Mar 172012

This is a really compact and cheap router to take with you to hotels etc. to secure your internet access via VPN or redistribute a network.

The Hardware

You can get some information on the used hardware from my /proc/cpuinfo, /proc/meminfo and dmesg.

I put some photos I made of the PCB online on this PicasaWeb album.

More details to be found in OpenWrt’s wiki page on the router.

Mar 132012

I probably bought this mixer for a somewhat different purpose compared to most people. I have active speakers connected directly to my computer sound card, and my idea was to route the sound card speaker output through this little mixer so I could have a volume and sound control on my desk.

Physically the mini-mixer exceeded my expectations. It is compact and small, but sturdy and the knobs are quite nicely dampened. Its weight is also a lot above that of consumer USB sound cards.

The obtained sound quality is decent without noticeable noise and you can go to quite high volumes.

Mar 122012

The following steps didn’t work for me (I could compile pulseaudio but it crashed when loading Apple’s Coreaudio support or it wouldn’t contain CoreAudio support). So I decided to use the Solution via Soundflower and esound described below the pulseaudio section.

As long as this pull request is not part of Homebrew I tried this way to install Pulseaudio on Mac OS X 10.7 and it works for me:

brew update
brew install


Alternative: The other formula ( can be installed as follows (but doesn’t support Apple’s CoreAudio):

Mar 112012

When I had to create a reverse DNS zone file for my Bind name server I wanted it to be as flexible as possible and thus created a Python script that generates the Bind zone file. This makes renumbering the network really easy.

The script is available as a gist on Github:

To create the zone file, customize the configuration section in the script. Then run it and the output to stdout should be sent to the zone file:

./ > /etc/bind/

The default output (of the example config settings) would look like this:

Mar 092012

The Behringer U-Control UCA202 is an inexpensive (~25 EUR) small USB sound card that I bought when my older M-Audio Transit USB wasn’t working well on my Seagate GoFlex Home. I’m also planning to use it on my Buffalo WZR-HP-AG300H WiFi router. This blog post documents some of its features and tests.

This sound card doesn’t need any drivers for Win, Mac or Linux. The built in TI PCM2902E Audio Chip is supported by the major operating systems.

I took a couple of photos of the hardware. You can see them in my Picasa Album Behringer U-Control UCA202.

Mar 092012

You can use lxsndtest on Linux based computers to test the performance and quality of your soundcard. You should read its user guide for help on installation and usage.

lxsndtest ist based on the older xsndtest (which you can compile using some hints from this build formula for Gentoo).

You may use speaker-test to check your speakers.


Mar 032012

The following collection of commands shows how to migrate your partition formatted with ext3 to an ext4 filesystem. The safest way is to do this when the partition is unmounted. However, if the partition to convert is where the root filesystem of your Linux distro is stored and you don’t have access / time to boot from a Live CD, you can also do the conversion while simply remounting the root filesystem read-only.

I’m not going to go into detail why you would want to migrate to ext4. Check Wikipedia for good reasons.

Mar 032012

If you want to use 10 Gigabit Ethernet at home you have to make a choice what technology you want to use. There are about eleven different standards for 10 Gigabit Ethernet, 6 using fiber optics and about 5 for copper connections.

Products are still relatively costly though. A cheaper alternative might be to use IP-over-Infiniband.

Fiber connectivity

At home you would rather choose multi-mode fibers (MMF) as they are cheaper and the distances at home are less than 300m long. (For long range communication you would use single-mode fibers – SMF.)
SMF cables are usually yellow, while MMF cables are orange or aqua.

Mar 022012

The Open Workbench Logic Sniffer is a great tool for everyday tasks in electronics. It is a cheap logic analyzer with software for all major operating systems. As a bonus, the hardware is open-source!


As of 2012-03-02, OLS is the most up-to-date software being updated regularly.

OLS (jawi / ols )

Jawi’s Logic Sniffer client software

Installing the latest OLS on Ubuntu 12.04:

sudo apt-get install maven2 openjdk-6-jdk
cd ~/Downloads
git clone git://
cd ols
mvn clean install
GadgetFactory / OpenBench-Logic-Sniffer


Mar 022012

Installation on Ubuntu / Debian:

sudo apt-get update && sudo apt-get install radvd

A typical radvd configuration file /etc/radvd.conf to advertise the prefix 2001:db8:2530:fa13::/64 for autoconfiguration on the network connected to the interface eth0 and to advertise the machine running radvd as a router for the local network (based on the routes on this host) would look like this:

interface eth0
    AdvSendAdvert on;
    AdvManagedFlag off;
    AdvOtherConfigFlag off;

    prefix 2001:db8:2530:fa13::/64
            AdvOnLink on;
            AdvAutonomous on;
            AdvRouterAddr off;