S. Bagnasco (INFN Torino)
AliEn (ALICE Environment) is a GRID middleware developed and used in the context of ALICE, the CERN LHC heavy-ion experiment. In order to run Data Challenges exploiting both AliEn “native” resources and any infrastructure based on EDG-derived middleware (such as the LCG and the Italian GRID.IT), an interface system was designed and implemented; some details of a prototype were already presented at CHEP2003. In the spring of 2004 an ALICE Data Challenge began with the simulated data production on this multiple infrastructure, thus qualifying as the first large production carried out transparently making use of very different middleware system. This system is a practical realisation of the “federated” or “meta-” grid concept, and it has been successfully tested in a very large production. This talk reports about new developments of the interface system, the successful DC running experience, the advantages and limitations of this concept, the plans for the future and some lessons learned.