/sys$common/syshlp/helplib.hlb CONVERT, file, Qualifiers, /PROLOG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specifies the prolog version number of the output indexed file.

    Format

      /PROLOG=n

    Specifies the prolog number 1, 2, or 3.

    If you specify 2 for n, the output file will be either a Prolog 1
    or a Prolog 2 file.

    If you specify 3, the Convert utility creates a Prolog 3 file
    for output. Prolog 3 files accept multiple keys (or alternate
    keys), all data types, and segmented keys. The only restriction
    to using a Prolog 3 file applies to files containing overlapping
    key segments for the primary key. In this case, you would have to
    use a Prolog 2 file. If you do not specify the /PROLOG qualifier,
    the Convert utility uses the prolog version of the first input
    file. If the input file is not indexed, the utility uses the RMS
    default. To see what this default is on your system, enter the
    DCL command SHOW RMS_DEFAULT.

    The /PROLOG qualifier overrides the value given with the FDL
    attribute KEY PROLOG.