30-10-2009, 03:55 PM
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Network File System
Network File System (NFS), originally developed by Sun Microsystems and then extended by IETF, allows file sharing over network among different types of systems. In other words, NFS was designed for remote file access and sharing over network with various types of machines, operating systems, network architecture and transport protocols.
NFS uses a client/server architecture and consists of a client program and a server program. The server program makes file systems available for access by other machines via a process called exporting. NFS clients’ access shared file systems mounting them from an NFS server machine. NFS mount protocol is used to communicate between the server and the client for the file access and sharing. NFS mount protocol also allows the server to grant remote access privileges to a restricted set of clients via export control.
File systems shared through NFS software can also be mounted automatically. Autofs, a client-side service, is a change directory intercept mechanism that catches the cases when user changes to NFS directory and transparently mounts it. the list of mount points should be provided to Autofs as a configuration file. Essentially any I/O operation on s program notifies the automount daemon, automountd, and it mounts it and then if there is long period of inactivity unmounts it. The auto mountd, daemon transparently performs mounting and unmounting of remote directories listed it Autofs configuration file on an as-needed basis. The NFS is in turn based on the Remote Procedure Call (RPC) protocol. For this reason, the RPC server daemon must be running for NFS to be implemented.
