The CMS ECAL non-event data handling

The Electromagnetic Calorimeter (ECAL) of the CMS experiment at the LHC includes about 76000 lead tungstate (PbWO4) scintillating crystals. The detector properties must be continuously monitored in order to ensure the extreme stability and precision required. This leads to a very large volume of non-event data to be accessed continuously by shifters, experts, automatic monitoring tasks, detector configuration for trigger and data acquisition systems and offline data reconstruction programs. This paper describes the measurements taken by the Detector Control System, the calibrations, the data handling strategy and the workflow as well as the architecture of the configuration and conditions databases and the web interface to access the data. An outlook is given on the experience with detector commissioning and during first beam days, which have allowed a system test in realistic run conditions.