Re: independence day

mbers of the U.S. legislative branch who are currently drafting revisions of the definition of U.S. national time may want to have a close look at the above wording. Markus P.S.: The above English translation is mine; a HTML transcript of the official German wording is at http://www.cl.cam.ac.uk/~m

Re: Precision vs. resolution

ognized formal international standard that defines the exact meaning of these terms. I have seen many slightly contradicting definitions of these terms used by different authors. Therefore, whenever you use terms, best attach a brief definition yourself to clarify what exactly you mean. Markus

Re: 24:00 versus 00:00

to change from year to year, where "march" can be MAR, MCH, MRH, MRC, etc. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Ambiguous NTP timestamps near leap second

hat would be 00:00:00.0001 instead. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: 24:00 versus 00:00

d to interval endpoints, only the 00:00 form should be used. See for example the railway timetable on http://en.wikipedia.org/wiki/24-hour_clock where trains arrive at 24:00 but depart at 00:00. http://en.wikipedia.org/wiki/Midnight Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Ambiguous NTP timestamps near leap second

C-SLS is what I'd recommend for most of these cases (but not for the NTP protocol itself). Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: An immodest proposal

quot; servers that replace UTC with TAI and UT1 have been around for quite some some; for instance Patrick Wallace (Rutherford Appleton Laboratory) reported at the 2003 Torino meeting about his "UT1P" server. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: wikipedia "Leap Seconds" collaboration

ipedia. Anything else will/should not survive there for very long and will hopefully be removed for being "just a personal pet theory". Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Risks of change to UTC

e you may find this old thread particularly interesting: Unifying Atomic Time and the post-Gregorian calendar corrections http://www.mail-archive.com/leapsecs@rom.usno.navy.mil/msg00206.html Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Internet-Draft on UTC-SLS

Tim Shepard wrote on 2006-01-19 20:29 UTC: > > > "Coordinated Universal Time with Smoothed Leap Seconds (UTC-SLS)", > > > Markus Kuhn, 18-Jan-06. (36752 bytes) > > > > > > http://www.ietf.org/internet-drafts/draft-kuhn-leapsecond-00.txt > > Th

McCarthy point (was: Fixing POSIX time)

second problem). The latter seems much easier to do for 2000 than for 1972 or even 1958. In applications such as observing planetary motion over many years, the difference matters. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Internet-Draft on UTC-SLS

on a proposed successor to adjtimex(), ntp_adjtime(), etc. I am not claiming that the spec-writing job is finished, or even half finished yet. I see a replacement for RFC 1589 etc. as the next job on the agenda before UTC-SLS (and lots of other time API ideas floating around here and elsewhere)

Re: Internet-Draft on UTC-SLS

to 59 sec before leap second insertion". That was the one I referred to. If you have a good and very reliable signal, it may be just good enough to insert 23:59:60 in time, but it is useless for anything really robust. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Fixing POSIX time

convert scalar <-> -MM-DD notation.) c) It is a date sufficiently recent, such that implementors will be forced to properly test their handling of pre-epoch arithmetic, something easily neglected in practice with epochs before 1980. Markus -- Markus Kuhn, Computer Labo

Re: Internet-Draft on UTC-SLS

9:60 2006-01-01 00:00:00 > 2006-01-01 00:00:00 2006-01-01 00:00:00.999 > 2006-01-01 00:00:01 2006-01-01 00:00:01.998 Wonderful observation! I will certainly add a note on this to Appendix A in the next iteration of this draft. Thanks! Markus -- Markus Kuhn, Computer Laboratory, Unive

Re: Internet-Draft on UTC-SLS

our view again, after you have appreciated that UTC-SLS *can* be implemented in NTP software easily and robustly in a way that is fully backwards compatible with the existing NTP protocol and infrastructure. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Internet-Draft on UTC-SLS

e whatsoever to expose real-world applications to the time value 23:59:60. I believe that UTC-SLS is not a kludge, but is a most sensible and practical solution, *if* we accept the premise that civilian time remains tied to UT1. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Internet-Draft on UTC-SLS

ys of interpreting UTC in such environments [e.g. those listed as options 1a) to 1i) in Appendix A]. Some of these alternatives have caused quite some off behaviour on 1 January in NTP-synced equipment. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Internet-Draft on UTC-SLS

