But open source protocols in hackerland are fragile, there's a danger they fragment. And that seems to be happening with BitTorrent. I'm seeing torrents now with three kinds of tracking: the standard TCP tracker, UDP tracking, and trackerless. Which client works for all?

I'd been wondering why my torrent downloads recently weren't working. I think the problem is that Debian testing installs bittorrent 3.4.2-4, which doesn't seem to work very well. The 4.0 .deb from bittorrent.com works better.

10,000 people grabbing a 2 gig file is a lot of video on demand. Still, crappy quality. The one sample I saw had decent sound and the picture didn't shake but the colour was all washed out. The cinematography in ROTK is so beautiful $9 is a bargain.

Using the same /scrape URL that torrentspy uses, I tracked the BitTorrent activity of a 1.2G copy of the movie over the last week (from the day after movie release).

More inside ...

Good things it does:

• Displays seed, leech data like TorrentSpy
• Saves .torrent files
• Resumes downloads on startup
• Gives unsorted view of downloaded pieces
• Fast resume algorithm based on piece files
• Simple bandwidth configuration
• Excellent documentation

BitTorrent has a flaw; it's easy to get 99.9% of a file and never complete because no one has the last few bits. The main use of TorrentSpy is to see if any client has a full copy. Unfortunately it can't detect if the whole file is out there, but no one client has it all. With the average torrent having only 20-30 clients I guess that's unlikely.

I don't think any of this would be a huge business, but it'd be enough to fund BitTorrent development. Customers: anyone hosting downloads of more than 10 megs.

Game demos are starting to be distributed via BitTorrent. Perfect use: lots of enthusiasts, giant files (200 megs is common). Places to go for legitimate BitTorrent game files: GameTab, 3dgamers. Try out the cool Tron demo!

I did a survey from three sites of dubious legality: torrentfiles.com, animetorrents.com, and torrents.co.uk. In 870 .torrent files I found 32 different trackers. The top 4 trackers accounted for 75% of all the files. Not a lot of diversity. Of course, my sample is biased.

I was also interested in how folks use the BitTorrent metainfo. About 80% of all files use a piece length of 256k, followed in popularity by 512k and 1024k. I also found a bunch of unofficial tags: path.utf-8, creation date, comment, and md5sum.

I'd like to do a more formal survey with a wider sample; this torrent search engine claims 8200+ files.

info                
  length          41470132
  piece length    262144
  name            Halo2_E3.wmv
  pieces          [159 SHA-1 values]
announce        http://news.gametab.com:6969/announce

But it's easy to criticize; BitTorrent is still awfully cool.

BitTorrent is pregnant hackerware - it works great but is still poorly documented. And the apps aren't well integrated. Someone could build a killer tech company out of it. Some extra info is available in Brian's BitTorrent FAQ and the BitTorrent Wiki.

Me, I started downloading by doing