1. Group Computing Strategy Introduction and BaBar Roger Barlow June 28 th 2005

2. Linux PCs list from Stuart.

3. Windows PCs

4. And we have afs server Disk server BaBar farm DØ farm Grid farm(s) Macintosh farm Various laptops

5. This is not a strategy “57 varieties” computing architecture leads to inefficient use of CPU Disk space System manager time User time

6. Coming soon: the Tier2 centre 2000 2.8 GHz CPUs 500 Tb of disk We have to share it – but we can give ourselves priority Why do we want anything else? (Rhetorical question)

7. BaBar Analysis Event Data Large (Tb) ntuples Small (Gb) ntuples Final plots Tier 2 farm Local cluster This assumes the Grid is working so we can all use it But it must!

8. 3 layer model Tier 2 centre. Batch processing. Local cluster. Powerful interactive facility and some storage. Used for compiling, linking, test jobs and final analysis. Desktop/laptop. Nice display. Connect to cluster (ssh, eXceed…) for anything intensive. Not a new idea! What SLAC and CERN do…

9. Points towards a strategy We want a group cluster. Not separate ATLAS and BaBar and DØ and SuperNEMO and Accelerator Science… clusters. Assemble and maintain ~15 high performance nodes as HEP cluster. Run lcg and SL3. (Migrate as needed) These are inside the firewall. The BaBar and DØ farms will wither away Little (or no) need for more data servers Everyone gets a desktop or a laptop. Linux desktop or PC? Macintosh? lcg UI? “Pretty but not powerful”

10. So we… Think and discuss Have another meeting in about a month (ask John Baines?) Keep September 21 st free