Commissioning and first experience of the ALICE Data Acquisition System

ALICE (A Large Ion Collider Experiment) is the heavy-ion detector designed to study the physics of strongly interacting matter and the quark-gluon plasma at the CERN Large Hadron Collider (LHC). A large bandwidth and flexible Data Acquisition System (DAQ) has been designed and deployed to collect sufficient statistics in the short running time available per year for heavy ion and to accommodate very different requirements originated from the 18 sub-detectors. This paper will briefly describe the different components of the DAQ and present the large scale tests conducted to assess the standalone DAQ performances, its interfaces with the other online systems and the extensive commissioning performed in order to be fully prepared for physics data taking. It will review the experience accumulated since May 2007 during the standalone commissioning of the main detectors and the global cosmic runs and the lessons learned from this exposure on the "battle field". It will also discuss the test protocol followed to integrate and validate each sub-detector with the online systems and the first results of the LHC injection tests and startup in September 2008. It will then conclude with the schedule and requirements for the second half of 2009 and the final deployment stage (both in terms of hardware and software) to bring the DAQ to its nominal performance in order to be fully ready for the long LHC run scheduled later this year and next year.