On Sun, 2017-10-22 at 23:46 -0600, Warner Losh wrote: > > > On Sun, Oct 22, 2017 at 11:02 PM, John Sauter <John_Sauter@systemeyes > computerstore.com> wrote: > > On Sun, 2017-10-22 at 17:53 -0700, Steve Allen wrote: > > > > > > The BIPM has contributed > > > CGPM draft Resolution "On the definition of Time-Scales" > > > For two years various meetings have indicated that a document > > like > > > this was under construction, so this is probably that result. > > > > > > A draft of the document seems to be at > > > http://www.iaufs.org/CCTF%20Recommendation-DRAFT.pdf > > > It largely seems to be a formal way for the CGPM to update the > > > definition of TAI and UTC to match what the IAU did over a decade > > > ago. > > > Unsurprisingly it makes no mention of the connection between the > > > calendar day and UT1. > > > > The next-to-last bullet point under "clarifies that" states that > > "UTC > > is also a means of dissemination of the standard of frequency; > > however > > this function is limited to intervals that do not contain leap > > seconds;". Why the concern about leap seconds? As long as you > > know > > the name of each second, why should it matter that there is a leap > > second in the interval? > > Because one cannot reliably know that. And by reliably, I mean > everybody knows, all the software knows, all the software agrees, > even among diverse groups whose primary purpose may not be time > keeping and may have sloppy habits about leap seconds (eg, the real > world). > > One can know it, sure, but one cannot count on every single other > person who touches the data knowing it with certainty. So it's just > best to avoid data that spans a leap second. >
By that logic, one should avoid any interval that includes June 30 or December 31, since such an interval might include a leap second. John Sauter (john_sau...@systemeyescomputerstore.com) -- PGP fingerprint E24A D25B E5FE 4914 A603 49EC 7030 3EA1 9A0B 511E _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs