Red Alert - Daylight Saving Time adjustment may not be reported correctly by Language Environment (LE) callable services if PTFS UI48771 / UI48801 / UI48802 are applied.

Date: 2017.10.27

Title:

Daylight Saving Time adjustment may not be reported correctly by Language Environment (LE) callable services if PTFS UI48771 / UI48801 / UI48802 are applied.

Users Affected:

All users with PTFs UI48771 / UI48801 / UI48802 installed, and change system time dynamically (ie without an IPL and regardless of technique).

Description:

A problem was introduced by Language Environment APAR PI78252 which is causing applications to receive an incorrect current local time value after a dynamic change to the system time, such as a Daylight Saving Time (DST) change. PTFs of PI78252 have been marked PE and PI89400 opened.

If you do NOT have the fixes for APAR PI78252 (i.e. PTFs UI48771 / UI48801 / UI48802) then you are NOT impacted by this alert.

A dynamic time change could be made in several ways, including:

• A DST change made via STP - System Timer Protocol (automatically or manually via HMC panel)
• SET TIMEZONE
• SET DATE
• SET CLOCK

If the time change is introduced via an IPL, then LE services will return the correct time. However, if the time change is introduced dynamically, subsequent calls to LE services may return the incorrect time.

The types of applications that are affected are Language Environment applications that make use of:

• Language Environment date/time callable services related to the local time: CEELOCT and CEEGMTO
• High-level language semantics that make use of these services, including the COBOL ACCEPT FROM TIME statement and the CURRENT-TIME function
• PL/I application which uses functions like date(), time(), datetime(), days(), and secs() which invoke the above services under the covers.

Recommended Actions:

Option 1: If the PTFs for PI78252 have not been ACCEPTed, you may back off (i.e. SMP/E RESTORE) the PTFs. This action requires an IPL in order to take effect.

Option 2: You may install the appropriate APAR fix for PI89400. Note that this is a temporary fix that backs out the incorrect code that was added by the PTFs for PI78252. Please refer to details in APAR PI89400 'LOCAL FIX' section to obtain information about ++APARs that are currently available and how to apply them.

Option 3: If option 1 or 2 cannot be done prior to the time change, then introduce the time change via an IPL. If using STP this means ensuring all the systems with the PE PTFs are down when the clock change takes place and IPLing afterwards. If not using STP, then the time change can be introduced via the CLOCKxx member by IPLing at a time determined by the customer.

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