臺灣博碩士論文加值系統

傳統上的傳播方式是採用“廣播”的方式，這種傳播方式的缺點為單一方
向、缺乏彈性及缺少互動性。近年來，由於科技的進步使得突破傳統傳播
方式限制的可能性大為提升，也因此產生了“隨選視訊”的概念。“隨選
視訊”系統基本上有二個特性：一是需要高網路頻寬一是需要高而穩定的
磁碟輸出量。在本論文中，我們利用雙階層式磁碟陣列架構及其資料擺放
方法來滿足高而穩定的磁碟輸出量的需求，並以此為基礎，我們設計了一
個利用該架構特性的檔案系統，來提高儲存系統的輸入／輸出效率以及系
統可容納的客戶端數目。基於此檔案系統，我們實作了隨選視訊系統伺服
器的部份，我們也實作了客戶端的播放程式，並設計了伺服器與客戶端溝
通的協定，完成一個隨選視訊系統。

This thesis discusses the design of a video-on-demand(VOD) file
system, which is based on a general two-level hierarchical disk
array structure and a novel data placement and retrieval
scheme. The main distinction of the design is that it achieves
effective utilization of disk bandwidth. Since VOD servers
require high I/O bandwidth to provide services to a large
number of viewers, effective utilization of disk bandwidth
means that the cost of the storage system is optimized. The two-
level hierarchical disk array is implemented on multiple
storage nodes, each of which is a personal computer. The
storage nodes are commanded by a host computer. This thesis
describes the implementation details of the file system and the
operations of the VOD server.