From clive at demon.net  Mon Nov  3 03:28:34 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Mon, 3 Nov 2008 08:28:34 +0000
Subject: [LEAPSECS] princes
In-Reply-To: <alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk>
References: <20081029054608.GA14129@ucolick.org>
	<alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk>
Message-ID: <20081103082834.GM81158@finch-staff-1.thus.net>

Tony Finch said:
> As well as the
> egregious example of the pre-Julian Roman calendar, I'm amused and
> disgusted by the anti-Jewish fiddles in the rules for determining Easter
> to minimise when it coincides with Passover.

Actually it was a pro-Jewish fiddle: by keeping the two dates apart it
minimized the risk of religious riots and/or pogroms.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From imp at bsdimp.com  Mon Nov  3 10:19:39 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Mon, 03 Nov 2008 08:19:39 -0700 (MST)
Subject: [LEAPSECS] princes
In-Reply-To: <20081103082834.GM81158@finch-staff-1.thus.net>
References: <20081029054608.GA14129@ucolick.org>
	<alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk>
	<20081103082834.GM81158@finch-staff-1.thus.net>
Message-ID: <20081103.081939.-233674271.imp@bsdimp.com>

In message: <20081103082834.GM81158 at finch-staff-1.thus.net>
            "Clive D.W. Feather" <clive at demon.net> writes:
: Tony Finch said:
: > As well as the
: > egregious example of the pre-Julian Roman calendar, I'm amused and
: > disgusted by the anti-Jewish fiddles in the rules for determining Easter
: > to minimise when it coincides with Passover.
: 
: Actually it was a pro-Jewish fiddle: by keeping the two dates apart it
: minimized the risk of religious riots and/or pogroms.

I was told in school a long time ago this was the same reason that
Christmas happened do late: It too was designed to not conflict with
Hanukkah and also the pagan solstice celebrations.  I have no source
for this information, so take it with a lot more skepticism than most
things you see here :-)

Warner

From cowan at ccil.org  Mon Nov  3 10:33:03 2008
From: cowan at ccil.org (John Cowan)
Date: Mon, 3 Nov 2008 10:33:03 -0500
Subject: [LEAPSECS] princes
In-Reply-To: <20081103.081939.-233674271.imp@bsdimp.com>
References: <20081029054608.GA14129@ucolick.org>
	<alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk>
	<20081103082834.GM81158@finch-staff-1.thus.net>
	<20081103.081939.-233674271.imp@bsdimp.com>
Message-ID: <20081103153303.GD1110@mercury.ccil.org>

M. Warner Losh scripsit:

> I was told in school a long time ago this was the same reason that
> Christmas happened do late: It too was designed to not conflict with
> Hanukkah and also the pagan solstice celebrations.  I have no source
> for this information, so take it with a lot more skepticism than most
> things you see here :-)

Christmas can coincide with Hanukkah, as in 2003, and it's an interesting
coincidence (if it is one) that whereas Christmas falls on the 25th of
December, Hanukkah falls on the 25th of Kislev.

-- 
You annoy me, Rattray!  You disgust me!         John Cowan
You irritate me unspeakably!  Thank Heaven,     cowan at ccil.org
I am a man of equable temper, or I should       http://www.ccil.org/~cowan
scarcely be able to contain myself before
your mocking visage.            --Stalky imitating Macrea

From imp at bsdimp.com  Mon Nov  3 10:41:42 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Mon, 03 Nov 2008 08:41:42 -0700 (MST)
Subject: [LEAPSECS] princes
In-Reply-To: <20081103153303.GD1110@mercury.ccil.org>
References: <20081103082834.GM81158@finch-staff-1.thus.net>
	<20081103.081939.-233674271.imp@bsdimp.com>
	<20081103153303.GD1110@mercury.ccil.org>
Message-ID: <20081103.084142.1973601707.imp@bsdimp.com>

In message: <20081103153303.GD1110 at mercury.ccil.org>
            John Cowan <cowan at ccil.org> writes:
: M. Warner Losh scripsit:
: 
: > I was told in school a long time ago this was the same reason that
: > Christmas happened do late: It too was designed to not conflict with
: > Hanukkah and also the pagan solstice celebrations.  I have no source
: > for this information, so take it with a lot more skepticism than most
: > things you see here :-)
: 
: Christmas can coincide with Hanukkah, as in 2003, and it's an interesting
: coincidence (if it is one) that whereas Christmas falls on the 25th of
: December, Hanukkah falls on the 25th of Kislev.

How often does this happen?  About 1 in 29 years?

Warner

From cowan at ccil.org  Mon Nov  3 11:34:40 2008
From: cowan at ccil.org (John Cowan)
Date: Mon, 3 Nov 2008 11:34:40 -0500
Subject: [LEAPSECS] princes
In-Reply-To: <20081103.084142.1973601707.imp@bsdimp.com>
References: <20081103082834.GM81158@finch-staff-1.thus.net>
	<20081103.081939.-233674271.imp@bsdimp.com>
	<20081103153303.GD1110@mercury.ccil.org>
	<20081103.084142.1973601707.imp@bsdimp.com>
Message-ID: <20081103163439.GH1110@mercury.ccil.org>

M. Warner Losh scripsit:

> How often does this happen?  About 1 in 29 years?

I assume you mean 1 in 19 years.  But the Jewish calendar doesn't actually
repeat every 19 years precisely: certain adjustments are made to prevent
certain dates from being consecutive or coincident.  For example, we
don't want Yom Kippur to fall adjacent to a Saturday, as that would make
two consecutive days on which bodies cannot be buried.  The exact rules
are available at http://tondering.dk/claus/cal/node5.html .

-- 
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                 cowan at ccil.org
    Then you generally can
Make the same stupid point seem profound!           --Jonathan Robie

From mgy1912 at cox.net  Mon Nov  3 22:11:35 2008
From: mgy1912 at cox.net (Brian Garrett)
Date: Mon, 3 Nov 2008 19:11:35 -0800
Subject: [LEAPSECS] princes
References: <20081029054608.GA14129@ucolick.org><alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk><20081103082834.GM81158@finch-staff-1.thus.net>
	<20081103.081939.-233674271.imp@bsdimp.com>
Message-ID: <E955DA344DB541FE83817D8470F36FEB@company48fcb68>


----- Original Message ----- 
From: "M. Warner Losh" <imp at bsdimp.com>
To: <leapsecs at leapsecond.com>; <clive at demon.net>
Sent: Monday, November 03, 2008 7:19 AM
Subject: Re: [LEAPSECS] princes


> In message: <20081103082834.GM81158 at finch-staff-1.thus.net>
>            "Clive D.W. Feather" <clive at demon.net> writes:
> : Tony Finch said:
> : > As well as the
> : > egregious example of the pre-Julian Roman calendar, I'm amused and
> : > disgusted by the anti-Jewish fiddles in the rules for determining 
> Easter
> : > to minimise when it coincides with Passover.
> :
> : Actually it was a pro-Jewish fiddle: by keeping the two dates apart it
> : minimized the risk of religious riots and/or pogroms.
>
I doubt that riots or pogroms were much of an issue. The Christians were at 
that time neither numerous enough, nor powerful enough, to be in a position 
to pick on the Jews, over religion or anything else.  Nor were the Jews 
interested in picking on the Christians; after all, they did worship the 
same God (the question of His parentage of a certain carpenter 
notwithstanding).  As for the Romans, the fall of Masada pretty much ended 
the Jews' ability to stage any organized revolt, so for Rome it was a 
non-issue.

By the fourth century C.E. there was actually a sizable number of Christians 
who were perfectly content with an Easter celebration focused around the 
fourteenth of Nisan, which would have been the anniversary of you-know-what 
according to the Jewish calendar.  This group were called the 
Quartodecimans, for obvius reasons.  The group that eventualy won out in the 
early church coucils were more concerned with making sure Christianity was a 
distinct religion and not a Jewish sect, which is when Easter went from 
being Nisan 14 to the first Sunday after Nisan 14.

> I was told in school a long time ago this was the same reason that
> Christmas happened do late: It too was designed to not conflict with
> Hanukkah and also the pagan solstice celebrations.  I have no source
> for this information, so take it with a lot more skepticism than most
> things you see here :-)
>
Again, the Romans couldn't have cared less about Hanukkah ("Feast of 
Rededication?  All your temple are belong to us, and we've got the Arch of 
Titus to comemorate the fact.").  It just happens that the Christians, under 
Constantine, co-opted the Roman feast of Saturnalia (December 25) which 
happens by sheer coincidence to overlap the eight-day Hanukkah period in 
SOME years, depending on the last insertion of Adar II (or whatever the 
month is, I'm too lazy to look it up now) in the Jewish calendar.

Brian 


From sla at ucolick.org  Tue Nov  4 23:11:04 2008
From: sla at ucolick.org (Steve Allen)
Date: Tue, 4 Nov 2008 20:11:04 -0800
Subject: [LEAPSECS] counting seconds
Message-ID: <20081105041104.GA4708@ucolick.org>

As the furor over counting votes dies down, we can turn our attention
toward the impending leap second and start counting seconds.
In the US the end of the year will bring the first legal leap second.
In Canada things will be even more confusing.

http://www.ucolick.org/~sla/leapsecs/epochtime.html

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From jnatale at juniper.net  Wed Nov  5 12:07:31 2008
From: jnatale at juniper.net (Jonathan Natale)
Date: Wed, 5 Nov 2008 12:07:31 -0500
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 3
In-Reply-To: <mailman.41.1225904471.18661.leapsecs@leapsecond.com>
References: <mailman.41.1225904471.18661.leapsecs@leapsecond.com>
Message-ID: <61767D4BE247724E8A1A8932B2B1B3DA06A5E1AD@emailwf1.jnpr.net>

Why is this the first *legal* leap sec?  It is certainly not the first
leap second?

-----Original Message-----
From: leapsecs-bounces at leapsecond.com
[mailto:leapsecs-bounces at leapsecond.com] On Behalf Of
leapsecs-request at leapsecond.com
Sent: Wednesday, November 05, 2008 12:01 PM
To: leapsecs at leapsecond.com
Subject: LEAPSECS Digest, Vol 25, Issue 3

Send LEAPSECS mailing list submissions to
	leapsecs at leapsecond.com

To subscribe or unsubscribe via the World Wide Web, visit
	http://six.pairlist.net/mailman/listinfo/leapsecs
or, via email, send a message with subject or body 'help' to
	leapsecs-request at leapsecond.com

You can reach the person managing the list at
	leapsecs-owner at leapsecond.com

When replying, please edit your Subject line so it is more specific
than "Re: Contents of LEAPSECS digest..."


Today's Topics:

   1. counting seconds (Steve Allen)


----------------------------------------------------------------------

Message: 1
Date: Tue, 4 Nov 2008 20:11:04 -0800
From: Steve Allen <sla at ucolick.org>
Subject: [LEAPSECS] counting seconds
To: Leap Second Discussion List <leapsecs at leapsecond.com>
Message-ID: <20081105041104.GA4708 at ucolick.org>
Content-Type: text/plain; charset=us-ascii

As the furor over counting votes dies down, we can turn our attention
toward the impending leap second and start counting seconds.
In the US the end of the year will bring the first legal leap second.
In Canada things will be even more confusing.

http://www.ucolick.org/~sla/leapsecs/epochtime.html

--
Steve Allen                 <sla at ucolick.org>                WGS-84
(GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat
+36.99855
University of California    Voice: +1 831 459 3046           Lng
-122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m


------------------------------

_______________________________________________
LEAPSECS mailing list
LEAPSECS at leapsecond.com
http://six.pairlist.net/mailman/listinfo/leapsecs


End of LEAPSECS Digest, Vol 25, Issue 3
***************************************

From imp at bsdimp.com  Wed Nov  5 12:46:04 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Wed, 05 Nov 2008 10:46:04 -0700 (MST)
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 3
In-Reply-To: <61767D4BE247724E8A1A8932B2B1B3DA06A5E1AD@emailwf1.jnpr.net>
References: <mailman.41.1225904471.18661.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E1AD@emailwf1.jnpr.net>
Message-ID: <20081105.104604.-1350498001.imp@bsdimp.com>

In message: <61767D4BE247724E8A1A8932B2B1B3DA06A5E1AD at emailwf1.jnpr.net>
            "Jonathan Natale" <jnatale at juniper.net> writes:
: Why is this the first *legal* leap sec?  It is certainly not the first
: leap second?

