Re: [LEAPSECS] LEAPSECS Digest, Vol 153, Issue 3
On Thu, Jul 16, 2020 at 2:37 AM Ask Bjørn Hansen wrote: > Am I oversimplifying if I’m hoping that means we might not have any leap > seconds for ~18 years? > > If that’s the case — no leap seconds for two decades and then the first > one will be the kind we haven’t tried before? > So the next leapsecond will be handled by code written by people who are still in school, and have to rely on this list archive for reports of *positive* leap seconds. I predict a scramble to SLS by the remaining Cloud Vendors when this happens. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] the inception of leap seconds
On Wed, Aug 15, 2018 at 11:59 PM Zefram wrote: > Warner Losh wrote: > >Eg, would we really be worse off if we'd said 'there will be a leap second > >every 18 months starting Jan 1 1972? > > That would be a pretty good result, but would anyone have picked that > rate of leaps in 1971? > All this means to me is that either time travel does not exist, or astronomers of the future have severe funding issues. Eg, if Warner had access to a time machine, he could have sent the "leap second every 18 months is good in the decade-scale future" message back to 1971. Maybe time travel is hard because you need to set the dial using UT2, but the UTC-UT2 difference is known only in the future of the traveler wanting to back? (I am in Singapore, which is perpetually on Summer Time (UTC+08), although we are 103E) -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The Fuzzball
On Tue, Jan 10, 2017 at 4:53 PM, Poul-Henning Kamp wrote: > Sanjeev Gupta writes: > > >Parting Shot (quoted from the Paper): > >The ideal next-generation Fuzzball would be programmed in C, support the > >Unix run-time environment, TCP/IP and ISO protocol suites and contain no > >licensed code. > > Yeah, it's called "FreeBSD" :-) Ah, thanks for that reminder. I did not think beyond Linux. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The Fuzzball
On Tue, Jan 10, 2017 at 10:57 AM, Brooks Harris wrote: > Ah. PDP 11 running RT11 (the RT stands for real-time, you know, and it > was!). Bigger and much heavier than a breadbox it had a lot of power. Oh, > wait, I mean it *used* a lot of power. And you could modify it with a > soldering iron and hammer. :-) Parting Shot (quoted from the Paper): The ideal next-generation Fuzzball would be programmed in C, support the Unix run-time environment, TCP/IP and ISO protocol suites and contain no licensed code. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] LEAPSECS Digest, Vol 124, Issue 17
On Thu, Jan 5, 2017 at 7:10 PM, Hal Murray wrote: > I started work at DEC on Feb 29th. 10 years later, I got a fancy > certificate > congratulating me on being there for 10 years. Want to guess what date was > on it? > Feb 29th, of course. The print macro just adds "10" to the year field. :-) -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
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 more interesting examples, I recommend, in the last year,
Venezuela, Egypt, Morocco, Palestine, etc. In Egypt, airlines were quoting
two times ("If you have implemented DST on your watch, the flight leaves at
8pm. Else it leaves at 7pm. We hope you know what your watch is doing").
The date and time for the shift was announced, re-announced, un-announced,
clarified, to be at midnight, ie 1am, etc.
In fact, much of the Middle East wishes to run DST, but not during
Ramadaan, and for reasons not clear to me, wants DST suspended precisely on
those 28-29 days. So we go on DST in summer, and then are told that DST
will be suspended from 9th Jun to 6th Jul, which changes a couple of times
as we argue on which day we will see the moon, or we might calculate it,
but for which longitude, and my father said he had been told by a wise old
man that ...
And yet planes refuse to fall out of the sky :-)
--
Sanjeev Gupta
+65 98551208 http://www.linkedin.com/in/ghane
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Re: [LEAPSECS] Time math libraries, UTC to TAI
On Tue, Dec 27, 2016 at 11:36 PM, John Sauter < john_sau...@systemeyescomputerstore.com> wrote: > > Also note that many large radar systems have built-in simulators, > > used > > for system integration during development and for training > > thereafter. > > Such simulators need to be able to work using system time that is > > not > > the present, say to rerun recorded observations or to simulate > > future > > or past scenarios. In both cases, the GPS receiver does not know > > the > > correct leap second offset to use. The usual solution is an > > application-provided table all past leap seconds, plus the next leap > > second (if known). The table is updated manually. > > That sounds like a fine solution. It would be nice if the table were > maintained by the group of people who needed it, so that everyone > wouldn't have to update his own table. > If I have understood you correctly, this is publicly available, based on the IERS Bulletin C: https://www.ietf.org/timezones/data/leap-seconds.list -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Leap Seconds schedule prior to 1972
On Sat, Apr 23, 2016 at 5:34 PM, Hal Murray wrote: > Don't over engineer it. Hal, why are you spoiling the fun? :-) Remember, ado did not over-engineer the Olson database, and we have fights daily on how to represent "third Saturday after the Passover is DST", or "Venezuela decided at dinner time not to start DST tonight". If only the zone files were a Turing-complete language ... -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Leap Seconds schedule prior to 1972
On Sat, Apr 23, 2016 at 3:47 AM, John Sauter < john_sau...@systemeyescomputerstore.com> wrote: > Column 1 can be the > Julian Day Number of the extraordinary day, column 2 can be the new > value of DTAI reached at the end of the day, and the text after the # > can be the date spelled out. Since DTAI is defined as 0 on January 1, > 1958, an entry would be > > 2436204 0 # 31 Dec 1957 > How far back do we have to go before we have multiple leap seconds *per day* ? -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap second festivities?
On Wed, Jul 1, 2015 at 3:51 AM, Rob Seaman wrote: > Is it too late to get an option E added of simply scheduling “summer" leap > seconds on the last Sunday morning in June? Depending on when on Sunday you do this, it may still after the Sydney Stock Exchange starts trading on *Monday* morning; or when the Middle East Exchanges are still running. Nasdaq Dubai trades 0600 to 1000 GMT (yes, GMT) Sunday to Thursday. DST transitions occur at off-peak times in local time. A leap second (which I think should continue) will have to be coordinated universally (*U* *T* *C*). Could we speed up the Cesium Hyperfine Transition, please? It might be easier than resolving the Leap Second Debate :-) Or we could all move to London? The UKIP may not like it, but they can shift to Greece, I supoose. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Google, Amazon, now Microsoft
On Tue, Jun 2, 2015 at 3:34 AM, Clive D.W. Feather wrote: > > Ah, there's almost a four-way meet. Afghanistan (UTC+4.5), Tajikistan > (UTC+6), and China (UTC+8) meet at a point and, less than 20 kilometres > south of there, is the China/Pakistan (UTC+5) border. There don't seem to > be roads, but an off-road vehicle ought to be able to do it in an hour. I do not think lack of roads is your biggest problem in this case. Driving around with a back seat full of equipment with ariels and batteries, in an area that has seen disputed borders since the mid-1800s, would add years to your visble age. A Leap Second may not be noticed. Note that according to India, Pakistan has no border with China, it is Indian teritorry. YMMV. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Google, Amazon, now Microsoft
On Wed, Jun 3, 2015 at 4:25 AM, Poul-Henning Kamp wrote: > Which is like saying that if only 50% of all programmers weren't > below the skill-median, we wouldn't have the problem. > What?!?!? 50% of programmers are below average? Why is no one doing something about it? We should not rest till at least half are above average! -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Look before you don't leap
On Fri, May 22, 2015 at 2:35 AM, Richard Clark wrote: > Which brings up the question of what sort of schedule do the people > in the western regions actually live their lives on? In the cities? How > about in the countryside? Regardless of the official time on the clock > how do people schedule their daily activities? > On the TZ list, there have been a set of long discussions on "Urumqi Time". This seems to be semi-official, and is UTC+0600. See: https://en.wikipedia.org/wiki/Time_in_China for a very short summary. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Look Before You Leap – The Coming Leap Second and AWS | Hacker News
On Wed, May 20, 2015 at 3:02 AM, Richard Clark wrote: > One of its examples of how the "metric system" is > bad was its confusing use of two units, the newton and the kilogram, to > measure weight. The US system is so much simpler and sensible with just > one unit, the pound. > I am not sure of what os common in the general US population, but engineers I have worked with outside the US used slug vs pound to differentiate mass vs weight (force). I also heard one US engineer use pound vs poundal (the pound being mass, the poundal weight), which he claimed was easier to use (scaling factors, got rid of the pesky 32.xxx). -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Look before you don't leap
On Wed, May 20, 2015 at 9:28 PM, Joseph Gwinn wrote: > The rationale is that by the time we get to 2038, all platforms will > have changed time_t to a 64-bit integer, deferring the problem for tens > of billions of years, by which time POSIX will be in museums, laughed > at by bored children. That is, if children still exist. > Children will exist, if for no other reason that someone will have to memorize POSIX time rules; the way I was forced to memorize Roman numbers. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] LOD and gravity connected ?
