As far as the computers were concerned, nothing was different.
It would have been better if they would have kept the time on the wire accurate or added mandatory protocol stuff to avoid confusing things for ntpds configured to different leap second handling.
If the question is "why bother syncing time to Earth's orbit around the sun at all", I don't have a good answer for that except at this point, it's tradition.
Correcting for a 3-minute offset every few millenia seems easier than trying to understand all this minutia about wobble and aquifer management and whatever else goes into a leap second.
Note that this is not an argument for leap seconds - just my understanding of their rationale.
GPS satellites probably handle it well too, but maybe some consumer or even industrial GPS receivers don't? Maybe some trading systems? I don't think crypto systems care too much.
I've worked on some extremely sensitive systems that had thousands of lines of C dedicated to handling skewing a time gap across an hour-per-second when necessary. I know that code assumed only "missing" time (jump-forwards)... Even knowing what I know as a developer now, if I was re-implementing that system from scratch and didn't have this top-of-mind, I'd bet I would miss "overlapping" or "duplicate" time entirely.
Maybe that is more of a me problem than others, but I'd bet there are some safety critical systems out there where the responsible engineers, QA, and specs all missed this as well.
But the meter/reporting tool would say "Well, we measure every second, and the meter reported a constant rate of 100 liter/second, and as we know we have 60 seconds in a minute, so we got 6000 liters!".
Or a database for "measurements every second for this minute" that has 60 fields, and don't have a field for the 61st measurement.
The last time this came up I thought “smearing” the second over the course of a day kind of solved the problem a discrete +/- 1 second suddenly appearing on the clocks.
We'll just get some poorly coded stuff claim that an operation took 1100ms instead of 100ms. Not great, but not -900ms.
Well, I say that, but per my link here F5 load balancers at least used to keep track of TCP connections using gettimeofday. And it's annoying that libpcap delivers metadata in wallclock time.
[1] https://blog.habets.se/2010/09/gettimeofday-should-never-be-...
Was involved in rolling out a large NTP annealing patch about ten years ago. We missed a couple and the effect was largely overall muted, but we did have one server with an old JVM hard crashing the server right at the second shift.
That specific server was already hobbling along so it wasn't a surprise. But it required a bit of firefighting.
d00d0ff000•4d ago
By any other standard, most manually set clocks are up to a full minute off all the time.
subscribed•4d ago
MiFID 2 alone forces sub-μs precision. Million times less than the leap 1 second.
NTP minute away is good for displaying date on the workstation, not for many of the devices that are critical to the modern world.
cyanydeez•4d ago
subscribed•4d ago
Sure they have their own time servers fed from the GPS, but they need to be _accurate_ in relation to the world.
But timestamps used by companies forced to use very accurate timing must be synchronised to UTC.