Periodic Calendars

Some rules must be scheduled periodically, according to schedules that are not easily expressed in terms of fixed days and dates within months. In these cases, monthly, or even yearly, scheduling definition is awkward.

For example:

• A payroll rule needs to be scheduled every other Wednesday.
  • In some months, the rule may be scheduled on the first, third, and even fifth Wednesday in the month. In other months, it may be scheduled on the second and fourth Wednesday in the month.
  • In some years, the rule may be scheduled beginning on the first Wednesday of the year. In other years, it may be scheduled beginning on the second Wednesday of the year.
• A rule must be scheduled every 25 days, regardless of date. Such a rule is scheduled on different dates each month and each year.

The IOA Calendar facility provides special calendars, called periodic calendars, to allow specification of these scheduling requirements. These periodic calendars are very flexible.

To designate a calendar as periodic, you must type the reserved string ==PERIODIC== in the first 12 positions of the description field. Any text can be entered in the rest of the description field. This is illustrated in Figure 87.

Figure 87 Use of the Reserved String "==PERIODIC=="

COMMAND ===>                                                    SCROLL===> CRSR

YEAR 2002  -  ==PERIODIC== GENERAL WORKDAY CALENDAR                          

The following are characteristics of periodic calendars:

• In a periodic calendar, days are not marked using the letters Y (Yes) or N (No). Instead, a period identifier is used to mark working days in a period. A period identifier can be any letter from A to Z (except Y and N), any number from 0 to 9, or any other printable sign. If you need more characters, use characters falling within the hexadecimal range 4A through F9. All working days within the same period must be marked using the same period identifier character so that different identifier characters indicate different periods. Days that are not marked are nonworking days because they do not belong to any period in this calendar.
• Identifiers from different periods can be interspersed throughout a periodic calendar.
• A periodic calendar can consist of smaller units that do not correspond to regular months, in that they can be longer or shorter than regular months.
• A periodic calendar can span a period, called a "logical year", which can be longer or shorter than one regular calendar year.

  When a periodic calendar spans parts of two regular calendar years, special considerations are likely to arise. For more information, see Special Year-End Handling of Periodic Calendars.

• A period can span any number of days, but no more than a preset number of days can elapse after the appearance of one identifier in a period until the appearance of the next matching identifier in the same period. After that period expires, the next matching identifier starts a new period.

  By default, this period is preset to 33 days. Once the length of the gap between matching identifiers exceeds 33 days, the period automatically closes.

Note: The length of the default period can be changed from 33 days by the INCONTROL administrator, using optional Wish WM2888.

For more information on the use of periodic calendars, see DAYS: Basic Scheduling Parameter and WDAYS: Basic Scheduling Parameter.

Examples

The following are examples of periodic calendars:

Figure 88 Periodic Calendar – Example 1

-----S-------------S-------------S-------------S-------------S-------------S--

   1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1            

12                         A         A   A B   A                             

-----S-------------S-------------S-------------S-------------S-------------S--

         1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1      

01             B                                       B                     

-----S-------------S-------------S-------------S-------------S-------------S--

This example contains two periods, A and B.

• Period A starts on December 13 and ends on December 23. During this period, the defined working days are December 13, December 18, December 20, and December 23.
• Period B spans more than one calendar year. It starts on December 21 and ends on January 24. During this period, the defined working days are December 21, January 4, and January 24.

  Figure 89 Periodic Calendar – Example 2

-----S-------------S-------------S-------------S-------------S-------------S----

               1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1

    03                         B             A         B         A           

-----S-------------S-------------S----------0---S-------------S-------------S---

       1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 + 1 2 3 4 5 6 7 8 9 +           

   04                                                B                       

-----S-------------S-------------S-------------S-------------S-------------S--

This example includes a period B that begins on March 9. The last marked working day of the period is March 21, which is followed by a 33-day gap. Assuming that Wish WM2888 has not been used to alter the default period of 33 days, period B automatically ends on April 23, and April 24 marks the beginning of a new period B. If no more B identifiers are added, this new B period ends on May 27.