what is a torrent?

[Hitokiri_Shinobi]

what is a torrent any way?????

[stos289]

Well, first of all, really cool sig. However, your going to have to remove it because the rules state that no animated avatars or sigs are allowed. Sorry about that. Now, a torrent is a small chunk of a certain file. Lets say you download Naruto 1.torrent. That is a tiny piece of an episode of Naruto. When you open it with Bittorrent, the piece looks for other pieces that are being uploaded. Eventually when the download completes, all the pieces are together and you have the file. Hope that cleared that up.

[Barumonk]

To be less blunt, a .TORRENT file contains values needed for a BitTorrent client to connect to other users so it can download and upload pieces. Each file is split up into very small pieces, and the .TORRENT file contains the checksum for each piece. A checksum is a virtually-unique value for a specific data chunk, in other words the checksum for the word "hey" can never be the same as the word "hello", or any other word for that matter. It uses the checksum to make sure that it has the *exact* same information as the original file, since if any of the information changed then the checksum would be different.

The .TORRENT file also contains the announce url, which is the location of the tracker. A user's BitTorrent client will tell the tracker "I need piece #213", and the tracker will give that user a list of people who have that piece. Once you finish downloading that piece, you tell the tracker "Ok, I have piece #213! Now I need piece #186". This will repeat until you have the entire file. The tracker will remember which pieces you say you have downloaded, and then when someone else asks for that piece then the tracker will tell that person that you have that piece, and they download that piece from you.

Among other things contained within the .TORRENT file, or what may be contained, is:
A list of alternate announce urls. (Optional)
A comment by the creator of the .TORRENT file (not necessarily the file your downloading). (Optional)
The date that the .TORRENT file was created. (Optional)
How many files are contained within the .TORRENT file.
If there are multiple files, then the location of those files.
The entire file's (or every file's) length.
The number of pieces.

There is more information, but most of it isn't directly related to the .TORRENT file itself. If your still curious then look at http://wiki.theory.org/index.php/BitTorrentFAQ for more information.

[Darkflare]

to make things simpler, a checksum is like an ID for a piece of data. a certain value corresponds to a certain piece of data. no two can be the same. the torrent has stuff that tells the bt client what to do to download everything.

[Barumonk]

(Note that this really has nothing to do with the original post, just clarifying something for the hell of it) Err >.> Checksums can be the same, reguardless of how big they are, its just extremely rare outside of CRC16/32 to find the exact same checksum. A checksum is just a number, for the sake of not going into giant numbers lets start with CRC32. A CRC32 checksum takes up 4 bytes, 0xFFFFFFFF. That is simply a number, its max value is 4,294,967,295. That means that if you line up 4,294,967,295 files plus 1 extra file, then atleast 2 files will have the same checksum. This is true no matter how many bytes the checksum contains, once the maximum value is reached, then any additional files will make the checksum useless to some extent. SHA-1, the checksum that BitTorrent uses can go upto 2048 bytes as far as I know, however BitTorrent only uses 20 byte checksums.

[Darkflare]

close enough i/expressions/face-icon-small-tongue.gif i must have misunderstood something or misread something when i was reading about checksums a little while back. thanks for the clarification