The DELPHI distributed information system for exchanging LEP machine related information

An information management system was designed and implemented to interchange information between the DELPHI experiment at CERN and the monitoring/control system for the LEP (Large Electron Positron Collider) accelerator. This system is distributed and communicates with many different sources and destinations (LEP) using different types of communication. The system itself communicates internally via a communication system based on a publish-and-subscribe mechanism, DIM (Distributed Information Manager). The information gathered by this system is used for on-line as well as off-line data analysis. Therefore it logs the information to a database and makes it available to operators and users via DUI (DELPHI User Interface). The latter was extended to be capable of displaying ''time-evolution'' plots. It also handles a protocol, implemented using a finite state machine, SMI (State Management Interface), for (semi-)automatic running of the Data Acquisition System and the Slow Controls System. ((orig.))