23 Feb 2003 raph   » (Master)

Crowd counting

I've been following the various crowd estimates for the peace marches and demonstrations in San Francisco. Traditionally, it's very much an inexact science, and estimates vary widely.

For the last march, the SF Chronicle did something very cool: they took high-resolution timestamped aerial photographs, measured them, and posted them to the Web. Surprisingly, this count (65,000 at the 1:45pm snapshot) is considerably smaller than the consensus estimate (200,000, including people who left the march earlier or joined later).

In the grand scheme of things, the exact number marching is not that important. The Jan 18 one was an amazing expression from the people, and my friends who were at the Feb 16 one tell me that it was even more intense. It's not just San Franciscans, and it's not just Americans. People from all over the world have expressed themselves.

Even so, the wide range of estimates, and the variations in the reporting, illustrate the impact of viewpoint on what should be, after all, a fairly easily quantifiable, objective truth. We are being asked to evaluate the risks of going to war against the risks of not going to war, based on data that's at least an order of magnitude fuzzier than the simple question of how many people were on the streets of San Francisco. This is not easy.

I am not impressed with the International Answer people's response: `"Oh my word. Come on, that's ridiculous," said Bill Hackwell, spokesman.' It's possible he was simply quoted out of context, but I'm curious to know exactly what he thought was ridiculous.

I am passionately anti-war, even more passionately anti this war, but most deeply pro-truth. The Chronicle showed how seat of the pants guesstimating can be replaced, using a bit of technology, with hard data. I think this is progress, and fervently hope that we see more of it.

Codecon, day 1

I just got back from the first day of codecon and the Google-sponsored speaker reception afterwards. I was expecting it to be intense, but misunderestimated exactly how so. I met a lot of people, including old friends, more than a few cypherpunks, people I know online but met for the first time in person, and people I've been wanting to meet for a while. There are lots more people I didn't get a chance to really talk to; hopefully Monday.

Google is snatching up lots of smart people now. Spencer Kimball and Peter Mattis, of Gimp fame, are reunited once again (in fact, for almost a year, but I only just learned this). We had a very nice talk. They're both passionate about their work for Google. There's a reason why Google is able to provide such an amazingly valuable service, and it has a lot to do with the caliber of people working for them. I also enjoyed talking with Nelson Minar.

I also got to meet Larry Page, but felt like I kinda flubbed it. I also managed to just about lose my temper with John Gilmore arguing about what properties a next-generation DNS should have. This caught me off guard - I'm generally pretty levelheaded. I did apologize, and afterwards John said it was the best discussion about DNS he'd had in a while, so I guess not all is lost.

Vipul, of Vipul's Razor and now CloudMark, is very cool. I was struck by his depth of thinking, and his efforts to balance the technology, the social good (including free software releases), and the business. We talked about some of my more speculative ideas about how to use trust to defeat spam, and we really connected. He seemed to immediately understand the goals of my research, and I appreciated his perspective on deploying real systems for paying customers. I hope we get to work together.

Of the Codecon talks, my favorite was the panel on version control, with Larry McVoy (Bitkeeper), Greg Stein (Subversion), and Jonathan Shapiro (OpenCM). The conference organizers were nervous that it would degenerate into a licensing flamewar, but they needn't have worried. It was obvious that the panelists have a tremendous amount of respect for each other's work, and that the differences between these projects largely reflect differing goals.

A common theme was how difficult it is to get configuration management right. Everybody seriously underestimated how much time it would take to get a usable system going. Also, while there was definite agreement that CVS is broken and not easily fixable, there wasn't a clear consensus that most people a strong motivation to migrate from CVS to any of these new systems. CVS actually works reasonably well for most open-source projects, where you don't typically have lots of people pounding concurrently on one file. This kind of scenario is very common with paying customers, and Bitkeeper handles it well. Of course, any modern configuration management tool (with atomic transactions, robust tracking of changes, etc.) will be able to do a much better job than CVS, but that's not saying much.

I haven't decided whether the Web-based infrastructure of Subversion (particularly WebDAV as the client/server protocol) is a good thing or a bad thing. I think it depends a lot on what kind of user we're talking about. Windows and Mac can mount WebDAV right onto the desktop, which means that unsophisticated users can do version controlled operations just by clicking and dragging. For some applications, this is a huge win, because you can do things like back out unintentionally bungled changes, roll the clock backwards to get a consistent snapshot at some particular time, and so on. These are real problems that users have, and which the stock filesystem based implementation of folders doesn't solve.

For free software programmers, I don't see this as such a big win. Regarding integration with existing tools, people don't mount WebDAV folders from an Emacs mode, but there are Emacs modes for CVS. Then you have to deal with cruft like HTTP authentication (most Subversion deployment seems to use HTTP basic auth over SSL, which I guess is workable, but doesn't strike me as exactly the right way to do this).

In any case, I'm really glad that good work is happening in this space, and I'm hopeful that a really viable alternative to CVS will emerge. Subversion could well be it, but that's not a given, and in the long run, one of the other projects could turn out to be more robust, scalable, and overall a better match for the needs of free software developers.

Oh, and while I generally respect Larry's right to license BitKeeper however he wants, I did not at all get a warm and fuzzy feeling about it. In fact, it feels to me that his "free use" licensing terms are in fairly direct conflict with the spirit of the free software community. I am definitely not tempted to use it for Ghostscript or related projects. But if you're looking at BitKeeper as an alternative to Perforce or some other proprietary CM system, take a look; there's a good chance it'll do what you want.

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