Re: [LEAPSECS] alternative to smearing

On Thu, Jan 12, 2017 at 9:12 AM, Clive D.W. Feather wrote: > Preben Nrager said: >> If you don't care about Christ, and the church, I can understand why you >> treat all timescales alike. But if you really care about the fundamental >> timescale of science and society, then I don't see how you can

Re: [LEAPSECS] alternative to smearing

Preben Nrager said: > If you don't care about Christ, and the church, I can understand why you > treat all timescales alike. But if you really care about the fundamental > timescale of science and society, then I don't see how you can ignore the > time of the incarnation. If you really want the fu

Re: [LEAPSECS] alternative to smearing

Preben Nrager said: > I quoted this from Newcomb: "To avoid the inconvenience thus arising > astronomers measure the years from a zero epoch one year earlier than the > birth of Christ ; that is, they place a year before the year 1, and measure > from its beginning." Is it irrelevant that Newcomb w

Re: [LEAPSECS] alternative to smearing

This is getting pretty far afield from the question of Coordinated Universal Time or leap seconds. Perhaps there is a more appropriate mailing list for such discussions? Rob Seaman Lunar and Planetary Laboratory University of Arizona — > On Jan 11, 2017, at 12:29 PM, Preben Nørager wrote: > >

Re: [LEAPSECS] alternative to smearing

Zefram wrote: "The birthdate of Jesus is a historical question, and (as I noted) historians are pretty sure that AD 0 isn't the answer. ISO 8601 takes no position on that question. .. If you get any more specific than he [Dionysius Exiguus] did, for example if you state that Jesus was born specif

Re: [LEAPSECS] alternative to smearing

slight revision On 11/01/2017 23:16, Robert Jones wrote: I should add that as the universe is now considered to be expanding at an accelerated rate, that should have some interesting relativistic effects on time and its measurement in the long term On 11/01/2017 23:04, Robert Jones wrote:

Re: [LEAPSECS] alternative to smearing

I should add that as the universe is now considered to be expanding, that should have some interesting relativistic effects on time and its measurement in the long term On 11/01/2017 23:04, Robert Jones wrote: Kaye and Laby (Tables of Physical and Chemical Constants, 15th Ed., 1986, Longman

Re: [LEAPSECS] alternative to smearing

Kaye and Laby (Tables of Physical and Chemical Constants, 15th Ed., 1986, Longman - G.W.C. Kaye and T.H. Laby - ISBN 0-582-46354-8) states that the year for which a mean solar day is 86,400.003 SI seconds was circa 1984. According to the given long term rates of change and assuming that this da

Re: [LEAPSECS] alternative to smearing

Just to clarify-- The changing length of the solar day affects the number of days in a year but not the actual length of the year. The earth is not near resonance with any other major solar system bodies so variations in the actual length of the year will be small and of long period. This remains

Re: [LEAPSECS] alternative to smearing

Having followed some of the arguments in this thread: For the very long time as the length of the day increases, leap seconds are imperative as they will become progressively more common and archaelogists may curse those that don't use them. There might be a case for temporarily discontinuing

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: >I see the proleptic gregorian calendar, represented by ISO 8601, and the >GDs I propose, as a scientific way to settle the time of the incarnation. It doesn't do that. The birthdate of Jesus is a historical question, and (as I noted) historians are pretty sure that AD 0 isn

Re: [LEAPSECS] alternative to smearing

Dear Zefram Please see my answer to Clive D.W. Feather at https://pairlist6.pair.net/pipermail/leapsecs/2017-January/006697.html I will not argue about what you have against my GDs. You are totally right in all you say. I can only say to you, as I said to Clive: "If you don't care about Chris

Re: [LEAPSECS] alternative to smearing

On Wed Jan 11 05:32:05 EST 2017, Clive D.W. Feather wrote: "Why [GDs]?" Because I want the proleptic gregorian calendar to represent Anno Domini. "Why [the zero point in time must be the same for both the daily, and the annual continuous timescale]?" I think there is something special about

Re: [LEAPSECS] alternative to smearing

Tony Finch said: > It's also worth remembering that with Old Style dates the year started on > the 25th March. It's very easy to be accidentally anachronistic :-) Sometimes and some places. This is why 1751 (not 1752) was the shortest ever year in England but not in Scotland. Wikipedia notes "At

Re: [LEAPSECS] alternative to smearing

Zefram wrote: > ("Julian epoch" is a somewhat confusing term: it refers to a linear > count similar to JD, but scaled by a factor of 365.25 such that over the > long term it is frequency locked to the years of the Julian calendar, > and with zero point chosen such that Julian epoch roughly matche

