:lmfao:
If all you are going to do is read stuff online and post like you know what you're talking about, save it. We don't need mis-information being spread anymore than it already is...

I've read your links and the "gasses" they are talking about is superheated air. In thermodynamics superheated air is a gas.

The holes and or slots are used to COOL the rotor no matter what you say you've read. I'm an experienced home mechanic and an Engineer and the heat that is built up in braking a car is orders of magnitude larger than any type of compound YOU say is being emitted by the brakes, period.

If there is not enough surface area (aka large rotors) the rotor will not be able to expel this heat efficiently. In order to remove more heat from the system vent holes or slots are used.