Does someone capture and archive these amazing discussions? Pardon silly questions from a newcomer.
This kind of knowledgeable exchange is what the ITU is missing. There are sound technical reasons for retaining or dispensing with the leap second. They need to be exposed, and the proponent of each should consider what others would have to do in order to accommodate an alternative. This discussion thread does that but only to a small audience of geeks. To reveal my bias, if the situation is this arguable, why change anything? We conjecture that whatever the cost or inconvenience of living with the leap second, the costs and difficulties of deprecating the leap second might be greater. It is most a matter of who pays the bill. Dave Finkleman Senior Scientist Center for Space Standards and Innovation Analytical Graphics, Inc. 7150 Campus Drive Colorado Springs, CO 80920 Phone: 719-510-8282 or 719-321-4780 Fax: 719-573-9079 Discover CSSI data downloads, technical webinars, publications, and outreach events at www.CenterForSpace.com. -----Original Message----- From: leapsecs-boun...@leapsecond.com [mailto:leapsecs-boun...@leapsecond.com] On Behalf Of leapsecs-requ...@leapsecond.com Sent: Friday, September 03, 2010 1:01 PM To: leapsecs@leapsecond.com Subject: LEAPSECS Digest, Vol 45, Issue 11 Send LEAPSECS mailing list submissions to leapsecs@leapsecond.com To subscribe or unsubscribe via the World Wide Web, visit http://six.pairlist.net/mailman/listinfo/leapsecs or, via email, send a message with subject or body 'help' to leapsecs-requ...@leapsecond.com You can reach the person managing the list at leapsecs-ow...@leapsecond.com When replying, please edit your Subject line so it is more specific than "Re: Contents of LEAPSECS digest..." Today's Topics: 1. Re: h2g2 (Nero Imhard) 2. Re: LEAPSECS Digest, Vol 45, Issue 1 (Tony Finch) 3. Re: LEAPSECS Digest, Vol 45, Issue 1 (Tony Finch) 4. Re: h2g2 (M. Warner Losh) 5. Re: h2g2 (Michael Sokolov) 6. Re: h2g2 (Ian Batten) 7. Re: LEAPSECS Digest, Vol 45, Issue 1 (Poul-Henning Kamp) 8. Re: h2g2 (Paul Sheer) ---------------------------------------------------------------------- Message: 1 Date: Fri, 3 Sep 2010 19:37:37 +0200 From: Nero Imhard <n...@pipe.nl> Subject: Re: [LEAPSECS] h2g2 To: Leap Second Discussion List <leapsecs@leapsecond.com> Message-ID: <67efec27-33c2-4d35-a48f-f7be2ed7d...@pipe.nl> Content-Type: text/plain; charset=us-ascii On 2010-09-03, at 15:56, p...@2038bug.com wrote: >> on the SAME time. Nobody cares here that solar time and civil time >> are 43 minutes off. > > *I* care Warner seems to be missing (or ignoring?) the point. The difference doesn't matter, the fact that the difference is constant does. N ------------------------------ Message: 2 Date: Fri, 3 Sep 2010 18:49:29 +0100 From: Tony Finch <d...@dotat.at> Subject: Re: [LEAPSECS] LEAPSECS Digest, Vol 45, Issue 1 To: Leap Second Discussion List <leapsecs@leapsecond.com> Message-ID: <alpine.lsu.2.00.1009031840050.31...@hermes-1.csi.cam.ac.uk> Content-Type: TEXT/PLAIN; charset=US-ASCII On Fri, 3 Sep 2010, Rob Seaman wrote: > On Sep 3, 2010, at 2:18 AM, Tony Finch wrote: > > > If you are syncing to what is now called "GMT" you are syncing to UTC > > because they are now in practice exact synonyms. > > And this is precisely what the ITU is planning to break. I'm not sure that's true. The only de jure definition of GMT is "civil time in the UK in winter". The British government and its agencies currently implement GMT as equivalent to UTC. If the ITU change the definition of GMT, and if the British government continues to follow ITU recommendations and to disregard the historical astronomical meaning of GMT, then the equivalence will continue. Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7, DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR ROUGH. RAIN THEN FAIR. GOOD. ------------------------------ Message: 3 Date: Fri, 3 Sep 2010 19:06:34 +0100 From: Tony Finch <d...@dotat.at> Subject: Re: [LEAPSECS] LEAPSECS Digest, Vol 45, Issue 1 To: Leap Second Discussion List <leapsecs@leapsecond.com> Message-ID: <alpine.lsu.2.00.1009031853220.31...