Control System Database for the D0 Detector

Laura A. Paterno, Stuart Fuess, S. Krzywdzinski
Fermi National Accelerator Laboratory

Harrison Prosper
Florida State University

A central control system database has been used in the monitoring and control of the D0 experiment. The database stores all of the essential attributes of the hardware and provides the Control Data Acquisition(CDAQ) processes with the access path required to read from or write to a device. It contains information on detector systems, low and high voltage power supplies, cryogenics and argon purity monitoring, and environmental conditioning. The central database also serves as the master copy of the local databases which reside in the front-end computers. It is a relational database, implemented under DEC Rdb.

A variety of utilities were provided for updating and accessing the hardware database, either interactively or in a batch mode. The utilities were written in C, Fortran and Pascal, with SQL statements embedded in the host languages. To speed up the access in the online environment, a read-only copy of the database is maintained and updated every day from the read-write master database; a detached server process with sufficient resources provides the CDAQ processes with fast and uninterrupted access to this read-only database. Merits and drawbacks of the present system are discussed along with recommendations for future implementation.