On Fri 2018-07-20T14:23:38+0000 Nero Imhard hath writ: > Leap second smearing by an NTP server effectively means that it uses > a different time. Without a way to indicate, within the protocol, > what time a server uses (and there isn't because UTC is implicit) this > seems a really bad idea. > > On another level, I regard it as some sort of "technical betrayal" > which erodes trust in protocols and standards, rendering them less > useful than they could be. > > Isolate your workarounds and don't let them pollute your environment.
In the arena of leap seconds, technical betrayal and dilution of the protocols and standards began before the inception date. Gernot Winkler of USNO is credited as one of the people who suggested that the leap second could be the solution to the problem. Gernot Winkler reported that radio broadcast time signals operated by the USNO would follow TAI and not implement leap seconds, while at the same time the USNO Nautical Almanac tabulated events in Ephemeris Time and UT1. This is clearly the USNO making use of the "two time scales" scheme that since 1948 astronomers had been saying would be necessary, and not following international protocols and standards. https://www.ucolick.org/~sla/leapsecs/leapincept.html Gernot Winkler was co-author of the 1970 report to the IAU that said leap seconds would cause problems for automated navigation systems. http://adsabs.harvard.edu/abs/1970IAUTA..14..343Z At the 1970 IAU Comm 31 meeting Gernot Winkler was acting president where in the transcript it is clear that at least one paragraph has been omitted about the response in the IAU meeting when the CCIR decision to implement leap seconds was announced. http://adsabs.harvard.edu/abs/1971IAUTB..14..193W At that same meeting IAU Comm 31 was led to yield that they had no influence over the leap seconds that the CCIR had instituted, and IAU Comm 31 was pressed to produce a statement declaring that leap seconds were "the optimum solution." http://adsabs.harvard.edu/abs/1971IAUTB..14..198W All of the above strike me as "something is seriously wrong here." Looking deeper into the history and memoirs by folks who were involved it becomes clear that the inception of leap seconds was the culmination of a 20 year game of international regulatory and scientific agency pinball. After the CCIR introduced them that game continued for another 10 years as other agencies and governments were led to approve the notion of UTC with leap seconds using words like "parfaitment recommandable". The game started when the IAU produced a recommendation for radio broadcast time signals that was not implementable within available resources. Another agency produced a recommendation based on criteria which were relevant to its particular mission. At subsequent meetings of other agencies the agreements made by previous agencies were represented as the basis for further recommendations. One of the agreements used in this game was achieved not at an international meeting, but in the living room of one of the delegates. This process continued until CCIR was led to approve leap seconds without any accompanying documentation about the technical details of how they would be implemented. Several documents indicate that the preparatory meetings prior to the international assemblies discussed that changes to national laws would be required in order to broadcast a purely atomic time scale. I have found nothing that directly explains why it was repeatedly deemed impossible for any of these agencies to explain and recommend the existence of two kinds of time scales, but it seems clear that the legal considerations led toward the notion of a compromise. I surmise that the folks who wanted to broadcast atomic frequency were in too much of a hurry to wait for a critical mass of nations to legislate and allow their national metrology agencies to recognize and broadcast purely atomic time, so they took a shortcut. Taking that shortcut meant going to the CCIR with a proposal that did not explain the consequences and mechanisms, neither to the delegates who voted nor to any implementors of systems using UTC. I am not sure whether these kinds of interaction among international regulatory and scientific agencies are perfectly normal business as usual, or an example of systematic abuse spanning over decades. I am sure that the result was dysfunctional operational systems (which still lack solid technical underpinnings) and a trail of technical folks who had withdrawn from the arena to have their agencies continue using time scales that were not UTC with leap seconds. I am also sure that after an ensemble of international agencies have been persuaded to approve something it becomes very difficult to unapprove it even if its initial approval was achieved under dubious circumstances with serious unaddressed technical questions. So we have betrayal, eroded trust, and reduced usefulness because some folks wanted to take what looked like a politically expedient shortcut which was full of unexplained technical complexities. It is not clear who can remedy things. -- Steve Allen <[email protected]> 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 _______________________________________________ LEAPSECS mailing list [email protected] https://pairlist6.pair.net/mailman/listinfo/leapsecs
