Categories of Data

The data we need to describe and configure the trigger falls into a few different categories which are distinguished by the nature of the data and how it changes with time. The main categories are summarised here and discussed in more detailed in subsequent sections.

• Hardware and Software Configuration: this category of data is concerned with the description of the hardware setup and its interconnections; also with the collection of programs used to configure and monitor the system. The database schema is largely that provided as part of the Online Software Configuration Databases [3] component - with some extensions to the hardware schema specific to the calorimeter trigger. The software schema requires little or no change.
• Trigger Menu: this describes the physics choices, ie trigger thresholds and algorithms, to be used for a particular run. There may be many trigger menus prepared offline and distributed to the trigger systems. Of these, one will be selected at run time.
• Calibration Data: this includes the energy calibration, timing calibration of the input signals and their pulse shapes, also internal timing of links between the processor subsystems, readout pipeline latencies etc. These data will be derived from a number of different calibration procedures which may be run regularly or occasionally. All calibrations will be stored in the offline database, but at run time only the latest one is ever used.
• Run Parameters: there may be some operational parameters for which the default values (taken from the above databases) can be overridden at run time. For example, the amount of readout data may be temporarily increased for detailed monitoring, etc.