MetaData

1. MetaData F.Carminati 24 February, 2005

2. Statement of the problem • A user wants to process “some events” • He/She needs to know where they are • Which file • Where in the file • Sounds simple! Offline Week

3. Tools at hand • In Grid file catalogues files may have MetaData that identify a file • However we are not sure what the Grid catalogue will look like in this moment • Given a ROOT file, a TRef allows us to “jump” directly to a given object Offline Week

4. General idea on the Grid TAG Database Event catalogue File catalogue Local catalogue MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD keys <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD LFN SE <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> MD MD MD PFN <guid> Offline Week

5. Main questions • What happens if we are not on the Grid • The system should not be too different • What do we put in each catalogue • How much do we depend on the file catalogue being exposed to us • Which information do we put in the TAG database • Which are its dimensions and its efficiency? Offline Week