how to archive log and unarchive log

SQL*Plus: Release 9.2.0.1.0 - Production on Thu Jan 7 21:50:54 2010

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SQL> conn /as sysdba;
Connected to an idle instance.
SQL> startup;
ORACLE instance started.

Total System Global Area  135338868 bytes
Fixed Size                   453492 bytes
Variable Size             109051904 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
Database mounted.
Database opened.


SQL> shutdown;
Database closed.
Database dismounted.
ORACLE instance shut down.


SQL> startup mount;
ORACLE instance started.

Total System Global Area  135338868 bytes
Fixed Size                   453492 bytes
Variable Size             109051904 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
Database mounted.
SQL> alter database archivelog;


Database altered.

SQL> alter database open;

Database altered.

SQL> alter system set log_archive_start=true scope=spfile;

System altered.


SQL> select log_mode from v$database;

LOG_MODE
------------
ARCHIVELOG

SQL> archive log list;

Database log mode              Archive Mode
Automatic archival             Disabled
Archive destination            e:\oracle\ora92\RDBMS
Oldest online log sequence     3
Next log sequence to archive   5
Current log sequence           5

SQL>


SQL> shutdown;
Database closed.
Database dismounted.
ORACLE instance shut down.

--------------------------------------------------------------------------------------------------------------------------
------startup and copy all datafile,control file and redolog file and paste new location and startup---(consistent backup)-----
------------------------------------------------------------------------------==========================================


SQL> startup;
ORACLE instance started.

Total System Global Area  135338868 bytes
Fixed Size                   453492 bytes
Variable Size             109051904 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
Database mounted.
Database opened.
SQL>


====================================================================================================
----------startup and make a backup of online tablespace-----------------------------
===============================================================================================

SQL> alter tablespace users begin backup;

Tablespace altered.

SQL> alter tablespace users end backup;

Tablespace altered.

SQL>
SQL> alter tablespace system begin backup;

Tablespace altered.

SQL> alter tablespace system end backup;

Tablespace altered.