Technical data

access directories and files on remote computers transparently, as if they were on
the local system. NFS accomplishes this because it is implemented on the both the
remote and the local computer.
NFS protocol achieves portability between different machines, operating systems,
network architectures, and transport protocols through the use of Remote
Procedure Call (RPC) and External Data Representation (XDR). For more
information about RPCs and XDR, refer to the Compaq TCP/IP Services for
OpenVMS ONC RPC Programming manual.
Using NFS is simple. Configuring and implementing NFS, however, are more
complex. For NFS concepts and considerations, as well as detailed configuration
and implementation information, refer to the Compaq TCP/IP Services for
OpenVMS Management guide.
TCP/IP Services accommodates the numerous key differences between UNIX and
OpenVMStomakeuserinteractionbetweenthetwooperatingsystemsappear
transparent. This enables all systems on a heterogeneous network to store and
share files and applications regardless of file specification and structure differences.
This section discusses:
• Directory hierarchies
• File specifications
• Linking files
• File structures
• File ownership
• File protection
• UNIX style file system on TCP/IP Services hosts
2.2.1 Directory Hierarchies
Unlike OpenVMS, the UNIX hierarchy appears as one tree (starting from the root
directory, or “/”) that can be located on more than one device. Table 2-1 describes
the differences between the OpenVMS and Tru64 UNIX directory hierarchies.
Table 2–1: Directory Hierarchy Differences
OpenVMS
UNIX
Reside on one volume having one root above
all directories on the volume.
Canresideonmultiplevolumes.
Device names included in file specifications. Device names not included in file
specifications.
Figure 2-2 illustrates the differences between a UNIX file structure and an
OpenVMS file structure.
Understanding OpenVMS and UNIX Implementations 2–3