Re: [time-nuts] Re: UTC

2005-07-31 Thread Magnus Danielson
From: Warner Losh <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Re: UTC Date: Wed, 27 Jul 2005 17:19:34 -0600 (MDT) Message-ID: <[EMAIL PROTECTED]> > > Certainly. But what's your point? I don't see these utilities failing > > if a second slips here or there. T

Re: [time-nuts] Re: UTC

2005-07-29 Thread Chuck Harris
Poul-Henning Kamp wrote: [1] likely in my mind. They have a war or two going on, they are not in a position to take a couple of hours off to see what doesn't work afterwards. The war in Iraq, though a pretty big thing for those who are in Iraq, isn't taxing the DoD much at all. I live near

Re: [time-nuts] Re: UTC

2005-07-28 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Warner Losh writes: > Within the respective zones created under the authority of sections > 261 to 264 of this title the standard time of the zone shall insofar > as practicable (as determined by the Secretary of Transportation) > govern the

RE: [time-nuts] Re: UTC

2005-07-28 Thread Bill Hawkins
Folks, This pointless argument is too reminiscent of what passes for politics here in the USA - unfounded allegations and sudden distractions from real issues. The only real example of a problem concerned a cell phone and an eclipse, and the desire to sell an application that would mark the cente

Re: [time-nuts] Re: UTC

2005-07-28 Thread Tom Van Baak
> The key to your claim, "coordinated," does not refer to the synchronization of UTC with UT1. It refers to coordination of multiple physical clocks Mike, Well, there's a lot of coordination going on. TAI is the coordination of multiple, physical atomic clocks. UTC is the coordination of astron

Re: [time-nuts] Re: UTC

2005-07-28 Thread Mike S
At 07:28 PM 7/28/2005, Tom Van Baak wrote... >or leap hours, is suitable to civil time. The key >thing about UTC is the C, the coordination >between atomic and astronomical time. The >UTC leap hour proposal honors that. The key to your claim, "coordinated," does not refer to the synchronization of

Re: [time-nuts] Re: UTC

2005-07-28 Thread Tom Van Baak
> Leap seconds are known with about 6 months warning. UTC has been well defined for over 30 years. Like it or not, "time" is astronomical, both historically and in actual civil use. ITYM "self-proclaimed timekeepers." Correct, and that's why, in the very long term, TAI is not suitable to civil tim

Re: [time-nuts] Re: UTC

2005-07-28 Thread Mike S
At 06:50 PM 7/28/2005, Bjorn Gabrielsson wrote... >[EMAIL PROTECTED] (Mike S) writes:> >> It will break if the system is built on the basis that UTC is within >> 0.9 seconds of UT1, which is how UTC is currently defined. > >Seems to be a minor concern. Personal opinions don't count. To you it's

Re: [time-nuts] Re: UTC

2005-07-28 Thread Bjorn Gabrielsson
[EMAIL PROTECTED] (Mike S) writes: > At 01:58 PM 7/28/2005, Bjorn Gabrielsson wrote... > >How does a properly implemented system accounting for leapseconds fail > >when leapseconds fail to come? Sure there will be unnessesary code > >that could be removed. But I do not see why the system would bre

Re: [time-nuts] Re: UTC

2005-07-28 Thread Bjorn Gabrielsson
[EMAIL PROTECTED] (Mike S) writes: > At 01:58 PM 7/28/2005, Bjorn Gabrielsson wrote... > >How does a properly implemented system accounting for leapseconds fail > >when leapseconds fail to come? Sure there will be unnessesary code > >that could be removed. But I do not see why the system would bre

Re: [time-nuts] Re: UTC

2005-07-28 Thread Warner Losh
> The legal system in the US (and many other countries) is based on > solar time, so it would break legal timekeeping. It is only kinda based on solar time. And only at certain locations, It is true that the definition of the time zones, in 15 USC 261 states, in part: the standard time

Re: [time-nuts] Re: UTC

2005-07-28 Thread Mike S
At 01:58 PM 7/28/2005, Bjorn Gabrielsson wrote... >How does a properly implemented system accounting for leapseconds fail >when leapseconds fail to come? Sure there will be unnessesary code >that could be removed. But I do not see why the system would break. It will break if the system is built on

