I had promised Prof David Luckham at the last EPTS meeting I would post some notes from a BCS event I attended a while back, given by the IT department of JET. The topic came up again in a response to Tim Bass’ Linkedin CEP blog where Tim implied the CERN LHC’s event processing was something the EPTS Languages Working Group should have (or should in future be) taken into account – a fair criticism provided you think the LHC and its ilk’s event processing needs are “typical” or repeatable elsewhere.
Back to my notes on JET: they used custom hardware (>21,000 rack mount modules of >400 types) for event-data compression and collection – what could be described as a “hardware tree database” with event channels leading to a “lightweight” software mapping system controlled via APIs. However, the IT systems were mainly concerned with collecting valid events and exceptions for post-experiment analysis – each experiment having something like 22,000 parameters to deal with! Events were not just from the Torus, either – with such expensive experiments they were monitoring things like the data collection hardware. The control systems used a state model and a control loop executing at 500 iterations per second. The experiments were defined as state models that were maintained in a custom content management solution based on RDF. If I recall, their main programming languages were C++ and Fortran.
Interestingly, state management was one of the language aspects covered by the EPTS Languages working group… and state modeling is also a feature of TIBCO Business Events…
