Technics and Techniques
In the Beginning…
File sharing is constantly pressing the boundaries of technology. There is a quest to find the fastest way to reliably distribute the greatest amount of data, without getting caught. The other major goal of these fringe programmers is to do it for free. What good is downloading if you have to pay for it? Prior to these progressives, file downloads were strictly from server to client. These are how web pages are displayed, and files are downloaded online. Your computer goes out to a server which is set up to handle requests. It then initiates the transfer of data directly from it to you. This technology that has developed in the spirit of file sharing has created an internet that is more malleable, and decentralized.
The Notorious Headphones Cat
To talk about the technology behind file sharing, it is necessary to delve a little into the history of it. Napster will always be remembered as the grandfather of illegal downloading as we know it, good old 1999. People had of course been swapping files before this. Up till Napster, there were much more difficult ways of getting what you wanted. People had adapted IRC, a chat program created in 1988, to trade goods. It was not nearly as easy and widespread as what was to come. Napster relied on what is called “first generation” technology. Back in these old days, each user’s client would send a list of their files to a central server. Any search you sent out would talk to this server, and in turn pulled off everybody else’s lists. This put a few restrictions on downloading. You could only transfer from one person, which limits speed. Second, the Napster server's list of files proved to be the legal downfall of our first P2P technology.
The Birth of the Swarm
So the next generation has two items to conquer; speed and decentralization. The newcomers in P2P created an environment in which data transfers are non-linear, and can have multiple sources. The multitude of users all sharing the same files started to be called a swarm. The great part about this is that these sources can freely go on or offline, with no noticeable effects. As long as the swarm still has enough people sharing, individuals going off the grid is not important.
The year of the Space Odyssey 2001 saw the birth of KaZaA. One month after its introduction, Napster pulls the plug. So with users forced to change, Kazaa became the most popular client around. It was also popular due to the introduction of some new technology. The main changes that the normal userwould see is the ability to resume downloads, and to pull files from multiple sources simultaneously, and all forms of digital media were up for grabs. This is when P2P started to realize its potential to be a completely non-linear network for transferring files. The other changes were to how the lists of files were stored. Remember, Napster was shut down because the owners had access to the list of files. Kazaa wanted to avoid this of course, so they made the file lists completely independent of the company, all stored on individual user’s computers. These nodes all stored sections of the list, andcommunicated amongst each other creating a searchable and decentralized database.
There were three flaws with the program that the developers didn’t understand during the creation. The first was the advertisements and spyware, as seen in the screenshot. Once word gets about that kind of activity, people start to hate your product. Second, the technology used to download from multiple sources simultaneously only worked on the goodwill of users. If somebody like the RIAA felt like sending out corrupt data, it was fairly easy to do. All they needed was a file of similar properties, but not exactly the same. This put Kazaa lower on their reliability marks. The other thing that brought them down was getting sued every other day. Eventually in 2005 a court in Australia ruled the creators of Kazaa responsible for their user’s actions, because they “authorized” their users to infringe on copyrights.
Enter the Torrent
So now there were two new challenges, one of technology, one of sticking it to the man. BitTorrent has so far managed both of these goals, to some extent. This file sharing system is different than other protocols, in that it was not intended for illegal activities. The author, Bram Cohen, originally built the tool for a music community called etree.org. This site only shares legally distributable recordings and those authorized by the artists. This means that BitTorrent is safe from industries forcing the author to destroy his work. He made it in good intention, and never uses it illegally nor endorses that use.
There is a weak point to this system though, it is not perfect yet. In order to initiate a download, you have to know who your peers are; this is handled by a tracker. This tracker has a web presence, and is very blatantly visible. These sites can be and are shut down by industries or governments. Suprnova.org, Finreactor.com, Elitetorrents.org, the list goes on. Cohen is working right now on a way to bypass these web servers, making BitTorrent entirely dependant on its swarm of users.
BitTorrent is technically brilliant. This is generation three in the evolution of P2Ptechnology, and the best of today. The man behind it is said to have a form of autism, which makes him obsessively try to solve complex problems. The nature of the program forces users to share what they are downloading, tit for tat as Cohen put it. This makes everything download faster, as there is nobody taking advantage of the systems. The protocol also has a corruption check that makes sure the received file is an exact copy of the original. I don't presume BitTorrent to be perfect, but it is getting closer.