Basically there are two modes of NoRH data recording. In the steady mode, the raw data is recorded as a frame after 1-sec integration. One raw-data file has 600 frames (i.e. 600 sec) each and is named with a sequential number. In the event mode, the raw data is recorded as a frame after 50 milli-seconds (before September 1995) or 100 milli-seconds (after October 1995) integration. The event data is recorded when a flare-event occurs on the Sun. One event-mode file corresponds to one flare-event and has almost no limitation on number of frames.