I am connected on my Oracle database by password file.Also,I can connect by entering
CONNECT / as sysdba

On my OS (Win2000) there is a group ORA_DBA which members are users what can be connected on oracle "as sysdba" without entering username and\or password.
Members of my password file are users SYS and user INTERNAL who are granted SYSDBA and SYSOPER authority.
Parameter REMOTE_LOGIN_PASSWORDFILE is EXCLUSIVE.

May I revoke sysdba and\or sysoper from SYS or INTERNAL?
What about data dictionary if I revoke that privileges?

I am running Oracle 8.1.7 on Windows 2000.
Thanks,Zvonimir