Re: [time-nuts] Re: UTC

2005-07-28 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "Poul-Henning Kamp" writes: >In message <[EMAIL PROTECTED]>, Bjorn Gabrielsson writes: >>[EMAIL PROTECTED] (Mike S) writes: >> >>> Programmers cause programming errors. Leap seconds may make them apparent. >>>=20 >>> >Certainly the death (if it occurred) was not an a

Re: [time-nuts] Re: UTC

2005-07-28 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Bjorn Gabrielsson writes: >[EMAIL PROTECTED] (Mike S) writes: > >> Programmers cause programming errors. Leap seconds may make them apparent. >>=20 >> >Certainly the death (if it occurred) was not an automatic result of the = >leapsecond, but rather was the result of

Re: [time-nuts] Re: UTC

2005-07-28 Thread Bjorn Gabrielsson
[EMAIL PROTECTED] (Mike S) writes: > Programmers cause programming errors. Leap seconds may make them apparent. > > >Certainly the death (if it occurred) was not an automatic result of the > >leapsecond, but rather was the result of something that broke because it > >wasn't properly programmed

Re: [time-nuts] Re: UTC

2005-07-28 Thread Mike S
At 08:29 AM 7/28/2005, John Ackermann N8UR wrote... >Mike S wrote: >>That is a deliberately misleading statement. It MUST be the case that the >>loss of life occurred due to and improperly designed, incorrectly specified, >>or improperly used system. The person/organization at fault seeks to misp

Re: [time-nuts] Re: UTC

2005-07-28 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> [EMAIL PROTECTED] (Mike S) writes: : At 02:40 AM 7/28/2005, M. Warner Losh wrote... : : >The Turin leap second survey said that loss of life had occurred due : >to a leap second insertion event. : That is a deliberately misleading statement. It MUST be

Re: [time-nuts] Re: UTC

2005-07-28 Thread John Ackermann N8UR
Mike S wrote: At 02:40 AM 7/28/2005, M. Warner Losh wrote... The Turin leap second survey said that loss of life had occurred due to a leap second insertion event. That is a deliberately misleading statement. It MUST be the case that the loss of life occurred due to and improperly design

Re: [time-nuts] Re: UTC

2005-07-28 Thread Mike S
At 02:40 AM 7/28/2005, M. Warner Losh wrote... >The Turin leap second survey said that loss of life had occurred due >to a leap second insertion event. That is a deliberately misleading statement. It MUST be the case that the loss of life occurred due to and improperly designed, incorrectly sp

Re: [time-nuts] Re: UTC, 60 Hz

2005-07-28 Thread John Ackermann N8UR
Tom Van Baak wrote: You know, if the stackable TAPR module project catches on another PCB on the list could be a mains frequency monitor. It would robustly filter and divide the 50/60 Hz mains frequency to 1 PPS and then onboard compare that 1 PPS against the local (OCXO, atomic, or GPS) 1 PPS

RE: [time-nuts] Re: UTC, 60 Hz

2005-07-28 Thread Bill Hawkins
TVB said, "If there's a power industry person in time-nuts we'd love to ask you a few questions." I'm not a power industry person, but I've researched the problem over the years. Here are some of the results. The generators are all synchronous machines. The ones in one power plant rotate with ve

Re: [time-nuts] Re: UTC

2005-07-28 Thread Tom Van Baak
> The Turin leap second survey said that loss of life had occurred due > to a leap second insertion event. The survey didn't provide any > additional details. However, I've not been able to find any media > coverage of such an event, nor find other documentary evidence to > support it. Sorry, I

Re: [time-nuts] Re: UTC

2005-07-27 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> "Poul-Henning Kamp" <[EMAIL PROTECTED]> writes: : >> Until after a leap-second hands in the unbudgeted expense or if : >> we are lucky: the budget request. : > : >You won't see any such budget request. None happened 7 years ago, : >and none will happen t

Re: [time-nuts] Re: UTC, 60 Hz

2005-07-27 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "Tom Van Baak" writes: >You know, if the stackable TAPR module >project catches on another PCB on the list >could be a mains frequency monitor. > >It would robustly filter and divide the 50/60 Hz >mains frequency to 1 PPS and then onboard >compare that 1 PPS against

Re: [time-nuts] Re: UTC

2005-07-27 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Warner Losh writes: >> Certainly. But what's your point? I don't see these utilities failing >> if a second slips here or there. The one case where time is critical >> is the power grid, and they keep their own time (Which, IIRC >> approximates UTC). > >The long

