BitTorrent : Java Glossary

*0-9ABCDEFGHIJKLMNOPQRSTUVWXYZ (all)

BitTorrent  BitTorrent

BitTorrent lets you efficiently download large files from small websites. You need to install a plug-in first. The current version is 7.9.2.33876 Last revised/verified: 2014-09-12.

It tries to install a task bar and a trial of a registry cleaner as part of the install. They have nothing to do with BitTorrent. Be very careful with your selections or you will accidentally install them.
Firewall Download Sites
Installing Upload Sites
Vocabulary Recommended Downloads
Under the Hood Fahrenheit 9/11
Downside Links

Firewall

BitTorrent, to work efficiently, requires you to open up a range of ports, one per simultaneous download e.g. 6881..6889 or 10000..10003 through your firewall. You also need a fixed internal IP e.g. 192.168.0.2 for your router, which means you have to turn off DHCP on your BitTorrent machines. The BitTorrent docs are remarkably detailed, explaining how to do this for scores of router models. Had BitTorrent implemented UPnP-NAT(PC) and NAT-PMP(Mac) this would not be necessary.

Installing

It installs itself in X:\Program Files\BitTorrent\ without asking permission. It sets up an association between *.torrent files and itself, so that when you click open in the browser on a *.torrent link, it takes over the download.

You may have to set up as association for your browser to tell it to execute *.torrent files with the default handler.

When you click on a BitTorrent link, at first it appears nothing happens. Give it 10 minutes or so to get going.

Remember to configure BitTorrent with the ports you have opened up in your firewall.

BitTorrent is frequently updated, so you might check every month to get the latest software.

Vocabulary

BitTorrent documentation tends to be technical. You don’t have to understand it to use BitTorrent, but it will make you more comfortable if you understand the terminology and roughly how BitTorrent works.
BitTorrent peer
A user who is downloading a file with BitTorrent. He automatically acquires pieces of the file from other users who are also downloading the same file and failing that, he acquires them from the server. He also offers pieces he already has to other users.
BitTorrent piece
A file to be downloaded is broken into chunks called pieces. Machines downloading get a missing piece from other users who are downloading the same file who already have that piece, or failing that, from the server.
BitTorrent seed
A user who has already downloaded every piece of a file, and is sticking around out of altruism to rapidly provide those pieces to other users. Seed also refers to the computer that has a compete copy of the file to be server. It is the original seed that gets the torrent going. A seed is effectively another server. You become a seed automatically when the download finishes. If you don’t check periodically that the download has completed, you will act as a virtuous seed without even intending to. You might decide to act as a seed to help promote some political movie. The more people download, the more people become seeds. The more seeds, the faster still others can download it to help spread the good word. About the only drawback to being a seed is if you pay by the gigabyte for your Internet access.
BitTorrent swarm
The entire network of computers downloading and serving a file to download.
torrent
The flow of traffic between a group of users co-operating to download a file. There may be other such groups co-operating to download the same file, but they don’t communicate with the members of this torrent.
BitTorrent tracker
The central conductor. It connects computers looking for a given piece with computers that have it. The piece flows directly from user to user, not through the tracker.

Under the Hood

BitTorrent is a distributed system for distributing files. Instead of a central server providing all the bandwidth, existing customers pass files on to other customers. When multiple downloads of the same file happen concurrently, the downloaders upload to each other, exchanging bits of the file they already have, making it possible for the file source to support very large numbers of downloaders with only a modest increase in its load.

BitTorrent then is only useful to deal with a popular single download. It is not like Napster picking files off other people’s disks they have previously downloaded. Downloads are huge, typically an entire CD (Compact Disc) or an entire movie, usually 700 MB to 1500 MB. BitTorrent is especially popular for distributing Linux distributions as iso CD images.

The torrent files arrive and automatically unpack themselves into a set of files in a directory. However, sometimes they will arrive in compressed form, and you will need to run a decompressor such as WinZip, PkUnzip, WinRAR, 7Zip depending on the extension.

