Re: A lurker surfaces

2007-01-02 Thread Ed Davies
Zefram wrote: ... The historical trend is towards using uniform time units. It seems curious now that when the atomic clock was invented astronomers opposed calling it a time standard. Well, it seems curious to everybody except Rob Seaman :-) ... It is much like the ancient Egyptians (IIRC)

Re: Introduction of long term scheduling

2007-01-02 Thread Ed Davies
Steve Allen wrote: On Mon 2007-01-01T21:19:04 +, Ed Davies hath writ: Why does the One sec at predicted intervals line suddenly diverge in the early 2500's when the other lines seem to just be expanding in a sensible way? ... I suspect that the divergence of the one line indicates

Re: Introduction of long term scheduling

2007-01-02 Thread Ed Davies
Warner Losh wrote: The IERS bulletin C is a little different than the ITU TF.460: Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to

Re: Introduction of long term scheduling

2007-01-01 Thread Ed Davies
Rob Seaman wrote: ... Obviously it would take at least N years to introduce a new reporting requirement of N years in advance (well, N years minus six months). Sorry, maybe I'm being thick but, why? Surely the IERS could announce all the leap seconds in 2007 through 2016 inclusive this week

Re: Introduction of long term scheduling

2007-01-01 Thread Ed Davies
Poul-Henning Kamp wrote: If you have subtle point, I'd love to hear it. Not even close to a subtle point, I simply cannot figure out what the graph shows... Me too. Is this an analysis or a simulation? What are the assumptions? What predicted intervals does he mean? The bullet points

Re: Introduction of long term scheduling

2007-01-01 Thread Ed Davies
Steve Allen wrote: On Mon 2007-01-01T17:42:11 +, Ed Davies hath writ: Sorry, maybe I'm being thick but, why? Surely the IERS could announce all the leap seconds in 2007 through 2016 inclusive this week then those for 2017 just before the end of this year, and so on. We'd have immediate 10

Re: A lurker surfaces

2006-12-31 Thread Ed Davies
Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Rob Seaman writes: Jim Palfreyman wrote: Just a reminder that UTC has no - none - nada - discontinuities. Various computer mis-implementations may, but the standard is very carefully constructed to avoid spring-forward or fall-back gaps

Re: what time is it, legally?

2006-12-13 Thread Ed Davies
Rob Seaman wrote: I'm given to wonder how much of the friction on this mailing list is simply due to the shortcomings in the technology that implements it. I've appended a message I sent in August with four plots attached. Can someone tell me whether it is readable now or was successfully

Re: how posterity will measure time

2006-12-04 Thread Ed Davies
Rob Seaman wrote: ... An amateur astronomer with a Celestron, the Astronomical Almanac and an atlas can recover UTC anywhere on Earth. ... Do you really mean UTC here? I can see that an amateur with a Celestron could recover UT (for some flavour of UT, I'm not sure which - UT0?, then

Re: building consensus

2006-06-07 Thread Ed Davies
Rob Seaman wrote: On Jun 7, 2006, at 2:03 AM, Clive D.W. Feather wrote: In the UK in 1750, there were two different Julian calendars in use: the day and month enumeration matched, but year numbers changed at different dates (1st January in Scotland, 25th March in England and Wales). I've

Re: building consensus

2006-06-06 Thread Ed Davies
Rob Seaman wrote: Doubt I can lay my hands on the copy of ISO 8601 from my Y2K remediation days. Anybody want to comment on whether it actually attempts to convey the Gregorian algorithm within its pages? Yes, it does. This International Standard uses the Gregorian calendar for the

Re: 24:00 versus 00:00

2006-02-17 Thread Ed Davies
Ed Davies scripsit: If only the 24:00 for end of day notation wasn't in the way we could look at positive leap seconds as just being the result of deeming certain days to be a second longer than most and just use 24:00:00. We wouldn't have to muck with the lengths of any of the hours or minutes

Re: 24:00 versus 00:00

2006-02-16 Thread Ed Davies
Markus Kuhn wrote: With the 24-h notation, it is a very useful and well-established convention that 00:00 refers to midnight at the start of a date, while 24:00 refers to midnight at the end of a date. Thus, both today 24:00 and tomorrow 00:00 are fully equivalent representations of the same