A new Internet-Draft with implementation guidelines on how to handle UTC leap seconds in Internet protocols was posted today on the IETF web site: "Coordinated Universal Time with Smoothed Leap Seconds (UTC-SLS)", Markus Kuhn, 18-Jan-06. (36752 bytes) http://www.ietf.org/inter

Re: The real problem with leap seconds

Ed Davies wrote on 2006-01-13 11:45 UTC: > The use of the 23:59:60 notation is described in ISO 8601. > Is it also specified in TF.460? It originally comes from ITU-R TF.460, which is a standard for radio time signals. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridg

Re: The real problem with leap seconds

leap-second table updates. You cannot get TAI from the BBC evening news, and you still cannot even get it reliably from your average local NTP server. (I know, we've already discussed this here, on [EMAIL PROTECTED], on pasc-time-study, and on austin-group-l in *very* great detail, many, man

Re: HBG transmitted wrong info during leapsecond

Which was also noted at http://wwwhome.cs.utwente.nl/~ptdeboer/ham/sdr/leapsecond.html Various other LF 2005 leap second recordings are listed at http://www.cl.cam.ac.uk/~mgk25/time/lf-clocks/#leapsec2005 Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http

Re: December 2005 leap second on MSF, Rugby, England

msf-leapsec2005 Anyone got a GLONASS recording? Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Things to do at about 2005-12-31 23:59:60Z

Neal McBurnett wrote on 2005-12-31 07:35 UTC: > On Mon, Dec 19, 2005 at 11:31:22PM +0000, Markus Kuhn wrote: > > I suspect, the basic exercise will be running a little test routines on > > various NTP-synchronized hosts, that log the progression of > > clock_gettime(), gettime

Re: Things to do at about 2005-12-31 23:59:60Z

le IF should be sufficient, I'd be happy to help out with the offline demodulation and decoding afterwards. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Things to do at about 2005-12-31 23:59:60Z

? http://www.startribune.com/stories/404/5508732.html It might be fun to compile a comprehensive documentary here on how the leap second is implemented in practice today ... Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great

Re: Lighter Evenings (Experiment) Bill [HL]

(~ UT + 1.5 h) c) Asia + Australia: use local time of Thailand (~ UT + 6.5 h) Sure, the hours of darkness would vary substantially within each of these zones. But they do already *today* for much of the world, thanks to summer/winder. China understood this a long time ago. Mar

Re: a system that fails spectacularly

facto rendered the entire idea utterly useless. It could be easily fixed by adding a publication requirement to the ISO 9000 certification process, but I doubt that anyone other than civilian customers would want that. And these standards are not written by civilian customers. Markus -- Mar

Re: Precise time over time

e is no need to attempt to continuously resynchronize them, or the rest of the factory, with UTC at all. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Precise time over time

IX users are very happy with how it encodes time. The only thing we slightly worry about is that existing ABIs may keep time_t restricted to 32 bits until 2038. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Stupid question from programmer: Why not just eliminate ALL UTC corrections ?

standard frequency transmitters, telecoms frame frequencies, etc. where UTC as a clock with continuous 1 s ticks works fine and needs no changes. See http://www.cl.cam.ac.uk/~mgk25/uts.txt for a more detailed rationale. Markus http://www.cl.cam.ac.uk/~mgk25/time/leap/ -- Markus Kuhn, Com

Re: Stupid question from programmer: Why not just eliminate ALL UTC corrections ?

eiver, if you don't want to. More on UTS: http://www.cl.cam.ac.uk/~mgk25/time/leap/utc-torino-slides.pdf Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: BBC beeps

nute accuracy clock displays (such as the famous beeps) from these broadcasts. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Stupid question from programmer: Why not just eliminate ALL UTC corrections ?

ime_t as an integer-encoding of a UTC clock value rather than as a simple count of seconds (although the historic term unfortunately "Seconds since the epoch" suggests otherwise to anyone who hasn't actually read its exact definition). Markus -- Markus Kuhn, Computer Laboratory,

Re: xntpd and adjtimex() handling of leap seconds

echanism front. Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Wall Street Journal Article

g 23:59:61 becomes acute in a few ten thousand years from now, (including, hopefully, the abolishion of our archaic base-60 time notation). Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Wall Street Journal Article

stone for real-world IT installations. Incompetent test design is an orders of magnitude heavier stone ... with or without leap seconds. I see leap seconds more as one one among thousands of things that can go wrong with computers, and not one that has good prospect of ever featuring promin

Re: Leap-second scare stories

t to make the change to UTC look less severe than it really is. If someone submits a proposal for discontinuing leap seconds, then it should say that |UTC-UT1| will from now on be allowed to grow unbounden, and they should choose a name that does not contain the astronomical term "Universal Time"

Leap-second scare stories

ter networks exactly *because* (unlike civilian local time) it is free of any disruptive DST leap hours! Let's not forget that this proposal is all about replacing a reasonably frequent minor distruption (UTC leap seconds) with a very rare catastrophically big one (UTC leap hours). Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: "Secular"

secular deviation. [Outside astronomy, there is of course the far more widely used political meaning "non-religious" for the same term, as in "Irak's secular government versus Iran's Islamic government".] Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: GMT -> UTC in Australia and elsewhere

Steve Allen wrote on 2005-02-23 02:27 UTC: > http://abc.net.au/science/news/space/SpaceRepublish_1307267.htm > The last line in the article implies other jurisdictions are doing the same. Or have done the same long ago ... The EU summer time directive remains agnostic on the issue and (deliberate

Re: Time after Time

Poul-Henning Kamp wrote on 2005-01-24 09:32 UTC: > In message <[EMAIL PROTECTED]>, Markus Kuhn writes: > > >In summary: There are basically three proposals on the table: > > > > a) Keep UTC as it is (|UTC - UT1| < 900 ms) and just make TAI more > > wid

Re: two world clocks AND Time after Time

prime meridian defined - if it is a solar time, which periodic deviations have been removed Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Time after Time

John Cowan wrote on 2005-01-23 18:37 UTC: > Markus Kuhn scripsit: > > > UTC currently certainly has *no* two 1-h leaps every year. > > There seems to be persistent confusion on what is meant by the term > "leap hour". Why? > I understand it as a secular change

Re: Time after Time

d by the legislation of individual member countries, as opposed to setting guidelines for future legislation there, then you have simply misunderstood the entire purpose of the process. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: TAI-UT1 prediction

bout the rotation of earth (UT1 clock frequency) slowing down roughly linearly, therefore the accumulation of the phase difference being (after integrating) an essentially quadratic function? Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: ITU Meeting last year

ere would be a clear need to keep them locked to UT1 + offset to within an hour or so. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: ITU Meeting last year

leap seconds! If ITU wants to turn UTC into an interrupt-free physical time scale decoupled from the rotation of the Earth, then it should say so honestly, by defining that UTC will *never* ever leap in any way, neither by a second, nor by an hour. Markus -- Markus Kuhn, Computer Lab, Univ

Re: GPS versus Galileo

s after which the agreement will be presented for signature" Does anyone here know where the actual technical details of that agreement may be available to the interested taxpayer, to help one untangle this diplomatic language? Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://w

ITU-R SRG7A Turin colloquium proceedings available online

The proceedings and final report of the ITU-R SRG7A Colloquium on the UTC Timescale, Turin, Italy, 28-29 May 2003, have now appeared online at the IEN web site: http://www.ien.it/luc/cesio/itu/ITU.shtml Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http

Re: GPS versus Galileo

e I, Progress in Astronautics and Aeronautics, Volume 163, American Institute of Aeronautics and Astronautics, Washington DC, 1996. -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: GPS versus Galileo

come not only a military concern, but also the topic of a serious turf fight between the Pentagon and the EU Commission. Is seems the Temporal Cold War has begun ... Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: name the equinox contest on now

be another very useful exercise towards making this work more accessable and therefore useable by a much larger community. Just a thought ... Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: CNN "story" and more media coverage

.jhtml?xml=%2Fconnected%2F2003%2F12%2F31%2Fecftime31.xml which seems to have in part been inspired by an earlier piece in the New Scientist http://www.cl.cam.ac.uk/~mgk25/volatile/leapsec-newscientist.pdf Full list of media coverage so far at the bottom of http://www.cl.cam.ac.uk/~mgk25/t

Re: trading time

l requirements in trading are more for exact and unambiguous rules and regulations for how to deal with and interpret timestamps, rather than for actual subsecond accuracy. I don't expect to see caesium fountains being installed in Wall Street offices any time soon. Markus -- Markus Kuhn, Comput

