Yes, enabling the Oracle 12c direct NFS client on Windows and it is documented, but I didn’t get changed on Oracle Support (I have send an improvement request for Doc ID 1468114.1)…
One needs to run ‘%ORACLE_HOME%\bin\enable_dnfs.bat’ now, which does NOT copy the ‘oranfsodm12.dll’ over the ‘oraodm12.dll’, but it copies the ‘oranfsodm12.dll’ to the ‘%ORACLE_HOME%\rdbms\lib\odm\’ directory!
After the file has been copied and Oracle is restarted, the [Oracle instance running with ODM: Oracle Direct NFS ODM Library Version 3.0] line in the alert.log is shown!
Enabling Direct NFS Client – documentation
Oracle Database Installation Guide for Microsoft Windows – Oracle Database Postinstallation Tasks – 184.108.40.206 Enabling Direct NFS Client: http://docs.oracle.com/database/121/NTDBI/postcfg.htm#CHDFGFDC
ps. on Windows the supported ‘nfs_version’ is still NFSv3 :(