Tuesday, March 11, 2008

Peer-to-Peer File Sharing

[Here's a recent piece I wrote for my monthly technology column in La Prensa, a Western Massachusetts Latino newspaper. To read a few of my previous La Prensa technology columns go here.]

Peer-to-peer (commonly referred to as “P2P” or “PtP”) networks are commonly used to share music and video files on the Internet. Much of the illegal file sharing you hear about in the news is handled using P2P networks. These networks are also used for legal file sharing and, in some ways, they have got a bad name because of the sharing of copyrighted materials.

You may recall the early version of Napster, a software program developed by Northeastern University student Shawn Fanning in 1999. Napster worked using a variation of a P2P network (some call it hybrid P2P) that used a centralized server to maintain a list of who was online and who had which MP3 music files for sharing. Because Napster used a centralized server, it was easy to trace users and effectively shut the service down which the Recording Industry Association of America (RIAA) did in the fall of 2001, after filing a lawsuit against Napster.

As Napster was going through the legal battle, programmers were working to develop other file sharing programs that did not use a centralized server. The first of these new programs was named BitTorrent, and created by Bram Cohen in the summer of 2002.

Hundreds of additional P2P programs have been created and they are almost all based on the BitTorent model. Some of the more common BitTorrent type applications include Gnutella, Bearshare, Morpheous and FastTrack.

BitTorrent type programs are true P2P programs, using ad-hoc connections so there is no central server. Every computer running a P2P program provides storage space, bandwidth and processing. As more people install and run the P2P program, more files are being uploaded and downloaded and more computers are participating in the file sharing process.

Here’s details on how a P2P program works. Let’s say you want to download a song (let’s also say this song can be legally distributed) and you’ve got one of these P2P programs installed on your machine. You start the P2P program and type in the name of the song you want in a search box. The program then goes out and looks for other users sharing that song. As users are found the song starts to download to your computer. As more users sharing the same song are found, additional connections are made (each connection is often referred to as a torrent) and the download speed to your computer increases. Also, as you download the song, you start sharing the song with others connected to your computer.

Popular songs and videos can have hundreds of torrents involved in a single download.

If you use P2P programs, you need to be very careful to only download content that can be legally shared. If downloading illegal content, you can be caught and lately some huge fines have been given out to violators.

Also be sure you are running up to date antivirus software and scan your system for spyware weekly. P2P networks can be used to spread malicious software.

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