Introducing the Magic That Is BitTorrent
BitTorrent isn't the newest of the peer-to-peer (often abbreviated as P2P) file-sharing technologies, but it is one with a major difference. (Peer-to-peer file sharing describes the process of sharing data between computer users, rather than using a Web server to host the content.) BitTorrent was designed to distribute the downloading load among many users of a file. The result is a technology that is ideal for sharing very large files. How large? Think gigabytes. Think movies, TV shows, large software applications, entire databases, complete inventory lists, scanned document collections, and more, all quickly and easily transferred across the Internet, many in their original, uncompressed format.
File-sharing technologies have generally worked this way:
1. You connect to the network of users of the file-sharing software.
The network enables you to search other members' computers for files you're interested in having.
2. You locate the file or files you want to download.
3. After you find a file you want, you connect to the computer that has the file saved on it so that you can download it.
4. You download til you drop.
This process ties up bandwidth — Internet connectivity — on your computer and on the computer of the person who is sharing the file during the transfer. If two people want to download the file at the same time, each person only gets half the bandwidth available.
Here's how BitTorrent changes the old-school P2P process:
1. While surfing the Web, you come across a link to a BitTorrent file, called a torrent, and click it.
A torrent is a very small file you download that contains a sort of table of contents to the actual file you want.
If you were using another P2P file-sharing system, you would start to download the actual file at this point.
2. You open the torrent in a BitTorrent software client.
The client connects to a Web site running tracker software that keeps tabs on who else is also downloading that main file. Your client downloads small pieces of the file from all those users who have a copy of it, keeping the file-sharing load from being borne by a single user.
3. As you download pieces of the file, the BitTorrent software client assembles the pieces using the table of contents in the torrent.
The software also begins to share those pieces you've received with other people who are also trying to download the file. By downloading, you're also helping to make parts of the file available. Without even trying. You're such a giver.
The result is a speedier process for everyone, and one in which the distributor of the data isn't hit with huge bandwidth problems. In fact, the more popular a file is, the faster you can obtain it, because more pieces of it are available; the only limit on the download is the speed of your own connection.