Hi, vaithy
I think the explanation is quite simple... anyway...
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Torrent Files
Torrents, typically ending in ".torrent", are control files for the peer-to-peer file sharing technology called BitTorrent.
It's actually pretty cool technology that really just boils down to another way to download files. So really, you just use .torrent files to download other files.
BitTorrent is a distributed file distribution technology. When you download a file using BitTorrent, the file is actually broken up into chunk that your BitTorrent client program then downloads and reassembles into the final file as the pieces arrive. To over-simplify, what makes it interesting are two things:
The different chunks you download can all be coming from different machines. A BitTorrent client will connect to many other BitTorrent clients and download several chunks at once, in random order. In the long run this makes the protocol fairly efficient, and very nicely scalable - the more BitTorrent clients that are serving up a given file, the faster other clients can download it.
As you start collecting chunks of the file, your BitTorrent client will start making those chunks available for downloading to other BitTorrent clients, and will become a part of the peer-to-peer file distribution network.
The ".torrent" file is simply the bootstrap for this whole process. You download that normally, for example in your web browser, and then it is read by your BitTorrent client. It has the information that the BitTorrent client then uses to begin to locate other BitTorrent clients that are serving up the file you're interested in.
"It's actually pretty cool technology that really just boils down to another way to download files."
Example- Let's say you've discovered that some Open Source Software is available via a torrent. You download the ".torrent" file, and open it in your BitTorrent client. It then goes out to the internet, locates other BitTorrent clients that are serving up that file, and begins downloading all the various chunks until it has a complete copy of the file.
Difference between Magnet Links and .torrent
When you download a torrent file, you’re essentially downloading a small file that contains information on the larger files you want to download. The torrent file tells your torrent client the names of the files being shared, a URL for the tracker and more. Your torrent client then calculates a hash code, which is a unique code that only that torrent has — kind of like an ISBN or catalogue number. From there, it can use that code to find others uploading those files, so you can download from them.
A magnet link does away with the middleman. A magnet link is essentially a hyperlink containing the hash code for that torrent, which your torrent client can immediately use to start finding people sharing those files. Magnet links don’t require a tracker, nor does it require you to download a separate file before starting the download, which is convenient.
A magnet consists of several parts:
magnet: (This is the magnet link identifier)
?xt=urn:btih: ( Defines a Bittorrent Info Hash, the Edonkey identifier would for instance look like this xt=urn:ed2k: )
5dee65101db281ac9c46344cd6b175cdcad53426 (The content hash)
&dn=name (The name of the file)
The full magnet link would look like this
magnet: ?xt=urn:btih:5dee65101db281ac9c46344cd6b175cdcad53426&dn=download ( There is is no space between ": ?" TDF treats it like a smiley )
Here is a excellent explanation if all this, Read it ( Strongly Recommended )
http://torrentfreak.com/bittorrents-future-dht-pex-and-magnet-links-explained-091120/