Sunday, July 3, 2011

HTTP proxy and apt

This might be well-known, but I though I'd mention it anyway, as it seems a bit mysterious at first sight.
If you live behind a HTTP proxy you probably are used to the two ways of making your system use the proxy: by http_proxy and no_proxy environment variables and by the GNOME Network Proxy Preferences (gnome-network-properties). But either way it can happen that simple sudo aptitude or sudo apt-get install foo fail because it tries to access the internet directly, ignoring the proxy setting. So, why is that?

Eclipse CDT: removing non-existent include paths

It seems that Eclipse CDT doesn't like it when you have a non-existent path in the list of project include paths. Fair enough. You can selectively remove the non-existent paths from your project via some mouse-clicking.

But if you are generating your Eclipse project via, say, CMake and you're unfortunate enough that you can't reasonably change the CMake project files (think of evil upstream and you not wanting to patch their overly complex build system changing with every release), what do you do? After a bunch of project regenerations removing of the include paths by hand becomes annoying.

As I was experiencing this issue, I decided to hack together an Eclipse plugin to resolve this for me. And here is the result: fixincludes Eclipse CDT plugin.

Saturday, July 2, 2011

Linux 3.0 on ALIX 2d3

Update: Due to the way the current ALIX LEDs driver is implemented it cannot be used at the same time the generic GPIO driver is loaded. :-/ Luckily there's some work going on to resolve the issue - see this commit in linux-next.

Just an update: Here's a linux 3.0-rc4 config file for ALIX 2, more specifically for the ALIX 2d3.
This should have all the basic things on the board running, including Ethernet, USB, LEDs, GPIO (not tested), watchdog.
You most certainly want to hand-tune it for your particular setup. No WiFi driver is enabled in the referenced config -- if you have one (or two :-)) wireless NICs in your ALIX, you certainly want to add that to your configuration.

Sunday, May 15, 2011

Creating animated SVG plots with GNU Octave and gnuplot

It's relatively easy to create an animated plot as either a video (AVI, MPEG, ...) file or an animated GIF file via GNU Octave or gnuplot -- one needs only to create a sequence of images and then use a tool like mencoder or ffmpeg to combine these into a single video file.

But how about an animated SVG file? As plots are vector by nature, an animated vector file sounds cool. Gnuplot is capable of producing output graphs in SVG format, but I was not successful in finding a way of converting these into a single animated SVG.

So I hacked together something for the task. If you have a recent-enough browser (tested in Firefox 4.0.1 and Chromium 11.0.696.65) you can have a look at a trivial example.
If you're interested, grab the scripts here: ani-plot

Friday, February 11, 2011

Windows XP both native and in VirtualBox

There are several good tutorials about similar topics, namely:
  1. How to migrate existing Windows installations to VirtualBox
  2. HOWTO: Windows XP in both VM and native
    but I couldn't find any that would describe what I was trying to achieve.

    What I had: Windows XP installed on a physical partition. What I wanted: Being able to run the installation both inside VirtualBox and also natively. I did not want to reinstall the WinXP installation nor did I want to have to fiddle with any Windows Genuine Disadvantage stuff. And I didn't want to break the native boot in the process. Also, as this was some ├╝ber-corporate install I didn't want to have to ever use the WinXP install CD + its rescue console.