Re: the legacy of ephemeris time

ts the International Date Line? http://www.mail-archive.com/[EMAIL PROTECTED]/msg00206.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg00195.html ... Markus http://www.cl.cam.ac.uk/~mgk25/time/leap/ -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Torino Meeting presentations and resolution

arkus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Wired magazine

t in a meaningful way. (But then, which topic isn't?) Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: power grids and leap seconds

id must on its own be able to cause such a change. Unfortunately, privatization has led to suppliers not taking these specifications as serious any more everywhere as they used to. Spare power plants and lines to quickly reroute 3000 MW cost money that managers would rather save. Markus -- Mark

More media coverage: Der Spiegel 2003-08-25

wing on my leap seconds link farm: http://www.cl.cam.ac.uk/~mgk25/time/leap/ Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: more fundamental solutions

of attitude control thrusters to the crust of the Earth (in some yet to be conceived environmentally-friendly way). Project LunarTick ... Let's give the International Earth Rotation Service some serious power! Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: mining for data about time

imple single-record-per-ASCII-line syntax (e.g., comma separated values, etc.) that can be parsed trivially with a simple single-line Perl or Awk regular expression. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: preferred months for leap seconds

any months (typically siz) in advance. Therefore, nobody at IERS has any reason to be "missing their New Year's Eve party year after year" in order to insert a leap second, because all their work has already been done half a year earlier. Markus -- Markus Kuhn, Computer Lab,

German Time Act of 1978, now available in English

ch things and and discuss the remaining technicalities with their international counterparts via the usual scientific communication channels. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

More media coverage: NZZ 2003-07-13

to be online. http://www.nzz.ch/ Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: Applications of earth-orientation information

ng as DST is in use, local civilian times will have very little problems following local solar time with leap hours. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: DRM broadcast disrupted by leap seconds

erly. I personally feel certainly not motivated to press ahead with proposals for handling leap seconds better, if there is a real chance that there might soon be no more of them. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

DRM broadcast disrupted by leap seconds

hour, in discussions the hope was expressed that in practice nobody will notice.] Either having a commonly used standard time without leap seconds (TI), or having TAI widely supported in clocks and APIs would have solved the problem. Markus -- Markus Kuhn, Computer Laboratory, University of

Re: UTH again

nia of high precision astronometric records, they will have far better data than we do, to make an informed choice of what to do with the Gregorian calendar. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: religious concerns

the year 5600). Apart from the weekday question, I haven't yet heard any argument on why it might not be one of the most feasible and desireable solutions. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: religious concerns

Steve Allen wrote on 2003-07-13 06:51 UTC: > On Sat 2003-07-12T11:19:22 +0100, Markus Kuhn hath writ: > > It seems, the true quarrel of this particular community is more with the > > Earth not being flat any more > > Nevertheless, most of the people in the world have not trave

Re: religious concerns

the Old Testament was written) ... http://www.flat-earth.org/ http://www.cca.org/woc/felfat/ Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

"Universial" Time, "Terrestrial" Time -- time for new terminology?

s while minimizing short-term controversy over backwards compatibility.] http://tycho.usno.navy.mil/systime.html http://scienceworld.wolfram.com/astronomy/Time.html Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Ruminations about time broadcast data formats

d for anything in between, and neither could anyone at the Torino meeting when Dennis McCarthy brought up the subject of whether there should be a UT1C. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

ISO standards on time and calendar

need to be updated. If you say in a UTC-replacement proposal exactly what would need to be fixed in ISO 8601 and POSIX, then it should be pretty obvious from that what should be fixed in many other similar specifications. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB

Re: Is Julian Date a time or an Earth angle?

Steve Allen wrote on 2003-07-03 18:09 UTC: > On Thu 2003-07-03T18:30:00 +0100, Markus Kuhn hath writ: > > Thanks for pointing this out! Weekday-continuity is indeed a bit of a > > problem of this approach. I can't see any other practical solution than > > skipping one

Re: Unifying Atomic Time and the post-Gregorian calendar corrections

ust be eager to fund research on when exactly Easter will happen in the year 10 anno domini ... Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Leapmilliseconds are not a solution

nsiderations where the reason for the introduction of the leap second in the first place. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Unifying Atomic Time and the post-Gregorian calendar corrections

ar every 4000 years. But my views may be biased ... Any comments? Markus -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain

Re: making leap hours workable

s at different dates, it is not feasible to change UTH at the same date all over the world. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: What to do if International Time hits the International Date Line?

