Bittorrent

[Livewire]

Will someone explain how Bittorrent works in detail?

[gd_nimrod]

Its rather simple the whole idea, but i don't feel like writing too much so visit the site (no illegal downloads for you though )

http://bitconjurer.org/BitTorrent/introduction.html

[narked]

Bittorrent (bt) can be a bit confusing if you have been used to the user interfaces of the likes of Kazaa, Morpheus, Edonkey etc. There is no user interface with which to interact (e.g. searching for files). Plus bt creates dummy/false files on your PC and then fills them in randomly with real data. There is no linear download and there are no shared folders.

This is not in detail, but this is how bt works:

First thing you need to do is install the bittorrent software. The software will associate with the torrent files that you download

So where do you get the files you want?
You download a torrent. Get the torrents from sites that are hosting them. Then either use that sites download function or right click on mouse to 'save target as'. At this stage all you are downloading is a very small file that will tell your PC about the file you are going to download (e.g. a torrent file for downloading 3 cds may only be 180kb). The file will have the extension .torrent

You double click on the torrent file on your PC and bt often allocates the space required on your PC for the download by creating a dummy file on your harddrive (depends which version of bt you use). The allocating process is very memory hungry and depends on the amount of RAm and CPU speed u have. I recommend that you only start up one torrent at a time during this period (try opening 2, and then try doing something else on PC). This doesnt mean that you can't have more than one bt download going on at one time, just the allocating of the dummy files.

The torrent file also tells your PC where to connect to find other users that are sharing that file. That is it tells you to connect to a certain tracker. e.g. you download a torrent from "myfiles.com" that has a tracker with the announce url "myfiles/announce:6996" in the torrent. When you open the torrent it will connect to this tracker. Try opening a few torrents with notepad to check where they are connecting..

The dummy file is not real despite having the correct name, size in Mbs and extension (e.g. NewAlbum.mp3). So for a download of 3cds using one torrent what you start with on your PC shortly after starting bt is

CD1 =fffffffffffff CD2 =ffffffffffffff CD3 =ffffffffffffff

where f stands for false or dummy data.

You wait while bt states it is connecting to peers. Soon after (if the tracker your using works OK) bt connects to other users who have the file you want.

bt will then show you an upload and download rate and give an estimated time for your file to complete downloading. Yes, when your downloading your uploading it's the way the system works. Everybody gets a random piece of file (no download is linear) and you can guarantee somebody you’re connected to wants the piece you have and so you send it to them. The principle is referred to as 'file swarming' I think.

When you have an incomplete file you are a peer. You will be connected to lots of other peers who have incomplete files but they need bits from you (and vice versa) and so you all share, all downloading the bits you need, and uploading the bits others need.

The download then fills in your dummy file with real data. It does this randomly.

Leave the bt window open and after a couple of hours the files become

CD1 =ffRRffffffRff CD2 =RfffffffRRRfff CD3 =RRRffffffRRRRR

where R stands for REAL data.

Only when the all the false data is filled in will the files work properly.

You can stop the download at any point by clicking on cancel. To resume the download double click on your torrent again and select the file to resume.

You will know when the download is completed because bt will state "download completed" . Sometimes your download may be greater than 100%. This is due to the fact that bt has an inbuilt file checker. So if your download goes corrupt at that point it will redownload it overwriting the corrupt data. An error message will appear when this happens: piece failed hash check, redownloading.

When you have a complete file you become a seed. You do not download anymore but you upload to others. This way you ensure that there are enough bits of the file out there for others to make a complete.

So for the system to work please seed for a reasonable time after the download is complete, especially if there are not a lot of seeders online.

There is nothing more irritating than being the only seed online for 24 hours and then watching others complete and then go offline. For the original seeder the thought is 'Whats the point if others are unwilling to seed'.... potential rant coming on here....

So stay online, or if you disconnect for burning reasons restart the torrent to seed the file afterwards.

[admin]

Moved to P2P forum, as this is not related to digital video.

[baltique]

i tried bittorrent once.

i uninstalled when the BEST estimate time remaining return iu got was

55 days.

hehehehehe 55 days.. yeah right i'm going to spend 2 months downloading something.