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: >Astronomy then have two different "eternal" timescales, with two >different starting points for zero: Many more than two. MJD, TJD, and the Julian epoch, for example, all have some currency in astronomy, and each have their own zero point. ("Julian epoch" is a somew

Re: [LEAPSECS] alternative to smearing

Preben Nrager said: > Let's say Newcomb envisions negative JDs, and astronomy thus uses the JD > system. Astronomy then have two different "eternal" timescales, with two > different starting points for zero: The one is the proleptic gregorian > calendar, represented by ISO 8601, with the starting y

Re: [LEAPSECS] alternative to smearing

I have updated my time papers to reflect Bulletin C number 53 from the IERS, which confirmed that there will not be a leap second for at least six months. "Extending Coordinated Universal Time to Dates Before 1972" is at this URL: https://commons.wikimedia.org/wiki/File:Extending_Coordinated_Univ

Re: [LEAPSECS] alternative to smearing

On Tue Jan 10 08:23:50 EST 2017, Zefram wrote: "He [Newcomb] envisions negative JDs, and we have no difficulty extending numbers in that direction as far as we care to go. The JD system thus does cover all of history." Let's say Newcomb envisions negative JDs, and astronomy thus uses the JD sys

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: >We now know that the julian period is not all of history, Newcomb didn't claim that it is. It is actually the case that the Julian Period covers all of *recorded* history (i.e., history that was written down at the time), and there is some small convenience in that fact. Bu

Re: [LEAPSECS] alternative to smearing

On Mon Jan 9 17:38:46 EST 2017 Zefram wrote: "[Preben Nørager: So in a very long time-span the number of julian days can no longer be used without cultural bias.] What do you mean by "cultural bias" here? Are you just suggesting that TAI, by its artificiality, is an example of cultural bias, whe

Re: [LEAPSECS] alternative to smearing

On Mon Jan 9 16:52:29 EST 2017 Steve Allen wrote: "As noted by the IAU recommendation two decades ago, it is important for the user to specify which time scale is being used for those days." So if I were to count days in the proleptic gregorian calendar I were to write number JD of the prolepti

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: >Julian days count solar days. They count whatever days they are applied to. Originally that was solar days, of course. >julian days somehow count from solar noon, and that is why I wrote the >julian period count apparent solar days. That's a misunderstanding. The Julian

Re: [LEAPSECS] alternative to smearing

On Mon 2017-01-09T22:45:19 +0100, Preben Nørager hath writ: > Julian days count solar days. No, Julian days count days. Those can be "days" in whatever time scale. The astronomical almanacs had a longstanding set of tables expressed in Julian Ephemeris Date (J.E.D.) which was a count of days of E

Re: [LEAPSECS] alternative to smearing

Dear Zefram, thank you for your comments. I have learned a lot from them, and will only discuss a few. On Mon Jan 9 13:57:13 EST 2017 you write: "No, there's no tie between Julian Dates and apparent solar time. JDs can be used equally well with apparent and mean solar time. JDs are in fact also

Re: [LEAPSECS] alternative to smearing

On Mon Jan 9 13:49:20 EST 2017 Gerry Ashton wrote: "As far as I can tell the Julian Period is no longer in use, although the derivatives, Julian date and Julian day number, are widely used in science and astronomy." The julian period is the number of julian days since the start of the julian er

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: > if leap seconds are abolished, then the >gregorian calendar is implicitly forced on, because of the implicit >connection between the international atomic timescale, and the gregorian >calendar. There is no such connection. TAI times are conv

Re: [LEAPSECS] alternative to smearing

On Mon Jan 9 12:55:32 EST 2017, John Sauter wrote: "I don't understand what you mean when you say "Leap seconds are really only a need for those who do not want to see the proleptic gregorian calendar become universal." I would have no objection to the proleptic Gregorian calendar becoming univer

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: > The clock track either the sun (apparent time), or the seconds >(mean time). That's not correct. Both apparent and mean solar time are described in seconds, and in both cases that's the angular second (1/86400 circle) rather than the second of physical time. Bot

Re: [LEAPSECS] alternative to smearing

On January 9, 2017 at 6:55 PM John Sauter wrote in part:ISO 8601 handles leap seconds perfectly well. In ISO 8601 format, the most recent leap second was named 2016-21-31T23:59:60Z.I don't understand what [Preben Nørager] mean when  [Preben Nørager said] "Leap seconds are really only a need

