POOL Integration into three Experiment Software Frameworks

The POOL software package has been successfully integrated with the three large experiment software frameworks of ATLAS, CMS and LHCb. This paper summarizes the experience gained during these integration efforts and highlights the commonalities and the main differences between the integration approaches. In particular, the role of the POOL object cache, the choice of the main storage technology in ROOT (Tree or Named Objects) and the approaches to catalogue integration are discussed.