Worldwide LHC Computing Grid - WLCG

CSCS operates a Tier-2 center for the Worldwide LHC Computing Grid (WLCG, http://lcg.web.cern.ch/lcg/public/) on behalf of the Swiss Institute of Particle Physics (CHIPP, http://www.chipp.ch/). It is the only Tier-2 center in Switzerland. Tier-3 centers are operated by PSI, the University of Bern and the University of Geneva. Switzerland as a member state of CERN (http://www.cern.ch/) contributes to the distributed data storage and analysis infrastructure for the users of the ATLAS, CMS and LHCb experiments at the Large Hadron Collider (LHC, http://public.web.cern.ch/public/en/LHC/LHC-en.html) - the largest scientific instrument on the planet.

The LHC is situated at CERN near Geneva. It produces roughly 15 Petabytes (15 million Gigabytes) of data annually, which thousands of scientists around the world will access and analyze. The mission of the WLCG project is to build and maintain a data storage and analysis infrastructure for the entire high-energy physics community that will use the LHC.
The data from the LHC experiments will be distributed around the globe, according to a four-tiered model. A primary backup will be recorded on tape at CERN, the “Tier-0” centre of LCG. After initial processing, this data will be distributed to a series of Tier-1 centers, large computer centers with sufficient storage capacity and with round-the-clock support for the Grid.
The Tier-1 centers will make data available to Tier-2 centers, each consisting of one or several collaborating computing facilities, which can store sufficient data and provide adequate computing power for specific analysis tasks. Individual scientists will access these facilities through Tier-3 computing resources, which can consist of local clusters in a University Department or even individual PCs, and which may be allocated to LCG on a regular basis.