Scenarios

These examples take place in the Pacific Time zone, where Pacific Daylight Time (PDT) is an hour later (ahead) of Pacific Standard Time (PST).

The official practice of observing daylight saving time is in the spring (generally in April), to move the time later (ahead) by one hour so that 2:00 A.M. PST will become 3:00 A.M. PDT.

In the autumn (in October), the time is moved one hour earlier (backwards) at 2:00 A.M. PDT to become 1:00 A.M. PST.

Each row in Table 1 is based on a time-initiated EXEC named BACKUP that has specified

  • a start time when the EXEC should run

  • either an end time when the EXEC should stop running or stop count (which specifies how many times the EXEC runs)

    Note

    Even when you specify a stop count instead of an end time, MainView AutoOPERATOR still internally calculates and converts the stop count to an end time and therefore, when the MVS Local Time changes, the number of times that the time-initiated EXEC runs might be affected and the EXEC will run more or fewer times.

  • an interval (20 minutes)

Table 1. Daylight saving time examples

Scenario

If a time-initiated EXEC is scheduled to run

Column 1: Changing the MVS system clock forward from 2:05 A.M. to 3:05 A.M., the EXEC

Column 2: Changing the MVS system clock backward from 2:05 A.M. to 1:05 A.M., the EXEC

A

start time = 1:00 A.M.

end time = 1:40 A.M.

The EXEC should execute 3 times from 1:00 A.M. to 1:40 A.M.

executes normally at

  • 1:00 A.M. PST
  • 1:20 A.M. PST
  • 1:40 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT.

executes a complete cycle at 1:00 A.M. PDT and a partial cycle after 1:05 A.M. PST, executing for a total of 5 times:

  • 1:00 A.M. PST
  • 1:20 A.M. PST
  • 1:40 A.M. PST

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST and the EXEC begins executing again at

  • 1:20 A.M. PST
  • 1:40 A.M. PST

B

start time = 1:00 A.M.

end time = 2:20 A.M.

The EXEC should execute 5 times from 1:00 A.M. to 2:20 A.M.

executes a partial cycle at 1:00 A.M. and stops earlier than expected at 2:05 PST, executing only 4 times:

  • 1:00 A.M. PST
  • 1:20 A.M. PST
  • 1:40 A.M. PST
  • 2:00 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute for the last time at 2:20

executes a partial cycle at 1:00 A.M. PDT and a partial cycle at 1:00 A.M. PST, executing for a total of 8 times:

  • 1:00 A.M. PST
  • 1:20 A.M. PST
  • 1:40 A.M. PST
  • 2:00 A.M. PST

At 2:05 PDT, the time changes backwards to 1:05 A.M. PST so the EXEC does not execute for the last time at 2:20.

The EXEC starts executing again at

  • 1:20 A.M. PST
  • 1:40 A.M. PST
  • 2:00 A.M. PST
  • 2:20 A.M. PST

C

start time = 1:00 A.M.

count = 5

Note that MainView AutoOPERATOR internally calculates that count = 5 is equivalent to specifying a stop time ending at 2:20 A.M.

executes a partial cycle at 1:00 A.M. and stops earlier than expected at 2:05 PST, executing only 4 times:

  • 1:00 A.M. PST
  • 1:20 A.M. PST
  • 1:40 A.M. PST
  • 2:00 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute for the last time at 2:20

executes a partial cycle at 1:00 A.M. PDT and a partial cycle at 1:00 A.M. PST, executing for a total of 8 times:

  • 1:00 A.M. PST
  • 1:20 A.M. PST
  • 1:40 A.M. PST
  • 2:00 A.M. PST

At 2:05 PDT, the time changes backwards to 1:05 A.M. PST so the EXEC does not execute for the last time at 2:20.

The EXEC starts executing again at

  • 1:20 A.M. PST
  • 1:40 A.M. PST
  • 2:00 A.M. PST
  • 2:20 A.M. PST
Example for row C, column 1

EXEC: runs1   runs2   runs3   runs4   clock 
                                     changes
                                    does not run
PST   1:00am  1:20am  1:40am  2:00am  2:05am
-------+-------+-------+-------+-------+-------+------+-----
PDT                                   3:05am  3:10am  3:30am
Example for row C, column 2

EXEC: runs1  runs2  runs3 runs4   clock  runs5  runs6  runs7  runs8
                                  changes                         
PST                               1:05am 1:20am 1:40am 2:00am 2:20am
-------+------+------+------+------+------+------+------+------+---
PDT   1:00am 1:20am 1:40am 2:00am 2:05am

D

start time = 1:30 A.M.

end time = 1:50 A.M.

