Data acquisition with the SCINET, a scalable-coherent-interface network

The goal of the SCINET project is to investigate the applicability of the scalable-coherent-interface (SCI) for data-acquisition systems in large-scale fusion-reactor experiments. SCI is a standardized, high-speed interconnect for peripheral devices, processors, memories, PCs and workstations that provides for a distributed shared memory with optional cache coherence between computing nodes. Up to 64 K SCI nodes can be closely coupled in one or more rings that are concatenated via SCI switches. In SCINET, it is investigated how data-acquisition computers can be efficiently connected with each other and with their sensors and actuators by means of SCI, what topological structure the network should have, and which bandwidth and latency can be expected. Test stands were established as a sample SCI-based data-acquisition system that showed up to 45 MB s−1 of throughput and <5 μs latency for end-to-end data transfers.