Re: [time-nuts] Re: UTC

2005-07-27 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Chuck Harris writes: >> Just because people don't care or notice, doesn't mean not important >> to them. >> >> Most people don't care about water, sewers, electricity and civil >> order. That doesn't mean it's not important to them. They care >> a lot as soon as

Re: [time-nuts] Re: UTC, 60 Hz

2005-07-27 Thread Tom Van Baak
> Does your phase plot mean that a mains powered wall clock might be off > by 10 seconds? > > Have Fun, > > Brooke Clarke, N6GCE Yes. I also keep an old AC synchronous motor wall clock around just to see this effect. To be fair, it is unusual for it to be off this much, or for very long. > May

Re: [time-nuts] Re: UTC, 60 Hz

2005-07-27 Thread Brian Kirby
I have a digital clock that runs from the 60 hertz power. I have noticed several times that TVA power can gain time up to 15 seconds compared to UTC. Takes a few weeks. I also did a stability test using a rubidium and dividers and I showed about a +/- 0.03 hertz deviation over one hour, duri

Re: [time-nuts] Re: UTC, 60 Hz

2005-07-27 Thread Brooke Clarke
Hi Tom: Does your phase plot mean that a mains powered wall clock might be off by 10 seconds? Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Tom Van Baak wrote: . . . For real plots of

Re: [time-nuts] Re: UTC, 60 Hz

2005-07-27 Thread Tom Van Baak
> > Certainly. But what's your point? I don't see these utilities failing > > if a second slips here or there. The one case where time is critical > > is the power grid, and they keep their own time (Which, IIRC > > approximates UTC). The power companies used to use GOES heavily; early this ye

Re: [time-nuts] Re: UTC

2005-07-27 Thread Warner Losh
> The truly critical time functions will continue to use TAI, > or some variant as they currently do TAI time isn't a silver bullet. It is a timescale that one can recover, with some effort, but only if one can get the leapsecond meta-data from somewhere else, since time is overwhelming distr

Re: [time-nuts] Re: UTC

2005-07-27 Thread Warner Losh
> Certainly. But what's your point? I don't see these utilities failing > if a second slips here or there. The one case where time is critical > is the power grid, and they keep their own time (Which, IIRC > approximates UTC). The long term average of the power grid in the US is 60.000 Hz. Sh

Re: [time-nuts] Re: UTC

2005-07-27 Thread Chuck Harris
Hi Poul, Poul-Henning Kamp wrote: hand. Seconds are just a frill to civil timekeeping. Wlll, almost. You see, the technocratic part of the population is very busy spinning a technological net around the rest of the population, a net where seconds can cost you fortunes one example being

Re: [time-nuts] Re: UTC

2005-07-27 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Chuck Harris writes: >> For almost the entire population, time is defined as SI seconds, >> 60 of which is a minute, 24 of which is an hour, 365 of which is a >> year. > >That is correct, but you must also remember that 99 and 44/100ths of >the population would do j

Re: [time-nuts] Re: UTC

2005-07-27 Thread Chuck Harris
Poul-Henning Kamp wrote: In message <[EMAIL PROTECTED]>, Chuck Harris writes: Poul-Henning Kamp wrote: In message <[EMAIL PROTECTED]>, Rob Seaman writes: Now, for 3 t-shirts Poul, reread Rob's last paragraph, but this time with your blinders removed. I'm still trying to get the same b

Re: [time-nuts] Re: UTC

2005-07-26 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Chuck Harris writes: >Poul-Henning Kamp wrote: >> In message <[EMAIL PROTECTED]>, Rob Seaman writes: >Now, for 3 t-shirts Poul, reread Rob's last paragraph, but this >time with your blinders removed. I'm still trying to get the same basic point across, and answeri

Re: [time-nuts] Re: UTC

2005-07-26 Thread Chuck Harris
Poul-Henning Kamp wrote: In message <[EMAIL PROTECTED]>, Rob Seaman writes: Pop quiz! What is the length of the day? No tricks - no gimmicks. Launch a tee-shirt to that guy in the last row. Right you are! A day on Earth is 23h 56m 4s. Now, for two t-shirts: Which fraction of the eart

Re: [time-nuts] Re: UTC

2005-07-26 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Rob Seaman writes: >Pop quiz! What is the length of the day? No tricks - no gimmicks. > >Launch a tee-shirt to that guy in the last row. Right you are! A >day on Earth is 23h 56m 4s. Now, for two t-shirts: Which fraction of the earths population would disagr

