/sys$common/syshlp/helplib.hlb FORTRAN, Statements, OPEN, STATUS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  STATUS = sta

  sta  Is a character expression with one of the following
       values:

  'OLD'       Open an existing file
  'NEW'       Create a new file; if the file already exists an
              error occurs
  'SCRATCH'   Create a new file and delete it when the file is
              closed
  'UNKNOWN'   Open the file as OLD; if it does not exist, then
              open the file as NEW

  The default is 'UNKNOWN'.  However, if you implicitly open a file
  using WRITE, or you specify the /NOF77 compiler option, or OPTIONS
  /NOF77, the default value is 'NEW'.  If you implicitly open a file
  using READ, the default value is 'OLD'.

  Scratch files (STATUS='SCRATCH') are created on the user's default
  disk (SYS$DISK) and are not placed in a directory or given a name
  that is externally visible.  To specify a different device, use the
  FILE keyword.