High energy & nuclear physics

15 PB of data per year; 100,000 CPUs

A 4 layers Computing Model

• A 4 layers Computing Model

• Tier-0: CERN: accelerator
• Data Acquisition and Reconstruction
• Data Distribution to Tier-1 (~online)
• Tier-1
• 24x7 Access and Availability,
• Quasi-online data Acquisition
• Data Service on the Grid
• “Heavy” Analysis of the data
• ~10 countries
• Tier-2
• Simulation
• Final User, Analysis of the data (batch and interactive modes)
• ~40 Countries
• Tier-3
• Final User, Scientific analysis

“Hardware and software infrastructure that provides dependable, consistent, pervasive and inexpensive access to high-end computational capabilities” (I. Foster)

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