I noticed that when I'm using 'nodrm' (e.g knoppix 2 nodrm)
every few seconds, the screen (in text mode) is black for a second and then turns on.

What does 'nodrm' do ?
Does it prevents loading a device driver ? which one ?

I have a PC104 based on Intel's CoreI7. The screen flickers and the problem is fixed upon Knoppix boot completion (also in Ubunto).