@hermes-1.csi.cam.ac.uk> Content-Type: TEXT/PLAIN; charset=US-ASCII On Fri, 3 Sep 2010, Zefram wrote: > Tony Finch wrote: > > As we have seen there are a lot of intricate > >details whose necessity people can legitimately disagree about and no way > >to determine an official consensus. Which is why I say that astronomical > >GMT doesn't exist. > > Interesting argument. I disagree with your central point: I don't > think an official realisation of GMT is required in order for GMT to > meaningfully exist. Note that in the above I'm talking about astronomical GMT. There is an official realisation of legal GMT, and it is UTC. If you create a new astronomical timescale it would be wrong to claim it is GMT. GMT(Zefram) is probably OK though :-) > Making a clear distinction between ideal and realisation smells like > modern behaviour; considering the many different meanings of "GMT" that > have already been identified, I would not be surprised at it being > irretrievably ambiguous in this respect. Yes, definitely. I'm stretching when I claim that the practical realities of time in the UK are enough to unambiguously define GMT == UTC (obviously, or we wouldn't be having this discussion). > Does anyone have relevant historical documentation on the philosophical > definition of GMT? This is brief and sketchy: http://www.nmm.ac.uk/explore/astronomy-and-time/astronomy-facts/history/ the-longitude-of-greenwich Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7, DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR ROUGH. RAIN THEN FAIR. GOOD. ------------------------------ Message: 4 Date: Fri, 03 Sep 2010 12:04:39 -0600 (MDT) From: "M. Warner Losh" <i...@bsdimp.com> Subject: Re: [LEAPSECS] h2g2 To: leapsecs@leapsecond.com, n...@pipe.nl Message-ID: <20100903.120439.431102609638877642....@bsdimp.com> Content-Type: Text/Plain; charset=us-ascii In message: <67efec27-33c2-4d35-a48f-f7be2ed7d...@pipe.nl> Nero Imhard <n...@pipe.nl> writes: : : On 2010-09-03, at 15:56, p...@2038bug.com wrote: : : >> on the SAME time. Nobody cares here that solar time and civil time : >> are 43 minutes off. : > : > *I* care : : Warner seems to be missing (or ignoring?) the point. : : The difference doesn't matter, the fact that the difference is constant does. I'm asking these question: Why does it matter so much? What does keeping things in sync buy you that merely measuring the difference and knowing that number doesn't? Why must UTC be used as the method to synchronize "noon and the sun is approx overhead" when we have wide timezones that already do that function? Does the cost of synchronizing to UTC exceed the benefits from synchronizing there and not at a different, easier to change level? Given the changes in how time is used, propagated, etc, in the last 20, 50 or 100 years, does it make sense to reevaluate things? We've undergone a fairy radical paradigm shift in how time is used and consumed in the past 20 years. Doesn't it make sense to reevaluate the system to make sure those items that used to be no big deal but have become big cost items still fit the needs of the majority of the users? Time was when there were hundreds of different fields that relied on having good time to know where they were (navigators, surveyors, etc), but with GPS eliminating those users of UTC, do we have enough of a community of |DUT1| < 1s to justify the costs to the rest of the world, or is it time that this crowd shoulder the costs of the raw data they need? Those are the questions I'm asking... Oh, and with Daylight Savings Time, the difference isn't even constant anymore. And why does MEAN solar time matter more than ACTUAL solar time? And what flavor of MEAN solar time is best? What does solar time mean on mars, the moon, etc? Warner ------------------------------ Message: 5 Date: Fri, 3 Sep 2010 18:31:32 GMT From: msoko...@ivan.harhan.org (Michael Sokolov) Subject: Re: [LEAPSECS] h2g2 To: leapsecs@leapsecond.com Message-ID: <1009031831.aa04...@ivan.harhan.org> p...@2038bug.com wrote: > > Nobody cares here that solar time and civil time > > are 43 minutes off. > > *I* care I do too! > but I'm not important - I'm just one person There are TWO of us now! > many people might care and many people are not getting to make > the decision because the decision is being made for them. That is why I am making preparations for generating my own synthetic time scale that is steered to serve a realization of MST, contingency plans for the day when we may no longer be able to depend on Daniel Gambis to do it for us. I really liked your earlier idea of setting up an NTP server that would serve a smooth, variable-rate timescale like UT1 or UTS or UTC-SLS, and have an associated pledge to continue serving this form of Earth-following time regardless of what the ITU does to UTC. I am thinking along very similar lines myself. > further, it's not a decision we can *ever* go back on once it is > made because reversing back to solar to time would be politically > far too difficult to get collaboration on. But as long as you and I continue to operate our own law-defiant NTP servers which serve our realization of Earth time instead of the s**t that ITU peddles, those nature-loving people who wish to live their personal lives on mean solar time can simply choose to point their own ntpd instances at our servers instead of those following the ITU - problem solved. Furthermore, there are still quite a few countries left on Earth whose system of rulership is very non-Western. Perhaps we can convince Raul Castro or Hugo Chavez to use MST instead of ITU time as the basis of legal time in Cuba or Venezuela, and to take their time reference from our "rebel" NTP servers? Or perhaps we can team with the folks in the Arab world who are working on the Mecca Time idea? I would be very willing to work with *anyone* who is in favor of Earth-anchored time. > that some NASA/ITU/whoever people find leap seconds "inconvenient" > for programmers is NOT sufficient reason to ever have started > pursuing this agenda. Total agreement! MS ------------------------------ Message: 6 Date: Fri, 3 Sep 2010 19:34:59 +0100 From: Ian Batten <i...