Database time stamps
We have talked about time stamps for database entries (and the time tags in the Event headers) in the past. So far we didn’t have a good common solution.
A tag in the database should give you the time an entry was made somewhat accurately, but time isn’t good enough to identify individual events from the DAQ. You will need that capability to drop individual events from the analysis later, or to maintain a “hit list” of your favorite events.
We will have a “composite” of time tag and run/event number for identifying events, and time only for things like HV readings, temperature readings, time a FPGA code was used, and so on.
Our “time” supports comparisons, time windows, <, >, ==, +, so it’s easy to find out whether an “event” is within a certain time window (such as validity range for a calibration) or not.
And the best: Offline and online use the same time format!
We will use that on Unix, NT, and VxWorks.