VMS Help CONVERT, file, Qualifiers, /FIXED_CONTROL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Controls file conversions between files having variable-length
    with fixed-length control field (VFC) records and files having
    other record formats.

    Format

      /FIXED_CONTROL

      /NOFIXED_CONTROL  (DEFAULT)

    This qualifier applies only to conversions where either the input
    or the output file, but not both, uses VFC records. This option
    is applicable only to sequential files.

    o  If you specify /FIXED_CONTROL and the input file uses VFC
       records but the output file does not, the fixed-length control
       field from the input record is inserted into the output record
       as data.

    o  If you specify /FIXED_CONTROL and the output file has VFC
       records but the input file does not, the leading part of the
       input record is used to fill the fixed-length control part of
       the output record.

    o  If you specify /NOFIXED_CONTROL and the input file uses VFC
       records but the output file does not, the fixed-length control
       field from the input record is not included as data in the
       output record.

    o  If you specify /NOFIXED_CONTROL and the output file has
       VFC records but the input file does not, the control field
       attached to the output record is set to null.