It is the first leap second that's been encountered since the US
officially adopted UTC.  Until recently, the official time of the US
was mean solar time.  However, it isn't quite that simple, since it
was mean solar time, as interpreted by the Secretary of Commerce,
which delegated it to NIST/NRO/etc who realized it with UTC since the
1980s at least...

I'm not sure that in this scenario, one can really say that the
elapsed time is different between the old system and the new...

Warner

: -----Original Message-----
: From: leapsecs-bounces at leapsecond.com
: [mailto:leapsecs-bounces at leapsecond.com] On Behalf Of
: leapsecs-request at leapsecond.com
: Sent: Wednesday, November 05, 2008 12:01 PM
: To: leapsecs at leapsecond.com
: Subject: LEAPSECS Digest, Vol 25, Issue 3
: 
: Send LEAPSECS mailing list submissions to
: 	leapsecs at leapsecond.com
: 
: To subscribe or unsubscribe via the World Wide Web, visit
: 	http://six.pairlist.net/mailman/listinfo/leapsecs
: or, via email, send a message with subject or body 'help' to
: 	leapsecs-request at leapsecond.com
: 
: You can reach the person managing the list at
: 	leapsecs-owner at leapsecond.com
: 
: When replying, please edit your Subject line so it is more specific
: than "Re: Contents of LEAPSECS digest..."
: 
: 
: Today's Topics:
: 
:    1. counting seconds (Steve Allen)
: 
: 
: ----------------------------------------------------------------------
: 
: Message: 1
: Date: Tue, 4 Nov 2008 20:11:04 -0800
: From: Steve Allen <sla at ucolick.org>
: Subject: [LEAPSECS] counting seconds
: To: Leap Second Discussion List <leapsecs at leapsecond.com>
: Message-ID: <20081105041104.GA4708 at ucolick.org>
: Content-Type: text/plain; charset=us-ascii
: 
: As the furor over counting votes dies down, we can turn our attention
: toward the impending leap second and start counting seconds.
: In the US the end of the year will bring the first legal leap second.
: In Canada things will be even more confusing.
: 
: http://www.ucolick.org/~sla/leapsecs/epochtime.html
: 
: --
: Steve Allen                 <sla at ucolick.org>                WGS-84
: (GPS)
: UCO/Lick Observatory        Natural Sciences II, Room 165    Lat
: +36.99855
: University of California    Voice: +1 831 459 3046           Lng
: -122.06015
: Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m
: 
: 
: ------------------------------
: 
: _______________________________________________
: LEAPSECS mailing list
: LEAPSECS at leapsecond.com
: http://six.pairlist.net/mailman/listinfo/leapsecs
: 
: 
: End of LEAPSECS Digest, Vol 25, Issue 3
: ***************************************
: _______________________________________________
: LEAPSECS mailing list
: LEAPSECS at leapsecond.com
: http://six.pairlist.net/mailman/listinfo/leapsecs
: 
: 

From sla at ucolick.org  Wed Nov  5 21:57:26 2008
From: sla at ucolick.org (Steve Allen)
Date: Wed, 5 Nov 2008 18:57:26 -0800
Subject: [LEAPSECS] counting seconds
In-Reply-To: <20081105.104604.-1350498001.imp@bsdimp.com>
References: <mailman.41.1225904471.18661.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E1AD@emailwf1.jnpr.net>
	<20081105.104604.-1350498001.imp@bsdimp.com>
Message-ID: <20081106025726.GA15661@ucolick.org>

On Wed 2008-11-05T10:46:04 -0700, M. Warner Losh hath writ:
> It is the first leap second that's been encountered since the US
> officially adopted UTC.  Until recently, the official time of the US
> was mean solar time.  However, it isn't quite that simple, since it
> was mean solar time, as interpreted by the Secretary of Commerce,
> which delegated it to NIST/NRO/etc who realized it with UTC since the
> 1980s at least...

I admit that I am pedantic.

The point is that no epoch-based time scale can retrospectively agree
with the times in actual use.  They're all a fiction.

also, Tom Van Baak pointed out that Internet Explorer did not like
the initial javascript.  The counts should now update with
any browser that's still reasonably safe to use on the web

http://www.ucolick.org/~sla/leapsecs/epochtime.html

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From seaman at noao.edu  Wed Nov  5 22:23:08 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 5 Nov 2008 20:23:08 -0700
Subject: [LEAPSECS] counting seconds
In-Reply-To: <20081106025726.GA15661@ucolick.org>
References: <mailman.41.1225904471.18661.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E1AD@emailwf1.jnpr.net>
	<20081105.104604.-1350498001.imp@bsdimp.com>
	<20081106025726.GA15661@ucolick.org>
Message-ID: <E56198EF-F293-4E74-B06A-E5CAF55379F3@noao.edu>

Even ignoring my usual rabidly drooling support for all aspects of  
mean solar time, I don't find the distinction pedantic at all.

Previously the U.S. had legal timescale A, realized by timescale B.   
Now (assuming any of us really understand the legal issues) we have  
legal timescale B, which (for the time being) implements an  
approximation to timescale A.  (I'll resist speculating on motivations.)

The point being, that the nature of those delegated responsibilities  
referred to by Warner changes depending on whether B implements an  
interface versus an abstract class.  (Object analogy very loosely  
ascribed, feel free to improve upon it :-)  There are likely to be  
functional side effects, not just issues of interpretation.

Such side effects might even be desirable, but one could wish that  
system engineering had been the driving force behind the change, not  
politics.

Rob
--

On Nov 5, 2008, at 7:57 PM, Steve Allen wrote:

> On Wed 2008-11-05T10:46:04 -0700, M. Warner Losh hath writ:
>> It is the first leap second that's been encountered since the US
>> officially adopted UTC.  Until recently, the official time of the US
>> was mean solar time.  However, it isn't quite that simple, since it
>> was mean solar time, as interpreted by the Secretary of Commerce,
>> which delegated it to NIST/NRO/etc who realized it with UTC since the
>> 1980s at least...
>
> I admit that I am pedantic.
>
> The point is that no epoch-based time scale can retrospectively agree
> with the times in actual use.  They're all a fiction.
>
> also, Tom Van Baak pointed out that Internet Explorer did not like
> the initial javascript.  The counts should now update with
> any browser that's still reasonably safe to use on the web
>
> http://www.ucolick.org/~sla/leapsecs/epochtime.html
>
> --
> Steve Allen                 <sla at ucolick.org>                WGS-84  
> (GPS)
> UCO/Lick Observatory        Natural Sciences II, Room 165    Lat   
> +36.99855
> University of California    Voice: +1 831 459 3046           Lng  
> -122.06015
> Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt  
> +250 m
> _______________________________________________
> LEAPSECS mailing list
> LEAPSECS at leapsecond.com
> http://six.pairlist.net/mailman/listinfo/leapsecs


From dot at dotat.at  Sat Nov  8 05:55:22 2008
From: dot at dotat.at (Tony Finch)
Date: Sat, 8 Nov 2008 10:55:22 +0000
Subject: [LEAPSECS] princes
In-Reply-To: <20081103082834.GM81158@finch-staff-1.thus.net>
References: <20081029054608.GA14129@ucolick.org>
	<alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk>
	<20081103082834.GM81158@finch-staff-1.thus.net>
Message-ID: <alpine.LSU.2.00.0811081039560.31998@hermes-1.csi.cam.ac.uk>

On Mon, 3 Nov 2008, Clive D.W. Feather wrote:
> Tony Finch said:
> >
> > As well as the egregious example of the pre-Julian Roman calendar, I'm
> > amused and disgusted by the anti-Jewish fiddles in the rules for
> > determining Easter to minimise when it coincides with Passover.
>
> Actually it was a pro-Jewish fiddle: by keeping the two dates apart it
> minimized the risk of religious riots and/or pogroms.

I got this claim from "Calendrical Calculations" which says:

	The concern that the date of Passover would influence the date of
	Easter goes back to the easliest days of Christianity. For
	example, Eusebius (Vita Constantini, book iii, 18-20) gives a
	letter of the Emperor sent to those not present at the Council of
	Nicaea:

		When the question relative to the sacred festival of
		Easter arose ... [it] was declared to be particularly
		unworthy for this, the holist of all festivals, to follow
		the custom of the Jews ... We ought not, therefore, to
		have anything in common with the Jews ... we desire,
		dearest brethren, to separate ourselves from the
		detestable company of the Jews, for it is truly shameful
		for us to hear them boast that without their direction we
		could not keep this feast. How can they be in the right,
		they who, after the death of the Saviour, have no longer
		been led by reason but by wild violence as their delusion
		may urge them? They do not posess the truth in this Easter
		question ... it would still be your duty not to tarnish
		your soul by communications with such wicked people.

	Avoiding Pasover was also evident in the Gregorian reform of the
	Easter calculation. Canon 6 of the Gregorian calendar, published
	in 1582 and probably written by the German Jesuit astronomer
	Christopher Clavius, says so twice: in the last sentence of the
	first paragraph

		ne cum Iudaeis conveniamus, si forte dies XIV lunae
		caderet in diem dominicum

		[so that we would not come together with the Jews if by
		chance day 14 of the moon may fall on a Sunday]

	and in the middle of the second paragraph

		Ne igitur cum Iudaeis conveniamus, qui Pascha celebrant
		die XIV lunae, ...

		[Hence so that we would not come together with the Jews
		who celebrate Passover on day 14 of the moon, ...]

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FAIR ISLE: SOUTHEAST 6 TO GALE 8, PERHAPS SEVERE GALE 9 LATER. ROUGH OR VERY
ROUGH. SHOWERS. MODERATE OR GOOD.

From seaman at noao.edu  Sat Nov  8 11:47:03 2008
From: seaman at noao.edu (Rob Seaman)
Date: Sat, 8 Nov 2008 09:47:03 -0700
Subject: [LEAPSECS] A treaty not sworn to, nor broken (was Re:  princes)
In-Reply-To: <alpine.LSU.2.00.0811081039560.31998@hermes-1.csi.cam.ac.uk>
References: <20081029054608.GA14129@ucolick.org>
	<alpine.LSU.2.00.0810291146550.30582@hermes-1.csi.cam.ac.uk>
	<20081103082834.GM81158@finch-staff-1.thus.net>
	<alpine.LSU.2.00.0811081039560.31998@hermes-1.csi.cam.ac.uk>
Message-ID: <6945B268-85B7-4744-BE19-FCE8CA72FE0F@noao.edu>

On Nov 8, 2008, at 3:55 AM, Tony Finch wrote:

> On Mon, 3 Nov 2008, Clive D.W. Feather wrote:
>> Tony Finch said:
>>>
>>> As well as the egregious example of the pre-Julian Roman calendar,  
>>> I'm
>>> amused and disgusted by the anti-Jewish fiddles in the rules for
>>> determining Easter to minimise when it coincides with Passover.
>>
>> Actually it was a pro-Jewish fiddle: by keeping the two dates apart  
>> it
>> minimized the risk of religious riots and/or pogroms.
>
> I got this claim from "Calendrical Calculations" which says:
>
> 	The concern that the date of Passover would influence the date of
> 	Easter goes back to the easliest days of Christianity. For
> 	example, Eusebius (Vita Constantini, book iii, 18-20) gives a
> 	letter of the Emperor sent to those not present at the Council of
> 	Nicaea:
>  ...

One might take exception to the author's assertion that the Council of  
Nicaea was the earliest days of Christianity - considering it didn't  
take place until the year 325.  I've appended some timeline entries  
for AD 1683 to show what can change and remain the same over 325  
years.  (Various harbingers of today's world, as well as echoes of  
Nicaea.)  I recommend listening to the empyrean Purcell from 1683 to  
put the rest of my more pedestrian message into its best context :-)

	http://www.youtube.com/watch?v=LLn-35h3V3g

Sidestepping the disturbing anti-semitic history of our calendar,  
there is indeed a useful insight one can draw from this analogy with  
the Council of Nicaea.

