Password file explanation

OS : Linux
DB:- Oracle 11gR2


Remote_Login_PasswordFile parameter explanation;

1:- Remote_Login_password=Exclusive means you can change,add,delete
    users from Passwordfile. Secondly you can use alter command to change
    Password of sys using "ALER USER" command. Eventually this command update
    underlying password file. Only one database will be able to use this file.

   eg. Grant SYSDBA to ETL_USER; <--- Successfull.
        Revoke SYSDBA from ETL_USER; <--- Succesfull
       ALter user sys identified by tiger; <--- Successful

    Thirdly by this setting you can connect to database with sys priv. from
     any server using TNSname alias.
    eg.
    sqlplus ETL_USER/tiger@orcl as sysdba <--- Successful
    
     You can get list of all ther users with SYSDBA priv. from v$pwfile_users;


2:- Remote_Login_Password=Shared means more than one database can use this    

passwordfile. You cannot change this file. You cannot alter,delete,add     users with

sysdba priv. if this file is in use.you can connect to database     with sys

priv. from any server using TNSname alias.
        eg.
      sqlplus ETL_USER/tiger@orcl as sysdba <--- Successful

    SQL> Grant sysdba to scott;
        Grant sysdba to scott
        *
        ERROR at line 1:
        ORA-01999: password file cannot be updated in SHARED mode


        SQL> Alter user SYS identified by tiger;
        Alter user SYS identified by tiger
        *
        ERROR at line 1:
        ORA-28046: Password change for SYS disallowed
    You can get list of all ther users with SYSDBA priv. from v$pwfile_users;

3:-     Remote_Login_Password=None means Database is not using password file;You    

    cannot     grant/revoke sysdba priv. to users. You cannot connect as sysdba    

from any other server than database server itself.
   
    There will no row in v$pwfile_users view.

    sqlplus ETL_USER/tiger@orcl as sysdba <--- fail dwith massage.