Meta-data  
  Time-stamp.

  Ownership  (multi-user support)

  Access control. (who can do what with the file)

  Type of file (Unix allows keyboard and display to be treated as file).
    And associating specific programs with specific data files.

  What program required to access data.

  User defined attributes (author's full name, etc.)


  Journaling - protects integrity of file while it being changed.
    If power fails, at least original version and, possibly, both versions
       of file recoverable.
 
  Versioning - ability to roll back to previous state of OS.
    Used when updating/patching if patch fails or creates problems. 

    Similar to backup but done at time of change.

    Similar to revision control but automated and mostly used for OS.
Next