What does DURN stand for?

Duration

A rating system applied to engine camshaft that determines how long the valves will be open relative to crankshaft movement in degrees. The elapsed time that a job is expected to take to complete (estimated duration) and actually takes (actual duration). Also CPU time, time restriction. 2.In Backup, Recovery, and Media Services, the length of time that the designated media is to reside at a location before moving to the next location or returning to the home location.