Notes on the Big Run and Monte Carlo Data Access

Wiki Markup\[prepared for short presentation on 19 March 2008\]

What is the Big Run?

What *types* of MC datasets are typically generated? 

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• The C&A group represents the largest initiator of new MC datasets...so stay in touch!
• Watch Richard's Big Run Checklist
• Watch the Service Challenge Monte Carlo Processing Summary page in confluence for new entries
• If already using an MC dataset, pay attention to its date of creation - be suspect if it is >> 1 month old, as there may be something more recent.
• To see what has changed between GlastReleases, https://confluence.slac.stanford.edu/display/SAS/GlastRelease+Updates^{Image Removed}

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Once I've figured out what data to use, how do I get my hands on it?

• This is obviously a very hot topic. OpsSim2 generated a lot of feedback and the situation is ... dynamic.
• Since November 2007, all MC data is no longer stored in NFS, but in xroot - a high-performance but specialized disk-based storage system
• More recently, Level 1 processed data is also in xroot. (I do not know the full story on half-pipe or ASP.)
• Quick data access tutorial is here: https://confluence.slac.stanford.edu/download/attachments/4784526/DataAccess-Glanzman-20080304.ppt?version=1^{Image Removed}
• Some specific questions that have come up in the recent past are answered here: https://confluence.slac.stanford.edu/display/ds/Data+Access+FAQ^{Image Removed}
• Be sure to consult the Workbook: http://glast-ground.slac.stanford.edu/workbook/^{Image Removed}