15 April 2002
Operating Systems

Network File System - NFS

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NFS - network file system
  - architecture/ protocol/ implementation
  - arbitrary collection of clients  have common FS
  - server: export directories (permissions/ access rights)
  - client: mounts
  - server need not know where mounted

  protocols - possibly heterogeneous environment
  options: hardmout: mount always
           automount: mount when accessed
  stateless server - each client call is self contained
    e.g., read contains file and fofset, not just read current position
  security using cryptography to validate users
  vnode - keep client-side state for remote files/directories
    virtual file system
  transfers done in 8kb chunks
  writes buffered until 8kb of data avail, or close
  client caching inodes, file data
    consistency of multiple users
      cache discarded after 2 seconds for data, 30 for directory
    if cache opened, qurey server for last mondified time