| The popularization of the Wide-Band Internet makes more and more resources appear on the Internet, the demand of people downloading network resources also gradually enlarges day by day. At present, there are already many network storage devices, but the network storage devices which are specially designed for individual and small-scale consumers are few. Especially, the devices which can automatically download resource from the network are scarce. This project is to make research on the embedded network downloader based on the PowerPC processor. This embedded network downloader is able to download resource from the network automatically and is able to support many downloading protocols including HTTP,FTP,BitTorrent,eMule. The downloader can connect to the network and download data all by itself. It is stable, low-power consumption, safe, and is suitable for long-time use, and this is a good method to download files from Internet compared with the traditional way.This project is an embedded system research which contains the hardware design and the software design. The paper is a part of the entire project. Based on the understanding of the basic hardware structure, the paper makes deep analysis about the BitTorrent protocol. Then according to the embedded downloader's characteristic that the resource is limited, under the Linux operation system, the paper develops a simple and practical client program which can support the BitTorrent protocol, and transplants the program to PowerPC platform through cross compiling.The paper divides the client program into some function modules, including decoding the torrent files, communication between the client and the tracker server as well as communication between the client and other peers, then analyses and realizes the BT downloading mechanism, finally realizes the basic function of the client program. After compiling and debugging, the client program can decode the torrent files and exchange data based on the BitTorrent protocol. The program works well on the PowerPC platform. |
