A distributed, heterogeneous control system for the ALICE TPC electronics

The ALICE detector is a dedicated heavy-ion detector currently built at the large hadron collider (LHC) at CERN. The detector consists of several sub-detectors each of them forming a highly complex device. The detector control system (DCS) covers the task of controlling, configuring and monitoring of the detector system. Since the experiment was running in a radiation environment, fault tolerance, error correction and system stability in general are major concerns. A system consisting of independently running layers has been designed, the functionality layers are running on a large number of nodes and sub-nodes. An autonomous single-board computer, the DCS board, has been developed which allows one to run the operating system Linux in an embedded environment and to perform tasks related to the hardware devices. Further custom hardware devices have been developed covering specific tasks and serving as sub-nodes. These devices together with standard computers in higher control layers form a distributed control system. This article focused on the concept and architecture of the DCS for the front-end electronics of the time-projection chamber (TPC) and present results and experiences from system integration tests.