CMS Computing: Technical Design Report

This document provides a top-level description of the organisation of the CMS Offline Computing systems. This organisation relies upon a number of co-operating pieces: • A tier-organised structure of computing resources, based on a Tier-0 centre at CERN and a small number of Tier-1 centres connected using high-speed networks. • A relatively large number of Tier-2 analysis centres where physics analysis will be performed. • A comprehensive and performant software framework designed for high-energy event streams. • Workload management tools to coordinate work at the centres and data management tools to ensure the efficient use of computing resources and the integrity of the data, including adequate auditing and safekeeping of raw and reconstructed data, calibration data, and job parameters. • A comprehensive project management plan so that the various project deliverables are tracked and potential bottlenecks are detected and eliminated. These pieces are discussed in this document in terms of the CMS Data Model and the Physics Analysis Models. The workload management is considered in the context of integration into the LHC Computing Grid.