 From Wikipedia:

> The Council of Nicaea was historically significant because it was  
> the first effort to attain consensus in the church through an  
> assembly representing all of Christendom.[3]

We can draw the insight, namely, that 1683 years later, we still  
remember its occurrence as historically significant and honor its work  
products:

	God from God, Light from Light,
	true God from true God,
	begotten, not made,
	of one Being with the Father.

(From the 1975 ecumenical translation.)  Not bad for poetry written by  
committee.

We remember the Nicene Creed and the Council that created it -  
precisely because Constantine sought consensus BEFORE decision-making,  
not after.

One seriously doubts that the work products of ITU-R WP7A will be  
remembered as long or will be regarded as poetic.  What is more  
lyrically elemental than time, however?

Surely it is in the interest of all parties to pursue a truly robust  
consensus.  As with the 1884 International Meridian Conference, echoed  
by the 1993 Longitude Symposium at Harvard, it is now time to organize  
an ecumenical (that is, broadly conceived and broadly attended)  
conference on civil timekeeping.

The alternative to doing so will be an awkward, fragile, and cramped  
decision, well short of consensus - immediately to splinter and  
ultimately to shatter.

It appears that some have taken the message from the 2003 Torino  
meeting that civil timekeeping is an obscure topic of little interest,  
with unbridgeable factional differences.  A more generous  
interpretation is that even on short notice, in a distant city, with  
an obscure title ("The ITU-R SRG 7A Colloquium on the UTC timescale")  
that still three dozen interested parties (from just one narrow  
segment of the broader "community of time") attended due to their  
perception of the key importance of the topic.  They were also able to  
reach an interim consensus (roughly "don't be hasty" and "call it  
something other than UTC if it IS other than UT"), that should inform  
future discussions.

A well advertised meeting in London or Washington (ie., one plane hop  
from either side of the Atlantic), planned a year or two in advance  
(as other scientific meetings are), promoted assiduously by a broad- 
based organizing committee (I nominate Steve Allen), would provide the  
foundation for actually accomplishing the underlying goal of devising  
a coherent long term plan for worldwide civil timekeeping.

This is also the quickest practical way to reach such a goal:
	"Let us enjoy the benefits of the time - but rather the benefits of  
their own valour and prudence, for time drives everything before it,  
and is able to bring with it good as well as evil, and evil as well as  
good."
					- Nicolo Machiavelli

(Exercise for the student:  Contrast Nicolo and Nicaea with Penn's  
son's "Walking Purchase" of land from the Lenni Lenape/Delaware.  "Not  
sworn to, nor broken"?  Maybe in 1683 while Penn himself was still  
around.)

Rob Seaman
National Optical Astronomy Observatory
----

 From http://timelines.ws/1661_1699.HTML:

1683        Feb 12, A Christian Army, led by Charles, the Duke of  
Lorraine and King John Sobieski of Poland, routed a huge Ottoman army  
surrounding Vienna.
     (HN, 2/12/99)

1683        Feb 20, Philip V, first Bourbon King of Spain, was born.  
[see Dec 19]
     (HN, 2/20/01)

1683        Apr 15, Catherine I (d.1727), empress of Russia  
(1725-1727), was born as Martha Skravonskaya in Jacobstadt, Latvia.  
Catherine was the daughter of Samuil Skavronski, a Lithuanian peasant.
     (HN, 4/15/98)(www.arthistoryclub.com/art_history/Catherine_I_of_Russia)

1683        Jun 23, William Penn signed a friendship treaty with Lenni  
Lenape Indians in Pennsylvania. It became the only treaty "not sworn  
to, nor broken."
     (HN, 6/23/98)(MC, 6/23/02)

1683        Jul 3, Edward Young, English poet, dramatist and literary  
critic, was born. He wrote "Night Thoughts."
     (HN, 7/3/99)

1683        Jul 21, Lord William Russell, English plotter against  
Charles II, was beheaded.
     (MC, 7/21/02)

1683        Jul 24, The 1st settlers from Germany to US left aboard  
the ship Concord.
     (www.ulib.iupui.edu/kade/germantown.html)

1683        Sep 3, Turkish troops broke through the defense of Vienna.
     (MC, 9/3/01)

1683        Sep 6, Jean-Baptiste Colbert (b.1619), French finance  
minister (1665-1683) under Louis XIV, died. He pioneered state control  
of the economy and state intervention in industry.
     (http://en.wikipedia.org/wiki/Jean-Baptiste_Colbert)(Econ,  
3/25/06, p.71)

1683        Sep 9, Algernon Sidney, English Whig politician and  
plotter, was beheaded.
     (MC, 9/9/01)

1683        Sep 12, A combined Austrian and Polish army defeated the  
Ottoman Turks at Kahlen-berg and lifted the siege on Vienna, Austria.  
Prince Eugene of Savoy helped repel an invasion of Vienna, Austria, by  
Turkish forces. Marco d'Aviano, sent by Pope Innocent XI to unite the  
outnumbered Christian troops, spurred them to victory. The Turks left  
behind sacks of coffee which the Christians found too bitter, so they  
sweetened it with honey and milk and named the drink cappuccino after  
the Capuchin order of monks to which d'Aviano belonged. An Austrian  
baker created a crescent-shaped roll, the Kipfel, to celebrate the  
victory. Empress Maria Theresa later took it to France where it became  
the croissant. In 2006 John Stoye authored ?The Siege of Vienna.?
     (Hem., Dec. '95, p.69)(WSJ, 3/27/96, p.A-16)(HN, 9/12/98)(SFEC,  
2/6/00, p.A1)(Reuters, 4/28/03)(WSJ, 6/3/03, p.D5) (WSJ, 12/6/06, p.D12)

1683        Sep 17, Antonie van Leeuwenhoek reported the existence of  
bacteria.
     (MC, 9/17/01)

1683        Sep 24, King Louis XIV expelled all Jews from French  
possessions in America.
     (MC, 9/24/01)

1683        Sep 25, Jean-Philippe Rameau, composer, was born in Dijon,  
France.
     (MC, 9/25/01)

1683        Sep 29, A small armada sailed from the Mexican mainland  
across the Sea of Cortez to the Baha Peninsula. Hostile natives had  
forced them back to the mainland on a first landing and a storm forced  
them back on a 2nd attempt.
     (SFEC, 5/18/97, p.T5)(WSJ, 12/26/97, p.A9)

1683        Oct 6, 13 Mennonite families from Krefeld, Germany,  
arrived in present-day Philadelphia to begin Germantown, one of  
America's oldest settlements. They were encouraged by William Penn's  
offer of 5,000 acres of land in the colony of Pennsylvania and the  
freedom to practice their religion.
     (AP, 10/6/97)(www.ulib.iupui.edu/kade/germantown.html)

1683        Oct 6, The small armada from the Mexican mainland landed  
on their 3rd attempt at crossing to the Baha peninsula and settled at  
the mouth of a river that they named San Bruno. The site was abandoned  
after 2 years. Spanish settlement on the Baha was later described by  
Father James Donald Francez in "The Lost Treasures of Baha California."
     (SFEC, 5/18/97, p.T5)(WSJ, 12/26/97, p.A9)

1683        Oct 30, George II, King of Great Britain (1727-60), was  
born. [see Oct 30]
     (MC, 10/30/01)

1683        Nov 10, George II, king of England (1727-60), was born.  
[see Nov 10]
     (MC, 11/10/01)

1683        Nov 22, Purcell's "Welcome to All the Pleasures,"  
premiered in London.
     (MC, 11/22/01)

1683        Dec 19, Philip V, King of Spain (1700-24, 24-46), was born  
in Versailles, France. [see Feb 20]
     (MC, 12/19/01)

1683        Dec 25, Kara Mustapha (b.~1634), chief of the Ottoman  
janissaries, appeared before the grand vizier in Belgrade. He was  
sentenced to death and executed for the military loss at Vienna.
     (WSJ, 12/5/06, p.D12)(http://en.wikipedia.org/wiki/Kara_Mustafa)

1683        Giovanni Battista Foggini created his sculpture "The Mass  
of Saint Andrea Corsini."
     (WSJ, 1/29/02, p.A18)

1683        The Ashmolean Museum was built in Oxford to house natural- 
history artifacts. It was the first such public museum. It gained its  
name and its first collections from Elias Ashmole (1617-1692), whose  
own collections were derived in part from those of John Tradescant  
(1608-1662).
     (WSJ, 1/11/99, p.R34)(http://myweb.tiscali.co.uk/speel//otherart/ashmole.htm 
)

1683        Alessandro Scarlatti (father of Domenico Scarlatti) wrote  
the score for his opera "L?Aldimiro." The only know score extant was  
found in a library in Berkeley, Ca., in 1989.
     (SFC, 5/26/96, DB p.26)

1683        Secatogue Indians deeded land on the South Shore of Long  
Island to William Nicoll.
     (WSJ, 10/9/07, p.D6)

1683        Roger Williams (b.1603) died in poverty in Rhode Island.  
Williams was the first cham-pion of complete religious toleration in  
America. In 2005 Edwin S. Gaustad authored the biog-raphy ?Roger  
Williams.?
     (HNQ, 5/1/99)(WSJ, 6/21/05, p.D10)

1683        Taiwan was claimed by China's Manchu dynasty after large- 
scale immigration from the Chinese mainland to the island.
     (AP, 8/12/06)

From jnatale at juniper.net  Sat Nov  8 19:05:37 2008
From: jnatale at juniper.net (Jonathan Natale)
Date: Sat, 8 Nov 2008 19:05:37 -0500
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 5
In-Reply-To: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
Message-ID: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>

Does anybody have any thoughts on the effect(s) of the previous and/or
upcoming leap seconds on NTP (v2, v3, and/or v4)?  For example, on
protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?

-----Original Message-----
From: leapsecs-bounces at leapsecond.com
[mailto:leapsecs-bounces at leapsecond.com] On Behalf Of
leapsecs-request at leapsecond.com
Sent: Saturday, November 08, 2008 12:01 PM
To: leapsecs at leapsecond.com
Subject: LEAPSECS Digest, Vol 25, Issue 5

Send LEAPSECS mailing list submissions to
	leapsecs at leapsecond.com

To subscribe or unsubscribe via the World Wide Web, visit
	http://six.pairlist.net/mailman/listinfo/leapsecs
or, via email, send a message with subject or body 'help' to
	leapsecs-request at leapsecond.com

You can reach the person managing the list at
	leapsecs-owner at leapsecond.com

When replying, please edit your Subject line so it is more specific
than "Re: Contents of LEAPSECS digest..."


Today's Topics:

   1. Re: princes (Tony Finch)
   2. A treaty not sworn to, nor broken (was Re:  princes) (Rob Seaman)


----------------------------------------------------------------------

Message: 1
Date: Sat, 8 Nov 2008 10:55:22 +0000
From: Tony Finch <dot at dotat.at>
Subject: Re: [LEAPSECS] princes
To: Leap Second Discussion List <leapsecs at leapsecond.com>
Message-ID:
	<alpine.LSU.2.00.0811081039560.31998 at hermes-1.csi.cam.ac.uk>
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Mon, 3 Nov 2008, Clive D.W. Feather wrote:
> Tony Finch said:
> >
> > As well as the egregious example of the pre-Julian Roman calendar,
I'm
> > amused and disgusted by the anti-Jewish fiddles in the rules for
> > determining Easter to minimise when it coincides with Passover.
>
> Actually it was a pro-Jewish fiddle: by keeping the two dates apart it
> minimized the risk of religious riots and/or pogroms.

