1. During the last three years, ALICE has used AliEn continuously. All the activities needed by the experiment (Monte Carlo productions, raw data registration, user analysis, data replication...) are being executed on a regular basis. The plots on the right present the number of simultaneous running jobs all over the ALICE sites, and the distribution of the finished jobs over a year. THE PAST: AliEn AliEn started in 2001, and since then, it has evolved, providing new functionality and interfaces to other grid environments. It was designed to fulfil all distributed computing requirements of the ALICE experiment, a High Energy Physics Experiment at the LHC at CERN (Geneva). The ALICE Environment "AliEn" is a lightweight Grid Framework built around Open Source components using the combination of a Web Service and Distributed Agent Model. S. Bagnasco, L. Betev, F. Carminati, O. Datskova, F. Furano, A. Grigoras, C. Grigoras, S. Lee, P. Mendez, A. Peter, P. Saiz, S. Schreiner THE FUTURE: AliEns AliEn2 was born as the new and improved version of the framework. First of all, it was generic, and other communities like CBM and PANDA started using it. Moreover, it included interfaces to other newly developed grid solutions. AliEn2 also simplified the job submission, making the system responsible of choosing the best location to save files. The figure on the left presents the current components of AliEn: First of all, central databases (for the file and metadata catalogue, tasks and transfers), and a set of services that allows users to operate the catalogue and submit jobs. Then, each site provides a set of services that allows AliEn to use the local resources (both disk space and computing capacity). Job Broker Job Manager File Catalogue LFN GUID Meta data SplittingExpired PrioritiesMerging Zombies Transfer & Job Optimizers FTD fts bbftp xrdcp Central services Site Services Non AliEn Services CE Packman MonALISA CM Site A SRM CE CM Packman MonALISA Site B SRM xrootd Task Queue Jobs Agents Sites Transfers Trans fers Agents Sites Transfer Broker Currently, ALICE has more than eighty sites distributed all over the world. The picture on the left shows all those sites with a colour dot representing the status of the site: Green for a site running jobs Blue if the site works, but is currently idle Yellow if one of the services is down Red if there is no information All the monitoring is done with: THE PRESENT: AliEn2 We are constantly working on AliEn to ensure that it can solve all the current challenges and that it can stand up also to future challenges. For instance, we have proved that we can handle more than twenty thousand concurrent jobs. Could we handle two hundred thousand? Two million? These are some of the areas where we are currently improving the system: JA Since there are already different communities using AliEn, creating a confederation of AliEn grids becomes a new possibility. Thanks to this, the different experiments and physicists could share the resources among each other. Finally, now that the LHC is running, the user support is even more important. Physicist belonging to the ALICE community should be able to analyze the data using all the distributed resources from the collaboration. http://alimonitor.cern.ch For a live version of this picture, please visit: