The introduction of the period (.) as a literal character in
    extended file names requires RMS to determine which periods are
    file name characters and which are delimiters.

    When only one period (.) is used in an extended file name, that
    period is interpreted as the delimiter, as in "Venice.Venezia;1"
    above. As in previous versions of OpenVMS, this behavior also
    occurs if the single period is followed by a number:

    $ CREATE Test.1

    creates the file:

    Test.1;1

    When there are multiple periods (.) in a file name, the system
    looks at all the characters after the last period. If those
    characters are five or fewer digits, or a minus sign (-) followed
    by five or fewer digits, the period is interpreted as a version
    delimiter and the period previous to it is a type delimiter.
    Notice that a legal version is less than or equal to 32767.
    If you try to create the file "grandioso.x.33333", the "33333"
    causes an illegal version error. If there is a nonnumeric
    character following the last period then it is interpreted as
    a type delimiter.

    For example, the following command: $ CREATE Test4.3.2.1

    creates the file: Test4^.3.2;1

    where .2 is the file type and 1 is the file version.