  In the context of the ATLAS experiment there is growing evidence of the
importance of different kinds of Meta-data including all the important details
of the detector and data acquisition that are vital for the analysis of the
acquired data. The Online BookKeeper (OBK) is a component of ATLAS online
software that stores all information collected while running the experiment,
including the Meta-data associated with the event acquisition, triggering and
storage. The facilities for acquisition of control data within the on-line
software framework, together with a full functional Web interface, make the OBK
a powerful tool containing all information needed for event analysis, including
an electronic log book.
  In this paper we explain how OBK plays a role as one of the main collectors
and managers of Meta-data produced on-line, and we'll also focus on the Web
facilities already available. The usage of the web interface as an electronic
run logbook is also explained, together with the future extensions.
  We describe the technology used in OBK development and how we arrived at the
present level explaining the previous experience with various DBMS
technologies. The extensive performance evaluations that have been performed
and the usage in the production environment of the ATLAS test beams are also
analysed.
