The Communication Library DIALOG for iFDAQ of the COMPASS Experiment

Modern experiments in high energy physics impose
great demands on the reliability, the efficiency, and the data rate
of Data Acquisition Systems (DAQ). This contribution focuses on
the development and deployment of the new communication library
DIALOG for the intelligent, FPGA-based Data Acquisition System
(iFDAQ) of the COMPASS experiment at CERN. The iFDAQ
utilizing a hardware event builder is designed to be able to readout
data at the maximum rate of the experiment. The DIALOG library is a
communication system both for distributed and mixed environments,
it provides a network transparent inter-process communication layer.
Using the high-performance and modern C++ framework Qt and its
Qt Network API, the DIALOG library presents an alternative to
the previously used DIM library. The DIALOG library was fully
incorporated to all processes in the iFDAQ during the run 2016.
From the software point of view, it might be considered as a
significant improvement of iFDAQ in comparison with the previous
run. To extend the possibilities of debugging, the online monitoring
of communication among processes via DIALOG GUI is a desirable
feature. In the paper, we present the DIALOG library from several
insights and discuss it in a detailed way. Moreover, the efficiency
measurement and comparison with the DIM library with respect to
the iFDAQ requirements is provided.

Authors:

• Y. Bai
• M. Bodlak
• V. Frolov
• S. Huber
• V. Jary
• I. Konorov
• D. Levit
• J. Novy
• D. Steffen
• O. Subrt
• M. Virius

Keywords:

• Data acquisition system
• DIALOG library
• DIM library
• FPGA
• Qt framework
• TCP/IP.

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