[time-nuts] Re: UTC

2005-07-26 Thread Rob Seaman
I think I will trouble the list with just one more message on this topic, as I'm in danger of repeating myself - certainly the folks I'm replying to have started to do so. It is also remarkable how many ways there are to make my arguments for me. Too expensive to revise documentation? So

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread Mike S
At 12:32 PM 7/20/2005, Chris O'Byrne wrote... >Mike wrote > >> They missed the event by 7 seconds instead of under 1. > >A one second difference in UT1 does not correspond to a one second >difference in the observed time of the eclipse in an atomic timescale >... I now think that is wrong - I now

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread Chris O'Byrne
Mike wrote > Assume someone chasing eclipses in the middle of the desert is an > "average person," as you have. Exact same scenario, but the program > was created 7 years prior to show all such events during the next > century. Because of the unreliable nature of the quadratic equations > which at

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> [EMAIL PROTECTED] (Mike S) writes: : I suppose you believe that DST makes the day longer, too. Clearly, the extra hour of daylight will burn up the crops! Warner ___ time-nuts mailing list time-nuts@febo.com

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread Mike S
At 07:39 AM 7/20/2005, Poul-Henning Kamp wrote... >In message <[EMAIL PROTECTED]>, Mike S writes: > >>I suppose you believe that DST makes the day longer, too. > >No Mike, but I belive some crania are to thick to make it >worth arguing with the inhabitant. You misspelled the word "too" in your sel

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Mike S writes: >I suppose you believe that DST makes the day longer, too. No Mike, but I belive some crania are to thick to make it worth arguing with the inhabitant. Welcome to my kill file. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECT

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread Mike S
At 06:38 AM 7/20/2005, Poul-Henning Kamp wrote... >Experience with daylight savings time and timezones indicate that >it can be two hours off and people still survive. That's a red herring. DST isn't applied to UTC. DST and timezones offset time by a fixed, well defined amounts. As long as a t

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-20 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "M. Warner Losh" writes: >In message: <[EMAIL PROTECTED]> >OK. For leap years, we know from 1500ish until ~4000 (assuming they >change it) the rule will be: > > if (y % 4 == 0) && (y % 100 != 0 || y % 400 == 0)) > leap-year > else >

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-19 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> "Chris O'Byrne" <[EMAIL PROTECTED]> writes: : > >Yes. Leap seconds are absurd enough, leap hours are 3,600 times more : > >absurd! : > : > You forgot to extrapolate that statement to leap days. : : Leap days are extrapolatable for the next 1,000 years

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-19 Thread Mike S
At 08:48 AM 7/19/2005, Chris O'Byrne wrote... >Now, can you come up with a scenario extolling the virtues to the >average person of leap seconds? Or a scenario in which an >ever-so-slightly variable second being used by a member of the public >proves disasterous? Your scenario has nothing to do wi

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-19 Thread Chris O'Byrne
Mike, Since you have asked me to extrapolate the leap second question to leap days, allow me to do the same. Would you settle for a system whereby you had to wait on some scientists' verdict before finding out if your next birthday was going to be on a Sunday or on a Monday? > It wasn't clear you

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-19 Thread Mike S
At 05:56 AM 7/19/2005, Chris O'Byrne wrote... >The rules are those of "simple arithmetic". You are not allowed to use >lookup tables, and you are not allowed to use quadratic equations. You >are in a hotel, without access to your normal sources of reference, >without access to a calculator, sittin

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-19 Thread Chris O'Byrne
Those of you on the LEAPSECS mailing list will aready have seen this, but I think its worth a read - http://www.startribune.com/stories/404/5508732.html I'm responding to Rob and Mike in this email. First, Rob said > And if your software reports eclipses later than 2007, it may need to > be up

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-19 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "M. Warner Losh" writes: >: 2005-07-18T12:34:56Z (UTC) >: 2005-07-18T12:35:28A (TAI - same instant) >: >: Multiple timescales will always exist. We should acknowledge that >: fact and move on. > >The reason that 'Z' is used for UTC is that A-X are used

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-18 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> [EMAIL PROTECTED] (Mike S) writes: : At 04:36 PM 7/18/2005, M. Warner Losh wrote... : : >: By attempting to ignore an intrinsic reality, we are making such : >: issues more likely, not less. How about an extension to ISO 8601 : >: that would permit

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-18 Thread Mike S
At 04:36 PM 7/18/2005, M. Warner Losh wrote... >: By attempting to ignore an intrinsic reality, we are making such >: issues more likely, not less. How about an extension to ISO 8601 >: that would permit distinguishing timescales, something like: >: >: 2005-07-18T12:34:56Z (UTC) >:

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-18 Thread Rob Seaman
Chris O'Byrne says: I'll give you a very concrete example of the harm of leap seconds. As part of my interest in astronomy, I chase total solar eclipses. I've written a program that runs on your mobile phone to calculate when you can expect to see the eclipse start and end from your location (ht

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-18 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> Rob Seaman <[EMAIL PROTECTED]> writes: : Your program could have been layered on TAI. Layering the program on TAI is likely a non-starter. Since the cellular networks use UTC, he'd still need to know about leapseconds. There's no way around that require

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-18 Thread Mike S
At 08:34 AM 7/18/2005, Chris O'Byrne wrote... >>>The kind of "simple arithmetic" that I was thinking about precludes >>>the use of look-up tables. >> >> Yet you consider quadratic equations to be "simple arithmetic?" > >Simple arithmetic would give an order of magnitude better ESTIMATE. That >ESTI

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-18 Thread Chris O'Byrne
Bill asked - > The initial message asserts that leap > seconds are harmful. The argument remains unfocused because the > nature of the harm has not been specified. I'll give you a very concrete example of the harm of leap seconds. As part of my interest in astronomy, I chase total solar eclipses.

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> Bill Janssen <[EMAIL PROTECTED]> writes: : Instead of trying, the impossible, task of coming up with a time scale : that everyone is happy with : why not come up with something easier, such as stabilizing the : rotational rate of mother Earth. It has g

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread Bill Janssen
Instead of trying, the impossible, task of coming up with a time scale that everyone is happy with why not come up with something easier, such as stabilizing the rotational rate of mother Earth. :-) Bill K7NOM ___ time-nuts mailing list time-nuts@f

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread Rob Seaman
Thanks to all for the excellent discussion - over the past five years I've seen much less diplomatic discussions on the issues. It has never bothered me that folks hold a diversity of opinions on UTC - time is a deeply interesting subject worthy of our best efforts. Any solution(s) worth

RE: [time-nuts] Re: UTC - A Cautionary Tale - My last word

2005-07-17 Thread Bill Hawkins
My apologies to those who are offended by a common-sense application of UTC as civil time. I apologize for not taking your argument seriously but adding it to the medical irritations in my life. I have no right to comment on the amount of traffic in this list. I measure caliber by correctness, com

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread Mike S
At 06:24 PM 7/17/2005, [EMAIL PROTECTED] wrote... >>>simple arithmetic with a timescale with a variable second would give an >>>order of magnitude better estimate of the amount of time between 2005 Dec 31 >>>23:59:59.9 and 2006 Jan 01 00:00:00.1 than UTC does! >> >>UTC will tell you that there is E

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread obyrne
>>simple arithmetic with a timescale with a variable second would give an >>order of magnitude better estimate of the amount of time between 2005 Dec 31 >>23:59:59.9 and 2006 Jan 01 00:00:00.1 than UTC does! > >UTC will tell you that there is EXACTLY 1.2 seconds between those two points. The kind

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread Mike S
At 08:25 AM 7/17/2005, [EMAIL PROTECTED] wrote... >simple arithmetic with a timescale with a variable second would give an order >of magnitude better estimate of the amount of time between 2005 Dec 31 >23:59:59.9 and 2006 Jan 01 00:00:00.1 than UTC does! UTC will tell you that there is EXACTLY 1

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-17 Thread obyrne
>: So here is my suggestion, and it is an amalgamation of ideas from >: various quarters. Civil time should be based on a quadratic formula >: involving TAI. In other words, civil time should track UT over the long >: term, and be allowed to drift against UT over the short term. > >Well, the varyin

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "Bill Hawk ins" writes: >Perhaps some of you didn't understand the paragraph on >process control systems, or perhaps you are still pondering. It sounds a lot more like you have no idea what caliber of people you are talking to Bill. I have spent 25 years doing all