On Wed, Apr 29, 2015 at 5:32 PM, Poul-Henning Kamp wrote: > > http://iopscience.iop.org/0295-5075/110/1/10002/article Wait, I am worried. Please assist a newbie. Can I summarize: the change in the length of 30 June 2015, will cause a change in the value of G? Which way will this shift be? Do I need to tie down my stuff, or prop up the supports? So Gravity is now in the control of Dr Gambis at BIPM? Note: Gravity G constant Gambis A coincidence? I don't think so. Why is this not on CNN yet? Why is no one else panicking? And if Gravity gets stronger, will the sky fall on our heads? -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] a Japanese leap smear?
On Thu, Mar 5, 2015 at 11:05 AM, Steve Allen wrote: > It looks like Kyushu Telecommunication network is considering its > own version of the leap smear > > > http://www.slideshare.net/apnic/the-leap-second-is-coming-by-tomonori-takada-apricot-2015 > The video of the talk is available on the APNIC channel on Youtube: http://bit.ly/1w6hZbg Starts at Minute 51. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Comments on predictions for this century
On Sun, Jan 18, 2015 at 7:36 AM, Poul-Henning Kamp wrote: > We have had almost overlapping hiatuses in global warming and > leap seconds in the last 10-15 years. > but, but ... From: http://cphpost.dk/news/2014-set-to-be-warmest-year-on-record.12039.html Denmark wasn't the only country to experience its warmest year. In fact, according to a UN weather agency WMO press release, 2014 is set to be the warmest year globally since records began approximately 150 years ago, pulling it ahead of the current top three warmest years of 2010, 2005 and 1998 respectively. "The provisional information for 2014 means that 14 of the 15 warmest years on record have all occurred in the 21st century," Michel Jarraud, the WMO secretary general, said in a press release. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] the big artillery
On Fri, Nov 7, 2014 at 2:24 AM, Dennis Ferguson wrote: > In some ways the UTC minute redefinition is even worse than that. A 6 > year old > might not know how many seconds are in a hectosecond but would often be > expected to know there are 60 seconds in a minute. Redefining this to be > otherwise > seems bound to cause cognitive dissonance in many grown up former 6 year > olds. > A six-year old can continue to believe that a minute has 60 seconds, and an year has 365 days, and a mile is 1 and a half km. When Rob Seaman decides to allow said six-year old near his telescope, he can teach the extra rules. But do not *define* the year to be 365 days. As a general rant, I still complain that (roughly) year 8 to year 12 of my schooling required me to learn stuff in physics, and then the next year, often the same teacher would tell me what I had learnt was wrong, and this was the correct way. We teach Newtonian mechanics in high school, and then a year or two later, *the same guy*, smirking, tells you that actually, that is wrong, a simplification for children. But we still teach and respect the Lorentz corrections, even though we all know that momentum is mass times velocity. Anyone who wishes to believe 60 secs always to a minute can continue to do so. Anyone who needs the extra accuracy (time-nuts, astronomers, pedants, old men like me) will learn the fact that a minute is not always 60 secs. Anyone who is unwilling to learn this should not be pointing the scope on Mt Palomar anyway. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] the big artillery
On Thu, Nov 6, 2014 at 10:37 PM, Poul-Henning Kamp wrote: > > In message tpb0rzuri8j4kmcezooa...@mail.gmail.com> > , Sanjeev Gupta writes: > > >Note that "seconds" are also a unit of angles, so UT1 seconds being a > >measure of angle is not strange. > > ...and I'm sure any surveyor or ships navigator would be extremely suprised > if somebody told him that the degree between 23°59' and 24°00' had > sixtyone seconds once every other year or so. To a person (me) who last used a theodolite in 1988, very surprising. But I assume that to a professional navigator, this would be just another correction he makes. After all, (an inexact analogy), every year has 365 days, but sometimes we slip in aa extra between 28 Feb and 01 Mar. Every fourth year. Except when we don't. We are lucky that 2000 was a leap year, so people who did not know the 100 and 400 year rules got it right by mistake. (back to Leapsecs) The difference, I suppose, and the point where I agree with you, is that we _know_ when the next leap year will happen, but Dr Gambis gives us shorter, and essentially surprising, notice on the leap minute. Removing leap seconds is OK with me, the fact that the earth angle will lose sync with civil time is a small price for 7 billion of us, and I willing to throw astronomers to the wolves. (What have the Romans ever done for us, anyway?) The point where I disagree with you is keeping the name "UTC". When we (and I use the term loosely) changed the rule from "leap every fourth year" to (except for 100th year, except for 400th year). the new calendar had a new name. Over time we stopped using Julian, but if I was to tell you 13 Jan 1300 Julian, you would know if it was a leap year or not. I believe the USA'ns make a big deal of George Washington's birthday being OS/NS, etc; but we can get the joke only because there are suffixes that tell me what scale it is. Look at this thread, and the efforts being made by you et al to remove the confusion about the word "second"; because the SI second, the TAI (term used without prior permission of BIPM) second, and the UT1 second. all use the word "second". -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] the big artillery
