Data analysis in the Grid era

The future HENP experiments at the LHC will create an unprecedented amount of data, which needs to be reconstructed, filtered and analyzed to extract the physics signals of interest. While the reconstruction and some part of the filtering can and will be done in a coordinated way for each experiment limiting the stress on the resources, the step of end-user data analysis is expected to put a large load on the resources. While it is clear that the present day tools will have to adapt to the new environment of the Grid, the exact way of how to use the resources most efficiently from a large number of physicists of an experiment doing analysis is today topic of several studies. The talk will give an overview on the critical issues of Data Analysis as foreseen for future HENP experiments. While emphasis will be given to aspects of data analysis related to the huge amount of data to be processed and analyzed at the LHC, the talk will also describe some of the present day tools and prototypes as well as architectures, which are used in running experiments and in the data challenges of the LHC experiments. (12 refs).