Re: [LEAPSECS] The relation between calendars and leap seconds.
Tony Finch said: Halsbury's Laws of England has some interesting (bizarre, self- contradictory) paragraphs on the meaning of civil time, which I'll append as a postscript because of their length. I'm going to comment on these, partly because Halsbury is well out of date. 215. Local time. Apart from statute [1] or special convention, the hour of the day has to be ascertained by reference to the sun in the particular place. True, but statute has made this effectively a dead piece of common law. 216. Greenwich mean time. For the purpose of statutes, subordinate legislation, deeds or other legal instruments, it is provided by statute that, unless the contrary is expressed (and subject to the provisions regarding Summer Time [1]), expressions of time are to be taken to refer to Greenwich mean time and not to local time [2]. [...] All this is sensible enough. It has been held that 'sunset' in certain enactments is not such an expression of time as previously mentioned [5], but refers to local time [6]. [...] [6] Gordon v Cann (1899) 80 LT 20, DC, where the obligation imposed by what is now the Road Vehicle Lighting Regulations 1989, SI 1989/1796, reg 25 (see road traffic vol 40(1) (2007 Reissue) para 393), to light a carriage used on the road half-an-hour after sunset was in question, and it was held that regard must be had to the actual hour of sunset at the particular place; MacKinnon v Nicolson 1916 JC 6, where 'sunset' and 'sunrise' in the Salmon Fisheries (Scotland) Act 1862 s 27 (repealed), which made it an offence to fish for salmon between those times in certain circumstances, were held in Scotland to mean the times at which the sun sets and rises at the locus of the alleged offence. See also the Night Poaching Act 1828 s 12 (as amended); and animals vol 2 (2008) para 791. My legal research has failed to find any definition in statute of sunrise and sunset. In particular, it is not clear whether sunset is when the (1) upper limb of the sun disappears below (2) centre of the sun passes (3) lower limb of the sun first touches the (4) theoretical horizon if the earth were a perfect airless geoid (5) theoretical horizon allowing for atmospheric diffraction (6) visible horizon including hills and valleys. 218. Reckoning of time during summer time. During the period of summer time, the time for general purposes in Great Britain [1] is one hour, or during any part of that period for which it is so directed by Order in Council [2], two hours, in advance of Greenwich mean time [3]. [...] [1] 'Great Britain' means England, Wales and Scotland: see the Union with Scotland Act 1706, art 1; and constitutional law and human rights vol 8(2) (Reissue) para 3. The Summer Time Act 1972, however, applies also to Northern Ireland, the Channel Islands and the Isle of Man (see ss 4(1), 5(1)), but Orders in Council under s 2 may make different provisions with respect to the islands (see s 5(2); and para 217 note 2 ante). In addition, a law of the States of Jersey or of Guernsey or an Act of Tynwald can override the application of the Act in the relevant territory (see s5(1)). But, more importantly, s.2 has been repealed and therefore s.5(2) is pining for the fjords. Only the States or Tynwald can alter the relationship. [2] The power to direct by Order in Council that the time for general purposes is, during any part of the period of summer time, to be two hours instead of one hour in advance of Greenwich mean time is conferred by ibid s 2(1)(b). At the date at which this volume states the law no Order in Council under s 2(1)(b) for any subsequent year had been made. As to Orders in Council under the Summer Time Act 1972 see para 217 note 2 ante. This provision was repealed on 2002-03-11 by S.I. 2002 No. 262. The same S.I. also fixed the transitions as being at 0100 GMT on the last Sundays in March and October. [4] Ibid s 3(1). A print-out from a Lion Intoximeter device recording results of a breath test for excess alcohol was not admissible for failure to comply with the Summer Time Act 1972 ss 1, 3 even though timed according to Greenwich mean time when British summer time was in effect at the time of the offence: Parker v DPP [1993] RTR 283, (1993) 157 JP 218. Um, that should read was not inadmissible. The Queen's Bench Division accepted that it was clear that the time on the printout was GMT, everybody knows that BST is one hour ahead of GMT, and the magistrates examining the case had correctly made the adjustment to match the printout with other evidence relating to times. I don't think that R. v Haddock on the meaning of general purposes is settled law in the UK, but courts have certainly been happy to accept other time bases in evidence; for example, Miranos International Trading Inc. v Voc Steel Services BV [2005] EWHC 1812 (Comm), where the judgement states: The relevant facts as found by the arbitrator are as follows: The vessel was
Re: [LEAPSECS] The relation between calendars and leap seconds.
On Nov 12, 2008, at 6:30 AM, Rob Seaman wrote: dawn's early light This better fits twilight. Perhaps crack of dawn? ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
On Wed, 12 Nov 2008, Rob Seaman wrote: Clive D.W. Feather wrote: No, it's because there are no applications where people need to say what would my GPS receiver had said in 1751?. Whereas people do need to represent older times in (say) POSIX time. Do they? Example use case from 1751? Well, not 1751, but 32 bit POSIX time is signed so extends back before its (proleptic) epoch of 1970-01-01, and it's not unreasonable to use negative times to represent (say) timestamps on files archived from the 1960s. Tony. -- f.anthony.n.finch [EMAIL PROTECTED] http://dotat.at/ HUMBER THAMES: NORTHWEST 4 OR 5, OCCASIONALLY 6 AT FIRST AND LATER. MODERATE, BECOMING OCCASIONALLY SLIGHT. SQUALLY SHOWERS AT FIRST. MAINLY GOOD. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
Poul-Henning Kamp wrote: Living in a country that legally still uses 'mean solar time on the 15the eastern longitude' I find this very hard to belive. We have not even come close to eradicating usage of GMT as an alias for UTC. Thanks for emphasizing this point. I think it is safe to say, that adding a new timescale will not result in its widespread adoption. Again, we're jumping vast numbers of steps forward to presuming a solution - even the form of a solution - before capturing use cases and deriving requirements. In fact, even before successfully notifying most stakeholders (and no, I don't mean everybody on the planet) that a change to the status quo is being considered. However, surely the point of coupling TI with the zoneinfo notion - just for the sake of argument - is to simply start distributing TI instead of UTC. Then UTC - a flavor of Universal Time, an alias for Greenwich Mean Time (which as you say is far from eradicated) - remains available for those who need it. The adoption of TI would be massive and immediate. UTC would remain behind like the Cheshire Cat's smile. There would be confusion, just as there is confusion now between UTC and GMT. However, unlike the ITU proposal, the confusion between UTC and GMT would not start to quadratically diverge. Over time there would be time to educate stakeholders about the new distinctions. Perhaps we could all stop thinking that this is a zero-sum game. I live in a world where the exact position of the sun in the sky is a lot less important, than what technically inept people have written on legally binding papers. The question is whether the position is stationary (versus a secular drift), not whether it is exact. Legally binding ultimately has to bow to physical reality. Breaking a human law results in various civil and criminal penalties (or often, does not). Physical law needs no penalties. Best practice system engineering is a very bad method for tackling legal problems. Many legal situations depend on systems architecture of one sort or another. (The law itself is a system, too, of course.) Asserting that law makers are flawed humans has no bearing on whether the underlying architecture should be properly built. What's the alternative? Throw darts? The levees failed in New Orleans creating massive legal issues. Should the levees be rebuilt by lawyers or by engineers? Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
Clive D.W. Feather scripsit: I don't think that R. v Haddock on the meaning of general purposes is settled law in the UK, Doubtless not. But, if you will, remind us just which piece of jolly ligitation that was? There were so many of them -- With techies, I've generally found John Cowan If your arguments lose the first round http://www.ccil.org/~cowan Make it rhyme, make it scan [EMAIL PROTECTED] Then you generally can Make the same stupid point seem profound! --Jonathan Robie ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
In message [EMAIL PROTECTED], Rob Seaman writes: Poul-Henning Kamp wrote: However, surely the point of coupling TI with the zoneinfo notion - just for the sake of argument - is to simply start distributing TI instead of UTC. Then UTC - a flavor of Universal Time, an alias for Greenwich Mean Time (which as you say is far from eradicated) - remains available for those who need it. The adoption of TI would be massive and immediate. And illegal on many systems, including all USGOV owned and operated systems. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
On Wed, 12 Nov 2008, Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Rob Seaman writes: Poul-Henning Kamp wrote: However, surely the point of coupling TI with the zoneinfo notion - just for the sake of argument - is to simply start distributing TI instead of UTC. Then UTC - a flavor of Universal Time, an alias for Greenwich Mean Time (which as you say is far from eradicated) - remains available for those who need it. The adoption of TI would be massive and immediate. And illegal on many systems, including all USGOV owned and operated systems. So would that mean that any USGOV owned and operated systems not running NTP (Window boxes, for example), or those running NTP but are in the middle of dealing with a leapsecond, are being illegally operated? How close to UTC do you have to be to be under the limit when the US Time Police pull you in? Pete. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
John Cowan said: Clive D.W. Feather scripsit: I don't think that R. v Haddock on the meaning of general purposes is settled law in the UK, Doubtless not. But, if you will, remind us just which piece of jolly ligitation that was? There were so many of them Drinking is not a general or normal purpose, it is a celebration, a special purpose. Therefore the Summer Time Act does not apply to pub opening times. -- Clive D.W. Feather | Work: [EMAIL PROTECTED] | Tel:+44 20 8495 6138 Internet Expert | Home: [EMAIL PROTECTED] | Fax:+44 870 051 9937 Demon Internet | WWW: http://www.davros.org | Mobile: +44 7973 377646 THUS - a Cable and Wireless business ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
