As of right now, the oxygen distributors simply create a bubble of breathable air around them. They have two values above them: P (which I'm assuming is pressure) and S (no idea on this one). I would really like to see this system revamped so that one oxygen distributor would completely fill a sealed base with oxygen. Solid blocks would obviously prevent oxygen from escaping, as would dual airlock systems. The pressure created by the distributor would depend on the size of its source of oxygen (leaves) as well as how much space it was providing oxygen for. In real life, the alveoli in human lungs cannot function below 15 kPa (2.2 psi for you standard people), so you would need to maintain that minimum pressure in your base to stay alive. I'm by no means a programmer, but I believe that would remove the need for an oxygen block, and may therefore help with technical bugs such as: 1)oxygen breaking redstone connections at corners 2)oxygen preventing piston deployment. Oh, and just to clarify, an oxygen distributor out in the open on the surface of the moon would have no effect, and neither would a distributor in a base with a hole in the wall.