--- NEWS | 4 ++++ theory.html | 15 ++++++++++++++- tz-link.html | 8 ++++++-- 3 files changed, 24 insertions(+), 3 deletions(-) diff --git a/NEWS b/NEWS index 9b2d202..9ac3367 100644 --- a/NEWS +++ b/NEWS @@ -42,6 +42,10 @@ Unreleased, experimental changes 'restrict' keyword consistently with their documentation. This may allow future optimizations. + Changes to commentary + + Note that leap seconds are planned to be discontinued by 2035. + Release 2022g - 2022-11-29 08:58:31 -0800 diff --git a/theory.html b/theory.html index fbbb9e4..88bf720 100644 --- a/theory.html +++ b/theory.html @@ -818,7 +818,8 @@ href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanes <li> The relationship between POSIX time (that is, <abbr>UTC</abbr> but ignoring <a href="https://en.wikipedia.org/wiki/Leap_second">leap - seconds</a>) and <abbr>UTC</abbr> is not agreed upon after 1972. + seconds</a>) and <abbr>UTC</abbr> is not agreed upon. + This affects time stamps during the leap second era (1972–2035). Although the POSIX clock officially stops during an inserted leap second, at least one proposed standard has it jumping back a second instead; and in @@ -1268,6 +1269,18 @@ between now and the future time. <section> <h2 id="leapsec">Leap seconds</h2> +<p> +Leap seconds were introduced in 1972 to accommodate the +difference between atomic time and the less-regular rotation of the earth. +Unfortunately they caused so many problems with civil +timekeeping that they +are <a href="https://www.bipm.org/en/cgpm-2022/resolution-4">planned +to be discontinued by 2035</a>, with some as-yet-undetermined +mechanism replacing them, perhaps after the year 2135. +Despite their impending obsolescence, a record of leap seconds is still +needed to resolve timestamps from 1972 through 2035. +</p> + <p> The <code><abbr>tz</abbr></code> code and data can account for leap seconds, thanks to code contributed by Bradley White. diff --git a/tz-link.html b/tz-link.html index d3b3766..608393f 100644 --- a/tz-link.html +++ b/tz-link.html @@ -1078,8 +1078,12 @@ leap second: its history and possible future</a>. <a href="https://www.ucolick.org/~sla/leapsecs/"><abbr>UTC</abbr> might be redefined without Leap Seconds</a> gives pointers on this -contentious issue, which was active until 2015 and could become active -again.</li> +contentious issue. +The General Conference on Weights and Measures +<a href="https://www.bipm.org/en/cgpm-2022/resolution-4">voted in 2022</a> +to discontinue the use of leap seconds by 2035, replacing them with an +as-yet-undetermined scheme some time after the year 2135. +</li> </ul> </section> -- 2.38.1