Commissioning of the ATLAS reconstruction software with first data

The ATLAS detector is being commissioned using all types of physics data available: cosmic rays, beam-halo and beam-gas events. In addition to putting in place the trigger and data acquisition chains, commissioning of the full software chain is a main goal. This is interesting not only to ensure that the reconstruction, monitoring and simulation chains are ready to deal with LHC physics data, but also to understand the detector performance in view of achieving the physics requirements.