For the new experiments at FAIR like CBM new concepts of data acquisition systems have to be
developed like the distribution of self-triggered, time stamped data streams over high performance
networks for event building. The Data Acquisition Backbone Core DABC is designed for FAIR detector tests,
readout components test, data flow investigations, and DAQ controls. All kinds of data channels (front-end systems)
are connected by plug-ins into functional components of DABC like data input, combiner, scheduler, event builder,
analysis and storage. On the other hand, the current GSI DAQ system MBS with its huge installed hardware base
(about 100 installed, 50% outside GSI) must be integrated in any new DAQ concept.
After detailed simulations now real tests (on InfiniBand clusters) of event building over networks had been performed.
Several software packages (uDAPL, OpenFabric IB Verbs, MPI2) have been used to measure the performance of InfiniBand.
One can achieve about 80% of the bidirectional nominal IB bandwidth of 1 GByte/s. To achieve real reliable performance with IB one needs the optional real time extensions of the latest Linux kernel 2.6.21. Some infrastructure components of the XDAQ package developed for the CMS experiment have been evaluated for DABC.
(European FP6 program "HadronPhysics", JRA1 "FutureDAQ" contract number RII3-CT-2004-506078)