All posts by vanessa

A New Spirit?

Perhaps a new spirit is rising among us. If it is, let us trace its movements and pray that our own inner being may be sensitive to its guidance, for we are deeply in need of a new way beyond the darkness that seems so close around us.

— Martin Luther King, Jr.

From Al Gore’s Martin Luther King Day address, via The Raw Story. One more teaser, then you’ll have to read the rest yourself.

Fear drives out reason. Fear suppresses the politics of discourse and opens the door to the politics of destruction. Justice Brandeis once wrote: “Men feared witches and burnt women.”

It is simply an insult to those who came before us and sacrificed so much on our behalf to imply that we have more to be fearful of than they. Yet they faithfully protected our freedoms and now it is up to us to do the same.

Happy Martin Luther King Day!

P2P Multicast Feed Distribution with FeedTree

I’ve been interested in P2P approaches to syndication for a while, and FeedTree is a research project offering one solution to the problem. This poster provides a good overview of how the system works. A more detailed technical description is available here.

In a nutshell, an HTTP proxy on each reader’s machine becomes a node in a Pastry overlay network. The node then joins a multicast tree for each subscribed feed, and updates are pushed to all subscribers using the Scribe group messaging protocol. Feeds are either directly published into the network by FeedTree-aware publishers, or are polled by some subset of interested nodes on behalf of all the others. A digital signature can be added to the feed by the publisher to prevent spoofing. Configuring your feed reader to use the proxy is quite simple, in most cases, and then you’re set. Publishing takes a bit more work to set up, at present, but I don’t see why you couldn’t eventually wrap a simple GUI/wizard around this process to make it painless.

I had every intention of giving FeedTree a go before posting this, but here’s the rub: “Step 2: Be sure that your computer is accessible from the Internet on port 29690.” Well, I could have done so, but it would have required re-configuring my entire home network first. I couldn’t justify the effort just to try out one piece of software. I suspect most software end-users either wouldn’t have the permissions necessary to meet this requirement; wouldn’t know how to go about it; or, like me, wouldn’t be sufficiently motivated to take the trouble. Alas, methinks this is a showstopper if FeedTree is to become anything more than a research project. That’s a shame.

The “not even on the napkin” approach I had in my head was based on JXTA, of course (a JXTA-based solution would remove the need to hack your network, making it end-user friendly, for one thing.) Rather than pushing updates to subscribers, I envisioned peers using the Discovery service to advertise and search for feeds. To wit: rather than polling feed A every hour, the peer would first try to discover a copy of the feed less than one-hour old. If none could be found, only then would it poll feed A’s source, and publish an appropriately time-stamped advertisement for other peers to discover. The FeedTree “push” approach provides for more timely updates than this if the publisher injects the feed directly into the FeedTree network. Also, I can see the potential in my scheme to end up with “too many” peers polling for a feed, if their desired polling frequencies are too much out of synch. This requires considerably more thought. FeedTree also allows multiple “volunteers” to poll a feed in order to maintain a certain level of timeliness, but the overall polling frequency is better controlled.

Anyway, I’m glad to see someone doing real work on alternatives to uncontrolled HTTP polling for feeds. Ultimately, though, I don’t see anything gaining wide usage that isn’t dead-simple to install and use, without regard to network topology. (Imagine that you did get FeedTree installed on your laptop at home. As soon as you take the machine to the office, or to school or wherever…you’re hosed. *sigh*) And without mass adoption and seamless mobile usage, no solution will be able to make any real dent in the scaling problem.

The $5-billion Rip-off

With regard to America’s illegal collection of $5-billion in tarrifs on Canadian softwood lumber, and their refusal to abide by the NAFTA rulings against them, Bloc Québecois leader Gilles Duceppe today put it with characteristic bluntness:

The American strategy is very clear. They want to gain time. They know they’ll lose in the end, but if the winners are dead—I mean, it’s not a win for us.

Well said. Canadians (specifically, the Mulroney Conservatives) foolishly entered into an agreement with the U.S. believing that the world’s most belligerent bully would abide by its signed agreements. Now that it’s clear to the entire world that America explicitly rejects the rule of law where the law infringes on its interests, maybe our politicians won’t be so gullible in future. I wouldn’t bet my life on it, though.

Moral Values

They are explicitly saying, for the first time, that the intelligence community should have the ability to treat prisoners inhumanely.

Apparently the willingness to torture other human beings is a sign of superior morality. With independent investigations into prisoner abuse also under veto threat, it seems those most militantly evangelical about democracy find transparency of government unthinkable. I’ve never been more disgusted in my life.

Network Visualization

I mentioned to someone the other day that I was a visualization junkie (long-time readers of may have noticed). Coincidentally I discovered a site that catalogs visualizations of complex networks: What’s nice is that you can suggest projects to add to the existing database, so this resource should continue to grow and remain fresh over time. Another current favourite is information aesthetics, a frequently updated blog highlighting information visualization in general, with many examples of networks. These are more than just eye candy, but it doesn’t hurt that the pictures are pretty.

The Empire of Reason…

…has fallen. But Al Gore’s still making some sense. This time, he laments that knowledge and ideas no longer mediate between wealth and power in America–thanks, in large part, to the nature of the television marketplace. I only wish he’d expanded on the bit at the end about the comparable threat to the Internet. As Jonathon Schwartz recently remarked, “the best thing about the internet is it doesn’t have an editorial policy”. Maybe we should not be so quick to take that for granted.