Re: [LEAPSECS] alternative to smearing

On Mon, 2017-01-09 at 13:41 +0100, Preben Nørager wrote: > On Tue Jan 3 14:18:52 EST 2017, John Sauter wrote: > > "I regard leap seconds as a reasonable compromise between the needs > of civil time and of science. Civil time needs a clock that tracks > the days and the seasons. Science requires a

Re: [LEAPSECS] alternative to smearing

On Tue Jan 3 14:18:52 EST 2017, John Sauter wrote: "I regard leap seconds as a reasonable compromise between the needs of civil time and of science. Civil time needs a clock that tracks the days and the seasons. Science requires a clock that measures time in precise intervals. UTC provides both,

Re: [LEAPSECS] alternative to smearing

Daniel R. Tobias wrote: > > It seems you can come up with quite a few "types of wait", or types > of scheduling for future events, appointments, announcements, and so > on, all of which ought to be supported in robust calendaring / > scheduling programs. That's a very good list. > * Events sched

Re: [LEAPSECS] alternative to smearing

On Sat, 2017-01-07 at 09:38 -0500, Daniel R. Tobias wrote: > On 6 Jan 2017 at 22:44, Hal Murray wrote: > > > I think there are two different types of wait.  One is the simple > > wait N  > > seconds.  The other is wait until a specified date-time, say a > > month from  > > now.  They really are di

Re: [LEAPSECS] alternative to smearing

On 6 Jan 2017 at 22:44, Hal Murray wrote: > I think there are two different types of wait. One is the simple wait N > seconds. The other is wait until a specified date-time, say a month from > now. They really are different so I don't see how to make your "one > interface" work. It seems yo

Re: [LEAPSECS] alternative to smearing

On Fri, 2017-01-06 at 22:44 -0800, Hal Murray wrote: > > I hate bloat and crufty code as much as anybody.  A library routine > to handle  > all the quirks of leap seconds and leap years and daylight savings > seems  > reasonable to me.  But maybe I'm overlooking somethings, so that's > why I  > a

Re: [LEAPSECS] alternative to smearing

Hal Murray wrote: >>> Are there any performance critical chunks of code that want to wait until N >>> years from now? I doubt it. > >> With due respect, that's a crappy attitude to getting something right. You >> want to have one interface that always works that's easy to use and schedule >> with.

Re: [LEAPSECS] alternative to smearing

>> Are there any performance critical chunks of code that want to wait until N >> years from now? I doubt it. > With due respect, that's a crappy attitude to getting something right. You > want to have one interface that always works that's easy to use and schedule > with. If you don't have that

Re: [LEAPSECS] alternative to smearing

Warner wrote: > There's problem, and trying to equivocate away by saying "well, > if you just did it right it would be OK" isn't a helpful position. > Requiring every computer to do complicated things so that a leap > second can work once in a blue moon isn't a good engineering tradeoff. > Ignoring

Re: [LEAPSECS] alternative to smearing

On Thu, Jan 5, 2017 at 4:26 AM, Hal Murray wrote: > > [do something N years in the future] >> Except that's not how things are programmed. Programming it that way would >> be very inefficient in a part of the kernel that has to be ultra-efficient. >> Since you don't know how many seconds it will f

Re: [LEAPSECS] alternative to smearing

On Thu, Jan 5, 2017 at 3:42 AM, Hal Murray wrote: > >> 1) The leap day in February can be handled by any isolated or autonomous >> clock or timekeeping system. A leap second can only be handled with periodic >> direct or indirect communication with IERS, or manual intervention with the >> likes of

Re: [LEAPSECS] alternative to smearing

On 2017-01-04 10:22 AM, Steve Summit wrote: John Sauter wrote: On Tue, 2017-01-03 at 13:28 -0500, Michael Rothwell wrote: Why are you in such favor of leap seconds? I regard leap seconds as a reasonable compromise between the needs of civil time and of science. Civil time needs a clock that t

Re: [LEAPSECS] alternative to smearing

On 2017-01-05 06:26 AM, Hal Murray wrote: [do something N years in the future] Except that's not how things are programmed. Programming it that way would be very inefficient in a part of the kernel that has to be ultra-efficient. Since you don't know how many seconds it will from now, you can't

Re: [LEAPSECS] alternative to smearing

On Thu, Jan 5, 2017 at 7:26 PM, Hal Murray wrote: > How far in advance were the last daylight savings changes announced? In the US, the Energy Policy Act of 2005 which changed onset of DST in Mar 2007, was enacted in Aug 2005, but this amount of notice is rare worldwide. If you wish to see mor

