NFS – Network File System. This was devised by Sun Microsystems in 1984 as a distributed file system; a way for a client computer system user to access files on another, server computer system over a network, as if they were accessing a local file. The client system issues a mount command to access the remote system’s files. It has become highly popular and there several several versions of NFS;

  • V1 – used by Sun internally.
  • V2 – released by Sun for external use and defined in 1989. It operated over UDP and supported virtual filesystem interface so target remote systems could make their own file systems, such as VAX/VMS, look like NFS. It used 32-bit addressing and so could only read the initial 2GB of a file, thus limiting file size.
  • V3 – came in 1995 with support for 64-bit file sizes and offsets so it could handle files larger than 2 gigabytes (GB), asynchronous server writes for faster write speed and more.
  • V4 – in 2000 with performance and security improvements. Sun gave NFS to the Internet Engineering Task Force (IETF) to safeguard its development.
  • V4.1 – in 2010 had a pNFS extension to enable parallel access to files distributed among multiple servers.
  • V4.2 – published in 2016 with features such as server-side clone and copy, application I/O advise, sparse files, space reservation and more.