oracle super user & authenticate

Database Administrators can authenticate database administrators through the data dictionary, (using an account password) like other users. Keep in mind that beginning with Oracle Database 11g Release 1, database passwords are case-sensitive. (You can disable case sensitivity and return to pre–Release 11g behavior by setting the SEC_CASE_SENSITIVE_LOGON initialization parameter to FALSE.)

In addition to normal data dictionary authentication, the following methods are available for authenticating database administrators with the SYSDBA or SYSOPER privilege:

• Operating system (OS) authentication

• Password files

• Strong authentication with a network-based authentication service, such as Oracle Internet Directory

These methods are required to authenticate a database administrator when the database is not started or otherwise unavailable. (They can also be used when the database is available.)