Last Update: 1/4/2019
The "@" system variables are used in Origin to control various behaviors, generally at a much lower level than settings found in Preferences: Options. For instance, Origin has an @DAM system variable that controls the default Recalculation mode when opening an Analysis dialog box that includes this control (0 = None; 1=Auto; 2=Manual). OriginLab publishes quite an extensive list of "@" variables that is continually added to and updated.
You can change the startup value of any of the "@" system variables by typing the Variable and its updated Value into the Set System Variables dialog box (Preference: System Variables...). Optionally, you can add a Comment that helps you to remember what the "@" variable controls.
If you only want to alter the value of an "@" variable for the duration of the current session, you can change its value by opening the Script Window (Window: Script Window) and typing an expression like "@DAM=1", then pressing ENTER.
Keywords:System Variable, "@" Variable, Set System Variables, session, system, variables