Performance and scalability of the back-end sub-system in the ATLAS DAQ/EF prototype

The DAQ group of the future ATLAS experiment has developed a prototype system based on the Trigger/DAQ architecture described in the ATLAS Technical Proposal to support studies of the full system functionality, architecture as well as available hardware and software technologies. One sub-system of this prototype is the back-end which encompasses the software needed to configure, control and monitor the DAQ, but excludes the processing and transportation of physics data. The back-end consists of a number of components including run control, configuration databases and message reporting system. The software has been developed using standard, external software technologies such as OO databases and CORBA. It has been ported to several C++ compilers and operating systems including Solaris, Linux, WNT and LynxOS. This paper gives an overview of the back-end software, its performance, scalability and current status.