On the one hand, abolishing leap seconds would help us with the problem of conversion from the UTC-based NTP timescale and the TAI-based IEEE-1588 and GPS timescales. On the other hand, it will require updating all software that computes local sunrise and sunset times (e.g., for radio propagation). However, the real problem is not related to communications or software. The real problem is that local time is based on UTC since it needs to be astronomically meaningful. If leap seconds are abolished and local time starts drifting away from "earth time" then in a few hundred years we will accumulate an hour of error, and in a few thousand years it will be dark during much of the working day. This is similar to the draft of the months of the Islamic calendar, where a particular month may appear in the winter or summer. I know that most of us don't worry about what is going to happen hundreds of years hence, but think of the Y2K-like fixes that will have to be made for leap-hours ! Y(J)S -----Original Message----- From: ietf-bounces@xxxxxxxx [mailto:ietf-bounces@xxxxxxxx] On Behalf Of Stephane Bortzmeyer Sent: Thursday, August 25, 2011 13:24 To: ietf@xxxxxxxx Subject: Questionnaire to survey opinion concerning a possible redefinition of UTC Since several RFCs rely on UTC and leap seconds (3339, 4765, 5905, etc), this questionnaire may be of interest for some persons [the Web page mentions two articles, if you are in a hurry, the first one is the PRO and the second one the CON]. One more week to comment. http://hpiers.obspm.fr/eop-pc/index.php?index=questionnaire QUESTIONNAIRE TO SURVEY OPINION CONCERNING A POSSIBLE REDEFINITION OF UTC Universal Time, the conventional measure of Earth rotation is the traditional basis for civil timekeeping. Clocks worldwide are synchronized via Coordinated Universal Time (UTC), an atomic time scale recommended by the Radiocommunications Sector of the International Telecommunications Union (ITU-R) and calculated by the Bureau International des Poids et Mesures (BIPM) on the basis of atomic clock data from around the world. UTC is computed from TAI by the introduction of leap seconds such that UTC is maintained within 1 second of UT1. Since 1972, these leap seconds have been added on December 31 or June 30, at the rate of about one every 18 months. Since 1 January 2009, 0:00 UTC, UTC-TAI= -34s. After years of discussions within the scientific community, a proposal to fundamentally redefine UTC will come to a conclusive vote in January 2012 at the ITU-R in Geneva. If this proposal is approved, it would be effective five years later. It would halt the intercalary adjustments known as leap seconds that maintain UTC as a form of Universal Time. Then, UTC would not keep pace with Earth rotation and the value of DUT1 would become unconstrained.Therefore UTC would no longer be directly useful for various technical applications which rely on it being less than 1 second from UT1. Such applications would require a separate access to UT1, such as through the publication of DUT1 by other means. The objective of the survey is to find out the strength of opinion for maintaining or changing the present system. Your response is appreciated before 31 August 2011 _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf