Month: December 2009

What’s with PulseAudio?

After my upgrade to OpenSUSE 11.2, I noticed that VLC was again stuttering when playing videos. A quick check revealed, that the upgrade re-installed the PulseAudio system. Removing all Pulse related stuff fixed the problem. I wonder why, oh why on earth all the sound servers under Linux suck? And why are they default for every installation, if they don’t work as expected? I still own a nice SoundBlaster Live, which does sound mixing in hardware, which means I do not even need a sound server, since the card can expect many different audio streams from many applications. Anyway, please, dear sound server developers: If you need to write such a beast of a tool, make it work as expected!

Using YMP URLs from the command line

I just upgraded my home machine to OpenSUSE 11.2, and needed a few programs from secondary repositories. SUSE comes with those nice YMP URLs, which allow one-click installation of programs. However, after my change to using sudo from a few weeks back, this does not work anymore. The One Click Installer does not seem to be compatible with sudo yet. So I now found a workaround, by just using the shell to do the same. E.g. if you wanted to install Amarok 2.2, which does not come with SUSE 11.2, you would do:

/sbin/OCICLI http://software.opensuse.org/ymp/KDE:Backports/openSUSE_11.2/amarok.ymp

Nice, isn’t it?

Printing the SSH host key fingerprint

Whenever you update your SSH host keys, your machine becomes compromised, or you re-install your system, the SSH host key will change. To check if there is really a man in the middle attack, it is nice to be able to print out the fingerprint of the SSH host key on the host itself. So locally log onto your machine, and do the following:

$ ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key.pub

If you are using the DSA key, you should replace rsa with dsa, naturally.

Computing the standard deviation of timings in OpenOffice

I took some timings during a user study, and tried to use NeoOffice (aka OpenOffice for OS X) to evaluate the results. I needed to compute the standard deviation of the timings. The data itself was in a format MM:SS. What does work is computing the sum, like this:

=SUMME(A1:A20)
Note that I am using the german function names. I don’t know all the english function names, so you have to check that yourself. Now I tried to compute the standard deviation as follows:
=STABW(A1:A20)
But all I got was 00:00 as the answer. I couldn’t get an answer why that is the case, not even by the helpful people in #openoffice.org on Freenode. What I did find out is that you can do the computation when converting the timings to another format, namely just seconds. You can do this in the following way:
=MINUTE(A1)*60+SEKUNDE(A1)
So you basically need another column, filled with the above formula, say column B, and then you can compute the standard deviation:
=STABW(B1:B20)

How to scrobble vinyl records

I like to listen to music. Mostly MP3, CD, and my all-time favourite: records. Yeah, those big, black 12″ monsters from your youth. Or maybe you don’t even remember those…?

It also happens that I like to scrobble my music. What’s scrobbling you ask? Easy: It means to track what you have been listening to, using the Audioscrobbling service of last.fm. This gives me the advantage of knowing what I listened to last week, getting recommendations on new music, and such stuff. This automatically happens when I listen using Amarok, Cog or some iPod.
But what do I do with my vinyl records? Turns out, that is simple as well. Just use Scrymble, which is available here: http://ansiform.afraid.org/scrymble/
Requirements are: Firefox, Greasemonkey and the scrymble script. I usually use Konqueror or Safari, but it’s ok to have Firefox around for purposes like this. After the installation of Scrymble, you can go to RYM (http://rateyourmusic.com/) to scrobble any album listed there, either in real time, or post auditem.
PS: I actually made up the auditem. Anybody here who knows the correct form? 🙂