I got this claim from "Calendrical Calculations" which says:

	The concern that the date of Passover would influence the date
of
	Easter goes back to the easliest days of Christianity. For
	example, Eusebius (Vita Constantini, book iii, 18-20) gives a
	letter of the Emperor sent to those not present at the Council
of
	Nicaea:

		When the question relative to the sacred festival of
		Easter arose ... [it] was declared to be particularly
		unworthy for this, the holist of all festivals, to
follow
		the custom of the Jews ... We ought not, therefore, to
		have anything in common with the Jews ... we desire,
		dearest brethren, to separate ourselves from the
		detestable company of the Jews, for it is truly shameful
		for us to hear them boast that without their direction
we
		could not keep this feast. How can they be in the right,
		they who, after the death of the Saviour, have no longer
		been led by reason but by wild violence as their
delusion
		may urge them? They do not posess the truth in this
Easter
		question ... it would still be your duty not to tarnish
		your soul by communications with such wicked people.

	Avoiding Pasover was also evident in the Gregorian reform of the
	Easter calculation. Canon 6 of the Gregorian calendar, published
	in 1582 and probably written by the German Jesuit astronomer
	Christopher Clavius, says so twice: in the last sentence of the
	first paragraph

		ne cum Iudaeis conveniamus, si forte dies XIV lunae
		caderet in diem dominicum

		[so that we would not come together with the Jews if by
		chance day 14 of the moon may fall on a Sunday]

	and in the middle of the second paragraph

		Ne igitur cum Iudaeis conveniamus, qui Pascha celebrant
		die XIV lunae, ...

		[Hence so that we would not come together with the Jews
		who celebrate Passover on day 14 of the moon, ...]

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FAIR ISLE: SOUTHEAST 6 TO GALE 8, PERHAPS SEVERE GALE 9 LATER. ROUGH OR
VERY
ROUGH. SHOWERS. MODERATE OR GOOD.


------------------------------

Message: 2
Date: Sat, 8 Nov 2008 09:47:03 -0700
From: Rob Seaman <seaman at noao.edu>
Subject: [LEAPSECS] A treaty not sworn to, nor broken (was Re:
	princes)
To: Leap Second Discussion List <leapsecs at leapsecond.com>
Message-ID: <6945B268-85B7-4744-BE19-FCE8CA72FE0F at noao.edu>
Content-Type: text/plain; charset=WINDOWS-1252; format=flowed;
	delsp=yes

On Nov 8, 2008, at 3:55 AM, Tony Finch wrote:

> On Mon, 3 Nov 2008, Clive D.W. Feather wrote:
>> Tony Finch said:
>>>
>>> As well as the egregious example of the pre-Julian Roman calendar,  
>>> I'm
>>> amused and disgusted by the anti-Jewish fiddles in the rules for
>>> determining Easter to minimise when it coincides with Passover.
>>
>> Actually it was a pro-Jewish fiddle: by keeping the two dates apart  
>> it
>> minimized the risk of religious riots and/or pogroms.
>
> I got this claim from "Calendrical Calculations" which says:
>
> 	The concern that the date of Passover would influence the date
of
> 	Easter goes back to the easliest days of Christianity. For
> 	example, Eusebius (Vita Constantini, book iii, 18-20) gives a
> 	letter of the Emperor sent to those not present at the Council
of
> 	Nicaea:
>  ...

One might take exception to the author's assertion that the Council of  
Nicaea was the earliest days of Christianity - considering it didn't  
take place until the year 325.  I've appended some timeline entries  
for AD 1683 to show what can change and remain the same over 325  
years.  (Various harbingers of today's world, as well as echoes of  
Nicaea.)  I recommend listening to the empyrean Purcell from 1683 to  
put the rest of my more pedestrian message into its best context :-)

	http://www.youtube.com/watch?v=LLn-35h3V3g

Sidestepping the disturbing anti-semitic history of our calendar,  
there is indeed a useful insight one can draw from this analogy with  
the Council of Nicaea.

 From Wikipedia:

> The Council of Nicaea was historically significant because it was  
> the first effort to attain consensus in the church through an  
> assembly representing all of Christendom.[3]

We can draw the insight, namely, that 1683 years later, we still  
remember its occurrence as historically significant and honor its work  
products:

	God from God, Light from Light,
	true God from true God,
	begotten, not made,
	of one Being with the Father.

(From the 1975 ecumenical translation.)  Not bad for poetry written by  
committee.

We remember the Nicene Creed and the Council that created it -  
precisely because Constantine sought consensus BEFORE decision-making,  
not after.

One seriously doubts that the work products of ITU-R WP7A will be  
remembered as long or will be regarded as poetic.  What is more  
lyrically elemental than time, however?

Surely it is in the interest of all parties to pursue a truly robust  
consensus.  As with the 1884 International Meridian Conference, echoed  
by the 1993 Longitude Symposium at Harvard, it is now time to organize  
an ecumenical (that is, broadly conceived and broadly attended)  
conference on civil timekeeping.

The alternative to doing so will be an awkward, fragile, and cramped  
decision, well short of consensus - immediately to splinter and  
ultimately to shatter.

It appears that some have taken the message from the 2003 Torino  
meeting that civil timekeeping is an obscure topic of little interest,  
with unbridgeable factional differences.  A more generous  
interpretation is that even on short notice, in a distant city, with  
an obscure title ("The ITU-R SRG 7A Colloquium on the UTC timescale")  
that still three dozen interested parties (from just one narrow  
segment of the broader "community of time") attended due to their  
perception of the key importance of the topic.  They were also able to  
reach an interim consensus (roughly "don't be hasty" and "call it  
something other than UTC if it IS other than UT"), that should inform  
future discussions.

A well advertised meeting in London or Washington (ie., one plane hop  
from either side of the Atlantic), planned a year or two in advance  
(as other scientific meetings are), promoted assiduously by a broad- 
based organizing committee (I nominate Steve Allen), would provide the  
foundation for actually accomplishing the underlying goal of devising  
a coherent long term plan for worldwide civil timekeeping.

This is also the quickest practical way to reach such a goal:
	"Let us enjoy the benefits of the time - but rather the benefits
of  
their own valour and prudence, for time drives everything before it,  
and is able to bring with it good as well as evil, and evil as well as  
good."
					- Nicolo Machiavelli

(Exercise for the student:  Contrast Nicolo and Nicaea with Penn's  
son's "Walking Purchase" of land from the Lenni Lenape/Delaware.  "Not  
sworn to, nor broken"?  Maybe in 1683 while Penn himself was still  
around.)

Rob Seaman
National Optical Astronomy Observatory
----

 From http://timelines.ws/1661_1699.HTML:

1683        Feb 12, A Christian Army, led by Charles, the Duke of  
Lorraine and King John Sobieski of Poland, routed a huge Ottoman army  
surrounding Vienna.
     (HN, 2/12/99)

1683        Feb 20, Philip V, first Bourbon King of Spain, was born.  
[see Dec 19]
     (HN, 2/20/01)

1683        Apr 15, Catherine I (d.1727), empress of Russia  
(1725-1727), was born as Martha Skravonskaya in Jacobstadt, Latvia.  
Catherine was the daughter of Samuil Skavronski, a Lithuanian peasant.
     (HN,
4/15/98)(www.arthistoryclub.com/art_history/Catherine_I_of_Russia)

1683        Jun 23, William Penn signed a friendship treaty with Lenni  
Lenape Indians in Pennsylvania. It became the only treaty "not sworn  
to, nor broken."
     (HN, 6/23/98)(MC, 6/23/02)

1683        Jul 3, Edward Young, English poet, dramatist and literary  
critic, was born. He wrote "Night Thoughts."
     (HN, 7/3/99)

1683        Jul 21, Lord William Russell, English plotter against  
Charles II, was beheaded.
     (MC, 7/21/02)

1683        Jul 24, The 1st settlers from Germany to US left aboard  
the ship Concord.
     (www.ulib.iupui.edu/kade/germantown.html)

1683        Sep 3, Turkish troops broke through the defense of Vienna.
     (MC, 9/3/01)

1683        Sep 6, Jean-Baptiste Colbert (b.1619), French finance  
minister (1665-1683) under Louis XIV, died. He pioneered state control  
of the economy and state intervention in industry.
     (http://en.wikipedia.org/wiki/Jean-Baptiste_Colbert)(Econ,  
3/25/06, p.71)

1683        Sep 9, Algernon Sidney, English Whig politician and  
plotter, was beheaded.
     (MC, 9/9/01)

1683        Sep 12, A combined Austrian and Polish army defeated the  
Ottoman Turks at Kahlen-berg and lifted the siege on Vienna, Austria.  
Prince Eugene of Savoy helped repel an invasion of Vienna, Austria, by  
Turkish forces. Marco d'Aviano, sent by Pope Innocent XI to unite the  
outnumbered Christian troops, spurred them to victory. The Turks left  
behind sacks of coffee which the Christians found too bitter, so they  
sweetened it with honey and milk and named the drink cappuccino after  
the Capuchin order of monks to which d'Aviano belonged. An Austrian  
baker created a crescent-shaped roll, the Kipfel, to celebrate the  
victory. Empress Maria Theresa later took it to France where it became  
the croissant. In 2006 John Stoye authored ?The Siege of Vienna.?
     (Hem., Dec. '95, p.69)(WSJ, 3/27/96, p.A-16)(HN, 9/12/98)(SFEC,  
2/6/00, p.A1)(Reuters, 4/28/03)(WSJ, 6/3/03, p.D5) (WSJ, 12/6/06, p.D12)

1683        Sep 17, Antonie van Leeuwenhoek reported the existence of  
bacteria.
     (MC, 9/17/01)

1683        Sep 24, King Louis XIV expelled all Jews from French  
possessions in America.
     (MC, 9/24/01)

1683        Sep 25, Jean-Philippe Rameau, composer, was born in Dijon,  
France.
     (MC, 9/25/01)

1683        Sep 29, A small armada sailed from the Mexican mainland  
across the Sea of Cortez to the Baha Peninsula. Hostile natives had  
forced them back to the mainland on a first landing and a storm forced  
them back on a 2nd attempt.
     (SFEC, 5/18/97, p.T5)(WSJ, 12/26/97, p.A9)

1683        Oct 6, 13 Mennonite families from Krefeld, Germany,  
arrived in present-day Philadelphia to begin Germantown, one of  
America's oldest settlements. They were encouraged by William Penn's  
offer of 5,000 acres of land in the colony of Pennsylvania and the  
freedom to practice their religion.
     (AP, 10/6/97)(www.ulib.iupui.edu/kade/germantown.html)

1683        Oct 6, The small armada from the Mexican mainland landed  
on their 3rd attempt at crossing to the Baha peninsula and settled at  
the mouth of a river that they named San Bruno. The site was abandoned  
after 2 years. Spanish settlement on the Baha was later described by  
Father James Donald Francez in "The Lost Treasures of Baha California."
     (SFEC, 5/18/97, p.T5)(WSJ, 12/26/97, p.A9)

1683        Oct 30, George II, King of Great Britain (1727-60), was  
born. [see Oct 30]
     (MC, 10/30/01)

1683        Nov 10, George II, king of England (1727-60), was born.  
[see Nov 10]
     (MC, 11/10/01)

1683        Nov 22, Purcell's "Welcome to All the Pleasures,"  
premiered in London.
     (MC, 11/22/01)

1683        Dec 19, Philip V, King of Spain (1700-24, 24-46), was born  
in Versailles, France. [see Feb 20]
     (MC, 12/19/01)

1683        Dec 25, Kara Mustapha (b.~1634), chief of the Ottoman  
janissaries, appeared before the grand vizier in Belgrade. He was  
sentenced to death and executed for the military loss at Vienna.
     (WSJ, 12/5/06, p.D12)(http://en.wikipedia.org/wiki/Kara_Mustafa)

1683        Giovanni Battista Foggini created his sculpture "The Mass  
of Saint Andrea Corsini."
     (WSJ, 1/29/02, p.A18)

1683        The Ashmolean Museum was built in Oxford to house natural- 
history artifacts. It was the first such public museum. It gained its  
name and its first collections from Elias Ashmole (1617-1692), whose  
own collections were derived in part from those of John Tradescant  
(1608-1662).
     (WSJ, 1/11/99,
p.R34)(http://myweb.tiscali.co.uk/speel//otherart/ashmole.htm 
)

1683        Alessandro Scarlatti (father of Domenico Scarlatti) wrote  
the score for his opera "L?Aldimiro." The only know score extant was  
found in a library in Berkeley, Ca., in 1989.
     (SFC, 5/26/96, DB p.26)

1683        Secatogue Indians deeded land on the South Shore of Long  
Island to William Nicoll.
     (WSJ, 10/9/07, p.D6)

1683        Roger Williams (b.1603) died in poverty in Rhode Island.  
Williams was the first cham-pion of complete religious toleration in  
America. In 2005 Edwin S. Gaustad authored the biog-raphy ?Roger  
Williams.?
     (HNQ, 5/1/99)(WSJ, 6/21/05, p.D10)

1683        Taiwan was claimed by China's Manchu dynasty after large- 
scale immigration from the Chinese mainland to the island.
     (AP, 8/12/06)


------------------------------

_______________________________________________
LEAPSECS mailing list
LEAPSECS at leapsecond.com
http://six.pairlist.net/mailman/listinfo/leapsecs


End of LEAPSECS Digest, Vol 25, Issue 5
***************************************

From sla at ucolick.org  Sat Nov  8 21:08:27 2008
From: sla at ucolick.org (Steve Allen)
Date: Sat, 8 Nov 2008 18:08:27 -0800
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 5
In-Reply-To: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
Message-ID: <20081109020827.GA4815@ucolick.org>

On Sat 2008-11-08T19:05:37 -0500, Jonathan Natale hath writ:
> Does anybody have any thoughts on the effect(s) of the previous and/or
> upcoming leap seconds on NTP (v2, v3, and/or v4)?  For example, on
> protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?

This question is made for the comp.protocols.time.ntp newsgroup.
I suggest asking over there.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From ashley at semantic.org  Sat Nov  8 21:12:59 2008
From: ashley at semantic.org (Ashley Yakeley)
Date: Sat, 08 Nov 2008 18:12:59 -0800
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 5
In-Reply-To: <20081109020827.GA4815@ucolick.org>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
Message-ID: <1226196779.12771.11.camel@glastonbury>

On Sat, 2008-11-08 at 18:08 -0800, Steve Allen wrote:
> On Sat 2008-11-08T19:05:37 -0500, Jonathan Natale hath writ:
> > Does anybody have any thoughts on the effect(s) of the previous and/or
> > upcoming leap seconds on NTP (v2, v3, and/or v4)?  For example, on
> > protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?
> 
> This question is made for the comp.protocols.time.ntp newsgroup.
> I suggest asking over there.

The Easter computus, by contrast, is right on topic.

-- 
Ashley Yakeley
Seattle, WA


From jhardis at tcs.wap.org  Sat Nov  8 21:30:46 2008
From: jhardis at tcs.wap.org (Jonathan E. Hardis)
Date: Sat, 8 Nov 2008 22:30:46 -0400
Subject: [LEAPSECS] Leap Seconds in NTP
In-Reply-To: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
Message-ID: <p0623090fc53bf89276ee@[192.168.0.5]>

>Does anybody have any thoughts on the effect(s) of the previous and/or
>upcoming leap seconds on NTP (v2, v3, and/or v4)?  For example, on
>protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?

Please see 
http://www.eecis.udel.edu/~ntp/ntpfaq/NTP-s-algo.htm#AEN2432 ("What 
Happens During a Leap Second").  It's not a complete answer, but it 
will get you started.

You can find additional information in the NTP RFC.  In 
http://www.eecis.udel.edu/~mills/database/rfc/rfc1305/rfc1305c.pdf , 
see "5. Appendix E. The NTP Timescale and its Chronometry" starting 
at page 70 (21 of the PDF).

For the most up to date information, browse around starting at 
http://www.ntp.org/ .

   - Jonathan

From imp at bsdimp.com  Sat Nov  8 22:48:09 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Sat, 08 Nov 2008 20:48:09 -0700 (MST)
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 5
In-Reply-To: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
Message-ID: <20081108.204809.-861030345.imp@bsdimp.com>

In message: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB at emailwf1.jnpr.net>
            "Jonathan Natale" <jnatale at juniper.net> writes:
: Does anybody have any thoughts on the effect(s) of the previous and/or
: upcoming leap seconds on NTP (v2, v3, and/or v4)?

NTP does nearly the right thing, so there's no worries there.  Except
for buggy implementations, missed leap second announcements and
administrative error.  Oh, and time exchanges that happen over the
actual leap second.  Some servers 'freeze' time for a second, while
others respond with the right bits set.  Some will discard queries
that were sent in the leap second, while others will compute a
one-time error of 1s which gets thrown away as an outlier and
ignored.

I'm sure that others on this list can recount other deviant
behavior..  I'm sure that some of the supposed 'normal' behavior will
be considered deviant by some, and vice versa.

: For example, on
: protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?

Most of these protocols are implemented using relative timers, not
absolute.  However, this is a matter for the OS to cope with, and
wonky behavior has been reported at previous leap seconds that settles
down within a few minutes after the event.

In general, steps in time are a bad thing.  Since most of the world
runs on time_t, leapseconds necessarily introduce a time step (or a
time error for the misguided folks that try to paper over the leap
second by running time slower on leap day...).

Many of the protocols don't define what happens at a leap second.
Often, this oversight doesn't matter, as the strong implications are
that timeouts are in wall seconds, not adjusted seconds.

There's a few APIs that specify an absolute time to sleep until which
have issues when the time steps on systems.  Typically, the issues are
relatively benign, although some systems have had bugs in the past
that caused all timeouts scheduled during the leap second (the second
playing of second 59 or second 0, depending on your OS's design
decisions (eg, which bug are you compatible with)).  Often, however,
timeouts are implements on a callout wheel, making them effectively
relative anyway...

Anyway, enough about leap seconds and the problems they cause....
Irregular counting systems rarely work at the irregularities
flawlessly.  Or should I saw 'variable radix systems suck'[*]

Warner

[*] There's technically no discontinuities in UTC, since it counts
23:59:59 23:59:60 00:00:00.  This is called a variable radix system.
The trouble comes when POSIX demands that the tree values in this
paragraph map to two integers, leading to ambiguity and
discontinuities....

