一個連續性媒體伺服器之設計與實作

Abstract

由於計算機處理速度及網路傳輸速度之大幅進步，因此需要大量計算及網 路傳輸的多媒體應用程式受到極大的注意。隨選視訊服務(Video-On- Demand) 是由一個多媒體伺服器即時的將連續性的大量資料由檔案系統讀 出並經由高速網路來傳遞到許多用戶端。然而，傳統的檔案系統在設計上 並未考慮到此種特性，使得多媒體伺服器無法有效利用到計算機處理速度 及網路頻寬。也因此，我們設計了一個連續性媒體的檔案伺服器，其包含 了一個平行存取介面以有效增加資料頻寬，並且實作了一個即時磁碟排程 演算法使其能符合即時限制。另外，經由改變資料傳輸的路徑，減少了資 料拷貝的次數，始得多媒體伺服器的效能提高。由實驗得知，我們設計的 連續性媒體檔案伺服器能同時支援22個用戶。 Multimedia applications have received a great deal of attention in recentyears. Most applications such as Video-On-Demand (VOD) need a highbandwidth storage server to support real-time data retrieval and transmission.However, the existing file system such as UNIX file system can not satisfythe requirement of high data transfer rates. This thesis focuses on thedesign and implementation of a continuous media storage server which cansupport the on-demand services. Our storage server contains a parallel I/Osubsystem using data striping and data interleaving on multiple disks. Thus,it can provide high data transfer rates. Furthermore, a real-time diskscheduling is involved to satisfy the timing constraint. In order to increasethe network throughput, we modify the data transmission path by a short cutfrom storage server to network. With this scheme, extra data copies can beeliminated. The performance measurement shows that the storage server cansupport 22 video streams simutaneously.