連續性媒體磁碟排程法之研究

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連續性媒體磁碟排程法之研究
著者: 廖淑婷; Liao, Shu-Ting
李建億; Chien-I Lee; 資訊教育研究所
主題: 連續性媒體; 磁碟排程; 及時性; 多重磁碟; Continuous Media; Disk Scheduling; real-time; multiple disk
描述: 為符合多媒體儲存系統及時性的要求，儘量減少磁碟讀取服務過程中的延遲是必要的，是故妥善地安排磁碟系統的工作順序將有助於達到服務品質的要求，提高工作的效率；所以對多媒體系統而言，一個好的磁碟排程策略就愈顯重要。一般而言，磁碟存取系統所可能產生的延遲要以磁碟頭移動所產生的延遲最為重要，因此大部分磁碟排程策略都為使磁碟移動時間縮短而設計。本論文針對多媒體儲存系統之磁碟排程問題，提出一套更有效率的及時性磁碟排程方法，在這套方法中，我們設法減少磁碟頭不必要的移動，以求得最佳存取時間；其主要構想是以各要求的存取期限與磁碟位置之相互關係為考量，在磁碟頭移動路途中將期限稍晚的要求預先讀取，減少磁碟頭不必要的回移，經由數學證明與模擬分析的結果，我們的方法確實能比現有其他的磁碟排程法減少一些不必要的延遲，更能增加多媒體儲存系統的服務效率。再則，我們將進一步考量多重磁碟儲存環境下的情形來進行實驗模擬分析，可以發現我們所提出的方法，比傳統的磁碟排程法更能適用於多重磁碟的環境並提供更佳的產能。最後的實驗，則為因應實際使用者可能會有不同頻寬資料流與動態讀取播放的要求，經由模擬的結果分析，我們所提出的方法在如此的需求環境下，亦能提供較好的儲存系統效能。
In order to meet the time constrains of multimedia system, it is necessary to avoid delay in process of disk services. To schedule the time critical tasks validly will help to guarantee the quality of services. Therefore, it is very important to apply an efficiency disk scheduling approach for multimedia system. In general, the disk seek time is the largest factor of the transfer delay, and most algorithms were proposed to minimize the seek cost of disk. In this thesis, we will propose an efficiency disk scheduling strategy for continuous media which can reduce the excessive disk-seek time in order to obtain the optimal service time. In this strategy, we consider the correlation between deadlines and storage locations of each request for disk accesses. Without disobey the deadline constrains, we try to perfetch the requests with later deadlines on the current disk-scan direction, where those later requests will soon be retrieved for display. From the mathematical analysis, we will prove that the validity of our new proposed strategy, and from the simulation analysis, we will find that our new proposed strategy have best performance than the other disk scheduling strategies. Moreover, by considering the multiple disk drivers for the requirements of storage space and transfer bandwidth of continuous media, we will extend our strategy. From the simulation results, we will also find that our method has best performance than others. Finally, we simulate streams with different bandwidth and dynamic consumer rate to adapt to the practical requirement of user. From the experiment results, we will find that under such cases, our new proposed strategy still has the better performance for continuous media storage server.
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建立日期: 1999
格式: 121 bytes
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語言: 中文
識別號: http://nutnr.lib.nutn.edu.tw/handle/987654321/4751
資源來源: NUTN IR

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連續性媒體磁碟排程法之研究

廖淑婷; Liao, Shu-Ting 李建億; Chien-I Lee; 資訊教育研究所 1999

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