VMS Help FORTRAN, Statements, OPEN, DEFAULTFILE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  DEFAULTFILE = ce

  ce  Is a character expression that specifies a default file
      specification string.

  This keyword supplies a value to the RMS default file specification
  string for the missing components of a file specification.  If you
  do not specify the DEFAULTFILE keyword, Fortran uses the default
  value 'FORnnn.DAT', where nnn is the unit number with leading
  zeros.

  The default file pathname string is used primarily when accepting
  file specifications interactively.  File specifications known to a
  user program are normally completely specified in the FILE keyword.

  You can specify default values for any one of the following file
  specification components:  node, device, directory, file name, file
  type, and file version number.

  When you specify any of the above components in the FILE keyword,
  they override those values specified in the DEFAULTFILE keyword.

  The following example uses the file name supplied by the user and
  the default file specification supplied by the DEFAULTFILE keyword
  to define the file specification for an existing file:

     TYPE *, 'ENTER NAME OF DOCUMENT'
     ACCEPT *, DOC
     OPEN (UNIT=1, FILE=DOC, DEFAULTFILE='[ARCHIVE].TXT',
    1     STATUS='OLD')