Hi Indra,
unfortunately this isn't the real deal. In your configuration file, you are suggesting:
backup_dev_type = disk
I have already tried a similar configuration. The result of the backup in DB14 is:
Full (level 0) online database backup to local disk
and the FID is fnd where d stands for disk.
while a backup done with RMAN is listed as follows:
Full (level 0) online database backup using RMAN
and the FID is fnr where r stands for RMAN.