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Run/File and Event Tag System


In order to characterize physics data it is useful to assign meta data to different levels of data abstraction. For data produced and used in the ALICE experiment a three layered structure seems feasible:

  • Run level meta data.
  • File level meta data.
  • Event level meta data.

This approach minimizes information duplication and accommodates for the actual structure of the data in the ALICE file catalog. The following pages intend to give a detailed description of all the above. In particular Run/File Tags provides all the necessary information about the structure of the file catalog and the files that are stored in it, the metadata fields on the run/file level and some practical examples on how to query the file catalog in order to retrieve the files needed. Finally, Event Tag System gives a detailed description of the existing Event Tag System that has been implemented (its structure and its usage), as well as some practical examples on how to create the tag files and how to use the system within the user's analysis code.


Please address questions about the Run/File metadata fields as well as the Event Tag System to Panos Christakoglou.

Last Changes: pchrist, 12.04.07