On 15 February the Worldwide LHC Computing Grid collaboration (WLCG) officially announced the successful completion of a service challenge at the Computing for High Energy and Nuclear Physics 2006 conference (CHEP'06) in Mumbai, India. The challenge involved sustaining a continuous flow of physics data on a worldwide Grid infrastructure at up to 1 GB/s. The maximum sustained data rates achieved correspond to transferring a DVD of scientific data from CERN every five seconds.

The data were transferred from CERN to 12 major computer centres worldwide. More than 20 other computing facilities were involved in successful tests of a global Grid service for real-time storage, distribution and analysis of the data. The completion of this service challenge is a key milestone on the way to establishing the necessary computing infrastructure for the Large Hadron Collider (LHC), which is scheduled to start up in 2007. The results represent a step forward from a previous service challenge in early 2005 that involved just seven centres in Europe and the US and achieved sustained rates of 600 MB/s.

LHC scientists designed a series of service challenges to ramp up to the level of computing capacity, reliability and ease of use that will be required by the worldwide community of more than 6000 scientists working on the LHC experiments. During LHC operation, the major computing centres involved in the Grid infrastructure, so-called Tier-1 centres, will collectively store the data from all four LHC experiments, in addition to a complete copy being stored at CERN.

Much of the data analysis will be carried out at more than 100 Tier-2 computing facilities in universities and research laboratories in more than 30 countries, where researchers will access the data via the Grid resources that the WLCG is bringing together. Already these computing facilities provide a combined computing power of more than 20,000 PCs, and this number is expected to reach 50,000 by the time the LHC is in operation. During the recent service challenge, the participating computing centres sustained more than 12,000 concurrent computing jobs.

Speaking on behalf of the organizers of CHEP'06, Sabyasachi Bhattacharya, director of the Tata Institute of Fundamental Research in Mumbai, remarked: "The fact that this announcement is being made in India reflects the truly global significance of these new results. This sort of collaboration, which we in India are delighted to be taking part in, provides an excellent example of what scientists from around the world can achieve when they have a clear, common goal."

• The computing facilities involved in this service challenge were: Academia Sinica Grid Center (ASGC); Brookhaven National Laboratory (BNL) in Brookhaven, NY; the Computing Center of the National Institute of Nuclear Physics and Particle Physics (CCIN2P3) in Lyon; the German Electron Synchrotron Laboratory (DESY) in Hamburg; Fermi National Accelerator Laboratory (FNAL) in Batavia, Illinois; Forschungszentrum Karlsruhe (FZK) in Karlsruhe; the National Center for Research and Development in Technology, Computer Science and Data Transmission (INFN-CNAF) in Bologna; the Nordic DataGrid Facility (NDGF), a distributed facility in Denmark, Finland, Norway and Sweden; Port d'Informació Científica (PIC) in Barcelona; the National Center for Computing and Networking Services and the National Institute for Nuclear Physics and High Energy Physics (SARA-NIKHEF) based in the Netherlands; the Rutherford Appleton Laboratory (RAL) in Oxfordshire; and the National Laboratory for Particle and Nuclear Physics (TRIUMF) in Vancouver.

Compiled by Hannelore Hämmerle and Nicole Crémel