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Torrent fundamentals

Torrent fundamentals

Saturday, 03 October 2009 07:13 |

Author: Arun Nair |

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BitTorrent popularly known as Torrent have become one of the most popular means of file sharing. Users can download movies, songs,games, softwares, ebooks and any file using a torrent. The flawless architecture of the BitTorrent protocol makes it so popular among the internet users when comapared to many other peer-to-peer (P2P) file sharing softwares like Limewire, Ares and morpheus. BitTorrent is likely to have no virus threats and vulnerabilities unlike Limewire which accidentally provides access to the "My Documents" folder if not configured properly.

I would like to make this article a kind of tutorial for those who are new to BitTorrent.

What is BitTorrent ?
How to download files using uTorrent ?
How to create a Torrent ?
How to send large files using a torrent ?
List of popular websites to download torrents
List of BitTorrent Clients

What is BitTorrrent ?

BitTorrent is a protocol for peer-to-peer (P2P) file sharing. Peer-to-Peer file sharing means sharing files between PCs and not uploading a file to a server and then downloading it from a server. For example,if I want to copy a file, say a movie of size 750 MB from Mike's computer who is living in Canada, I can directly download the file from Mike's computer without him uploading it on the server. Now if another person say Keith who is living in the UK has the same movie, I can download a part of the movie from Mike and the rest from Keith. So with BitTorrent, a file is virtually split into a number of tiny pieces and different pieces are downloaded from different computers that has the same file. In the above example, lets say there is a third person named Adam who has the same movie. The entire movie of 750 MB is virtually broken into say 750 pieces with each piece of around 1 MB and few pieces are downloaded from Mike's comptuer, few from Keith's computer and the rest from Adam's computer. The size of the piece can be changed by the user.

0016_bittorrent

Now the question is how does my computer know how to arrange those 750 pieces ? This is where a torrent file comes into play. A torrent file keeps track of the pieces that are downloaded from each computer, their order to be arranged and the remaining number of pieces to be downloaded. You have to load the torrent file into a software called BitTorrent Client. There are many BitTorrent clients available in the market. My favorite is uTorrent. Click here to see the list of BitTorrent clients.

Peer: Each comptuer involved in sharing a file is referred to as a Peer. In the above example, My computer and Mike's computer are 2 individual Peers.

Seeder: The person (computer) who serves or contributes the file is known as a seeder (also known as seeds). In the above example Mike, Keith and Adam are the seeders.

Leecher: Ther person (computer) who downloadd the file is known as a leecher. In the above example, I'm the leecher.

How to download files using uTorrent ?

To download a file using a torrent, you first need to download a BitTorrent client. As I mentioned earlier, uTorrent is my favorite. It is very small and does not require any installation. The below steps will guide you on using uTorrent to download a file.

Download uTorrent and save it to any location on your computer, preferably desktop.
Download the torrent file that you need. (Click here to see a list of torrent websites.)
Now double click the file uTorrent.exe from the location where you saved it in the first step. uTorrent opens up, as I mentioned earlier it does not require any installation.
Click File -> Add Torrent
Select the torrent file and click Open.
Click the "..." button to select the location where you want to save the file on your computer and choose the files that you want to downoad by clicking the check boxes as shown in the below picture.
Right click on the torrent file to see set the upload and download speed limit and to check the properties of the torrent file.

How to create a Torrent ?

In this section I will explain to you how to create a torrent if you want to send large files to someone.

Open uTorrent and click File -> Create new torrent.
Click on 'Add file' to add a single file or 'Add directory' to add a folder. Enter the list of trackers you need. Trackers are servers that coordinate the communication between the peers. A tracker will update the peer with information like which peers are online, what are the newly added peers, etc. There are 2 types of trackers - private tracker and public tracker. A private tracker requires you to sign up for the webiste which provides you the tracker where as a public tracker does not require a login. The following are few of the public trackers that I use.

http://tracker.thepiratebay.org/announce
http://tracker.openbittorrent.com/announce
http://www.sumotracker.com/announce
http://denis.stalker.h3q.com:6969/announce
http://tracker.mightynova.com:4315/announce
http://open.tracker.thepiratebay.org/announce
http://tracker.prq.to/announce
Do not click on "Private Torrent" unless you are going to use a private tracker.
Select start seeding and click "Create and Save as" to save the torrent.

How to send large files ?

This is a question that people ask me very frequently. How do I send a large file to my friend. Usually when you want to send a movie or a software which is very large in size, you can use torrent to send it. So what do you have to do ?

Create a torrent for the file that you want to send as described above and start seeding it.
Send the torrent via email or IM file transfer (like gtalk or Yahoo messenger) to the person who wants to receive the file.
Have them to open the torrent in uTorrent or any other BitTorrent client.