Transfer I/O statements include READ, WRITE, REWRITE, ACCEPT, TYPE,
  and PRINT.  Auxiliary I/O statements include OPEN, CLOSE, INQUIRE,
  REWIND, BACKSPACE, ENDFILE, DELETE, and UNLOCK.

  Transfer I/O statements may be formatted (F), unformatted (U),
  list-directed (L-D), or namelist (N) as follows:

     ACCEPT     Sequential -- F, L-D, N
     DELETE     Relative -- U
                Indexed -- U
     PRINT      Sequential -- F, L-D, N
     READ       Sequential -- F, U, L-D, N
                Direct Access -- F, U
                Internal -- F, L-D
                Indexed -- F, U
     REWRITE    Relative -- F, U
                Sequential -- F
                Indexed -- F, U
     TYPE       Sequential -- F, L-D, N
     WRITE      Sequential -- F, U, L-D, N
                Direct Access -- F, U
                Internal -- F, L-D
                Indexed -- F, U

1  –  Formatted

  Formatted I/O statements contain explicit format specifiers that
  are used to control the translation of data from internal (binary)
  form within a program to external (readable character) form in the
  records, or vice versa.

  Formatted I/O statements must have a format (FMT=) specified in the
  control list (clist).  Additional "clist" elements are required
  depending on the type of access.

  Formatted sequential READ:

    READ (UNIT=u,FMT=f[,ADVANCE=exp][,SIZE=var][,IOSTAT=ios]
          [,ERR=err][,END=end]) [iolist]
    READ f [,iolist]

  Formatted direct access READ:

    READ (UNIT=u,REC=rec,FMT=f[,IOSTAT=ios][,ERR=err]) [iolist]

  Formatted indexed READ:

    READ (UNIT=u,FMT=f,KEY=k[,KEYID=n][,IOSTAT=ios]
         [,ERR=err]) [iolist]

  Formatted internal READ:

    READ (UNIT=u,FMT=f[,IOSTAT=ios][,ERR=err][,END=end]) [iolist]

  Formatted sequential WRITE:

    WRITE (UNIT=u,FMT=f[,ADVANCE=exp][,IOSTAT=ios]
          [,ERR=err]) [iolist]

  Formatted direct access WRITE:

    WRITE (UNIT=u,REC=rec,FMT=f[,IOSTAT=ios][,ERR=err]) [iolist]

  Formatted indexed WRITE:

    WRITE (UNIT=u,FMT=f[,IOSTAT=ios][,ERR=err]) [iolist]

  Formatted internal WRITE:

    WRITE (UNIT=u,FMT=f[,IOSTAT=ios][,ERR=err]) [iolist]

2  –  Unformatted

  Unformatted I/O statements do not contain format specifiers and
  therefore do not translate the data being transferred.

  Unformatted I/O is especially appropriate where the output data
  will subsequently be used as input.  Unformatted I/O saves
  execution time by eliminating the data translation process,
  preserves greater precision in the external data, and usually
  conserves file storage space.

  Unformatted I/O statements do not specify a format (FMT=) in the
  control list (clist).  Other "clist" elements are required
  depending on the type of access.

  Unformatted sequential READ:

    READ (UNIT=u[,IOSTAT=ios][,ERR=err][,END=end]) [iolist]

  Unformatted direct access READ:

    READ (UNIT=u,REC=rec[,IOSTAT=ios][,ERR=err]) [iolist]

  Unformatted indexed READ:

    READ (UNIT=u,KEY=k[,KEYID=n][,IOSTAT=ios][,ERR=err]) [iolist]

  Unformatted sequential WRITE:

    WRITE (UNIT=u,[,IOSTAT=ios][,ERR=err]) [iolist]

  Unformatted direct access WRITE:

    WRITE (UNIT=u,REC=rec[,IOSTAT=ios][,ERR=err]) [iolist]

  Unformatted indexed WRITE:

    WRITE (UNIT=u[,IOSTAT=ios][,ERR=err]) [iolist]

3  –  List-Directed

  List-directed I/O statements are similar to formatted statements in
  function, but control the translation of data through data types
  instead of explicit format specifiers.

  List-directed I/O statements specify a format (FMT=) in the control
  list (clist).  Other "clist" elements are required depending on the
  type of access.

  List-directed sequential READ:

    READ (UNIT=u,FMT=*[,IOSTAT=ios][,ERR=err][,END=end]) [iolist]
    READ * [,iolist]

  List-directed internal READ

    READ (UNIT=u,FMT=*[,IOSTAT=ios][,ERR=err][,END=end]) [iolist]

  List-directed sequential WRITE

    WRITE (UNIT=u,FMT=*[,IOSTAT=ios][,ERR=err]) [iolist]

  List-directed internal WRITE

    WRITE (UNIT=u,FMT=*[,IOSTAT=ios][,ERR=err]) [iolist]

4  –  Namelist

  Namelist I/O statements are similar to formatted statements in
  function, but control the translation of data through data types
  instead of explicit format specifiers.

  Namelist I/O statements do not specify a format (FMT=) in the
  control list (clist).

  Namelist sequential READ:

     READ (UNIT=u,NML=nml[,IOSTAT=ios][,ERR=err][,END=end])
     READ n

  Namelist sequential WRITE:

    WRITE (UNIT=u,NML=nml[,IOSTAT=ios][,ERR=err])

  Comments (beginning with !  only) can appear anywhere in namelist
  input.  The comment extends to the end of the source line.