Poul-Henning Kamp wrote:And illegal on many systems, including all USGOV owned and operatedsystems.I thought the ITU had treaty status, therefore that they could decree that we all must henceforth wear Goofy watches that run CCW, and that this sober determination would supersede all other laws of God and man.Also, is it truly illegal for computers to keep time two different ways? After all, nobody really promulgates UTC even now - rather, various messages are passed using other protocols such as NTP resulting in a separate timescale realization on each computer. TI could be interposed at one layer as long as UTC remains available (perhaps only notionally) at another.In general, any strong assertions about overriding legal entanglements will tend to emphasize the importance of maintaining an unbroken chain of historical precedent, ie., that UTC == GMT.Rob___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
Clive D.W. Feather wrote: No, it's because there are no applications where people need to say what would my GPS receiver had said in 1751?. Whereas people do need to represent older times in (say) POSIX time. Do they? Example use case from 1751? ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
On Wed, 12 Nov 2008, Rob Seaman wrote: Are people really convinced by the argument that badly implemented systems should determine policy? I'm arguing about deployment pragmatics. Note that the systems aren't badly implemented, they are just following specs based on UT sans leap seconds. If you simply change broadcast time signals to be TI instead of UTC then the POSIX spec and the NTP spec and ... will no longer describe reality. I don't think this kind of incompatible change is good sysems engineering. Tony. -- f.anthony.n.finch [EMAIL PROTECTED] http://dotat.at/ SOLE: WEST OR SOUTHWEST 4 OR 5. ROUGH BECOMING MODERATE. RAIN OR DRIZZLE. GOOD BECOMING MODERATE OR POOR. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
On Wed, 12 Nov 2008, Jonathan E. Hardis wrote: * Who can cite case law, where a court has had to decide an actual controversy on timekeeping? (Courts don't deal with hypothetical controversies or arguments over trivia. De minimis non curat lex.) Curtis v. March, cited earlier in the quotations from Halsbury's, establishing the proposition in English law that custom setting clocks in a way at variance with what the time is according to the law does not change what the time is according to the law. (If time signals, and so clocks, were to diverge from GMT with the law remaining referencing GMT, this could become relevant again; the original context was when clocks generally were set to GMT but the common law was that time was local mean time.) Miller v. Community Links Trust Ltd (UKEAT/0486/07), where a claim that arrived nine seconds late was held to be out of time. (The timekeeping was not in dispute in this case, but if GMT and the time used by time signals and computer clocks had diverged by nine seconds then a claim the computer ruled was out of time by being received at 00:00:08 could in fact have arrived at 23:59:59 GMT and so be in time according to the law.) -- Joseph S. Myers [EMAIL PROTECTED] ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
In message [EMAIL PROTECTED], Poul-Henning Kamp writes: But more importantly, they put their lives, unaware of this fact, in hands of automatic systems, which work on the mistaken POSIX interpretation of the UTC timescale. I should add, that the legal impact of POSIX seems to be vastly underestimated by the astronomers in this forum, so let me explain how deeply this cuts. For our purposes, the paper trail starts with the C-language (STD-C) International Standard ISO/IEC 9899 Programming Languages -- C which defines the time_t data type pretty loosely, and with certain auxillary time conversion functions of which some offer support for handling leap-seconds, provided you know what the leap second count is for the time you are trying to deal with. Then comes: International Standard ISO/IEC 9945-1:1990 Information Technology - Portable Operating System Interface (POSIX) which imports STD-C and in section 4.14 codifies the troublesome stupidity: 4.14 Seconds Since the Epoch [...] As represented in seconds since the Epoch, each and every day shall be accounted for by exactly 86400 seconds. This is not as much an active choice of the standardization body, as it is a codification of widespread and existing practice, which they dared not change, should they even have wanted to. For full details on this tragedy, see chongos excellent saga here: http://www.mail-archive.com/[EMAIL PROTECTED]/msg00109.html The full scale of the scientific ignorance employed is indicated from this horror: 2) We defined the epoch as 1970 Jan 1, 00:00:00 UTC. This was defeated and UTC was replaced with GMT. (The fact that ISO cannot find their ass with a flashlight when it comes to IT related standards, have been so amply demonstrated by POSIX, that the OOXML debacle shouldn't surprise anybody.) Then, examining USA as an example, NIST comes in: FIPS-151-2 Portable Operating System Interface (POSIX) - System Application Program Interface [C Language] Which adopts POSIX, and makes it a requirement for pretty much all federal, and in particular the lucrative DoD and DoE, IT investments. The success of this push for standardization can be seen from the fact that all currently viable operatingsystems, from Windows to IBM's MVS sport a POSIX facility, see for instance: Microsoft: http://technet.microsoft.com/en-us/library/cc768080.aspx IBM: http://www-01.ibm.com/cgi-bin/common/ssi/ssialias?infotype=ansubtype=cahtmlfid=897/ENUS294-152appname=isourcelanguage=enus Whereas the non-POSIX compliant operating systems, such as VMS, AOS and their ilk, have all gone to rest peacefully at http://bitsavers.trailing-edge.com/ And there you have it: by the sheer effort of scientific incompetence, all federal and defense systems acquired in the last decade has been very very careful to screw up leap second handling, precisely as to specified in POSIX. The situation everywhere else in the world is exactly the same, with more or less awareness of there even being an issue. The only change to leap seconds we can come up with, that does not require all of this to be treated to a Y2K style audit, is to stop sticking leap seconds in UTC and live with it. And even if we do get political acceptance of such a revision, we have still not solved the issue with dissemination of leap second warnings with short (ie: less than 10 years) notice. Any technical or practical problems with telescopes which the astronomers might encounter due to lack of leap seconds in UTC will cost less than the feasibility study NIST will have to do on the regulatory change. The true cost of the change would be staggeringly unknownable. Poul-henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The relation between calendars and leap seconds.
