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2. 7000 tons, 150 million sensors generating data 40 millions times per second producing 1 petabyte per second The ATLAS experiment

3. 3 A collision at LHC The Worlwide LHC Computing Grid 3 ATLAS Experiment LHC Beam

4. Ian.Bird@cern.ch4 The Data Acquisition 4 Data from ATLAS 1 PB/sec from all sub-detectors 1 GB/sec raw data sent to Data Centre Reduction factor of 1 million.

5. CERN Computer Centre (Tier-0): Acquisition, First pass reconstruction, Storage & Distribution The Worlwide LHC Computing Grid ALICE 1.25 GB/sec (ions) 2012: ~1 GB/sec 2012: ~300 MB/sec 2012: ~4GB/sec ATLAS ~320 MB/sec CMS ~220 MB/sec LHCb ~50 MB/sec

6. WLCG: Worldwide LHC Computing Grid Typical simultaneous jobs: more than 250,000 Global Transfer rate: 12-15 billion bytes per second

7. Tier 0 (CERN) Data recording Initial data reconstruction Data distribution Tier 1 (11 + KISTI,Korea in progress) Permanent storage Re-processing Analysis 10 Gbit/s links Tier 2 (~150 centres) Simulation End-user analysis Overall ~160 sites, 39 countries 300,000 cores 200 PB of storage 2 million jobs/day WLCG: Worldwide LHC Computing Grid Tier-2 sites (about 150) Tier-1 sites - - - - 10 Gbit/s links

8. WLCG sites in the United Kingdom 8 20 WLCG sites in the UK –1 Tier-1 site: RAL/STFC –19 Tier-2 sites 2 WLCG sites in Scotland –Edinburgh (ECDF) –Glasgow –used by ATLAS & LHCb

9. Thank You! 9