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
Perhaps some of you didn't understand the paragraph on process control systems, or perhaps you are still pondering. Let me restate the solution for those who can only get UTC but need monotonically increasing wall clock time. Note that "you" is no one specific, just not me. 1. Provide your compu

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
M. Warner Losh said, "Time sources are in UTC, and you need a leapsecond count to recover TAI." Is this what all the fuss is about? UTC is all that is distributed and you have to do a subtraction to get TAI? He also said, on the subject of NTP and one days notice, "So while the computers are lik

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> "Bill Hawkins" <[EMAIL PROTECTED]> writes: : My little program served the needs of civil time. It backs up : at 59 seconds because the display software can't handle 60. : That seems close enough for civil work. If you must have : monotonically increasing

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
Oh, dear. I have made a mistake. I had not realized that I was dealing with purists who love to argue. Here are my understandings of the time scales: UTC: Civil time, what most people mean by time of day. Was determined by star crossings at Greenwich, now related to TAI in that both use the same

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> "M. Warner Losh" <[EMAIL PROTECTED]> writes: : In message: <[EMAIL PROTECTED]> : [EMAIL PROTECTED] (Mike S) writes: : : At 06:36 PM 7/16/2005, Robert Lutwak wrote... : : >As for concern that people in 10,000 years won't conform to having the s

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> [EMAIL PROTECTED] (Mike S) writes: : At 06:36 PM 7/16/2005, Robert Lutwak wrote... : >As for concern that people in 10,000 years won't conform to having the sun come up 15 minutes earlier, I'd say y'all are underestimating the power of adaptive evolutio

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Mike S
At 06:36 PM 7/16/2005, Robert Lutwak wrote... >As for concern that people in 10,000 years won't conform to having the sun >come up 15 minutes earlier, I'd say y'all are underestimating the power of >adaptive evolution. Innumeracy or deliberate and egregious understatement? AM and PM would be re

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Mike S
At 06:12 PM 7/16/2005, Bill Hawkins wrote... >Um, would you care to point out the more serious bugs? > >Bill The UTC time sequence with your code would go (at the 1 second interrupts): 23:59:59.0 23:59:59.0 00:00:00.0 Leading to ambiguous (duplicated) timestamps. The correct solution is closer t

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Robert Lutwak
[EMAIL PROTECTED] (Business) (978) 927-4099 FAX [EMAIL PROTECTED] (Personal) (339) 927-7896 Mobile - Original Message - From: "Bill Hawkins" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Saturday, July 16,

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> "Bill Hawkins" <[EMAIL PROTECTED]> writes: : Um, would you care to point out the more serious bugs? (1) Leap seconds can happen at the end of any month, not just june/decemeber. (2) Leap seconds can be both positive and negative (3) Local time is typ

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
gt;From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >Sent: Saturday, July 16, 2005 3:47 PM >To: [EMAIL PROTECTED]; Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] Re: UTC - A Cautionary Tale > > >In message <[EMAIL PROTECTED]>, "Bil

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
Um, would you care to point out the more serious bugs? Bill -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Saturday, July 16, 2005 3:47 PM To: [EMAIL PROTECTED]; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Re: UTC - A

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "Bill Hawk ins" writes: >Garbage is in the eye of the beholder. Indeed. That your "I'm gonna show those morons!!!" example contains serious bugs in the leap second handling makes this one of my most treasured emails in this entire debate. Welcome to category 3) B

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
Robert Lutwak said, "It ain't "...a few lines." Properly dealing with timezones, daylight savings, and leapseconds can easily run into thousands of lines of code, by the time you include of of the oddball irregularities around the world. Not only does the clockmaker have to implement all of this

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Rob Seaman writes: >Why are you so convinced that there couldn't possibly be negative >ramifications associated with the unexamined assumptions underlying >the distinction between time-of-day and interval time? Or simply >with the unwarranted assumption that

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, "Bill Hawk ins" writes: >Anybody *know* how The Clock of the Long Now proposed >to handle leap seconds over 10,000 years? Please note >the emphasis on "know." We have enough shared >ignorance as it is, from myself included. I don't think the intra-day timekeeping w

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
Poul-Henning Kamp said, "Hopefully not too many people will be hurt trying to convince you." The great majority of people do not know that leap seconds exist. They set their watches by their WWVB (or whatever) inexpensive atomic clock receiver if they care about time at all. If you don't have le

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Bill Hawkins
Anybody *know* how The Clock of the Long Now proposed to handle leap seconds over 10,000 years? Please note the emphasis on "know." We have enough shared ignorance as it is, from myself included. The Moon does not cause leap seconds. That effect is measured in milliseconds per century. John, shou

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Rob Seaman
Hopefully not too many people will be hurt trying to convince you. Amen. And hopefully any resulting lawsuits will assign blame and damages where they belong - with the financial backers and managers and designers of systems that failed to implement the appropriate international standard.

