It depends. If you have an external time source (or the hardware STP feature), this is probably automatic. Check your CLOCKxx members in SYS1.PARMLIB.
The other alternative is to manually issue a SET TZ command at the appropriate time (either by automation or human). For the record, all of the major subsystems (DB2, IMS, CICS, z/OS, Websphere, BMC..., Compuware... CA,,, ) I am aware of need no intervention to handle the time change. The only remaining hurdle in most shops regarding time change is application logic. For the Spring time change there is usually no issue, for the Fall time change, many shops go idle for 1 hour to prevent the possibility of duplicate time stamps (based on local time). HTH, -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Charles Mills Sent: Wednesday, February 21, 2018 6:46 PM To: [email protected] Subject: Two summer time change questions First though, apologies for asking what perhaps has been covered before -- perhaps even asked by me. I am having no luck searching the archives. I search on CVTTZ and get no hits even though I have IBM-MAIN messages in my own Outlook that contain CVTTZ. 1. Humor a guy with almost no operations experience with the world's most newbie operations question. If you are a shop in North America, how will you "convert" your z/OS instances to summer time next month? Do you or does your console automation software have to enter a SET command, or does it happen automagically internally to z/OS on some pre-configured schedule? (I remember I had a P/390 back in the day and VM had an internal table that did the time change automagically but I recall I had to re-IPL OS/390 to pick up the change.) 2. When the above happens, will CVTTZ and CVTLDTO get updated on the fly? If I inspected them one second would I see an offset of, e.g., 8 hours (in TOD or "TOD-high word" format as appropriate) and if I inspected them a second later I would see 7 hours? Charles ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ::DISCLAIMER:: -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. E-mail transmission is not guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or may contain viruses in transmission. The e mail and its contents (with or without referred errors) shall therefore not attach any liability on the originator or HCL or its affiliates. Views or opinions, if any, presented in this email are solely those of the author and may not necessarily reflect the views or opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of authorized representative of HCL is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any email and/or attachments, please check them for viruses and other defects. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
