What you need to know about Daylight Saving Time

In the United States, Daylight Saving Time (DST) officially begins the second Sunday of March and ends the first Sunday of November. For 2010, that means DST begins March 14 and ends November 7.

Whether you change the time manually or have the system change the time automatically, the most important thing to keep in mind is that Robot/SCHEDULE must be inactive when you make the time change.

Last year, an article in an industry newsletter made the complaint that Help/Systems doesn’t automatically switch Robot/SCHEDULE’s internal clock. That’s true—we don’t know the best time to move the clock forward or backward for your schedule. If we did this automatically at midnight, you might miss or rerun jobs.

You and your operations team should control your Daylight Savings changes because you understand your business schedule. For instance, some customers change the time before night processing; others wait until 7:00 a.m. to switch.

Three documents worth reading
Help/Systems has prepared three Help/FACTS documents to assist you in making decisions about how to handle the Daylight Savings changes. To get an overview, download "Daylight Saving Time Impact on the Robot Products."

Basically, there are two ways to make the time change in Robot/SCHEDULE:

1. Create a CL program to end Robot/SCHEDULE, change the time, and restart Robot/SCHEDULE. (You can set up a Robot/SCHEDULE job to call this program.) This approach is explained in the Help/FACTS “Using Robot/SCHEDULE to automate Daylight Saving Time change.” Note: In addition to restarting Robot/SCHEDULE, modify the program to restart Robot/ALERT and Robot/NETWORK so they also pick up the time change.
    
2. Use the QTIMZON system value to make the time change. You need to create two Robot/SCHEDULE jobs to make Robot/SCHEDULE inactive during the time change. Read the Help/FACTS “Using Robot/SCHEDULE with the QTIMZON System Value” for details.

Important! If you use the QTIMZON system value, IBM has issued Program Temporary Fixes (PTFs) that add updated time zone descriptions for older versions of the operating system (OS).

• For those of you still using V5R4, apply PTFs SI26040 and SI25990. Check with IBM for future PTFs.
• If you are using V6R1, no changes are required.

After you apply the appropriate PTFs for your OS level (if needed), you can change the QTIMZON system value to the new value for your region.

Note: If your system uses a Hardware Management Console (HMC), you may need to apply additional fixes.

Contributed by Jeanne Thiesfeld, Technical Consultant