From tvb at LeapSecond.com Wed Jun 6 11:11:22 2018 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 6 Jun 2018 08:11:22 -0700 Subject: [LEAPSECS] comments on UTC Message-ID: Below are recent threads about UTC on HN & reddit. There's a few comments about leap seconds as well. Read it not so much to learn something new about UTC or leap seconds, but to get a snapshot of real world timing problems that programmers face. "UTC Is Enough for Everyone, Right?" https://news.ycombinator.com/item?id=17181046 "UTC Is Enough for Everyone, Right?" https://www.reddit.com/r/programming/comments/8n1rrd/utc_is_enough_for_everyone_right/.compact?limit=500 /tvb From seaman at lpl.arizona.edu Wed Jun 6 12:57:18 2018 From: seaman at lpl.arizona.edu (Rob Seaman) Date: Wed, 6 Jun 2018 09:57:18 -0700 Subject: [LEAPSECS] comments on UTC In-Reply-To: References: Message-ID: Usual range of opinions. These guys think they've solved the problem for all time: ??? https://news.wisc.edu/thank-the-moon-for-earths-lengthening-day/ As you say, not much pertinent to leap seconds. Rob -- I'm not sure any solution created by a computer programmer is "real world" :-) -- On 6/6/18 8:11 AM, Tom Van Baak wrote: > Below are recent threads about UTC on HN & reddit. There's a few comments about leap seconds as well. Read it not so much to learn something new about UTC or leap seconds, but to get a snapshot of real world timing problems that programmers face. > > "UTC Is Enough for Everyone, Right?" > https://news.ycombinator.com/item?id=17181046 > > "UTC Is Enough for Everyone, Right?" > https://www.reddit.com/r/programming/comments/8n1rrd/utc_is_enough_for_everyone_right/.compact?limit=500 > > /tvb > > _______________________________________________ > LEAPSECS mailing list > LEAPSECS at leapsecond.com > https://pairlist6.pair.net/mailman/listinfo/leapsecs -------------- next part -------------- An HTML attachment was scrubbed... URL: From ashtongj at comcast.net Wed Jun 6 18:01:51 2018 From: ashtongj at comcast.net (GERRY ASHTON) Date: Wed, 6 Jun 2018 18:01:51 -0400 (EDT) Subject: [LEAPSECS] comments on UTC In-Reply-To: References:

Message-ID: <847774200.2007915.1528322511706@connect.xfinity.com> > On June 6, 2018 at 12:57 PM Rob Seaman wrote: > > > Usual range of opinions. These guys think they've solved the problem for > all time: > > https://news.wisc.edu/thank-the-moon-for-earths-lengthening-day/ > > As you say, not much pertinent to leap seconds. > > Rob > -- > > I'm not sure any solution created by a computer programmer is "real > world" :-) > -- > The work does not seem pertinent to near-term calculation of leap seconds. But it might be pertinent to establishing policy about leap seconds. One of the arguments that comes up in policy discussions is that in several thousand years, the method of adapting to changing LOD by leap seconds breaks down because more than one leap second will be required per day. But such calculations fall outside the range of validity of models typically used for ephemeris calculations. Those performing such calculations would have to select longer-term models. The longer-term models might be invalidated, at least at the extremes of their claimed range of validity. If a researcher's chosen model were shot down, over any part of its range, the researcher's conclusions would be cast into doubt, even if the researcher avoided the extremes of the model range. Gerard Ashton From sla at ucolick.org Thu Jun 7 00:51:42 2018 From: sla at ucolick.org (Steve Allen) Date: Wed, 6 Jun 2018 21:51:42 -0700 Subject: [LEAPSECS] the inception of leap seconds Message-ID: <20180607045142.GB12937@ucolick.org> Back in March Demetrios Matsakis objected to some of my web pages and also pointed out the role that Gernot Winkler had in their inception. That led me to dive deeper into the Lick Observatory Library and find more documents which present contemporary views of the people who were there at the inception. Among many things I have found is a paraphrase of Arthur C. Clarke in Childhood's End Leap Seconds are not for Navigation https://www.ucolick.org/~sla/leapsecs/leapincept.html Even deeper in the libary are other documents which shed light on things that went wrong before the inception of the earlier form of coordinated time in radio broadcasts. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From sla at ucolick.org Mon Jun 25 10:28:02 2018 From: sla at ucolick.org (Steve Allen) Date: Mon, 25 Jun 2018 07:28:02 -0700 Subject: [LEAPSECS] anybody watching the NTP pool? Message-ID: <20180625142802.GA9342@ucolick.org> It will be interesting to see how many systems try to implement a leap second at the end of this week. Sites with broken leapseconds files are invisible beforehand, but stuck NTP leap bits may be showing up already. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From dwmalone at maths.tcd.ie Mon Jun 25 10:31:02 2018 From: dwmalone at maths.tcd.ie (David Malone) Date: Mon, 25 Jun 2018 15:31:02 +0100 Subject: [LEAPSECS] anybody watching the NTP pool? In-Reply-To: <20180625142802.GA9342@ucolick.org> References: <20180625142802.GA9342@ucolick.org> Message-ID: <20180625143102.GA9116@walton.maths.tcd.ie> Hi Steve, > It will be interesting to see how many systems try to implement a > leap second at the end of this week. > Sites with broken leapseconds files are invisible beforehand, but > stuck NTP leap bits may be showing up already. I'm collecting my usual data. I will see if I update the graphs at: https://www.maths.tcd.ie/~dwmalone/time/leaps/ fairly promptly... David.