tecznotes

Bits On Wheels is a Mac-only Bittorrent client. It's freeware (but not open source or public domain) and it looks like this:

It has the usual Bittorrent features, and runs a little faster than my other client, Azureus.

The neat thing that sets it apart is the 3D swarm view, shown above. Bittorrent works by enabling participants to self-organize into a swarm: a group of machines group-hosting a particular file at a given time. When you connect to a Bittorrent tracker, your client can coordinate with others also connected to that tracker. Machines with the entire file are called seeders; they share pieces of the file with machines seeking the file. It's akin to book printing through coordinated xeroxing: I'll do the first ten pages, you do the next, then we trade. Easy.

The 3D swarm view shows yourself in the center. Hosts you are connected to lie around the periphery: although a Bittorrent swarm can be a complex graph, the swarm view is self-centered. Hosts around the edges may be connected to each other, but that is not shown.

Each host is represented by a translucent box, whose filling represents the percentage of the file that host has. As you obtain more pieces of the file, your box slowly fills up to 100%. Connections to those hosts are shown as spokes on the wheel, along which data packets travel. Links are bidirectional (you can be sending pieces to a host that you are also grabbing pieces from), and data travels along the spoke at a rate representative of your connection speed. Speedy connections are immediately apparent, as are stalled ones.

The colored circular rail fills up with green as you get more of the file. The screen shown above shows how much of the file I have, and which parts. Each host-box also has a little pie-chart above it, for which I haven't yet found a satisfactory explanation. I'm guessing it shows a host's share ratio, the relative amount of data uploaded vs. downloaded.

The hosts are divided into seeders and leechers: seeders have a red background, and they are completely full. These are hosts that already have the entire file, but are continuing to share more. Leechers are on the blue background, and they are hosts seeking pieces of the file. When your client has successfully downloaded 100% of the file, the background becomes solid-blue: you no longer need to be connected to other seeds, because you yourself are now sharing the entire file.

The beautiful thing about Bits on Wheels is the way in which it makes this process visually coherent. The first few times I tried it, I was mesmerized for up to twenty minutes at a time, watching the connections speed up or slow down as hosts came and went.

I don't think I really grokked Bittorrent until I used this app.

The one thing I would change about it would be to add RSS awareness. Or, to remove the mandatory "where do I save this?" dialog at open-time so I can add my own commandline RSS parser onto it, without having to learn AppleScript.