External table option uses directory objects to indicate where data files and output files are located.  User must have read on input files and write on output files at OS level.  If directory location does not exist, SQL*Loader will create it but user must have CREATE ANY DIRECTORY privilege and DROP ANY DIRECTORY privileges.

Direct NFS – Oracle Direct NFS (dNFS) is an internal I/O layer to provide faster access of NFS client files.  You use the DNFS_ENABLE=TRUE command parameter to user with SQL*Loader.  dNFS is used by default on files larger than 1GB.

Larry Catt

OCP