The EXEC should execute 2 times starting at 1:30 A.M.

executes normally at

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT.

executes through 2 complete cycles beginning at 1:30 A.M. PDT and again at 1:30 A.M. PST, executing for a total of 4 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST and the EXEC begins executing again at

  • 1:30 A.M. PST
  • 1:50 A.M. PST

E

start time = 1:30 A.M.

end time = 2:30 A.M.

The EXEC should execute 4 times starting at 1:30 A.M.

executes a partial cycle at 1:30 A.M. and stops earlier than expected, executing only 2 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute for the last 2 times at 2:10 A.M. PST and 2:30 A.M. PST.

executes a partial cycle at 1:30 A.M. PDT and executes a complete cycle at 1:30 A.M. PST, executing for a total of 6 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST and the EXEC begins executing again at

  • 1:30 A.M. PST
  • 1:50 A.M. PST
  • 2:10 A.M. PST
  • 2:30 A.M. PST

F

start time = 1:30 A.M.

end time = 3:30 A.M.

The EXEC should execute 7 times starting at 1:30 A.M.

executes a partial cycle at 1:30 A.M. and stops earlier than expected, executing only 4 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute at 2:10, 2:30, and 2:50 A.M. PST but continues at

  • 3:10 A.M. PDT
  • 3:30 A.M. PDT

executes a partial cycle at 1:30 A.M. PDT and executes a complete cycle at 1:30 A.M. PST, executing for a total of 9 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST and the EXEC begins executing again at

  • 1:30 A.M. PST
  • 1:50 A.M. PST
  • 2:10 A.M. PST
  • 2:30 A.M. PST
  • 2:50 A.M. PST
  • 3:10 A.M. PST
  • 3:30 A.M. PST

G

start time = 1:30 A.M.

count=5

Note

MainView AutoOPERATOR internally calculates that count = 5 is equivalent to specifying a stop time ending at 2:50 A.M.

executes a partial cycle at 1:30 A.M. and stops earlier than expected, executing only 2 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute for the last 3 times at 2:10, 2:30 and 2:50.

executes a partial cycle at 1:30 A.M. PDT and executes a complete cycle at 1:30 A.M. PST, executing for a total of 7 times:

  • 1:30 A.M. PST
  • 1:50 A.M. PST

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST and the EXEC begins executing again at

  • 1:30 A.M. PST
  • 1:50 A.M. PST
  • 2:10 A.M. PST
  • 2:30 A.M. PST
  • 2:50 A.M. PST
Example for row G, column 1

EXEC: runs1   runs2            clock
                              changes
PST   1:30am  1:50am  2:00am  2:05am
-------+-------+-------+-------+-------+-------+------+-----
PDT                           3:05am  3:10am  3:30am 3:50

The EXEC runs for a total of 2 times.

H

start time = 2:30 A.M.

end time = 2:50 A.M.

The EXEC should execute 2 times starting at 2:30 A.M.

does not execute at all as the clock time is changed

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute at 2:30 or 2:50.

executes through 1 complete cycle but the cycle begins 3.5 hours after midnight instead of 2.5 hours after midnight

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST so the EXEC does not run at 2:30 PDT but when the time becomes 2:30 A.M. PST, the EXEC begins executing at

  • 2:30 A.M. PST
  • 2:50 A.M. PST

I

start time = 2:30 A.M.

end time = 3:50 A.M.

The EXEC should execute 5 times starting at 2:30 A.M.

executes a partial cycle executing 3 times starting at 3:10 A.M. PDT

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute at 2:30, 2:50 A.M. and starts to run at

  • 3:10 A.M. PDT
  • 3:30 A.M. PDT
  • 3:50 A.M. PDT

executes through 1 complete cycle but the cycle begins 3.5 hours after midnight instead of 2.5 hours after midnight

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST so the EXEC does not run at 2:30 PDT but when the time becomes 2:30 A.M. PST, the EXEC begins executing at

  • 2:30 A.M. PST
  • 2:50 A.M. PST
  • 3:10 A.M. PDT
  • 3:30 A.M. PDT
  • 3:50 A.M. PDT

J

start time = 2:30 A.M.

count = 2

Note

MainView AutoOPERATOR internally calculates that count = 2 is equivalent to specifying a stop time ending at 2:50 A.M. in the morning.

does not execute at all as the clock time is changed:

At 2:05 A.M. PST, the time changes to 3:05 A.M. PDT so the EXEC does not execute at 2:30 and 2:50 A.M. in the morning.

executes through 1 complete cycle but the cycle begins 3.5 hours after midnight instead of 2.5 hours after midnight

At 2:05 A.M. PDT, the time changes backward to 1:05 A.M. PST so the EXEC does not run at 2:30 but when the time becomes 2:30 A.M. PST, the EXEC begins executing at

  • 2:30 A.M. PST
  • 2:50 A.M. PST

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