Steve Allen wrote on 2003-07-01 19:52 UTC: > On Tue 2003-07-01T20:34:58 +0100, Markus Kuhn hath writ: > > Newcomb's formula for the geometric mean longitude of the Sun is > > > > L = 279° 41' 48".04 + 129602768".13 C + 1".089 C^2 > > not really

What to do if International Time hits the International Date Line?

ogians back into this discussion after so many centuries ... ;-) Reference: - Nelson, McCarthy, et al.: The leap second: its history and possible future. Metrologia, Vol. 38, pp. 509-529, 2001. http://www.cl.cam.ac.uk/~mgk25/time/c/metrologia-leapsecond.pdf -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Nature, June 12 & ITU WRC

(I was also contacted by someone from the Guardian recently, so there might be more media coverage ahead.) Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Torino SRG resolution

I'd be curious to hear from anyone who stayed in Torino for the Friday meeting of the SRG what happened there. In particular, was a final resolution fleshed out, and what is the text of that? Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | _

Re: timestamps on death certificates

wyers about fuzzy logic. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Torino meeting and implications of international time >> UT1

apidly decaying memory of course ...] Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: timestamps on death certificates

s significatly longer than 1000 ms. I seriously doubt that the authors of the US regulations for timestamps on death certificates even understand the difference between GMT, UT1 and UTC, neither have they any practical need to do so. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: pedagogically barren?

where even air travel tickets still use the awkward notation (and solve the ambiguity problem by never scheduling any event exactly on noon or midnight). More information on ISO 8601: http://www.cl.cam.ac.uk/~mgk25/iso-time.html Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: pedagogically barren?

of good will with regard to international standardization. (I'm talking about commercial, not scientific practice.) Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Some personal notes on the Torino meeting

Steve Allen wrote on 2003-06-03 02:26 UTC: > On Mon 2003-06-02T17:58:36 +0100, Markus Kuhn hath writ: > > backgrounds, one of the first presentations that gave a case for > > abandoning leap seconds was given by William Klepczynski. He took the > > ADS-B (Automatic Dependent

Some personal notes on the Torino meeting

ervice before any changes take effect. The SRG was going to meet on Friday morning to revise and flesh out this concluding recommendation. I left Italy already Thursday evening and I hope we will see the final result here sometimes this or next week. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: NASA GMT vs UTC

f Celsius for temperatures; feet instead of meters; etc.)] Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Leap seconds in the European 50.0 Hz power grid

Steve Allen wrote on 2003-01-30 20:58 UTC: > On Thu 2003-01-30T12:54:09 +0000, Markus Kuhn hath writ: > > The UCPTE specification says that the grid phase vectors have to rotate on > > long-term average exactly 50 * 60 * 60 * 24 times per UTC day. > > Obviously the grid frequ

Re: Subtracting two UTC/time_t timestamps under POSIX

seconds since power-up. If you have a reference clock, you can frequency control CLOCK_MONOTONIC, but you must not phase-control it. Literature: http://www.opengroup.org/onlinepubs/007904975/basedefs/time.h.html Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Telescope pointing and UTC

y come with integrated GPS receivers) been asked, what |UT1-UTC| > 0.9 s would means for the many thousands of systems that they have already sold? Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: What problems do leap seconds *really* create?

y that. I rest my case. Are there any more interesting problems with leap seconds than misinterpretations of old Unix manuals? Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__

Re: Unix notion of "Seconds since the Epoch"

John Cowan wrote on 2003-01-30 16:35 UTC: > Markus Kuhn scripsit: > > > As I noted earlier, de facto and "de jure" (meaning POSIX.1:1996, > > section 2.2.2.113), any real world Unix file system (and that's where > > the term "seconds since t

Re: Calabretta's 86400 s + epsilon day proposal

and this way your proposal would be similar to UTS, except that you make the correction every day whereas I prefer to limit it to the vicinity of each current UTC leap second. But pulse-per-second signals would experience a phase jump at the end of every day ... :-( Markus -- Markus Kuhn, Computer

Re: What problems do leap seconds *really* create?

John Cowan wrote on 2003-01-30 13:01 UTC: > Markus Kuhn scripsit: > > > Unix timestamps have always been meant to be an encoding of a > > best-effort approximation of UTC. > > Unix is in fact older than UTC. This is getting slightly off-topic, but Unix slowly evolved and w

Re: What problems do leap seconds *really* create?

Ken Pizzini wrote on 2003-01-30 06:06 UTC: > On Wed, Jan 29, 2003 at 07:04:23PM +0000, Markus Kuhn wrote: > > Who really needs to maintain a full list of leap seconds and for what > > application exactly? > > If a file storage system stores timestamps as "SI seconds

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