For what are these seven files on my DVD?

VIDEO_TS.BUP 8/16/2009 8:00 AM BUP File 12 KB
VIDEO_TS.IFO 8/16/2009 8:00 AM IFO File 12 KB
VIDEO_TS.VOB 8/16/2009 8:00 AM VOB File 122 KB
VTS_01_0.BUP 8/16/2009 8:00 AM BUP File 40 KB
VTS_01_0.IOF 8/16/2009 8:00 AM IOF File 40 KB
VTS_01_1.VOB 8/16/2009 12:55 AM VOB File 1,040,384 KB
VTS_01_2.VOB 8/16/2009 12:55 AM VOB File 275,328 KB