: -----Original Message-----
: From: leapsecs-bounces at leapsecond.com
: [mailto:leapsecs-bounces at leapsecond.com] On Behalf Of
: leapsecs-request at leapsecond.com
: Sent: Saturday, November 08, 2008 12:01 PM
: To: leapsecs at leapsecond.com
: Subject: LEAPSECS Digest, Vol 25, Issue 5
: 
: Send LEAPSECS mailing list submissions to
: 	leapsecs at leapsecond.com
: 
: To subscribe or unsubscribe via the World Wide Web, visit
: 	http://six.pairlist.net/mailman/listinfo/leapsecs
: or, via email, send a message with subject or body 'help' to
: 	leapsecs-request at leapsecond.com
: 
: You can reach the person managing the list at
: 	leapsecs-owner at leapsecond.com
: 
: When replying, please edit your Subject line so it is more specific
: than "Re: Contents of LEAPSECS digest..."
: 
: 
: Today's Topics:
: 
:    1. Re: princes (Tony Finch)
:    2. A treaty not sworn to, nor broken (was Re:  princes) (Rob Seaman)
: 
: 
: ----------------------------------------------------------------------
: 
: Message: 1
: Date: Sat, 8 Nov 2008 10:55:22 +0000
: From: Tony Finch <dot at dotat.at>
: Subject: Re: [LEAPSECS] princes
: To: Leap Second Discussion List <leapsecs at leapsecond.com>
: Message-ID:
: 	<alpine.LSU.2.00.0811081039560.31998 at hermes-1.csi.cam.ac.uk>
: Content-Type: TEXT/PLAIN; charset=US-ASCII
: 
: On Mon, 3 Nov 2008, Clive D.W. Feather wrote:
: > Tony Finch said:
: > >
: > > As well as the egregious example of the pre-Julian Roman calendar,
: I'm
: > > amused and disgusted by the anti-Jewish fiddles in the rules for
: > > determining Easter to minimise when it coincides with Passover.
: >
: > Actually it was a pro-Jewish fiddle: by keeping the two dates apart it
: > minimized the risk of religious riots and/or pogroms.
: 
: I got this claim from "Calendrical Calculations" which says:
: 
: 	The concern that the date of Passover would influence the date
: of
: 	Easter goes back to the easliest days of Christianity. For
: 	example, Eusebius (Vita Constantini, book iii, 18-20) gives a
: 	letter of the Emperor sent to those not present at the Council
: of
: 	Nicaea:
: 
: 		When the question relative to the sacred festival of
: 		Easter arose ... [it] was declared to be particularly
: 		unworthy for this, the holist of all festivals, to
: follow
: 		the custom of the Jews ... We ought not, therefore, to
: 		have anything in common with the Jews ... we desire,
: 		dearest brethren, to separate ourselves from the
: 		detestable company of the Jews, for it is truly shameful
: 		for us to hear them boast that without their direction
: we
: 		could not keep this feast. How can they be in the right,
: 		they who, after the death of the Saviour, have no longer
: 		been led by reason but by wild violence as their
: delusion
: 		may urge them? They do not posess the truth in this
: Easter
: 		question ... it would still be your duty not to tarnish
: 		your soul by communications with such wicked people.
: 
: 	Avoiding Pasover was also evident in the Gregorian reform of the
: 	Easter calculation. Canon 6 of the Gregorian calendar, published
: 	in 1582 and probably written by the German Jesuit astronomer
: 	Christopher Clavius, says so twice: in the last sentence of the
: 	first paragraph
: 
: 		ne cum Iudaeis conveniamus, si forte dies XIV lunae
: 		caderet in diem dominicum
: 
: 		[so that we would not come together with the Jews if by
: 		chance day 14 of the moon may fall on a Sunday]
: 
: 	and in the middle of the second paragraph
: 
: 		Ne igitur cum Iudaeis conveniamus, qui Pascha celebrant
: 		die XIV lunae, ...
: 
: 		[Hence so that we would not come together with the Jews
: 		who celebrate Passover on day 14 of the moon, ...]
: 
: Tony.
: -- 
: f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
: FAIR ISLE: SOUTHEAST 6 TO GALE 8, PERHAPS SEVERE GALE 9 LATER. ROUGH OR
: VERY
: ROUGH. SHOWERS. MODERATE OR GOOD.
: 
: 
: ------------------------------
: 
: Message: 2
: Date: Sat, 8 Nov 2008 09:47:03 -0700
: From: Rob Seaman <seaman at noao.edu>
: Subject: [LEAPSECS] A treaty not sworn to, nor broken (was Re:
: 	princes)
: To: Leap Second Discussion List <leapsecs at leapsecond.com>
: Message-ID: <6945B268-85B7-4744-BE19-FCE8CA72FE0F at noao.edu>
: Content-Type: text/plain; charset=WINDOWS-1252; format=flowed;
: 	delsp=yes
: 
: On Nov 8, 2008, at 3:55 AM, Tony Finch wrote:
: 
: > On Mon, 3 Nov 2008, Clive D.W. Feather wrote:
: >> Tony Finch said:
: >>>
: >>> As well as the egregious example of the pre-Julian Roman calendar,  
: >>> I'm
: >>> amused and disgusted by the anti-Jewish fiddles in the rules for
: >>> determining Easter to minimise when it coincides with Passover.
: >>
: >> Actually it was a pro-Jewish fiddle: by keeping the two dates apart  
: >> it
: >> minimized the risk of religious riots and/or pogroms.
: >
: > I got this claim from "Calendrical Calculations" which says:
: >
: > 	The concern that the date of Passover would influence the date
: of
: > 	Easter goes back to the easliest days of Christianity. For
: > 	example, Eusebius (Vita Constantini, book iii, 18-20) gives a
: > 	letter of the Emperor sent to those not present at the Council
: of
: > 	Nicaea:
: >  ...
: 
: One might take exception to the author's assertion that the Council of  
: Nicaea was the earliest days of Christianity - considering it didn't  
: take place until the year 325.  I've appended some timeline entries  
: for AD 1683 to show what can change and remain the same over 325  
: years.  (Various harbingers of today's world, as well as echoes of  
: Nicaea.)  I recommend listening to the empyrean Purcell from 1683 to  
: put the rest of my more pedestrian message into its best context :-)
: 
: 	http://www.youtube.com/watch?v=LLn-35h3V3g
: 
: Sidestepping the disturbing anti-semitic history of our calendar,  
: there is indeed a useful insight one can draw from this analogy with  
: the Council of Nicaea.
: 
:  From Wikipedia:
: 
: > The Council of Nicaea was historically significant because it was  
: > the first effort to attain consensus in the church through an  
: > assembly representing all of Christendom.[3]
: 
: We can draw the insight, namely, that 1683 years later, we still  
: remember its occurrence as historically significant and honor its work  
: products:
: 
: 	God from God, Light from Light,
: 	true God from true God,
: 	begotten, not made,
: 	of one Being with the Father.
: 
: (From the 1975 ecumenical translation.)  Not bad for poetry written by  
: committee.
: 
: We remember the Nicene Creed and the Council that created it -  
: precisely because Constantine sought consensus BEFORE decision-making,  
: not after.
: 
: One seriously doubts that the work products of ITU-R WP7A will be  
: remembered as long or will be regarded as poetic.  What is more  
: lyrically elemental than time, however?
: 
: Surely it is in the interest of all parties to pursue a truly robust  
: consensus.  As with the 1884 International Meridian Conference, echoed  
: by the 1993 Longitude Symposium at Harvard, it is now time to organize  
: an ecumenical (that is, broadly conceived and broadly attended)  
: conference on civil timekeeping.
: 
: The alternative to doing so will be an awkward, fragile, and cramped  
: decision, well short of consensus - immediately to splinter and  
: ultimately to shatter.
: 
: It appears that some have taken the message from the 2003 Torino  
: meeting that civil timekeeping is an obscure topic of little interest,  
: with unbridgeable factional differences.  A more generous  
: interpretation is that even on short notice, in a distant city, with  
: an obscure title ("The ITU-R SRG 7A Colloquium on the UTC timescale")  
: that still three dozen interested parties (from just one narrow  
: segment of the broader "community of time") attended due to their  
: perception of the key importance of the topic.  They were also able to  
: reach an interim consensus (roughly "don't be hasty" and "call it  
: something other than UTC if it IS other than UT"), that should inform  
: future discussions.
: 
: A well advertised meeting in London or Washington (ie., one plane hop  
: from either side of the Atlantic), planned a year or two in advance  
: (as other scientific meetings are), promoted assiduously by a broad- 
: based organizing committee (I nominate Steve Allen), would provide the  
: foundation for actually accomplishing the underlying goal of devising  
: a coherent long term plan for worldwide civil timekeeping.
: 
: This is also the quickest practical way to reach such a goal:
: 	"Let us enjoy the benefits of the time - but rather the benefits
: of  
: their own valour and prudence, for time drives everything before it,  
: and is able to bring with it good as well as evil, and evil as well as  
: good."
: 					- Nicolo Machiavelli
: 
: (Exercise for the student:  Contrast Nicolo and Nicaea with Penn's  
: son's "Walking Purchase" of land from the Lenni Lenape/Delaware.  "Not  
: sworn to, nor broken"?  Maybe in 1683 while Penn himself was still  
: around.)
: 
: Rob Seaman
: National Optical Astronomy Observatory
: ----
: 
:  From http://timelines.ws/1661_1699.HTML:
: 
: 1683        Feb 12, A Christian Army, led by Charles, the Duke of  
: Lorraine and King John Sobieski of Poland, routed a huge Ottoman army  
: surrounding Vienna.
:      (HN, 2/12/99)
: 
: 1683        Feb 20, Philip V, first Bourbon King of Spain, was born.  
: [see Dec 19]
:      (HN, 2/20/01)
: 
: 1683        Apr 15, Catherine I (d.1727), empress of Russia  
: (1725-1727), was born as Martha Skravonskaya in Jacobstadt, Latvia.  
: Catherine was the daughter of Samuil Skavronski, a Lithuanian peasant.
:      (HN,
: 4/15/98)(www.arthistoryclub.com/art_history/Catherine_I_of_Russia)
: 
: 1683        Jun 23, William Penn signed a friendship treaty with Lenni  
: Lenape Indians in Pennsylvania. It became the only treaty "not sworn  
: to, nor broken."
:      (HN, 6/23/98)(MC, 6/23/02)
: 
: 1683        Jul 3, Edward Young, English poet, dramatist and literary  
: critic, was born. He wrote "Night Thoughts."
:      (HN, 7/3/99)
: 
: 1683        Jul 21, Lord William Russell, English plotter against  
: Charles II, was beheaded.
:      (MC, 7/21/02)
: 
: 1683        Jul 24, The 1st settlers from Germany to US left aboard  
: the ship Concord.
:      (www.ulib.iupui.edu/kade/germantown.html)
: 
: 1683        Sep 3, Turkish troops broke through the defense of Vienna.
:      (MC, 9/3/01)
: 
: 1683        Sep 6, Jean-Baptiste Colbert (b.1619), French finance  
: minister (1665-1683) under Louis XIV, died. He pioneered state control  
: of the economy and state intervention in industry.
:      (http://en.wikipedia.org/wiki/Jean-Baptiste_Colbert)(Econ,  
: 3/25/06, p.71)
: 
: 1683        Sep 9, Algernon Sidney, English Whig politician and  
: plotter, was beheaded.
:      (MC, 9/9/01)
: 
: 1683        Sep 12, A combined Austrian and Polish army defeated the  
: Ottoman Turks at Kahlen-berg and lifted the siege on Vienna, Austria.  
: Prince Eugene of Savoy helped repel an invasion of Vienna, Austria, by  
: Turkish forces. Marco d'Aviano, sent by Pope Innocent XI to unite the  
: outnumbered Christian troops, spurred them to victory. The Turks left  
: behind sacks of coffee which the Christians found too bitter, so they  
: sweetened it with honey and milk and named the drink cappuccino after  
: the Capuchin order of monks to which d'Aviano belonged. An Austrian  
: baker created a crescent-shaped roll, the Kipfel, to celebrate the  
: victory. Empress Maria Theresa later took it to France where it became  
: the croissant. In 2006 John Stoye authored ?The Siege of Vienna.?
:      (Hem., Dec. '95, p.69)(WSJ, 3/27/96, p.A-16)(HN, 9/12/98)(SFEC,  
: 2/6/00, p.A1)(Reuters, 4/28/03)(WSJ, 6/3/03, p.D5) (WSJ, 12/6/06, p.D12)
: 
: 1683        Sep 17, Antonie van Leeuwenhoek reported the existence of  
: bacteria.
:      (MC, 9/17/01)
: 
: 1683        Sep 24, King Louis XIV expelled all Jews from French  
: possessions in America.
:      (MC, 9/24/01)
: 
: 1683        Sep 25, Jean-Philippe Rameau, composer, was born in Dijon,  
: France.
:      (MC, 9/25/01)
: 
: 1683        Sep 29, A small armada sailed from the Mexican mainland  
: across the Sea of Cortez to the Baha Peninsula. Hostile natives had  
: forced them back to the mainland on a first landing and a storm forced  
: them back on a 2nd attempt.
:      (SFEC, 5/18/97, p.T5)(WSJ, 12/26/97, p.A9)
: 
: 1683        Oct 6, 13 Mennonite families from Krefeld, Germany,  
: arrived in present-day Philadelphia to begin Germantown, one of  
: America's oldest settlements. They were encouraged by William Penn's  
: offer of 5,000 acres of land in the colony of Pennsylvania and the  
: freedom to practice their religion.
:      (AP, 10/6/97)(www.ulib.iupui.edu/kade/germantown.html)
: 
: 1683        Oct 6, The small armada from the Mexican mainland landed  
: on their 3rd attempt at crossing to the Baha peninsula and settled at  
: the mouth of a river that they named San Bruno. The site was abandoned  
: after 2 years. Spanish settlement on the Baha was later described by  
: Father James Donald Francez in "The Lost Treasures of Baha California."
:      (SFEC, 5/18/97, p.T5)(WSJ, 12/26/97, p.A9)
: 
: 1683        Oct 30, George II, King of Great Britain (1727-60), was  
: born. [see Oct 30]
:      (MC, 10/30/01)
: 
: 1683        Nov 10, George II, king of England (1727-60), was born.  
: [see Nov 10]
:      (MC, 11/10/01)
: 
: 1683        Nov 22, Purcell's "Welcome to All the Pleasures,"  
: premiered in London.
:      (MC, 11/22/01)
: 
: 1683        Dec 19, Philip V, King of Spain (1700-24, 24-46), was born  
: in Versailles, France. [see Feb 20]
:      (MC, 12/19/01)
: 
: 1683        Dec 25, Kara Mustapha (b.~1634), chief of the Ottoman  
: janissaries, appeared before the grand vizier in Belgrade. He was  
: sentenced to death and executed for the military loss at Vienna.
:      (WSJ, 12/5/06, p.D12)(http://en.wikipedia.org/wiki/Kara_Mustafa)
: 
: 1683        Giovanni Battista Foggini created his sculpture "The Mass  
: of Saint Andrea Corsini."
:      (WSJ, 1/29/02, p.A18)
: 
: 1683        The Ashmolean Museum was built in Oxford to house natural- 
: history artifacts. It was the first such public museum. It gained its  
: name and its first collections from Elias Ashmole (1617-1692), whose  
: own collections were derived in part from those of John Tradescant  
: (1608-1662).
:      (WSJ, 1/11/99,
: p.R34)(http://myweb.tiscali.co.uk/speel//otherart/ashmole.htm 
: )
: 
: 1683        Alessandro Scarlatti (father of Domenico Scarlatti) wrote  
: the score for his opera "L?Aldimiro." The only know score extant was  
: found in a library in Berkeley, Ca., in 1989.
:      (SFC, 5/26/96, DB p.26)
: 
: 1683        Secatogue Indians deeded land on the South Shore of Long  
: Island to William Nicoll.
:      (WSJ, 10/9/07, p.D6)
: 
: 1683        Roger Williams (b.1603) died in poverty in Rhode Island.  
: Williams was the first cham-pion of complete religious toleration in  
: America. In 2005 Edwin S. Gaustad authored the biog-raphy ?Roger  
: Williams.?
:      (HNQ, 5/1/99)(WSJ, 6/21/05, p.D10)
: 
: 1683        Taiwan was claimed by China's Manchu dynasty after large- 
: scale immigration from the Chinese mainland to the island.
:      (AP, 8/12/06)
: 
: 
: ------------------------------
: 
: _______________________________________________
: LEAPSECS mailing list
: LEAPSECS at leapsecond.com
: http://six.pairlist.net/mailman/listinfo/leapsecs
: 
: 
: End of LEAPSECS Digest, Vol 25, Issue 5
: ***************************************
: _______________________________________________
: LEAPSECS mailing list
: LEAPSECS at leapsecond.com
: http://six.pairlist.net/mailman/listinfo/leapsecs
: 
: 

From dwmalone at maths.tcd.ie  Sun Nov  9 03:30:51 2008
From: dwmalone at maths.tcd.ie (David Malone)
Date: Sun, 09 Nov 2008 08:30:51 +0000
Subject: [LEAPSECS] LEAPSECS Digest, Vol 25, Issue 5
In-Reply-To: Your message of "Sat, 08 Nov 2008 19:05:37 EST."
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net> 
Message-ID: <200811090830.aa74435@walton.maths.tcd.ie>

> Does anybody have any thoughts on the effect(s) of the previous and/or
> upcoming leap seconds on NTP (v2, v3, and/or v4)?  For example, on
> protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?

I recorded the behaviour of a couple of different systems during
the last leap second:

	http://www.maths.tcd.ie/~dwmalone/time/leap2005.html

The bottom of the page has links to other people's observations.
I did hear a report of one protocol stalling because it saw an
out-of-order timestamp over the last leap second, but it was an
in-house protocol and I wasn't able to get details to actually
confirm the problem.

