Hi Tom, Thanks for your insights on days past, and great website. I haven't convinced myself that you can always guarantee | DUT1 | <= 1 if you force a leap second at the end of each month. Certainly would aid in combating sketchy code. I tried it on a very rudimentary model to visualize it.
On Thu, Jul 21, 2016 at 6:58 PM, Tom Van Baak <[email protected]> wrote: > > If UTC time was adjusted every month would stick with one full second? Or > > some smaller quantity? > > Hi Scott, > > The LSEM month suggestion retains the UTC policy of leaps being exactly +1 > or -1 second, never larger, never smaller. > > There's a world of hurt if anyone even dreamed of shifting UTC by a > fraction of a second. In fact, one of the main reasons UTC was created in > the 70's was to put an end to the dreaded fractional jumps in atomic > timekeeping during that era. Fractional steps atomic frequency and > fractional steps in atomic time were both tried during 60's. For example: > > http://www.leapsecond.com/history/wwvb1966.htm > > Eliminating frequency jumps completely (by defining the UTC second to be > 9,192,631,770 Hz cesium), and > changing any steps to be full +1 or -1 second integers (and not fractions) > was why UTC was created. > > /tvb > > ----- Original Message ----- > From: "Scott Stobbe" <[email protected]> > To: "Discussion of precise time and frequency measurement" < > [email protected]> > Sent: Thursday, July 21, 2016 3:06 PM > Subject: Re: [time-nuts] LSEM (Leap Second Every Month) > > > > If UTC time was adjusted every month would stick with one full second? Or > > some smaller quantity? > > > > On Thursday, 21 July 2016, Brooke Clarke <[email protected]> wrote: > > > >> Hi Tom: > >> > >> I like this idea. I addresses the lesson from Y2K that something done > >> often works much better than something done only occasionally. > >> That's way you see the firetruck at the local store, because it's used > all > >> the time and so is more likely to work when needed. > >> > >> -- > >> Have Fun, > >> > >> Brooke Clarke > >> http://www.PRC68.com > >> http://www.end2partygovernment.com/2012Issues.html > >> The lesser of evils is still evil. > >> > >> -------- Original Message -------- > >> > >>> Hi Tom... > >>> > >>> Does your proposal allow for a Zero leap second, or does it require > >>> either plus or minus 1 to work? Seems like you could stay closer to the > >>> true value if you also have a zero option. Might also cause less > >>> consternation for some services, like the finance and scientific > worlds, > >>> that seem to have critical issues when an LS appears. > >>> > >>> I like your point that by having it occur monthly it forces systems to > >>> address issues promptly, and maybe that's the argument for the non-zero > >>> option. > >>> > >>> Tom Holmes, N8ZM > >>> > >>> > >>> -----Original Message----- > >>> From: time-nuts [mailto:[email protected]] On Behalf Of Tom > Van > >>> Baak > >>> Sent: Thursday, July 21, 2016 1:28 PM > >>> To: Discussion of precise time and frequency measurement < > >>> [email protected]> > >>> Cc: Leap Second Discussion List <[email protected]> > >>> Subject: Re: [time-nuts] Leap second to be introduced at midnight UTC > >>> December 31 this year > >>> > >>> Time to mention this again... > >>> > >>> If we adopted the LSEM (Leap Second Every Month) model then none of > this > >>> would be a problem. The idea is not to decide *if* there will be leap > >>> second, but to force every month to have a leap second. The IERS > decision > >>> is then what the *sign* of the leap second should be this month. > >>> > >>> Note this would keep |DUT1| < 1 s as now. UT1 would stay in sync with > >>> UTC, not so much by rare steps but by dithering. There would be no > change > >>> to UTC or timing infrastructure because the definition of UTC already > >>> allows for positive or negative leap seconds in any given month. > >>> > >>> Every UTC-aware device would 1) know how to reliably insert or delete a > >>> leap second, because bugs would be found by developers within a month > or > >>> two, not by end-users years or decades in the future, and 2) every > >>> UTC-aware device would have an often tested direct or indirect path to > IERS > >>> to know what the sign of the leap second will be for the current month. > >>> > >>> The leap second would then become a normal part of UTC, a regular > monthly > >>> event, instead of a rare, newsworthy exception. None of the weird bugs > we > >>> continue to see year after year in leap second handling by NTP and > OS's and > >>> GPS receiver firmware would occur. > >>> > >>> Historical leap second tables would consist of little more than 12 bits > >>> per year. > >>> > >>> Moreover, in the next decade or two or three, if we slide into an era > >>> where average earth rotation slows from 86400.1 to 86400.0 to 86399.9 > >>> seconds a day, there will be zero impact if LSEM is already in place. > >>> > >>> /tvb > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >>> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >
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