The ATLAS Collaboration at CERN is preparing for the data taking and analysis at the LHC that will start in
2007. Therefore, a series of Data Challenges was started in 2002 whose goals are the validation of the
Computing Model, of the complete software suite, of the data model, and to ensure the correctness of the
technical choices to be made for the final offline computing environment. A major feature of the first Data
Challenge (DC1) was the preparation and the deployment of the software required for the production of large
event samples as a worldwide distributed activity.