As Warner said, NTP should behave fine modulo bugs. Most low level
shouldn't need to convert from machine counters to real time, so
the leap seconds shouldn't have an impact. For example, TCP timestamps
in FreeBSD are implemented using the kernel "get*uptime" functions
and in other OSes they often seem to be implemented in terms of
interrupt ticks/jiffies/... Interestingly, this can actually offer
some chances for fingerprinting devices based on clock drift:

	http://www.caida.org/~yoshi/KoBrCl05PDF-hires.pdf

David.

From psb at ast.cam.ac.uk  Sun Nov  9 04:15:13 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Sun, 9 Nov 2008 09:15:13 +0000 (GMT)
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: <1226196779.12771.11.camel@glastonbury>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
Message-ID: <Pine.GSO.4.58.0811090857500.23237@cass03>



On Sat, 8 Nov 2008, Ashley Yakeley wrote:

> On Sat, 2008-11-08 at 18:08 -0800, Steve Allen wrote:
> > On Sat 2008-11-08T19:05:37 -0500, Jonathan Natale hath writ:
> > > Does anybody have any thoughts on the effect(s) of the previous and/or
> > > upcoming leap seconds on NTP (v2, v3, and/or v4)?  For example, on
> > > protocols that implement sub-second timers (such as BFD)?  TCP?  IGMPv3?
> >
> > This question is made for the comp.protocols.time.ntp newsgroup.
> > I suggest asking over there.
>
> The Easter computus, by contrast, is right on topic.
>
I think it is; raised from time to time in this list is the capture of
user requirements for time/calendar.
Civil time is for the people; some people have deeply felt beliefs on the
timing of religious festivals; while an overlapping group have deeply felt
beliefs about noon being around the time when the Sun is highest in the
sky.

So a User requirement might be:
The rythms of life, including the orbits of the earth and the moon,
the rotation of the earth, and convenient sub-divisions of the rotation
down to nearly  the limit of human perception, shall be expressed in
a single monotonic calendar.


Pete

From seaman at noao.edu  Sun Nov  9 09:38:37 2008
From: seaman at noao.edu (Rob Seaman)
Date: Sun, 9 Nov 2008 07:38:37 -0700
Subject: [LEAPSECS] Easter and NTP
In-Reply-To: <Pine.GSO.4.58.0811090857500.23237@cass03>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
Message-ID: <EC401BD3-DA69-4E42-9173-300E63E498DE@noao.edu>

After nine years of this discussion, the most flabbergasted I've been  
is when I realized that asserting proper system engineering principles  
riled the mailing list more than my most extreme flights of rhetorical  
fancy.  So Pete has identified a system requirement, and Warner  
(rather too heavily excerpted below), has done a nice job at writing a  
problem statement.

A fundamental aspect of system engineering is to separate the  
definition of the problem from the specification of a satisfactory  
solution.  Each problem has many possible solutions.  Say again:  each  
problem has many possible solutions.

To constrain the solution parameter space, we have to discover the  
requirements implicit in the problem statement in front of us.  This  
process is rarely straightforward since the problem can only be  
understood in its full context (typically expressed as use cases).   
For timekeeping, this context is vast indeed.  There is a very strong  
benefit to writing down a set of requirements, however; the discussion  
can focus on the proper description of the problem before entertaining  
trade-offs among the many possible solutions.

Once a consensus is reached about the requirements for a project, a  
technically savvy crowd will have significantly less trouble agreeing  
on solutions that implement those requirements.

After those nine years - even following a very ad hoc process - the  
problem facing civil timekeeping is much better understood (by this  
group, anyway).  After nine years, however, all we still understand  
about the one-and-only notion ever proposed for WP7A deliberation is  
that they (whoever "they" are) think they've found a sly, zero effort,  
way to avoid the problem entirely.  This doesn't comprise a "solution"  
at all.

This is what my grandfather called a "lazy man's load" - piling up too  
many items into a single precarious heap, rather than making the two  
trips - with manageable loads - that are really required.

Civil timekeeping comprises two parts - two lists of requirements.   
There is the Earth orientation part that Pete is discussing, and there  
is the interval time part that Warner is referring to.  It isn't  
surprising that it is a challenge to find a single set of requirements  
that satisfies both.  It will ultimately prove much easier to do so -  
and to entertain solutions implementing those requirements - if we  
don't spurn the tools of system engineering.

Rob Seaman
NOAO
--

On Nov 9, 2008, at 2:15 AM, Peter Bunclark wrote:

> So a User requirement might be:
> The rythms of life, including the orbits of the earth and the moon,
> the rotation of the earth, and convenient sub-divisions of the  
> rotation
> down to nearly  the limit of human perception, shall be expressed in
> a single monotonic calendar.

On Nov 8, 2008, at 8:48 PM, M. Warner Losh wrote:

> Since most of the world
> runs on time_t, leapseconds necessarily introduce a time step (or a
> time error for the misguided folks that try to paper over the leap
> second by running time slower on leap day...).

From dot at dotat.at  Mon Nov 10 07:11:53 2008
From: dot at dotat.at (Tony Finch)
Date: Mon, 10 Nov 2008 12:11:53 +0000
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: <Pine.GSO.4.58.0811090857500.23237@cass03>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
Message-ID: <alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>

On Sun, 9 Nov 2008, Peter Bunclark wrote:
>
> So a User requirement might be:
> The rythms of life, including the orbits of the earth and the moon,
> the rotation of the earth, and convenient sub-divisions of the rotation
> down to nearly the limit of human perception, shall be expressed in
> a single monotonic calendar.

I guess you mean the limits of human perception as assisted by suitable
tools...

Most common calendars have given up trying to track both the moon and
the sun. Most of them prefer to track the sun; the Muslims track the moon;
and the Jews track both and the result is impressively complex.

Your specification doesn't capture how to measure the rotation of the
Earth. We used to use apparent solar time, then we switched to local
mean solar time, then we switched to standard time, then we added
arbitrary unpredictable seasonal offsets.

My point is that user requirements change. The relation between natural
phenomena and our consensus idea of time depends on how accurately and
quickly we can measure those phenomena, and which phenomena we care about
tracking.

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
DOGGER FISHER: SOUTHWEST, BECOMING CYCLONIC LATER, 6 TO GALE 8, OCCASIONALLY
SEVERE GALE 9 AT FIRST. ROUGH OR VERY ROUGH, OCCASIONALLY HIGH AT FIRST. RAIN
OR SQUALLY SHOWERS. MODERATE, OCCASIONALLY POOR.

From phk at phk.freebsd.dk  Mon Nov 10 07:27:40 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Mon, 10 Nov 2008 12:27:40 +0000
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: Your message of "Mon, 10 Nov 2008 12:11:53 GMT."
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk> 
Message-ID: <19081.1226320060@critter.freebsd.dk>

In message <alpine.LSU.2.00.0811101155370.30582 at hermes-1.csi.cam.ac.uk>, Tony F
inch writes:

>My point is that user requirements change. The relation between natural
>phenomena and our consensus idea of time depends on how accurately and
>quickly we can measure those phenomena, and which phenomena we care about
>tracking.

Couldn't the opposite argument be made:  The majority of users don't care
a hoot about time (ref: flashing 12:00 everywhere) and therefore the
scientists and engineers who have to care, are free to implement
any working solution ?

After all, with the cavalier attitude politicians have to time, (ref
timezone changes with short notice, century old laws etc), I can't
see any good coming out of involving them.

In other words: WP7A may not be the best place, but it is probably
as good as any.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From seaman at noao.edu  Mon Nov 10 09:01:14 2008
From: seaman at noao.edu (Rob Seaman)
Date: Mon, 10 Nov 2008 07:01:14 -0700
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: <19081.1226320060@critter.freebsd.dk>
References: <19081.1226320060@critter.freebsd.dk>
Message-ID: <B397E9A9-E609-497A-A467-3D4143F59E28@noao.edu>

This is an excellent example of how focusing on the requirements  
(rather than notional solutions) helps to clarify the discussion.  For  
one thing, the issue becomes one of describing the problem before  
trying to figure out what to do about.  For another, the discussion is  
abstracted from entrenched positions.  For a third, we start to reveal  
underlying points of agreement (eg., disdain for politicized issues),  
not just differences.  And for a fourth, the process finds a natural  
pace.  If there are important scheduling drivers, what are they?  In  
short, what is the hurry?

Regarding the specific points here:

1) Yes, indeed!  Requirements change.  This is all the more reason to  
focus on characterizing them now, and as they evolve.  How else to  
figure out what's going on?

2) Describing the process is separate (although entangled) from  
describing the problem.  I could wish some other process were being  
followed, most obviously that whatever standards body this drama is  
played out in, the deliberations should be open.

3) Virtually all system engineering is for the benefit of users who  
are non-experts.  This does not distinguish timekeeping in any special  
way.  What users want and what they need are often very different.   
They may not care (or think they care - or even be aware) about time,  
but that doesn't mean timekeeping doesn't enter the user requirements  
in numerous ways.

4) A large project will have a long list of requirements.  Timekeeping  
is deceptively simple.  Stepping aside from solar time for a moment,  
just think of the very complex system of systems that generates and  
delivers interval time, whether "atomic" or GPS.  Ensembles of very  
complex clocks.  Multiple interlocking strata of NTP servers.  Host OS  
support.  (Bad solutions are likely to be even more complex than good  
ones :-)  Etc and so forth.

5) Elected government officials are already involved.  They changed  
DST last year (and not just in the U.S.)  The ITU is an assemblage of  
government representatives, only by happenstance are they scientists.

6) To focus on the requirement at hand for a moment:  Pete Bunclark's  
comment about "a single monotonic calendar" points out that we already  
have this situation.  A mean solar clock is a subdivision of the  
calendar.  Modifying UTC to eliminate leap seconds would violate this  
requirement.  It is better to state and debate - and yes, perhaps  
reject - the requirement, than it is to leave the requirement hidden  
and violate it for some imagined short term political expediency.

6a) Why?  Because if the requirements aren't stated, then engineers  
and decision-makers creating contingent systems (and there are many,  
many systems contingent on timekeeping) can draw diverse - and  
diversely wrong - conclusions about the behavior of time.  This is  
precisely the situation decried now with leap seconds.

6b) It is not sufficient to describe a solution.  If the problem that  
a system or standard is intended to solve is left poorly described,  
stakeholders won't comprehend the context to apply it appropriately  
across all (or perhaps any) situations.  Again - see leap seconds.  A  
hasty elimination of leap seconds will leave them as the proverbial  
dog that didn't bark - not present, but not absent either.

7) Requirements are not demands from stakeholders (although  
stakeholders make lots of - often incoherent - demands :-)  Rather,  
proper requirements form a coherent and self-consistent set of  
descriptors of the problem and project at hand.  Think of them as an  
orthogonal set of basis vectors in a multidimensional parameter space  
that captures the essence of the problem and supplies constraints on  
the acceptable solutions.

Rob Seaman
NOAO
---

Poul-Henning Kamp wrote:

> Tony Finch writes:
>
>> My point is that user requirements change. The relation between  
>> natural
>> phenomena and our consensus idea of time depends on how accurately  
>> and
>> quickly we can measure those phenomena, and which phenomena we care  
>> about
>> tracking.
>
> Couldn't the opposite argument be made:  The majority of users don't  
> care
> a hoot about time (ref: flashing 12:00 everywhere) and therefore the
> scientists and engineers who have to care, are free to implement
> any working solution ?
>
> After all, with the cavalier attitude politicians have to time, (ref
> timezone changes with short notice, century old laws etc), I can't
> see any good coming out of involving them.
>
> In other words: WP7A may not be the best place, but it is probably
> as good as any.

