On Sat, 29 Dec 2018 05:21:30 +0000, Farley, Peter x23353 wrote:
>"A STCK value came from the clock and is not to be considered UTC time."
>
>Then what is STP/NTP (or whatever the current mechanism is named) supposed to
>do? Isn't the entire point of a hardware clock-setting mechanism to set the
>hardware clock to some agreed-upon and internationally-supported standard
>time? Isn't that agreed-upon time (**at IBM's strong recommendation**) at
>least UTC time? If so then STCK/STCKE/STCKF do indeed produce UTC time as a
>function of the IBM-chosen hardware epoch. QED.
>
I believe otherwise. In order to avoid discontinuities at leap seconds of the
sort
that cause network failures:
https://en.wikipedia.org/wiki/Leap_second#Examples_of_problems_associated_with_the_leap_second
the TOD clock runs (**at IBM's strong recommendation**) at a constant rate,
TAI - 10 seconds. (I know no clear documentation of this (can someone help
me?),
but inferred it by converting the hex values in the PoOps.) So I believe that
STCK
followed by STCKCONV will return TAI - 10 seconds at the instant of the STCK.
Not
very useful, nor intuitive. The more reason for documenting affirmatively, not
merely stating what it *does*not*do*.
-- gil
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