From LQWiki
http://bitconjurer.org/BitTorrent/bittorrent_logo.png
BitTorrent is a peer to peer file distribution system that uses swarmcasting for it's distribution which eases the network load from the original distributor. The name is a play on Bitstream, emphasizing the speed of BitTorrent. BitTorrent was created by Bram Cohen.
Using traditional distribution methods, such as ftp, the same information is sent from a central server to many clients. Sending huge amounts of data across the Internet can be expensive. Using the traditional ftp model the more computers that are connected, the slower downloading will be, or the server must be more powerful and have more bandwidth to keep up. Because ftp needs large servers and lots of bandwidth, private individuals have previously been precluded from distributing large, popular files on the Internet. The ftp model can be improved using local mirrors, but still uses only a fraction of the Internet's full potential.
However, most of the clients downloading the file will have spare upload bandwidth. If this potential is used so that clients also send data to each other a network can function more efficiently and at less cost to the distributor. This is how BitTorrent works.
With a BitTorrent download, the more demand for a file the quicker the download can be, because there are more peers on the network to receive data from. A download over BitTorrent is called a torrent, details are distributed in small 'torrent files' with the extension .torrent and MIME type application/x-bittorrent. Torrent files are normally downloaded via ftp or http and opened by a bittorrent client.
The reference BitTorrent client implementation is written in python. It is a command line tool with basic GTK GUI interface. If you want to use the standard GUI from the desktop you can set application/x-bittorrent to open with btdownloadgui.py in the file associations of your desktop environment
Technology such BitTorrent democratizes distribution of popular or large files on the net, opening possibilities to individuals that were previously available only to large companies. For example, the Internet release of an indie film or new Linux distribution is possible by anyone at almost zero cost.
When downloading via bittorrent please leave the client running after the download has finished. This is called seeding, and allows other users to get the file from you. Most people on DSL have plenty of spare upload bandwidth so seeding costs them nothing. If you leave your computer on overnight consider leaving it seeding your favorite distribution, or some other large file. People who do not allow uploading from their computer are known as leeches. Individuals gain nothing by refusing to share bandwidth via BitTorrent, but benefit all users by cooperating.
There are many other BitTorrent clients available, with more advanced features than the standard offering. The most popular seems to be Azureus, an Open Source Java-based client. It is distributed as a Jar file.
Applications to use it
External links
- Official BitTorrent page (bitconjurer.org)
- BitTorrent introduction (www.bittorrent.com)
- Azureus (azureus.sourceforge.net)
- torrent search engine (throughput.de)
- rTorrent (libtorrent.rakshasa.no)
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