CMS distributed data analysis challenges

In Spring 2004, CMS will undertake a 100 TeraByte-scale Data Challenge (DC04) as part of a series of challenges in preparation for running at CERNʹs Large Hadron Collider. During 1 month, DC04 must demonstrate the ability of the computing and software to cope with a sustained event data-taking rate of 25 Hz, for a total of 50 million events. The emphasis of DC04 is on the validation of the first pass reconstruction and storage systems at CERN and the streaming of events to a distributed system of Tier-1, and Tier-2 sites worldwide where typical analysis tasks will be performed. It is expected that the LHC Computing Grid project will provide a set of grid services suitable for use in a real production environment, as part of this data challenge. The results of this challenge will be used to define the CMS software and computing systems in their Technical Design Report.