As far as I understand, CICS uses the local time in its logs, not UTC (and that's the reason that CICS must be kept down). So keeping CICS down for an hour will be enough. What the HW clock is doesn't matter for CICS. But, if you'd have DB2, that will use UTC -or more exact: the HW clock- in its logs (just like SFS), playing with the HW clock may mean you have to keep them down ...
2009/10/15 Shimon Lebowitz <shim...@iname.com> > Here in Israel we have already changed our clocks back, > but I need to understand a bit more about how CICS journaling > works with time changes. > > Until now, we have always had our hardware on local time. > (As you may guess, the Israel Police Dept. is not exactly > a multinational globe-spanning enterprise). > Because of an open PMR which had us very worried about doing > an IPL for our clock change, what we actually did was: > > 1) define a VM timezone with an offset of -1 hour > 2) close down CICS and VSE, and log off the VSE machine > 3) SET TIMEZONE in VM > 4) wait 1 hour > 5) restart VSE, whose time is defined as having an offset of zero > (NOT zone=VM!) > > This was my idea, because of the worry over the open PMR, but > actually I have wanted to work with SET TIMEZONE for years, > and the powers that be resisted it for whatever reasons. > > Now that everyone saw how much easier it was, I want to > schedule a real IPL (the PMR has been solved!) and set the > hardware clock to UTC so I can use two timezones: > standard time at UTC+2 and summertime at UTC+3. > > My question is: If I now > -- shut down my system at > 8PM local time, when our hardware clock is 9PM > (according to our current settings: the hardware is still set > to local summer time), > -- and I change the hardware clock to > 6PM (UTC, 2 hours behind standard local, and 3 behind > summer local), > -- and set the VM timezone to 'standard local' at UTC+2, > which will be 8PM > ----> what will happen with CICS? > Do I need to have it down for 3 hours (since the HW clock went > from 9PM to 6PM) ?? > Or can I start it up immediately (since the VM local time > stayed 8PM) ? > > Thanks for any explanations, > Shimon > > > -- > ************************************************************************ > Shimon Lebowitz mailto:shim...@iname.com > VM System Programmer . > Israel Police National HQ. > Jerusalem, Israel phone: +972 2 542-9877 fax: 542-9308 > ************************************************************************ > -- Kris Buelens, IBM Belgium, VM customer support
