前的working-set有效地管理RAM緩衝區，而實驗結果顯示在不同的工作負載下，我們的方法可以有效改善SSD的效能。

Recently, NAND flash memory has been rapidly used on desktop computers, storage systems, and other embedded devices because of its unique advantages such as non-volatile feature, low-power consumption, small size, shock resistance, and high I/O performance. Due to the physical limitations of NAND flash memory, many management methods have been proposed to improve the internal software and hardware components of NAND flash memory. In particular, the internal RAM buffer management of SSDs that adopt NAND flash memory has become an important problem. SSDs’ RAM buffer is mainly used for data buffer and mapping buffer. Data buffer can handle frequently read and write requests and mapping buffer can maintain the mapping information from logical addresses to physical addresses. We also observe that the performance of SSDs could change with the different workload characteristics. Therefore, we propose a working-set-aware RAM buffer management design for high-performance NAND-based devices. The purpose of the thesis is to analyze the workload characteristics and effectively manage the RAM buffer based on the current working set. The experimental results show that the performance can be improved for different workloads.

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