The BitTorrent algorithm works in such a way that the longer you stay connected the faster you download. This is because you have more of the file to trade with others for parts they have. Unlike ordinary downloads, nothing much happens for a long while after you first start the download. You start as a beggar, in BitTorrent terms a leech, and gradually work your way up in status to a seed when you have the complete file, and stay connected out of altruism just to serve others with it. This progression happens automatically. You don’t have to do anything other than stay connected.

Creating a bundle of files for others to download with BitTorrent is called making a Torrent. You can use the makeTorrent utility or the Make new Torrent option on the BitTorrent client.

To serve BitTorrent files, you need an ordinary HTTP (Hypertext Transfer Protocol) server that is configured to deliver the application/x-bittorrent MIME (Multipurpose Internet Mail Extensions) type. You upload the tiny *.torrent files to your website and reference them in your webpages. You also need to package your downloads as *.torrent files, containing embedded SHA-1 (Secure Hash Algorithm 1) digests to detect errors. You also need to start one or more trackers that orchestrates the flow of traffic between multiple people downloading your files. The trackers don’t know who has which pieces of the file. They just make introductions between the various parties downloading each file. BNBT and CBTT are names of common BitTorrent tracker toolkits. The peers announce what they have to each other. This requires a tiny amount of bandwidth. It is also possible now to use BitTorrent without a tracker server. There are two incompatible schemes for every client to act as a tracker: Azureus and BitComet. For trackerless torrents, you use the DHT option when creating the bundle. If you don’t have a server to run the tracker, you have to use the URL (Uniform Resource Locator) of the tracker server you plan to use, e.g. http://my.tracker.com:6969/announce. The tracker overhead of serving a torrent to the world is minuscule, about 1/1000 that of serving a single HTTP download. You still need to leave at least one seed running somewhere on the bundle. Oddly, any tracker could manage any bundle that contains its URL. The tracker server does not need to be configured with a list of bundles to serve. So likely you will use somebody else’s tracker server.

There is a requirement to set up an endlessly-running dummy seed downloader for each file that has also has a complete copy of the file. This is needed because the tracker does not have a copy of the bundle. The way files are served with BitTorrent clients. There is no special way to serve the master copy.

The net result is, you can serve BitTorrent from your website without anything special other than setting up the MIME type for .torrent files to application/x-bittorrent. You need a PC (Personal Computer) dedicated somewhere, running client BitTorrent with all your bundles.

The BitTorrent docs tell you mostly how it works inside not how to use it, which is pretty confusing to a newcomer. The newbie does not understand that all this talk of leaching, sharing and tit for tat, has nothing to do with his behaviour, just a model of how the program works inside and how it works to combat pirates using the same protocol.

Unfortunately, BitTorrent files don’t seem to come with a built-in synopsis of what the file is. You have to download the whole thing to find out what it is.

There are a number of BitTorrent client implementations. The official one forgets your download directory and makes you navigate to it every time. It does not tell you anything about what other clients are doing or even if there are any.

BitTorrent is quite a bit slower than ordinary downloading, because your download speed is limited by other ordinary users upload speeds. Some may even be on dial up. The torrent is in the aggregate flow. The paradoxical is that the more people download a file at once, the faster the downloads go. BitTorrent works because altruistic (or perhaps just inattentive) people leave downloads running after they complete, donating upload time to others. Usually you set BitTorrent going and then go to bed and come back in the morning.

BitTorrent can take quite a while to get started before it picks up steam. right click Start Download, then be patient. It can just sit there apparently inert for 10 minutes or so before it gets rolling.

Downside

BitTorrent is designed to distribute very large files to large numbers of people. It is not suited for distributing small files since the start up time is so long and there is so much fussing with both *.torrent and *.zip files, and running a seed server for each file, and requiring special download software. It is designed for distributing files to the general public; it has no built-in provision to deal with limiting access, though you could limit access to the contents of the original *.torrent file, which might not be that hard to guess. BitTorrent is based on TCP/IP (Transmission Control Protocol/Internet Protocol). TCP/IP presumes you have a good connection where few packets get lost.

The frightening weakness of BitTorrent is an 8 hour download can fail if the master seed PC goes south or its owner turns it off or the tracker server shuts down. You don’t even get a message that this has happened, though there are some hints in the log. If you leave the download running it might eventually recover when a seed, not necessarily the original owner’s, restarts. A partial download is not useful since it contains holes, not just the tail chopped off.