Re: the tail wags the dog

2006-01-24 Thread Ed Davies
Rob Seaman wrote: All proposals (other than rubber seconds or rubber days) face the same quadratically accelerating divergence between clock and Earth. By rubber seconds you, presumably, mean non-SI seconds. What do you mean by rubber days? I'd guess you mean days which are

Re: Accommodating both camps

2006-01-24 Thread Ed Davies
James Maynard wrote: I wonder, though, whether those in the other camp would find it acceptable to have the standard time and frequency stations not only broadcast UTC and DUT1 (= UT1 - UTC, to 0.1 s resolution), but also to broadcast DTAI (= TAI - UTC, 1 s resolution)? A full

Re: NOT A cruel fraud!

2006-01-22 Thread Ed Davies
M. Warner Losh wrote: : TAI is specifically contraindicated as a time : scale. : : TAI is not currently recommended by its creators as a viable time : scale. : : : These claims are intellectually fraudulent. The archives in fact support : the opposite of what Mr. Losh contends.

Approach to leap second discussion

2006-01-22 Thread Ed Davies
The way I think exploration in this group should be going is to seriously examine what engineering steps can be taken to deal with leap seconds properly. This means looking at changes to Posix and NTP, new protocols for disseminating leap second information, new APIs for accessing clock

Re: Approach to leap second discussion

2006-01-22 Thread Ed Davies
Rob Seaman wrote: I hope we can all continue this discussion in a more positive manner. I'm of the opinion that messages on this list (no matter how tricky :-) are always positive. Timekeeping is a fundamental issue. It would be remarkable if there weren't diverse opinions. Any negative

Re: Internet-Draft on UTC-SLS

2006-01-19 Thread Ed Davies
Markus Kuhn wrote: 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)

Re: Internet-Draft on UTC-SLS

2006-01-19 Thread Ed Davies
Ed Davies: Appendix A argues against putting the adjustment interval after the leap second (method 4a) by pointing out that some time signals contain announcements of the leap second before it happens but not after. Rob Seaman: Right, ... Ed Davies: I think a stronger argument against

Re: The real problem with leap seconds

2006-01-18 Thread Ed Davies
Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Francois Meyer writes: On Mon, 16 Jan 2006, Mark Calabretta wrote: 1. UTC and TAI share the same rate, the same origin, the same second. And therefore : UTC - TAI = 0 This is wrong, plain and simple wrong. Well, if

Re: The real problem with leap seconds

2006-01-13 Thread Ed Davies
Michael Deckers wrote: I believe I'm now grasping what you mean: the rate of UTC is the same as the rate of TAI (since 1972), that is, the derivative d( UTC )/d( TAI ) = 1. ... This conversation is making something of a meal of a simple point. You can treat UTC as a real in either of

Re: The real problem with leap seconds

2006-01-13 Thread Ed Davies
Michael Deckers wrote: Sort of like, is it a particle or a wave? :-) At the risk of being misunderstood as sarcastic: if users of UTC were really expected to understand such strange concepts (Schrodinger time) I would plead for the immediate abolishment of UTC. Why cannot UTC

Re: The real problem with leap seconds

2006-01-13 Thread Ed Davies
Markus Kuhn wrote: 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. OK, thanks. Ed.

Re: The real problem with leap seconds

2006-01-08 Thread Ed Davies
Wow, things have got really stirred up around here. Lots of interesting points but I'll just concentrate on one... Poul-Henning Kamp wrote: Well, the BIPM doesn't really want anybody to use TAI, their director said as much last year, and I can see where he is coming from on that one. Since

Re: The real problem with leap seconds

2006-01-07 Thread Ed Davies
Poul-Henning Kamp wrote: What a weird concept... Why not go the full distance and define a timescale for each particular kind of time-piece: and give each of them their own unique way of coping with leapseconds ? Ignoring the ridiculous parody - no, it's not a weird concept.

