Describe the Network File System and Network File Services

When stand-alone computers ruled the computer industry, users shared files with 8-inch floppy disks or cassette tapes.
When the hardware and protocol for networking computers became available, users needed a convenient way to transfer files and share resources among computers. The first mechanism to transfer files was FTP^[1], but using it was cumbersome: users paused their session, moved some files with the FTP client, and then resumed their session.

A network file system (NFS) is a type of file system that allows files and directories to be shared over a network, while a non-network file system is a file system that is designed to be used on a local disk or storage device. Here are some of the key differences between a network file system and a non-network file system:

1. Network access: A network file system can be accessed over a network, while a non-network file system can only be accessed locally.
2. Performance: A network file system may have slower performance than a non-network file system due to the overhead of network communication and potential network congestion.
3. Security: A network file system may have different security considerations compared to a non-network file system, since it is accessible over a network and may be vulnerable to network-based attacks.
4. Scalability: A network file system may be more scalable than a non-network file system, since it can be accessed by multiple users and systems over a network.
5. Administration: A network file system may require different administration and configuration considerations compared to a non-network file system, such as configuring network access and security settings.
6. Location: A network file system can be located on a remote server or storage device, while a non-network file system is located on a local disk or storage device.

Overall, the key difference between a network file system and a non-network file system is the ability to share files and directories over a network. While a non-network file system is designed for local access and may have faster performance and simpler administration, a network file system allows for sharing and collaboration across multiple systems and users.

Enter the Network File System or NFS. NFS allows users to manipulate files on a remote computer as if they were local. NFS transparently supports the usual file operations, including:

1. copy (cp)
2. move (mv)
3. delete (rm)
4. link (ln)
5. list (ls)

NFS frees users from the inconveniences of FTP. A user can access and modify files anywhere on the network using the standard command-line programs.

NFS operates using the common client-server model. NFS servers can export entire filesystems, optionally making them publicly available and NFS clients then mount the exported filesystems.
Once mounted, the server's remote filesystem is attached to the client's local filesystem.
When any file modifications on the NFS filesystem occur, the NFS client sends the modifications to the NFS server for processing.
Client-server model: A computer design model, where servers offer up one or more services for client use.
The next lesson discusses the relationship between NFS and remote procedure calls.

[1] File Transfer Protocol (FTP): FTP is one way to move a file from computer to computer.