Re: [LEAPSECS] alternative to smearing

[do something N years in the future] > Except that's not how things are programmed. Programming it that way would > be very inefficient in a part of the kernel that has to be ultra-efficient. > Since you don't know how many seconds it will from now, you can't schedule a > timeout. The current setu

Re: [LEAPSECS] alternative to smearing

> 1) The leap day in February can be handled by any isolated or autonomous > clock or timekeeping system. A leap second can only be handled with periodic > direct or indirect communication with IERS, or manual intervention with the > likes of keyboard input or toggle switches. For secure or embedd

Re: [LEAPSECS] alternative to smearing

On Wed, Jan 4, 2017 at 9:36 PM, Steve Summit wrote: > Warner Losh wrote: >> Steve Summit wrote: >> > The requirement for tables (and, correspondingly, the >> > "impossibility" of dealing with future UTC dates more than a few >> > months out) depends on what you're trying to do... >> > In particul

Re: [LEAPSECS] alternative to smearing

Warner Losh wrote: > Steve Summit wrote: > > The requirement for tables (and, correspondingly, the > > "impossibility" of dealing with future UTC dates more than a few > > months out) depends on what you're trying to do... > > In particular, if right now it's 2017-01-05T01:56:13, I can > > obvious

Re: [LEAPSECS] alternative to smearing

> The requirement for tables (and, correspondingly, the > "impossibility" of dealing with future UTC dates more than a few > months out) depends on what you're trying to do. You can *talk* > about the dates, and you can do interval arithmetic with a > precision of days, hours, or minutes, perfectl

Re: [LEAPSECS] alternative to smearing

t...@leapsecond.com (Tom Van Baak), > The February leap day is a useful analogy when describing leap seconds > to non-technical people. But when you get into the details the two are > vastly different. A well-written list, thanks. One quibble, though: > 2) Past dates involving February can be h

Re: [LEAPSECS] alternative to smearing

Oops; typo; sorry; I'm an idiot by a factor of millions. s/seconds/years/ and it should read: 9) Exposing citizens to leap days is near universal. Printed and computer calendars have no trouble with that extra day. Almost every child learns about leap years during their schooling. Some people a

Re: [LEAPSECS] alternative to smearing

Tom Van Baak said: > Because most people don't live in Greenwich Greenwich isn't the only relevant place. I think I'm probably the person on this list who lives closest to the Prime Meridian, at 0.027066 degrees east according to Google Maps (I used to live at 0.011605 but moved house). I'm in f

Re: [LEAPSECS] alternative to smearing

> There's a big difference between these two: February varies in a fixed, > regular manner, whereas UTC days are unpredictable. The Gregorian > calendar is of the arithmetic variety, whereas UTC is an observational > calendar. UTC is qualitatively more difficult to handle. > > -zefram Agreed. T

Re: [LEAPSECS] alternative to smearing

On Wed, 2017-01-04 at 19:04 +0100, Preben Nørager wrote: > On Wed, 2017-01-04 at 18:11 +0100, John Sauter wrote: > > "I am curious: since you do not think my moral concern is future > generations, what do you think it is?" > > I think your moral concern is the misguided belief, that abolishing >

Re: [LEAPSECS] alternative to smearing

On Wed, 2017-01-04 at 18:11 +0100, John Sauter wrote: "I am curious: since you do not think my moral concern is future generations, what do you think it is?" I think your moral concern is the misguided belief, that abolishing leap seconds will mean our official time will depend solely on cesium a

Re: [LEAPSECS] alternative to smearing

On Wed, 2017-01-04 at 16:29 +0100, Preben Nørager wrote: > On Wed, 2017-01-04 at 15:25 +0100, John Sauter wrote: > > "Preben, You and I disagree on this issue.  For me this is > fundamentally a moral > concern.  I believe that each generation should handle its problems > as > best it can, leaving

Re: [LEAPSECS] alternative to smearing

John Sauter wrote: >I don't regard leap seconds as being a special kind of awful. The >Gregorian calendar has February, which if it had been introduced in >1972 would have been regarded as "awful" for computers because it has a >variable length. There's a big difference between these two: Februar

Re: [LEAPSECS] alternative to smearing

Preben Norager wrote: > The other aspect was the dropping of ten days. I don't know >exactly why the march equinox shall occur allways around march 21. Would >allways around march 11 not have been just as good? There was a sense of there being a "correct" phase alignment between the calen

