RUNNING THE ACQUISITION

ODB Pages

The various parameters for experimental configuration, e.g. detector high voltages, waveform digitizer thresholds, etc, are stored in a shared memory segment called the online database (ODB). The ODB is copied into the data files at the run start and the run end to ensure the experimental configuration is stored.

The ODB is arranged as a file system with various sub-directories for different catergories of experimental parameters. For example the WFD frontends and CAEN frontend have individual entries in the Equipment sub-directory, i.e. "Equipment/WFD01" for the WFD01 frontend process and "Equipment/CAEN" for the CAEN frontend. The slow control frontends, including the high voltage (HV) and the flight simulator (FS), also have corresponding entries in the Equipment sub-directory. Programs such as the event builder, data logger, data analyzer, have entries for their setup parameters.

The ODB is accessible by clicking on the ODB button at the top left of the Midas status page. ODB entries can be changed by clicking the parameters setting. Adding or deleting the ODB entries is possible via "create" and "delete" buttons on the ODB pages.

Additionally the ODB is accessible via the utility program odbedit. Its commands include "ls" for listing directories, "cd" for changing directories, "set" for change parameters, and "create" and "delete" for adding or removing an ODB entry. It permits the use of macros for quickly modifying the ODB entries for diffferent experimental configurations.