2001年题

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Project Overview ?鳋 F {缎  
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Project Statement (壿in?lt;锧? 
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File sharing community is designed for users who want to share their files with other users on the Internet. ?lt;庘鈌  
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Project Objectives " i?鐰  
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The main objective of file sharing community is to provide facilities for users to easily exchange their files on the Internet. Whenever a user joins the file sharing community, he/she can advertise files he/she wants to share with other members, query other membersˇ shared files, search for specific files, fetch files from specified locations, and so on. 

Brief Statements about Requirements 溦$yx 楍?  
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1. Join/Leave the Community 轈n橂峿z%&  
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We assume that there is only one file sharing community in the world. A user who wants to join/leave the community only needs to start/stop a process (we call this process ¨FSC daemon〃 hereafter). Need no authentication when joining the community. After joining the community, the new community member must be able to explore other members in the community. V<a苴a? 
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2. Directory Services and Information Exchange ??瞱? 
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In order to provide shared file and membership information to other members, there must be a storage (also called ¨cache〃, or ¨database〃 in this document) accommodating file information with each community member. The entity that maintains the storage is called the directory service (or DS for brevity). Different directory services could exchange their information so that query/search time might be reduced. ?/d疝 ? 
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3. Commands u??B倫  
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Any member in the community could issue at least three commands: query, search, and fetch. He/she could ask other members to provide shared file information (query), find out the locations of specific files (search), or get other membersˇ shared files (fetch). }毬桷沯呲  
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4. The Configuration File ?綽;囑,  
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FSC daemons are controlled by configuration files. For example, the files to be shared, the timeout value of each command,  etc. might be defined in configuration files. 飠U軖籐/Mk  
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5. Interactive Mode vs. Batch Mode (Silent Mode) ? 怷?  
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Users should be able to join/leave the community, issue commands, etc. in both batch and interactive modes. In batch mode, commands are written in a batch file in advance. The FSC daemon will then silently issue commands specified in the batch file. In interactive mode, users could issue commands from a user interface. Results of issued commands should be displayed on the UI after they are completed.