Rob Seaman scripsit:
But you're right - I see the light! I now acknowledge that it is more
important to kowtow to international standards - standards that you
loudly blare are badly conceived and written - than to acknowledge
minor facts of physical reality such as that Earth has a moon.
What has the Moon to do with it? The connection of the Moon to the
calendar was lost in Julius Caesar's time -- doubtless to great howling
by the astro{nom,log}ical community.
--
Cash registers don't really add and subtract; John Cowan
they only grind their gears.[EMAIL PROTECTED]
But then they don't really grind their gears, either;
they only obey the laws of physics. --Unknown
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Re: [LEAPSECS] The relation between calendars and leap seconds.
John Cowan wrote:
What has the Moon to do with it? The connection of the Moon to the
calendar was lost in Julius Caesar's time -- doubtless to great
howling
by the astro{nom,log}ical community.
...and around we go again. This was my shorthand way of referring to
all the issues associated with variations in Earth orientation, in
particular the secular trend leading to the quadratic behavior. As a
reminder, it has long since been shown that leap seconds would be
required even in the absence of tidal deceleration.
The issue with the calendar, is, has been, and always will be that a
clock is a subdivision of a calendar. You can't muck around with leap
seconds without calling into question the definition of the day.
It is a false equivalence to point to the multitude of cyclic
celestial phenomena, and draw a conclusion that none matter because
some are of little importance to our daily lives. Just examine that
phrase - daily lives. Days matter in civil timekeeping. Fractions of
days matter. Secular drift of days matter.
Every scheme proposed in the original GPS World article amount to sly
cheats on mean solar time - including the eradication of leap
seconds. This is not an option that could possibly work if the SI
second were much more different from the mean solar second (1/86400 of
a solar day) than it is now. The only reason we're having this
discussion is that the paleo timelords didn't stick to the plan to
call the SI unit an essen instead of a second, thus avoiding the
whole confusion in the first place.
Adi Stav wrote:
We don't how many seconds there will be in 2009-12-31 23:59; there
might be 60, 59, or 61. So the UTC calendar is not predictable.
I can easily imagine such predictable systems, such as adding
permenant
leap seconds regularly into the year according to some pre-determined
formula, but I don't think I've every seen such a thing proposed.
We've thrashed out seven (no, not literally seven) different
variations over the unending aeons of this discussion. There is
absolutely nothing in the current definition of UTC to stop us from
announcing a schedule years in advance. This is by far the easiest
change to make to UTC.
If we weren't spending all our time trying to fend off the unilateral
cessation of leap seconds, we could put that energy into discussing a
new scheduling algorithm. Not permanent, perhaps, but some other
trade-off between amplitude and scheduling horizon seems eminently
achievable.
UTC is not perfectly predictable because the Earth is not.
Emasculating UTC won't make the Earth any more predictable, or human
civilization any less synchronized with diurnal cycles.
There are options yet unexplored. We'll get to them faster by
focusing on requirements than by reiterating our talking points over
and over and over again.
Rob
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Re: [LEAPSECS] The relation between calendars and leap seconds.
On Mon, Nov 10, 2008 at 04:13:25PM +, Tony Finch wrote: I agree with your requirements 2,3,4 and I note that UTC doesn't satisfy 3, which is another statement of this timeless predictability requirement. (Your requirement 4 is only relatively timeless, since it allows for changes in the definition of the second.) Have there been suggestions, indeed, for such a predictable SI-second-based calendar that synchronizes with the Earth's rotation? ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
