Enabling archive log mode

How to enable archive log mode of database ?

Follow the below steps to enable archive log mode:
OS]~ sqlplus / as sysdba
1.Check whether archive log mode is enabled or not
SQL> SELECT LOG_MODE FROM SYS.V$DATABASE;
LOG_MODE
------------
NOARCHIVELOG
2.Shut down the database because we have to do it in mount state only.
SQL>shut immediate
3.Start the database in mount state
SQL>startup mount
4.Enable the archive log mode
SQL> alter database archivelog
5.Open the database
SQL>alter database open
6.Check the archive log mode now.
SQL> SELECT LOG_MODE FROM SYS.V$DATABASE;
LOG_MODE
------------
ARCHIVELOG

Note: The purpose why we enable archive log mode is for supporting backup operation of database etc.

cheers..........!!!!!!!!!