Network File System (NFS)

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Network File System (NFS)

Network File System ( NFS ) is a distributed file system ( DFS ) developed by Sun Microsystems. This allows directory structures to be spread over the net- worked computing systems. A DFS is a file system whose clients, servers and storage devices are dis- persed among the machines of distributed system. A file system provides a set of file operations like read, write, open, close, delete etc. which forms the file services. The clients are provided with these file services. The basic features of DFS are multiplicity and autonomy of clients and servers.
NFS follows the directory structure almost same as that in non-NFS system but there are some differences between them with respect to:

• Naming
• Path Names
• Semantics

Naming

Naming is a mapping between logical and physical objects. For example, users refers to a file by a textual name, but it is mapped to disk blocks. There are two notions regarding name mapping used in DFS.

• Location Transparency: The name of a file does not give any hint of file's physical storage location.
• Location Independence: The name of a file does not need to be changed when file's physical storage location changes.