1) During hot backup db/tbsp is put into backup mode, "alter database begin backup;" or "alter tablespace tbsp_name begin backup;" 2) Then we copy datafiles to disk or tape, cp *.dbf /backup 3) Take db out of backup mode. "alter database end backup;" or "alter tablespace tbsp_name end backup;" 4) Check the backup mode from V$BACKUP view. "select status from v$backup;" if status is active means there are some files still in backup mode if status is not active means no files are in backup mode we have a couple of questions here which we face in every interview???? Is the datafile available for dml during backup? If not, then where is the data going ? The misconception start what is actually done during hot backup, is data file opens writeable during backup process? or changes are stored somewhere in the SGA, the redologs, the rollback/undo segments or some combination thereof, and then written back into the da...