[tz] New Yorker article on David Mills and NTP

[Steffen Nurpmeso]

Garrett Wollman wrote in
 <25407.23180.512283.959616 at khavrinen.csail.mit.edu>:
 |<<On Thu, 6 Oct 2022 15:35:01 -0700, Guy Harris via tz <tz at iana.org> said:
 |> On Oct 6, 2022, at 1:41 PM, Brooks Harris via tz <tz at iana.org> wrote:
 |>> I would add that Posix relies on the c standard,
 |
 |> Which appears neither to mandate nor forbid leap seconds.
 ...
 |The POSIX standard, on the other hand, requires that time_t be an
 |integral type, and gives a closed-form formula for how a UTC time is
 |to be converted to a time_t which explicitly requires every day to be
 |exactly 86,400 seconds long.  (POSIX does not include tzcode's
 |timegm() interface; applications are expected to copy the formula from
 |the standard.)  The practical upshot of this is that POSIX systems
 |that implement leap seconds must tick the same second twice for a
 |positive leap second, and must skip a tick if there is ever a negative
 |leap second -- either way, making interval calculations inaccurate if

But only to throw in that for most systems which are not
always-on, and even for some which are, this is rather
hypothetic since hardware clocks that i know drift (and
Linux hwclock(8) documents "The Hardware Clock is usually not
very accurate. However, much of its inaccuracy is completely
predictable - it gains or loses the same amount of time every
day. This is called systematic drift.")

To misuse this drift (it is -2.577933 per ~35 hours here without
/etc/adjtime) to adjust clocks seems quite natural; to me being
able to keep a human clock (civil time) synchronized with the real
day length of our planet remains a cultural achievement, even
extending the according predictive capabilities of Stonehenge or
the Pyramids (in fact many cultures had something similar it
seems).

I agree it is all wrong and when i really focus on the problem
i am always frustrated how bad i code.
CLOCK_TAI would be an alternative for programming purposes, and
having a nice leap second table at hand is a good thing (on the
according ML PH-Kamp came over with a DNS-based solution for leap
announcement a few years back, later stating he was just
reiterating an idea from over a decade earlier: i jumped on this
idea, because i really liked it!)
Unfortunately CLOCK_TAI is not available everywhere.

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)