*.torrent files don’t contain a proper description of the bundle. You often have no idea what platform or format the file is. You don’t even know if is audio, video, software, or text. The directory of files gives some hints, but it needs a proper descriptor with standard fields to facilitate searching.

You have to download the entire bundle before you know if you have got what you wanted. You may have totally the wrong thing or a file in a format your machine does not support. There need to be a scheme to include a trailer or sampler than is downloaded first.

BitTorrent is very slow to get started. The problem is it is very concerned about counterfeit BitTorrent clients behaving in a greedy fashion and in the process, it wastes a lot of time, though not bandwidth.

BitTorrent client won’t tell you if it has successfully negotiated the firewall and what ports it is using. Perhaps other clients do.

Often there are several possible trackers to use. There should be a way to automatically join the one with the most activity.

BitTorrent Download Sites

Torrent Download Websites
Site Cost Notes
Linux Tracker free torrents relevant to Linux
OneBigTorrent free host Noam Chomsky’s torrents among other things.
The Pirate Bay free the dark side of BitTorrent — distributing pirated copies of movies and music. It gets shut down frequently. The resurrect under a slightly different name.
Torrentz free a search engine for torrents

The nice thing about this service is it links you to free downloads. Others often try to trick you into signing up for pay services.

BitTorrent Upload Sites

These sites let you distribute your own files to the planet. You might create your own Internet radio or TV show, promote your band, stand on a soapbox, distribute huge software downloads. There a lot of copyrighted material there as well, including pornography. You can download from the following sites as well as upload.
Torrent Upload Websites, use their Tracker
Site Cost
MiniNova free
PirateBay, TorentPoranl, TorrentSpy and TortentR shut down, frightened by the legal ramifications.

Fahrenheit 9/11

dvd cover recommend DVD⇒Fahrenheit 9/11to dvd home
DVD
byMichael Moore
birth1954-04-23 age: 60
asinB00005JNEI
upc043396086708
This documentary on DVD is fun, entertaining, and light. It allows Bush to hang himself simply by showing footage of him. Viewing this film is the fastest way to disabuse someone of their notions that Bush is an admirable guy. I strongly suggest you buy a copy and show it as many people as possible as soon as possible.
Chinese flag amazon.cn amazon.co.uk UK flag
German flag amazon.de amazon.ca Canadian flag
Spanish flag amazon.es amazon.com American flag
French flag amazon.fr powells.com American flag
Italian flag amazon.it Barnes & Noble American flag
India flag junglee.com other stores UN flag
Greyed out stores probably do not have the item in stock
Michael Moore has given his blessing to pirating his movie Fahrenheit 9/11 with BitTorrent. The following links will be useful if you want to get a copy: After download, you burn the movie onto a DVD (Digital Video Disc). You will need access to a DVD burner, and a DVD player.

Disadvantages

BitTorrent tries to install bits of crap including Conduit search and a registry scanner when you install BitTorrent. There is BitTorrent client built into the Opera browser, so you don’t need BitTorrent itself.

Azureus: an opensource Java BitTorrent client
BitComet: Chinese BitTorrent client
BitTorrent
BNBT: tracker server
Bulk File Distributor Student Project
ByteMonsoon: tracker server software written in PHP
EasyTracker BNBT: tracker server
How to use BitTorrent to download Ubuntu
Internet Radio Project
Napster
Opera
Opera: the Opera browser has BitTorrent support built-in
peer to peer
SAX: student project
Tomato: Mac BitTorrent client
µTorrent: tiny BitTorrent client

This page is posted
on the web at:

http://mindprod.com/jgloss/bittorrent.html

Optional Replicator mirror
of mindprod.com
on local hard disk J:

J:\mindprod\jgloss\bittorrent.html
logo
Please the feedback from other visitors, or your own feedback about the site.
Contact Roedy. Please feel free to link to this page without explicit permission.
Blog
IP:[65.110.21.43]
Your face IP:[54.83.243.107]
You are visitor number