Re: civil time = solar time

2006-01-05 Thread Ed Davies
Rob Seaman wrote: I said: all parties must certainly agree that civil time (as we know it) IS mean solar time. Ed says: saying that it IS civil time is probably a bit strong. Probably a bit strong is not precisely a staunch denial. It's not meant to be a staunch denial. I'm mostly

Re: went pretty dang smoothly at this end

2006-01-01 Thread Ed Davies
Keith Winstein wrote: Some minor glitches: (a) My Garmin 12XL GPS receiver (software version 4.53) did not register the leap second on its time display. It went from 58 to 59 to 00, and stayed one second ahead for the next few minutes until I rebooted it. Then it came up

Lighter Evenings (Experiment) Bill [HL]

2005-12-16 Thread Ed Davies
period; and for connected purposes. Well, at least we'd be in sync with most of the rest of the EC. Don't know if it'll get anywhere, of course. Ed Davies.

Be thankful for John Flamstead

2005-11-10 Thread Ed Davies
BBC article, Leap second proposal sparks row: http://news.bbc.co.uk/1/hi/sci/tech/4420084.stm I found this bit particularly amusing: The decision stemmed from the work 200 years previously of the first English Astronomer Royal, John Flamsteed, who calculated that the Earth rotated on its

BBC on-line article

2005-09-28 Thread Ed Davies
The BBC web site has an article about the leap second debate: http://news.bbc.co.uk/1/hi/sci/tech/4271810.stm Ed Davies.

Re: RAS hits the news

2005-09-26 Thread Ed Davies
Hornaday, Tem SPAWAR wrote: ... 3. As has been pointed out, some receivers also implement a clever hack to determine date that looks at UTC Leap Second (LS) value, and chooses a date based on WN, TOW, and LS. That is, the receiver implements a sliding 1024-week window whose limits are

Re: Consensus rather than compromise

2005-08-31 Thread Ed Davies
to their own little time- zone not being good enough), have a clock stable enough to do so and yet are not connected by any mechanism which could potentially provide leap-second information? Presumably there are a few but I find them hard to imagine. Ed Davies

Re: decision tree for civil time

2005-08-14 Thread Ed Davies
Rob Seaman wrote: This is a first draft of what is intended to be a complete inventory of options for civil timekeeping.Just compile the options now - we'll undoubtedly express our opinions about each later. ... C) Method 1) steps (I'm tired of the word leap) a)

Re: Precise time over time

2005-08-12 Thread Ed Davies
with the difference going over 0.9 second is, I think, a relatively minor point but it does need to be considered. Ed Davies.

Re: new beginning

2005-08-04 Thread Ed Davies
. Ed Davies.

Re: ITU-R TF.460 past, present, and future

2003-07-30 Thread Ed Davies
Steve Allen wrote: ... Basically, as a result of this case it has been established that the law in the United States must be in the public domain, and this holds true even if the law incorporates an external document merely by reference. So, if NIST tries again to modify the US Code in this

Re: more media coverage

2003-07-24 Thread Ed Davies
, lighting up times, etc. Others? Ed Davies.

Re: DRM broadcast disrupted by leap seconds

2003-07-19 Thread Ed Davies
Markus Kuhn wrote: When the scheduled transmission time arrives for a packet, it is handed with high timing accuracy to the analog-to-digital converter, I assume you mean digital-to-analog. ... [In fact, since short-wave transmitters frequently switch between programmes at the full hour,

Re: Universial Time,Terrestrial Time -- time for new terminology?

2003-07-08 Thread Ed Davies
Markus Kuhn wrote: A point that was made repeatedly at Torino is that the term UT traditionally meant in astronomy a time scale defined by the Earth's rotation, and that therefore a leap-second free uniform atomic time should not be called UTC, even if doing so would of course avoid the need

Re: Torino presentation

2003-05-27 Thread Ed Davies
Ed Davies wrote on 2003-05-27 13:56 UTC: Slightly more relevantly: I was a bit surprised that you did not put more emphasis on the need to distinguish the different types of time scales an application program can ask for from an operating system, as your ctime library highlights. Markus Kuhn