I was hacking around and hoping to direct some random data using pipes at /dev/dsa as follows  cat random.file > /dev/dsa...to get some random noise, but I can't manage to find an audio device. I have looked all around the dev folder, there is nothing called /dev/mixer or /dev/audio. I am running Ubuntu 11.04 on an Eeepc 1001p. 
I don't have a /dev/dsa yet I have audio!
ubuntu;audio
You might well be using alsa--If there is a /dev/snd directory, then that likely the case. Also, according to the  Alsa-mini Howto, the results of running cat /proc/asound/cards should contain information on your soundcard. 