The DABC framework interface to readout hardware

The Data Acquisition Backbone Core (DABC) is a new GSI software framework to run data acquisition with distributed event building on high performance Linux clusters. Experimental data input is provided by means of generic Device and Transport interfaces. DABC offers elaborate mechanisms for multiprocessing, buffer management, and dataflow throttling. These are transparently available for all implemented plug-ins of the hardware interface. Device plug-ins can link a DABC node to remote readout hardware via network connections, such as Ethernet or InfiniBand. Other Device plug-ins can communicate on the Linux device driver level with custom boards directly plugged to the node. Besides delivering the data input, a DABC Device can also provide controls access to the connected hardware. This functionality can be used for setting up, or monitoring the frontends from the application via DABC parameters and commands. DABC was applied for data taking from readout controller (ROC) boards during CBM experiment´s test beam times at GSI in 2008 and 2009. Here the data was exchanged with the remote boards over Ethernet via UDP based protocol. In next beam tests, CBM experiment is going to use PCIe boards with FPGA and optical data connections to access the ROCs. Such board was already integrated to the DABC hardware interface. DABC can configure the DAQ transport media from the ROC to work transparently either via UDP, or via the PCIe board. Another implementation example is a multi purpose PCI Express Optical Receiver (PEXOR) board developed at GSI. This board features FPGA and 4 optical links and may be used for different front-ends, depending on the FPGA programming. Kernel driver and DABC Device for this board were developed and were tested.