Thanks a lot,
Would you tell me how to create another database in the same machine. You mean another instance in the the same machine maybe.
I create catalog like the following. Would you correct me where in the instructions is wrong:
1. Create tablespace rman_ts ,20 MB
2. create user rman_dba and rman_ts as default tablespace
3. grant connect, resource, recover_..owner to rman_dba
4. create catalog tablespace rman
5. register databse.

Would you tell me what is wrong and how to create another database for catalog.

Thanks
Hamhey