The GNAM monitoring system and the OHP histogram presenter for ATLAS

ATLAS is one of the four experiments under construction along the Large Hadron Collider at CERN. During the 2004 combined test beam, the GNAM monitoring system and the OHP histogram presenter were widely used to assess both the hardware setup and the data quality. GNAM is a modular framework where detector specific code can be easily plugged in to obtain online low-level monitoring applications. It is based on the monitoring tools provided by the ATLAS trigger and data acquisition (TDAQ) software, OHP is a histogram presenter, capable to perform both as a configurable display and as a browser. From OHP, requests to execute simple interactive operations (such as reset, rebin or update) on histograms, can be sent to GNAM