Commissioning of the ATLAS calorimeters with perspective on early physics

The ATLAS calorimeters have recorded millions of cosmic ray and random trigger. Detailed understanding and improvement of the signal reconstruction has made it possible to study the performance on these events of higher level quantities such as missing ET and jets. The talk will in particular show that these performances are already close to expectation. This reinforces the confidence of the capability of ATLAS in some key early physics item which will be discussed.