On Thu, Nov 6, 2014 at 8:38 PM, Tony Finch wrote: > The UT1 second is 2pi/86400 times the reciprocal of the angular velocity > of the Earth. The units for this quantity are just seconds (because angles > are dimensionless), or if you want to be more explicit, seconds per > 2pi/86400 radians. > ... which I think is the clearest definition I have heard so far. Note that "seconds" are also a unit of angles, so UT1 seconds being a measure of angle is not strange. Thank you, Tony. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] the big artillery
On Fri, Oct 31, 2014 at 7:01 AM, Harlan Stenn wrote: > I'm still thinking the answer is "leave existing 'names' alone - if you > want TAI use TAI. If you want UTC, use UTC. If you want something new, > call it something new." > > If people are using a defined name for a defined purpose and it works > for them, leave it alone. If people are using a defined name for a > defined purpose and it does not work for them, this group needs to come > up with a new name for the thing they think will solve their problems > +1 I understand the issue that "UTC" is a part of many laws and documents that will be difficult to change, so it is easier to change the definition of UTC. But this still does not make it right. As an extreme example, and more in jest, consider if a number of legislatures enacted laws to make maths simpler, by declaring that the "adjustments past the second decimal place to pi need not apply", and hence "pi will be fixed at 3.14". This will save lots of time and effort, and help programmers and implementers make fewer mistakes. Will we, because it is hard to get governments to make changes, say, "OK, pi = 3.14, and any one (like Rob) who still wants the old figure can look up the correction from IAU (but not call it pi)"? I know this is an inexact analogy. When it was realised that the it was easier to work with a value of (Planck Constant / 2 pi), that (h-bar) was not renamed to by the Plank Constant, it has a new name: Dirac Constant or Reduced Planck Constant. We use the h-bar more often, but do not re-purpose the original name. Give it a new name, please. Independent of what the "fundamental unit" is. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Changing the name of UTC
On Fri, Oct 17, 2014 at 9:44 PM, Steve Allen wrote: > > I prefer to believe that clear explanation of the intentions behind > the time scales will result in engineers making choices that conform > with the new recommendations, and I would rather see the ITU-R take > that course than follow one based on fear and ignorance. I would like to believe that is true. Many of you on the list are, unlike me, Americans, and have more experience in engineering. You managed to build Hoover Dam while remembering that a hundredweight is not a 100 lbs. Engineering is hard. There is no getting around that. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Changing the name of UTC
On Fri, Oct 17, 2014 at 9:33 PM, Warner Losh wrote: > I’m afraid that if there are two official time scales, both maintained, > and both propagated due to contract language, then the “new” one > without leap seconds would be this oddball thing that nobody actually > implements or that some people implement and others don’t and we’d > be left with a mess. Perhaps not the same mess we have today, but > a new, different mess. > I agree with your problem definition, but I do not think your solution to redifine "UTC" is the best way forward. I have seen examples of people (software programers) who coded 18:25 when they meant 18:15, to refer to the quarter hour after 6pm. The solution to this is (in my view) not redefining an hour to be 100 mins, but re stressing that units matter. And this has happened multiple times, sometimes repeatedly within the same team (English was not their native language, but that is neither here nor there) Unfortunately, in most cases, my pointing out the error was met by, "Oh, OK, we will fix that, stop nitpicking". I am not saying the current status is not fraught with corner cases, and your solution to drop Leap Seconds may well be the least evil method. It still pains me to have to say "UTC before 2021 was loosly coupled to the sun, but now it floats freely" -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Changing the name of UTC
