Allows you to define which days are primary days and which days
    are secondary days.

    The syntax for this qualifier is as follows:

        [/PRIMEDAYS = ([no]day[,...])]

    You specify primary days as MON, TUE, WED, THU, FRI, SAT, and
    SUN. You specify secondary days as NOMON, NOTUE, NOWED, NOTHU,
    NOFRI, NOSAT, and NOSUN.

    The default is MON through FRI and NOSAT and NOSUN. Any days
    omitted from the list take their default value. You can use the
    DCL command, SET DAY, to override the class definition of primary
    and secondary days.