D. Klose

Online software for the ATLAS test beam data acquisition system

The Online Software is the global system software of the ATLAS data acquisition (DAQ) system, responsible for the configuration, control and information sharing of the ATLAS DAQ System. A test beam facility offers the ATLAS detectors the possibility to study important performance aspects as well as to proceed on the way to the final ATLAS DAQ system. Last year, three subdetectors of ATLAS-separately and combined-were successfully using the Online Software for the control of their datataking. In this paper, we describe the different components of the Online Software together with their usage at the ATLAS test beam.

CONTROL IN THE ATLAS TDAQ SYSTEM

The unprecedented size and complexity of the ATLAS TDAQ system requires a comprehensive and flexible control system. Its role ranges from the so-called run- control, e.g. starting and stopping the data taking, to error handling and fault tolerance. It also includes initialization and verification of the overall system. Following the traditional approach a hierarchical system of customizable controllers has been proposed. For the final system all functionality will be therefore available in a distributed manner, with the possibility of local customization. After a technology survey the open source expert system CLIPS has been chosen as a basis for the implementation of the supervision and the verification system. The CLIPS interpreter has been extended to provide a general control framework. Other ATLAS Online software components have been integrated as plug-ins and provide the mechanism for configuration and communication. Several components have been implemented sharing this technology. The dynamic behavior of the individual component is fully described by the rules, while the framework is based on a common implementation. During this year these components have been the subject of scalability tests up to the full system size. Encouraging results are presented and validate the technology choice.

Deployment and use of the ATLAS DAQ in the combined test beam

The ATLAS collaboration at CERN operated a combined test beam (CTB) from May until November 2004. The prototype of ATLAS data acquisition system (DAQ) was used to integrate other subsystems into a common CTB setup. Data were collected synchronously from all the ATLAS detectors, which represented nine different detector technologies. Electronics and software of the first level trigger were used to trigger the setup. Event selection algorithms of the high level trigger were integrated with the system and were tested with real detector data. A possibility to operate a remote event filter farm synchronized with ATLAS TDAQ was also tested. Event data, as well as detectors conditions data were made available for offline analysis

The ATLAS experience with databases for structured data with temporal and hierarchical order

Developing systems for the ATLAS (A Toroidal LHC ApparatuS) detector at LHC poses a new set of challenges like the storage of enormous amounts of data with different structures. This data is not only traditional Conditions Data which is slowly evolving data but also data from the online systems which cannot be stored with the event data but must be accessible from each event, like run information. Following the requirements from such systems we have developed a system which provides the facility to store structural data in a time order and with the possibility to classify hierarchically. We will also present a case study of use in the online systems of the ATLAS experiment where this system was used to store online data. Furthermore, we will show the different interfaces developed for this system and its use in different areas of application

The ATLAS Experience With Databases for Structured Data With Temporal and Hierarchical Order

Developing systems for the A Turoidal LHC Aparattus (ATLAS) detector at LHC poses a new set of challenges like the storage of great amounts of data with different structures. This data can be not only from the conditions data which is slowly evolving data but also data from the online systems which cannot be stored with the event data and must be accessible from each event. Following the requirements from such systems we have developed a system which provides the facility to store data with structure in a temporal evolution and with the possibility to classify in a hierarchical order. We will also make a case study of use in the online systems of the ATLAS experiment where this system was used to store online data. Furthermore, we will expose the different interfaces developed for this system and its use in different areas of application