What is the difference between NFS and CIFS?
NFS is the "Network File System" for Unix and Linux operating systems. It allows files to be shared transparently between servers desktops laptops etc. It is a client/server application that allows a user to view store and update files on a remote computer as though they were on their own computer. Using NFS the user or a system administrator can mount all or a portion of a file system.
CIFS is the "Common Internet File System" used by Windows operating systems for file sharing. CIFS uses the client/server programming model. A client program makes a request of a server program (usually in another computer) for access to a file or to pass a message to a program that runs in the server computer. The server takes the requested action and returns a response. CIFS is a public or open variation of the Server Message Block Protocol (SMB) developed and used by Microsoft and it uses the TCP/IP protocol.
NFS and CIFS are the primary file systems used in NAS. CIFS tends to be a bit more "chatty" in its communications.