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Rob Seaman writes: >There will be no need to reeducate anybody if the civil time standard >is left unchanged. That is why I'm sort of happy we got a leap-second next january: that will allow us to judge claims like yours. Hopefully not too many people will be hu

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Rob Seaman
On Jul 16, 2005, at 12:07 AM, Poul-Henning Kamp wrote: No, you can not tell me today how many seconds between now and 2010-01-01 00:00:00 UTC and that is the whole problem. That is *part* of the problem - a part that is intrinsic to living within a non-inertial reference frame. Folks who n

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Mike S writes : >_All_ uses of civil time expect it to be synchronous with astronomical >time, to varying degrees of precision. An absence of leap (seconds) >will eventually cause it to be dark at noon, unadjusted use of the >current formula for leap days will eventu

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Mike S
At 07:37 AM 7/16/2005, Robert Lutwak wrote... >Personally, I'd like to eliminate timezones and daylight savings, as well as >leapseconds. Why is it so important that everyone on the planet clock in at 8 >a.m. or that we all have dinner at 6 p.m. ? That's a short term view. Eliminate the leap se

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Robert Lutwak
Rob Seaman wrote: Straightforward algorithms (a few lines of C) can convert standard time to local time and mean time to apparent time. It ain't "...a few lines." Properly dealing with timezones, daylight savings, and leapseconds can easily run into thousands of lines of code, by the time

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Rob Seaman writes: >Nobody has invested ten cents in a >good luck safety net toward the retirement of leap seconds. The entire problem is that people have not spent ten cents on properly handling leap seconds. >The public - including folks like applications prog

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-16 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Rob Seaman writes: >No - by standardizing the meaning of the terms, we made it possible >to easily convert between all the flavors of solar time using closed >form algorithms accurate to whatever precision is required. No, you can not tell me today how many sec

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread Rob Seaman
Warner Losh says: We already have ambiguity in when something occurs, as defined by Earth. Each timezone is 15 degrees wide, and thus something may happen at 11:59:59pm local standard time, but really happen at 12:01:01am the next day 'solar' time. Ambiguity cuts both ways. Standard tim

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread Mike S
At 07:07 PM 7/15/2005, M. Warner Losh wrote... >In message: <[EMAIL PROTECTED]> >Rob Seaman <[EMAIL PROTECTED]> writes: >: Historians may care deeply about whether some event >: occurred on one day (as defined by the Earth) as opposed to another >: day (as defined by mid-level inter

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> Rob Seaman <[EMAIL PROTECTED]> writes: : Historians may care deeply about whether some event : occurred on one day (as defined by the Earth) as opposed to another : day (as defined by mid-level international bureaucrats). Religious : issues anybody

[time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread Rob Seaman
Poul-Henning Kamp replies: Shouldn't we explore the requirements and use cases before making a change to the standard? Absolutely, but shouldn't we look at more than astronomy while doing so? Are you under the impression that the folks pushing this proposal are looking anywhere beyond t

RE: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread Bill Hawkins
Last time I heard anybody jump into an argument with "surely" was in college in 1958. Harrumph. Surely this list hasn't been hit with a group of sophomores because someone posted the address on a campus bulletin board. Chris O'Byrne said, "Civil time should be based on a quadratic formula involvin

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread M. Warner Losh
In message: <[EMAIL PROTECTED]> "Chris O'Byrne" <[EMAIL PROTECTED]> writes: : The rest of us need a useable timescale where the sun is basically due : south in Greenwich at 12:00:00.000. However, since the equation of time : introduces a natural error of +/- 15 minutes or so in the exac

Re: [time-nuts] Re: UTC - A Cautionary Tale

2005-07-15 Thread Chris O'Byrne
Surely the way to look at the timescales and leap second issues are to look at the requirements and go from there. It seems to me that there are two basic requirements. Scientists of various colours need a regular timescale, and are not particularly concerned if the sun is above or below the horiz

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