VMS Help RUN, Process, Qualifiers, /INTERVAL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /INTERVAL=delta-time

    Requests that the created process be placed in hibernation and be
    awakened at regularly scheduled intervals.

    Specify the delta time according to the rules given in the
    OpenVMS User's Manual or the online help topic DCL_Tips (subtopic
    Date_Time).

    If you specify the /DELAY or the /SCHEDULE qualifier with the
    /INTERVAL qualifier, the first wakeup request occurs at the
    time specified by the /DELAY or the /SCHEDULE qualifier; all
    subsequent wakeup requests occur at intervals specified by the
    /INTERVAL qualifier. If you specify neither the /DELAY nor the
    /SCHEDULE qualifier with the /INTERVAL qualifier, the first
    wakeup request occurs immediately by default.