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Workbench

Programming, Publishing, Politics, and Popes

The Sarah Connor's Great-Grandparents ChroniclesJanuary 1

David Friedman asks a good question:

Why does Skynet keep sending Terminators after Sarah Connor? Or even John Connor, for that matter? Why not go back a hundred years, or two hundred years, and kill her great grandparents? ...

Future John Connor would surely send a human into the past to stop the Terminator from killing his great great grandparents. So how does this person fight against a robot killer in an age when technology is so primitive, using his knowledge from the future? And how does the Terminator blend in? What materials does he use to repair himself when he's been damaged? Over time, as he gets more and more damaged, does he go from glistening machine to steampunk hodgepodge of parts?

I think there’s a lot of potential for period Terminator stories. Maybe there's an 18th Century Ireland Terminator trying to kill Johnny O'Connor before he comes to America. Or a Dark Ages Terminator who’s trying to kill Sarah the bar wench.

Peace Declared Between Myself and SwedenDecember 30 2008

As it turns out, Sweden did not intentionally declare war on my web server earlier this month. Programmer Daniel Stenberg explains how the international incident happened:

A few years ago I wrote up silly little perl script (let's call it script.pl) that would fetch a page from a site that returns a "random URL off the internet." I needed a range of URLs for a test program of mine and just making up a thousand or so URLs is tricky. Thus I wrote this script that I would run and allow to get a range of URLs on each invoke and then run it again later and append to the log file. It wasn't a fancy script, but it solved my task.

The script was part of a project I got funded to work on, that was improving libcurl back in 2005/2006 so I thought adding and committing the script to CVS felt only natural and served a good purpose. To allow others to repeat what I did.

His script ended up on a publicly accessible web site that was misconfigured to execute the Perl script instead of displaying the code. So each time a web crawler requested the script, it ran again, making 2.6 million requests on URouLette in two days before it was shut down.

Sternberg's the lead developer of CURL and

Using Treemaps to Visualize Complex InformationDecember 23 2008

I spent some time today digging into treemaps, a way to represent information visually as a series of nested rectangles whose colors are determined by an additional measurement. If that explanation sounds hopelessly obtuse, take a look at a world population treemap created using Honeycomb, enterprise treemapping software developed by the Hive Group:

This section of the treemap shows the countries of Africa. The size of each rectangle shows its population relative to the other countries. The color indicates population density, ranging from dark green (most dense) to yellow (average) to dark orange (least dense). Hovering over a rectangle displays more information about it,.

A treemap can be adjusted to make the size and color represent different things, such as geographic area instead of population. You also can zoom in to a section of the map, focusing on a specific continent instead of the entire world. The Honeycomb treemapping software offers additional customization, which comes in handy on a Digg treemap

Sweden Declares War on My Web ServerDecember 20 2008

Since 4 a.m. Friday, a computer at a Swedish IT company made more than 1.5 million web requests to my web site URouLette, which links to random web pages stored in a MySQL database. They're coming in at a speed of 38 requests a second. My MySQL database server can't handle that many requests, so by Friday afternoon Workbench and a bunch of other sites slowed to a crawl as the web server began belching black smoke. A massive crash was imminent.

The last time somebody did this, I used the Linux utility iptables to reject all connections from the offending IP address, which solved the problem easy peasy lemon squeezy. This time around, iptables failed with a "Can't open dependencies file" error.

My new friend in Sweden appears to be building a database of web addresses by requesting a URouLette script that loads a random web page over and over. This is both obnoxious and dumb -- all links on URouLette come from the Open Directory Project and can be downloaded in one file. I've reduced the severity of the problem by sending the same link with every request -- the company's home page.

Flooding a web server with this many requests constitutes a denial of service attack. In

Fixing Page Not Found Errors on FeedBurner MyBrand DomainsDecember 19 2008

Google has begun integrating FeedBurner, the service for publishing, tracking and promoting RSS feeds, into the rest of the Don't Be Evil Empire. As part of the move, FeedBurner users who are employing the MyBrand feature must make a change to the name service for their domain names.

MyBrand makes it possible to host your feeds on FeedBurner without losing any subscribers if you decide later to quit the service. I'm using it to host four feeds, including SportsFilter's RSS feed, on my own domains.

MyBrand domains used to point to feeds.feedburner.com, but they must be changed to a new subdomain of feedproxy.ghs.google.com. Each FeedBurner user is assigned a different subdomain. For SportsFilter, I updated it by revising one line in the BIND zone file for sportsfilter.com:

feeds IN CNAME subdomain.feedproxy.ghs.google.com.

The subdomain portion is based on your Google account.

This is supposed to be all that's required to make the move. Unfortunately, a giant honking bug in FeedBurner broke three of my four MyBrand domains this morning. Users received a 404 "Page Not Found" error when they tried to access my feeds. I found a workaround on Google's FeedBurner help site that explains how to fix