Re: [LEAPSECS] alternative to smearing

On Wed, 2017-01-04 at 09:42 -0500, Michael Rothwell wrote: > The Gregorian calendar doesn't mess up how computers keep track of > time, like leap seconds do. Neither do time zones. Leap seconds are > different -- a special kind of awful. I don't regard leap seconds as being a special kind of awful

Re: [LEAPSECS] alternative to smearing

On Sun, 2017-01-01 at 16:29 -0500, John Sauter wrote: > > If anyone has difficulty extracting the software from the PDF using > okular, e-mail me and I will provide the files separately. Steve Summit has been kind enough to host the code on his web site. The URLs are: http://www.eskimo.com/~scs/

Re: [LEAPSECS] alternative to smearing

On Wed, 2017-01-04 at 15:25 +0100, John Sauter wrote: "Preben, You and I disagree on this issue. For me this is fundamentally a moral concern. I believe that each generation should handle its problems as best it can, leaving to the next generation only unforeseen problems. The tension between t

Re: [LEAPSECS] alternative to smearing

We don't know how future generations will see the "problem", if leap seconds are abolished. As generations today see it, the "problem" is that without leap seconds the sun is getting ahead or behind the official international timescale, so that the noon transit not normally will occur around 12 mid

Re: [LEAPSECS] alternative to smearing

On Wed, 2017-01-04 at 13:57 +0100, Preben Nørager wrote: > We don't know how future generations will see the "problem", if leap > seconds are abolished. As generations today see it, the "problem" is > that without leap seconds the sun is getting ahead or behind the > official international timescal

Re: [LEAPSECS] alternative to smearing

John Sauter wrote: > On Tue, 2017-01-03 at 13:28 -0500, Michael Rothwell wrote: > > Why are you in such favor of leap seconds? > > I regard leap seconds as a reasonable compromise between the needs of > civil time and of science. Civil time needs a clock that tracks the > days and the seasons. Sc

Re: [LEAPSECS] alternative to smearing

Michael Rothwell wrote: > The Gregorian calendar doesn't mess up how computers keep track of time, > like leap seconds do. Neither do time zones. Leap seconds are different > -- a special kind of awful. I think this depends on what your basic time is, and what time you derive from it. If the syst

Re: [LEAPSECS] alternative to smearing

The Gregorian calendar doesn't mess up how computers keep track of time, like leap seconds do. Neither do time zones. Leap seconds are different -- a special kind of awful. On Wed, Jan 4, 2017 at 9:25 AM, John Sauter < john_sau...@systemeyescomputerstore.com> wrote: > On Wed, 2017-01-04 at 13:57

Re: [LEAPSECS] alternative to smearing

On Tue, 2017-01-03 at 14:53 -0500, Michael Rothwell wrote: > > > On Tue, Jan 3, 2017 at 2:18 PM, John Sauter mputerstore.com> wrote: > > On Tue, 2017-01-03 at 13:28 -0500, Michael Rothwell wrote: > > > > > > This was probably covered elsewhere, and I apologize if I missed > > it, > > > but I hav

Re: [LEAPSECS] alternative to smearing

On Tue, Jan 3, 2017 at 2:18 PM, John Sauter < john_sau...@systemeyescomputerstore.com> wrote: > On Tue, 2017-01-03 at 13:28 -0500, Michael Rothwell wrote: > > > > This was probably covered elsewhere, and I apologize if I missed it, > > but I have a question: > > Why are you in such favor of leap s

Re: [LEAPSECS] alternative to smearing

On Tue, 2017-01-03 at 13:28 -0500, Michael Rothwell wrote: > > This was probably covered elsewhere, and I apologize if I missed it, > but I have a question: > Why are you in such favor of leap seconds? >   > --  > Michael Rothwell > mich...@rothwell.us > (828) 649-ROTH I regard leap seconds as a

Re: [LEAPSECS] alternative to smearing

On Sun, Jan 1, 2017 at 4:29 PM, John Sauter < john_sau...@systemeyescomputerstore.com> wrote: > I have updated my paper on avoiding the use of POSIX time_t for telling > time, adding some example code and some recommendations for improving > the Linux kernel. The updated paper is at the same URL:

Re: [LEAPSECS] alternative to smearing

I have updated my paper on avoiding the use of POSIX time_t for telling time, adding some example code and some recommendations for improving the Linux kernel.  The updated paper is at the same URL: I intend

[LEAPSECS] alternative to smearing

An alternative to smearing is to persuade applications to deal with UTC and the Gregorian calendar as it is, with its variable-length months and minutes. In support of that alternative, I am making available some subroutines which applications can use to deal with time. This is an update to the p