Commissioning the ATLAS reconstruction software with first LHC beam and cosmic ray data

Looking towards first LHC collisions, the ATLAS detector is being commissioned using all data available: cosmic rays and events produced during a few days of LHC single beam operations. Commissioning of the full software chain is a main goal, not only to ensure that the reconstruction, monitoring and processing chains are ready to deal with LHC physics data, but also to understand the detector performance as a first step in achieving the ultimate physics expectations. The recorded data have allowed us to study the ATLAS detector in terms of efficiencies, detector integrity, alignment and calibrations. They have also allowed us to test and optimise the sub-systems reconstruction as well as some combined algorithms, such as combined tracking tools. The status of the integration of the complete software chain will be presented and illustrated with data analysis results.