Last Saturday we came back from a week in the snow in the French alpes. Luckily for us a fresh batch of snow (the first of the season) had fallen a couple of days before we left the Netherlands. So we actually had a chance to do some skiing. [And after that got a little boring on the one run that had decent snow left, we tried a little first-time hurtful snowboarding.] Besides the usual business of racing down, waiting for the lift, falling out of the lift, and working our way up the mountain, I had some time for a couple of photoshoots. Overall this was delightful; the weather was great all week (mostly clear skies) and the light reflecting on the snow makes for fantastic light conditions. [The only downside was the detection of dust that must be on the sensor of the EOS30D, since I established it wasn’t on the lens; still have to find out how to clean that. Luckily, photoshop comes to the rescue; a free cup of coffee for whoever finds spots on any of these photos.] Here are some samples from various genres.


the end is where it starts



after the crash a mountain of ice (kekker)
after the crash


And Janine took quite a decent portrait of me:

For more see the photoset on flickr or the one in the photo department.

buildfarm bokeh

Executive summary: new hardware for buildfarm at Delft University of Technology has arrived.

In the TraCE project at Utrecht University we had incrementally constructed a buildfarm for continuous integration of Stratego/XT and related software projects. With two Intel-based PCs as the basis complemented with spare machines scavenged from the ST student lab the buildfarm now continuously builds, tests, and releases the software of over 50 projects (packages).

While we started with Merijn de Jonge’s Unix shell-based autobundle software, it soon became clear that dealing with the variability of software building — building against different versions of libraries, with different compilers, on different platforms — required a more scalable solution.

The Nix software deployment system developed by Eelco Dolstra for his PhD thesis turned out to be the perfect tool for constructing a buildfarm. Nix builds software components in isolation and can naturally deal with variability; that is, different versions of the same component can peacefully co-exist without interfering. Furthermore, the functional language that Nix provides for describing component compositions supports the parametric description of a component. That is, the build of a component can be defined as function of it dependencies. Thus, the same function can be used to build different versions of the component.

The Nix buildfarm is basically a script that continuously runs a Nix function to build a software project from the trunk of its version management repository; when a change has been committed or one the dependencies is changed, the project is built again. The result is either a new source and/or binary release in case the build succeeded, or a log of build showing where the build went wrong.

buildfarm wires

With the move to Delft, a plan emerged to do it bigger and better. That is, to build a mega buildfarm for supporting many different (types of) software projects with integrated support for version management, issue tracking, continuous integration, and release management. I would like to provide such a setup as a service for hosting open source and academic projects. Especially the build and release management aspect of the Nix buildfarm would greatly enhance the software engineering of such projects. (Also of many industrial projects is my impression, but they’d have to pay for the service;) We have submitted a proposal to fund the hardware and humanware to build the foundation of such a megafarm.

5 buildmachines!

In the meantime, it seemed like a good idea to start with a small buildfarm — a bootfarm so to say — in Delft to support at least the activities of the Stratego/XT project, and possibly other projects in department. The Software Technology department generously provided us with resources to set up such a bootfarm, and now the hardware has actually arrived and has been mounted in a very professional looking rack.

and two macminis

Here’s what we have: 5 Intel Core 2 Duo DualCore machines with 1GB RAM , 2 Mac minis with 1,83-GHz Intel Core Duo-processor, another Core 2 Duo a UPS to deal with spikes in power supply, a console with integrated monitor and keyboard switches, a rack with room for a couple more machines .

Here’s what we’re going to do with the goodies. The five Intel machines and the two MacMinis (also Intel) are going to be used to crank at building hundreds of software packages. Using virtualisation we should be able to run builds on multiple operating system distributions. The hardware portfolio is limited to Intel at the moment. This is motivated by the observation that the majority of our userbase is using this platform. With the adoption of Intel by Apple, even the motivation to support the PowerPC is decreasing rapidly.

and a webserver

The webserver will be used to run a number of virtual servers, including a subversion server for version management, a JIRA server for issue tracking, wiki servers for project sites, a mailinglist server, the buildfarm supervisor, and the release management server.


At POPL 2007 I met William Cook, who is working on model-driven engineering. We had a good talk on modeling web applications.

nice is not bad

Nice (France) is not bad, once you down a bunch of sugar to boost the senses. I walked around town after arriving in the afternoon. It was a rather bland day today, even in nice (france), and I didn’t see much to shoot up. The coke did wonders, at least for the inspiration. I’ll have to see if the results are any good. I’m in town to attend the PEPM and POPL conferences. A report should follow soon. For more photos see the Nice photoset.

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