On Fri, Oct 17, 2014 at 6:02 AM, Matsakis, Demetrios < demetrios.matsa...@usno.navy.mil> wrote: > 3. There is no one who says he/she would support UTC redefinition, but > ONLY IF the name is also changed. For what its worth (and it is worth little, I redistribute NTP services and like to read stuff), I am against dropping leap seconds, but not by much. It makes no real difference to me, and people smarter than will come to a good decision. As an engineer, and an ISO auditor, I _am_ against reusing terms. I am not saying it never makes sense, just that we need not do that. There is no shortage of 3 letter terms (yet), use a new one. That way, everyone can be happy, and some of us can plot pretty graphs of what should have been, and pedantically celebrate New Year "the old way, when time was earth angle, sonny"; while others have a smooth timescale which makes more sense. Basically, let us not have the "is this pre-1959 inches, or post" issue. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Standards of time zones -Brooks Harris
On Thu, Jan 9, 2014 at 1:34 PM, Steve Allen wrote: > The past decade of non-consensual non-decision discussion documents > from various bodies who have considered leap seconds and the failed > draft revisions for TF.460 leave me unconvinced that that there is > anyone with enough zeal to become such an authority. > You want zeal? ZEAL? I volunteer :-) I assume you also want correctness, in which case I withdraw my nomination :-) -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Rubber seconds
On Thu, Jan 26, 2012 at 06:54, Ask Bjørn Hansen wrote: > > On Jan 25, 2012, at 1:05, Michael Sokolov wrote: > > > I vigorously advocate only the general idea of rubberization. The > > exact mode of rubberization is up to each individual implementor in > > practice. > > Why do we even try coordinating our clock-ticking if that's okay? > > > Alice and Bob may choose two different rubberization schemes, but the > > magnitude of the difference between their clock readings can't exceed > > 1 s at any point. > > How should public NTP servers behave during the leap second period if > there's no agreed upon "rubberization scheme"? > Background that may be helpful: Ask runs/coordinates the pool.ntp.orginfrastructure, providing NTP to the masses. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Metrologia on time
On Wed, Aug 3, 2011 at 02:47, Steve Allen wrote: > ... but the whole point of tz/zoneinfo is to provide that > kind of tables. Currently we see that ftp://elsie.nci.nih.gov/pub/ > has tzdata2011h.tar.gz , so the politicians and bureaucrats have > already messed with civil time on 8 occasions during this year. > > Much more than 8 changes this year. And some of the changes are unclear till after they have gone into effect (including conflicting info from Ministries and Airlines). -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Looking-glass, through
On Fri, Jan 14, 2011 at 13:47, Tom Van Baak wrote: > You really didn't expect 250 diffeent atomic clocks around > the world to all agree at the ns level at all times did you? > Why not? nano is 10E-9, and I see references to people trying for clocks with 10E-12 on this list. And what good is the "atom" part of an atomic clock, if it can't even handle "nano"? Still waiting for the flying cars I was promised ... -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] IERS Message No. 180: Revision of IERS Earth Rotation Series effective 1 February 2011
(OT) phk, Rob, I am a long-time lurker on this list. Over the years, I have tried to make people care about TZ, leap seconds, and date handling (I work in IT Support). Guy in my team picked up this item, and asked me to check if the sun had risen correctly today :-) You will be happy to know that I have been asked by my team to take them out for lunch and drinks today, to mark this agreement. About 13:00 Singapore Time, we will raise a toast to this. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane On Thu, Jan 6, 2011 at 04:33, Rob Seaman wrote: > > No, I'm saying that people who write standards often don't know what they > should be doing. > > Finally! Something we can agree on! > > ___ > LEAPSECS mailing list > LEAPSECS@leapsecond.com > http://six.pairlist.net/mailman/listinfo/leapsecs > ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] UTC Redefinition Advanced
On Mon, Oct 25, 2010 at 15:29, Poul-Henning Kamp wrote: > In message , > Sanj > eev Gupta writes: > > >I am still opposed, in principle, to letting NTP time (for example) > diverge > >from The One True Cosmic Time; > > What "One True Cosmic Time" would that be ? > My apologies, I left out the "smiley". I know there is no such "Time", I was being tongue-in-cheek. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] UTC Redefinition Advanced
