No. While UTC is preferred. it is normal to use local time when Linux and windows run on the same machine.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Mike Schwab <[email protected]> Sent: Saturday, October 25, 2025 10:36 AM To: [email protected] <[email protected]> Subject: Re: Time Change Delima External Message: Use Caution Yes, Linux require the PC set the BIOS clock to UTC, Windows requires you set the PC to Local time zone. On Sat, Oct 25, 2025 at 9:11 AM Jay Maynard < [email protected]> wrote: > Actually, Unix (at least; I can't speak to Windows) keeps all times > internally in UTC and only converts to local time for display. > > On Sat, Oct 25, 2025 at 8:59 AM Jon Perryman <[email protected]> wrote: > > > On Fri, 24 Oct 2025 16:01:50 -0500, Paul Gilmartin <[email protected] > > > > wrote: > > > > >This problem was solved long ago: <https://www.iana.org/time-zones> > > >Inexplicably, IBM shuns that solution, almost pervasive elsewhere. NIH? > > > > IANA solution does not solve the time change problem (DST nor ST). > > > > Unix & Windows completely ignore the implications of that hour change. > > These machines are so much slower where an hour time change goes > unnoticed. > > A single z/OS is many times more active and SYSPLEX makes this far more > > complex. > > > > >>that issuing the TIMEZONE W.05.00.00 or set CLOCK=hh.mm.ss commands > > should do the trick. > > > > Time change occurs on Sunday's at 2:00am which will go unnoticed but > there > > are still risks. > > > > Some STC's have an optional timezone specifications that can override the > > z/OS timezone (e.g. CICS) for the product. If you never use them, then > they > > most likely won't be a problem. > > > > Do you avoid specifically specifying Sunday between 1AM to 2AM (e.g. > > automation, job scheduler and more). For instance, does a job scheduled > for > > 1:30am run twice for DST and never run for ST. I would hope job > schedulers > > warn you but some products might not. > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > -- > Jay Maynard > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