@batten.eu.org> Subject: Re: [LEAPSECS] h2g2 To: Leap Second Discussion List <leapsecs@leapsecond.com> Message-ID: <7a21eaec-bb0a-4966-a8db-86b084df0...@batten.eu.org> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes > do we > have enough of a community of |DUT1| < 1s to justify the costs to the > rest of the world, or is it time that this crowd shoulder the costs of > the raw data they need? Of course, one issue is that it's not a matter of |DUT1|<1s, but having DUT1 at all. The formats by which DUT1 is propagated in time signals deeply assume <1, so if it became >1 it couldn't be propagated in those signals. Which means that any and all equipment that consumes it is instantly broken, as it can't recover UT1. Even if the format could accommodate >1, of course, one assumes that almost all sane implementations would sanity check the value of DUT1 to confirm it's <1, so would reject the larger value anyway. You could modify the format, but you'd have to do so in a way which didn't then break all the equipment that wants UTC but pokes around in the extra data to recover the date, or the summer time indicator, or whatever. And it would involve replacing all the UT1 equipment anyway. I don't know, and I suspect the ITU don't either, how much (if, indeed, there is any) equipment is currently consuming the DUT1 portion of the national time standards, and why. ian ------------------------------ Message: 7 Date: Fri, 03 Sep 2010 18:50:16 +0000 From: "Poul-Henning Kamp" <p...@phk.freebsd.dk> Subject: Re: [LEAPSECS] LEAPSECS Digest, Vol 45, Issue 1 To: Leap Second Discussion List <leapsecs@leapsecond.com> Message-ID: <89565.1283539...@critter.freebsd.dk> In message <alpine.lsu.2.00.1009031840050.31...@hermes-1.csi.cam.ac.uk>, Tony F inch writes: >If the ITU change the >definition of GMT, and if the British government continues to follow ITU >recommendations and to disregard the historical astronomical meaning of >GMT, then the equivalence will continue. Just to highlight how laughable the retroimperialist love for GMT is: Which exact meridian are we talking about again ? Are we talking about the meridian Airy drew through his telescope or the one we actually use, about 100m east of his telescope ? Did anybody in England gather an orderly mob around GMT, to protect its imperial virginity, when the WGS84 redefinition of the geodesic origo changed it by five and a half second ? Let me remind you that WGS84 _also_ redefined UTC. Can we please drop this nonsense now ? Or at least queue it, where it belongs, behind the still pending tax-refund for the 12 missing days in september 1752 ? Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ------------------------------ Message: 8 Date: Fri, 03 Sep 2010 20:59:31 +0200 From: Paul Sheer <p...@2038bug.com> Subject: Re: [LEAPSECS] h2g2 To: Leap Second Discussion List <leapsecs@leapsecond.com> Cc: Michael Sokolov <msoko...@ivan.harhan.org> Message-ID: <1283540371.2334.27.ca...@localhost> Content-Type: text/plain > I really liked your earlier idea of setting up an NTP server that would > serve a smooth, variable-rate timescale like UT1 or UTS or UTC-SLS, and > have an associated pledge to continue serving this form of Earth-following > time regardless of what the ITU does to UTC. I am thinking along very > similar lines myself. really, it would be a bit of a gimmick if you are serious though and implement some server and client softare - I'd be happy to host the downloads and deploy on 2038bug.com > But as long as you and I continue to operate our own law-defiant NTP > servers which serve our realization of Earth time instead of the s**t > that ITU peddles, those nature-loving people who wish to live their > personal lives on mean solar time can simply choose to point their own > ntpd instances at our servers instead of those following the ITU - > problem solved. well the number of user's we are likely to accrue would be small - most people that use NTP need their servers to stay within a few milliseconds of everyone else - that is *why* they use NTP. -paul ------------------------------ _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs End of LEAPSECS Digest, Vol 45, Issue 11 **************************************** _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs