Data Prefetching in Thin-Client/Server Computing over Wide Area Network

• Main Authors: Feng-Wen An, 安豐文
• Other Authors: San-Yih Hwang
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/93380558141077897707

碩士 === 國立中山大學 === 資訊管理學系研究所 === 91 === The thin-client/server computing model mandates applications running solely on a server and client devices connecting to the server through the Internet for carrying out works. Traditional thin-client/server computing model comprises only a single server and works only within LAN environment, which severely restrict its applicability. To meet the demand of reasonable response time over WAN, a modified thin-client/server computing model, MAS TC/S, was proposed. In MAS TC/S, multiple application servers spreading over WAN are installed, and each client device can freely connect to any application server that is close to it. However, reducing delay associated with fetching absent files, which are stored in other servers, is a challenging issue in MAS TC/S. We propose to employ data prefetching mechanisms to speed up file fetching. We use the suffix tree-like structure to store users’ previous file access records and define two temporal relationships between two records: followed by or concurrent with, to decide the set of files that should be prefetched together. Each file access subsequence is associated with a set of predicted file sets, each carrying a different weight. Given a current file access session, we will first find a matching file access subsequence and then choose the predicted set that has the highest weight. Based on the chosen predicted set, suitable files are prefeteched to the connected server. We compare our method with All-Kth-Order Markov model and find our method gets higher hit ratio under various operating regions.