Snipped some stuff. This is the best definition of the problem I have seen for quite some time. I thought I was firmly in the camp of keeping leap-seconds, but put this way, it seems to me that I was staying within an error bound, and now (taking Jonathan as an example), all that is being done is to increase the error bound. And since everyone who really cares about solar/pulsar time would have to be applying DUT1 now, the cost to them is ensuring that their software (and processes) do not have variables that chuck out values of DUT1 greater than 1s.This _is_ a real cost, no doubt, but it seems less of a problem than I assumed. I am still opposed, in principle, to letting NTP time (for example) diverge from The One True Cosmic Time; but my principles are cheap, and my engineering work does not suffer under Jonathan's formulation. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane On Mon, Oct 25, 2010 at 07:42, Jonathan E. Hardis wrote: > There is merely a reexamination of the presumption that DUT1 has to be > kept to less than 0.9 seconds, which -- when you stop to think about it -- > is a rather arbitrary requirement. > > Let's get quantitative. What magnitude of DUT1 would be tolerable to you? > > Based on your postings here, I presume that you're fine with 0.9 seconds. > One could also, arbitrarily, limit it to 0.6 seconds by having the IERS > declare leap seconds every few months, both + and -. However, since I > haven't heard you suggest that, may I presume that you would agree with me > that DUT1 need not kept that small? Can we agree that reasonable people can > discuss what an appropriate bound on DUT1 should be for the purposes of > civil time? > > What about the public at large? In most of the world, we're long past the > point of arguing that sundials are divine and time zones are the work of the > devil. Time zones with the width of an hour are generally acceptable, which > indicates that the public might accept DUT1 as large as 1800, or so. > Certainly no one today gets bent out of shape because sundial time in > Boston is 1200 seconds different than sundial time in Washington, DC, or > that sundial time in Los Angeles is 1000 seconds different than sundial time > in San Francisco. > > So, hypothetically, what would happen if we had no leap seconds for the > next 100 years? There are people who have analyzed how the deceleration of > the Earth's rotation will affect the need for leap seconds -- and I'm not > one of them. Let me make a simple guestimate that with leap seconds > occurring about once every 18 months, in the next 100 years there would need > to be about 80 of them to maintain DUT1 at 0.9 seconds or less. This means > that, without any leap seconds, sundial time at JFK Airport in New York > would become what sundial time at Liberty Airport in Newark is now, and > sundial time in Long Beach would become what sundial time in Santa Monica is > now. DUT1 up to 100 isn't likely to cause the public much if any heartburn. > > The point is that, even if we went 100 years and did nothing, the magnitude > of the effect would be so small as to be inconsequential for most if not all > purposes of civil time. However, I don't hear people talking in terms of > doing nothing in the next 100 years. In international metrology definitions > tend to change with a natural time constant (tau) of about 30 or 40 years -- > a unit of time called a "career." And 100 years is about 2 or 3 tau. The > people at the ITU today couldn't stop their successors from changing UTC > even if they wanted to. Their successors can and will have a reasoned > debate on the best way, in their time, to take account of the fact that -- > to use your expression -- the SI second is not 1/86,400 of a day. > > The debate today is not about setting a course for all future human > history. It is only about whether -- in our time -- keeping DUT1 to 0.9 > seconds is worth the grief that it causes. > > So, to repeat what I told you at the outset of this thread, if you believe > that leap seconds are the best technical approach, long term, for keeping > DUT1 below some threshold, your challenge is to make the world safe for leap > seconds. > >- Jonathan > ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] "UTC is derived from TAI"
On Mon, Mar 15, 2010 at 10:23, M. Warner Losh wrote: > In message: <20100315014100.ga15...@ucolick.org> >Steve Allen writes: > : On Sun 2010-03-14T21:11:58 -0400, Matsakis, Demetrios hath writ: > : > However, there is only one UTC, which has many realizations. The > : > true UTC is determined not from the realizations, but from the clocks > : > behind those realizations. > : > : At the end of the flower sermon Buddha said > : I possess the true Dharma eye, the marvelous mind of Nirvana, the > : true form of the formless, the subtle dharma gate that does not > : rest on words or letters but is a special transmission outside of > : the scriptures. > : yet I find that for the sake of practicality I must ask: > : > : How do I get this one, true UTC? Where do I find it? > : How can I share it with others? > > Is it not true that all suffering comes from desire? > The Sakyamuni's last words are said to be: *Remember, everything is impermanent. Work out your own salvation with diligence.* -- Sanjeev Gupta http://www.linkedin.com/in/ghane ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] 2008-12-31T23:59:60Z
Folks, Any help on how to use a Linux PC driving a large monitor/LCD projector to show a group of school children the leap second? It will be in daylight hours here (Singapore). -- Sanjeev Gupta +65 98551208 On Tue 2008-12-23T20:08:06 -0800, Brian Garrett hath writ: > > examples of how the leap second > > to be thrust upon us next week is affecting list members' current > > projects. > > ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
