volume shader output tutorial?

i was trying to find out what does it do but it’s not working and i tried to find it in internet and no tutorials, so… any tutorials on what does it do cuz it’s out since 2.65 and now it’s 2.67 but still none. thx!
by the way i heard that using another OS could speed up blender, is it true, if yes what is it, i preferre free ones

it’s not working

That’s the current situation. The input is just a placeholder for now.

there is a GSOC project on this
so we might get something this fall if it works!

happy cycles

Regarding the second question: Blender is known to work faster on Linux (as opposed to Windows). I can confirm myself that at least viewport performance and rendering with Blender Render are indeed better. Can’t say anything about Cycles though, because I have no means to compare (don’t have Windows).