Daylight Saving Time changes for IBM CL/SUPERSESSION and IBM CL/CONFERENCE



Information about how changes to Daylight Saving Time (DST) in 2007 may affect systems and applications, worldwide.


A provision of the US Energy Policy Act of 2005 extends DST by four weeks, beginning in 2007. Several countries (Canada, Bermuda) are also implementing the same DST change; other countries are expected to make similar changes.

DST in 2009 begins the second Sunday in March (8 March) and ends the first Sunday in November (1 November). Systems or applications that process dates and times could be affected by this change. If not addressed, time and date calculations could be incorrect.

DST in 2010 begins on 14 March and ends on 7 November

DST in 2011 begins on 13 March and ends on 6 November

DST in 2012 begins on 11 March and ends on 4 November

How do I know if my systems could be affected?
Your systems are likely to be affected by this change, even if you are operating outside of the US.

Date and time processing functions in systems and applications in countries implementing the new DST rules (U.S., Canada, Bermuda) are affected. Systems and applications in countries not implementing the DST changes could be impacted if they support users, transactions or applications originating in countries which are implementing the new DST rules. For example, scheduling or synchronizing problems may arise where systems make or check date or time stamps relating to transactions in other countries, or there may be difficulty in scheduling meetings.

What will happen if I fail to update my systems?
Systems or applications that rely on date or time processing functions could make incorrect calculations. Calendar, scheduling, or synchronizing problems could arise where systems use date or time stamps, or if dates or times are processed or manipulated in any way.

In short, if your system makes date or time calculations, you may experience calculation errors.

What do I need to do to protect my systems and applications?
Some systems and applications can be fixed now. Other systems and applications recognize only one DST rule at a time and should not be patched until after the first Sunday in November, 2006 when the US has returned to Standard Time.

This site will help you find the necessary information for affected products so that you can plan updates and eliminate the risk of application failure.

There are no fixes for either IBM CL/SUPERSESSION or IBM CL/CONFERENCE.

The workaround is to issue the TIME RESET command, or recycle the address space.

Cross Reference information
Segment Product Component Platform Version Edition
Host Transaction Processing IBM CL/CONFERENCE Availability z/OS 1.4.1

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