Got it! Thanks much.


-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On
Behalf Of George Kozakos
Sent: Wednesday, October 12, 2016 3:52 PM
Subject: Re: How set CVTLSO?

On 12/10/2016 05:45:48 PM, , Charles Mills wrote:
> @George, thanks. I'm looking at the from a software development point 
> of view, not a sysprog point of view.
> So if a shop is using an ETS and does not schedule the change then the
> clock will be steered into reflecting the leap seconds, right? The TOD 
> clock will slow down until it falls back to the correct time, right?

Yes, the TOD is steered to reflect the change in the ETS. This takes about
7 hours, the steering rate is 7 hours per second of adjustment.

> For a "Time Control Parameter Change event" where does the leap second
> reflected? Still in the hardware TOD clock? It effectively stops for 
> one second? Or in CVTLSO?

z/OS does not affect the hardware TOD clock. If the leap second change is
positive, Timer processing spins on all CPUs for the amount of the leap
second change and CVTLSO is updated. STCK time does not change but UTC/GMT
jumps backward due to the change in CVTLSO.

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