Notably NTPd doesn't support leap-smear, which means those who absolutely must have monotonic time can't use it at all.
... shouldn’t be using a Unix timestamp, or anything else that’s not a count of SI seconds elapsed since a fixed reference point, to begin with.
[1] https://people.csail.mit.edu/rachit/post/you-have-built-a-co..., https://news.ycombinator.com/item?id=29891428
It should be noted that there currently exists no standard, technical or statutory, for how to do leap smearing. If an event happens and you need to tie your timestamped event logs to the 'greater reality' in some legally binding way there's (AIUI) no way to do that.
A few years ago there was a draft on the idea:
* https://datatracker.ietf.org/doc/draft-stenn-ntp-leap-smear-...
And the currently-draft NTPv5 has something about:
* https://datatracker.ietf.org/doc/draft-ietf-ntp-ntpv5/
Though the flag simply says that the timescale is smeared and not (AFAICT) how it is being done.
See also perhaps RFC 8633 § 2.7.1:
[…]
Operators who have legal obligations or other strong requirements to
be synchronized with UTC or civil time SHOULD NOT use leap smearing
because the distributed time cannot be guaranteed to be traceable to
UTC during the smear interval.
[…]
Any use of leap-smearing servers should be limited to within a
single, well-controlled environment. Leap smearing MUST NOT be used
for public-facing NTP servers, as they will disagree with non-
smearing servers (as well as UTC) during the leap smear interval, and
there is no standardized way for a client to detect that a server is
using leap smearing. However, be aware that some public-facing
servers may be configured this way in spite of this guidance.
* https://datatracker.ietf.org/doc/rfc8633/ntpsec as a project seems to be doing ok. They are releasing new versions, fix reported issues, accept patches, and develop the code publicly. While ntp still has a huge list of acknowledged but unfixed CVEs.
It is not even his beliefs, though many of them are — to my ears and hopefully to most — quite repugnant.
It is his attitude, approach, and at various times the kinds of people he attracts.
As it goes, I've seen him speak, back in the 90s, CatB era. He was genial enough but he seemed to have a coterie around him of rather less pleasant people. It could just have been a bad day but it has stuck in my mind ever since: it was the first time I understood that there's not really any sort of inclsive geek community.
TAI (Temps Atomique International), is UTC without leap seconds and is the source of truth for "what time is it"
I'm finding conflicting reports of being able to actually use TAI on linux but there are several claims of at least specialty setups existing. You would absolutely not want smearing or anything like that in your time synchronization software in this case.