From psb at ast.cam.ac.uk  Mon Nov 10 09:02:24 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Mon, 10 Nov 2008 14:02:24 +0000 (GMT)
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: <alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
Message-ID: <Pine.GSO.4.58.0811101216410.27695@cass03>

I deliberately chose words that didn't refer to being right here in the
early 21st century;

On Mon, 10 Nov 2008, Tony Finch wrote:

> On Sun, 9 Nov 2008, Peter Bunclark wrote:
> >
> > So a User requirement might be:
> > The rythms of life, including the orbits of the earth and the moon,
> > the rotation of the earth, and convenient sub-divisions of the rotation
> > down to nearly the limit of human perception, shall be expressed in
> > a single monotonic calendar.
>
> I guess you mean the limits of human perception as assisted by suitable
> tools...

No. Tools evolve a lot more quickly than we do.  I had around 1s in mind.
My radio-synchronised wristwatch seems to me to be perfectly accurate; but
really only has to achieve sub-second for that. TV frame rate is beyond my
perception, by design (just about).

>
> Most common calendars have given up trying to track both the moon and
> the sun. Most of them prefer to track the sun; the Muslims track the moon;
> and the Jews track both and the result is impressively complex.

We have months, which are lunar-ish.

>
> Your specification doesn't capture how to measure the rotation of the
> Earth. We used to use apparent solar time, then we switched to local
> mean solar time, then we switched to standard time, then we added
> arbitrary unpredictable seasonal offsets.

That's because it's not a specification, it's a requirement. It should not
pre-empt a solution.  What you might be on to, is that "earth rotation"
should actually be "daily solar cycle". See how hard it is; even in a
quick attempt I let my astronomical knowledge get in the way. The Sun
comes up in the morning, doesn't it, the world doesn't sink; duh!

>
> My point is that user requirements change. The relation between natural
> phenomena and our consensus idea of time depends on how accurately and
> quickly we can measure those phenomena, and which phenomena we care about
> tracking.
>
Again, I tried to be as timeless as possible.

Note, this is "*A* user requirement" not "the ..."; another might be:

2. For the purposes of temporal metrology, clocks must be built to the
best accuracy of the technology of the period.  Clock keepers must combine
output to ensure a single consensus of current synchronous time.
This coordinated time must be available as widely, efficiently and freely
as possible to all users.

well I'm on a roll now:

3. The relationship between the Calendar(1) and Synchronous Time(2) must
be deterministic, such that an instant represented in one system may be
uniquely identified in the other.

and now to the rub:

4. The fundamental unit of both systems shall be the SI second.

Hm we need a snappy title...
"Requirements for improving the accuracy of Civil Time while
 reconciling the Calendar with Precision Timekeeping". Ug...

When the requirements are agreed, tenders are in and you've won the
contract to produce a preliminary design, section headings in the
Preliminary Design Document might include

Measurement of the rotation of the Earth

Propogation of Atomic Time across the Internet

Algorithm for conversion of Atomic Time to Calendar Time.

Pete.

From psb at ast.cam.ac.uk  Mon Nov 10 09:18:35 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Mon, 10 Nov 2008 14:18:35 +0000 (GMT)
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: <19081.1226320060@critter.freebsd.dk>
References: <19081.1226320060@critter.freebsd.dk>
Message-ID: <Pine.GSO.4.58.0811101411590.27878@cass03>



On Mon, 10 Nov 2008, Poul-Henning Kamp wrote:

> In message <alpine.LSU.2.00.0811101155370.30582 at hermes-1.csi.cam.ac.uk>, Tony F
> inch writes:
>
> >My point is that user requirements change. The relation between natural
> >phenomena and our consensus idea of time depends on how accurately and
> >quickly we can measure those phenomena, and which phenomena we care about
> >tracking.
>
> Couldn't the opposite argument be made:  The majority of users don't care
> a hoot about time (ref: flashing 12:00 everywhere) and therefore the

Don't be ridiculous, everybody cares about missing a bus or a favourite TV
show.

> scientists and engineers who have to care, are free to implement
> any working solution ?

Again, you've got a solution but no clearly stated problem.

>
> After all, with the cavalier attitude politicians have to time, (ref
> timezone changes with short notice, century old laws etc), I can't
> see any good coming out of involving them.

We're all involved. The gulf between narrow-minded politicians and
tunnel-visioned computer programmers must be bridged as part of the
process.

>
> In other words: WP7A may not be the best place, but it is probably
> as good as any.

Not until it is fully open and inclusive.

Pete.

From dot at dotat.at  Mon Nov 10 11:13:25 2008
From: dot at dotat.at (Tony Finch)
Date: Mon, 10 Nov 2008 16:13:25 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <Pine.GSO.4.58.0811101216410.27695@cass03>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
Message-ID: <alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>

On Mon, 10 Nov 2008, Peter Bunclark wrote:
> On Mon, 10 Nov 2008, Tony Finch wrote:
> >
> > On Sun, 9 Nov 2008, Peter Bunclark wrote:
> > >
> > > So a User requirement might be:
> > > The rythms of life, including the orbits of the earth and the moon,
> > > the rotation of the earth, and convenient sub-divisions of the rotation
> > > down to nearly the limit of human perception, shall be expressed in
> > > a single monotonic calendar.
> >
> > I guess you mean the limits of human perception as assisted by suitable
> > tools...
>
> No. Tools evolve a lot more quickly than we do.  I had around 1s in mind.

But unassisted human perception can't tell the time of day to 1s accuracy.

Perhaps I misunderstood you and you meant this to be a requirement on the
resolution of time measurements, and not (as I understood) some statement
about using the best available technology used to make those measurements.
If so that doesn't get us any further than the state of the art 100-200
years ago.

> We have months, which are lunar-ish.

They don't express the orbit of the moon, so they don't satisfy your
requirement.

> Again, I tried to be as timeless as possible.

You have to be careful that timeless requirements (haha) are not going to
be undermined by changes in technology. For example, there's no problem
dividing a day into 86400 equal seconds if you can't measure time
accurately enough to detect variations in the length of a day. If you need
the kind of accuracy you get from atomic time, you cannot satisfy the
requirement for equal subdivisions of a day.

While we are taking a historical view of calendars, it's probably worth
observing how past problems similar to the current situation have been
resolved. UTC is an observational calendar, and over history these have
almost always been replaced with arithmetic calendars: this eliminates
problems of communication from the observers who determine the calendar to
its users, gives users more independence and allows them to make more
accurate plans for the future, at the cost of a smallish error that makes
future dates drift away from the events they were previously attached to.
Calendars get reformed if they are not sufficiently predictable. This is
happening now to UTC, which seems to be the result of a timeless human
factors requirement in action.

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.)

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FAIR ISLE: SOUTHEASTERLY 6 TO GALE 8, OCCASIONALLY SEVERE GALE 9 AT FIRST,
BACKING EASTERLY 5 OR 6 LATER. ROUGH OR VERY ROUGH. SQUALLY SHOWERS. MODERATE
OR GOOD, OCCASIONALLY POOR.

From adi at stav.org.il  Mon Nov 10 17:07:46 2008
From: adi at stav.org.il (Adi Stav)
Date: Tue, 11 Nov 2008 00:07:46 +0200
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
Message-ID: <20081110220746.GB5965@stav.org.il>

On Mon, Nov 10, 2008 at 04:13:25PM +0000, 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?

From seaman at noao.edu  Tue Nov 11 00:23:36 2008
From: seaman at noao.edu (Rob Seaman)
Date: Mon, 10 Nov 2008 22:23:36 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
Message-ID: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>

Tony Finch wrote:

> there's no problem dividing a day into 86400 equal seconds if you  
> can't measure time accurately enough to detect variations in the  
> length of a day.

A single day, no.  An unending sequence of days?  Yes, there is a  
problem - the problem we have.  In addition to Pete's stated  
requirement, or perhaps a corollary, is some sort of requirement on  
the secular rate between the solar timescale and the interval timescale.

> If you need the kind of accuracy you get from atomic time, you  
> cannot satisfy the requirement for equal subdivisions of a day.

Right.  Which is why we're going to continue to find it impossible to  
discover a complete and self-consistent set of requirements that  
pretends there is a single timescale, not two different timescales.

> While we are taking a historical view of calendars, it's probably  
> worth
> observing how past problems similar to the current situation have been
> resolved. UTC is an observational calendar, and over history these  
> have
> almost always been replaced with arithmetic calendars: this eliminates
> problems of communication from the observers who determine the  
> calendar to
> its users, gives users more independence and allows them to make more
> accurate plans for the future, at the cost of a smallish error that  
> makes
> future dates drift away from the events they were previously  
> attached to.

Words like "smallish" are to be avoided when writing requirements.   
Fundamentally your assertion is still that nobody but astronomers will  
notice, right?  So how might this be characterized in specific terms?   
That will give us something to grapple with.

I like your observational/arithmetic formalism - although I might draw  
different conclusions.  The thing about calendars is that the  
observational aspect is quantized - today is today, tomorrow is  
tomorrow.  Underneath the sexagesimal notation (even variable radix),  
a clock is an unending count of tick, tick, ticks.  (To oversimplify,  
days are integers, seconds are reals.)  It is precisely the chunking  
into those inconvenient things called "days" (the mean solar part of  
the situation) that creates our dilemma.

> Calendars get reformed if they are not sufficiently predictable.  
> This is
> happening now to UTC, which seems to be the result of a timeless human
> factors requirement in action.

I'm skeptical, but that's ok.  The way to conquer skepticism in system  
engineering is to refine such points of friction into clear  
requirements, functional or non-functional ("thou shalt" sort of  
statements).  What is this human factors requirement?

Adi Stav wrote:

> On Mon, Nov 10, 2008 at 04:13:25PM +0000, 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?


Well, that is the UTC that we have.  Two timescales, earth orientation  
and interval.  Compromise a little on the SI part and a little on the  
solar day part to jigger these two things into a single standard.

I'd be complaining just as loudly if the relentless suggestion over  
the past nine years had been to ratchet the balance the other way and  
completely jettison SI.  (Lest folks think I'm a one note kind of  
guy :-)

However, this is short-circuiting the process to jump to speculating  
on solutions before we've finished describing the problem.  At some  
point we'll have a candidate set of requirements - this doesn't have  
to be finalized, just somewhat complete.  At that point, a trade-off  
study between various solutions - really between classes of solutions  
- can be compiled.  Write down a list of various figures of merit,  
score them for each solution, weight and combine the scores (really  
the scoring functions).  Look at the holy trinity of cost, performance  
and schedule that can be achieved for each option.  Iterate, since the  
first few trade-offs will inevitably reveal additional requirements  
(and perhaps suggest new kinds of solution).  Throw in a sensitivity  
analysis, perhaps.  Look at the risks.  And continue the basic idea of  
arguing about the methodology, not entrenched positions.

Note one strong advantage to such a process.  It enables the  
stakeholders to ignore the various proposed solutions (ie., those  
entrenched positions), while gathering support for the eventual winner  
in an unbiased fashion in the mean time.

Rob Seaman
National Optical Astronomy Observatory

From phk at phk.freebsd.dk  Tue Nov 11 03:59:38 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 11 Nov 2008 08:59:38 +0000
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: Your message of "Mon, 10 Nov 2008 14:18:35 GMT."
	<Pine.GSO.4.58.0811101411590.27878@cass03> 
Message-ID: <74480.1226393978@critter.freebsd.dk>

In message <Pine.GSO.4.58.0811101411590.27878 at cass03>, Peter Bunclark writes:

>> Couldn't the opposite argument be made:  The majority of users don't care
>> a hoot about time (ref: flashing 12:00 everywhere) and therefore the
>
>Don't be ridiculous, everybody cares about missing a bus or a favourite TV
>show.

You are not thinking clearly here.

People do care about agreeing with the busdriver and the TV station,
about what time it is.


They do not care about the absolute numerical state of time relative
to earth rotation as long as it is within a couple of hours.


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From psb at ast.cam.ac.uk  Tue Nov 11 04:14:20 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Tue, 11 Nov 2008 09:14:20 +0000 (GMT)
Subject: [LEAPSECS] The relation between Easter and leap econds.
In-Reply-To: <74480.1226393978@critter.freebsd.dk>
References: <74480.1226393978@critter.freebsd.dk>
Message-ID: <Pine.GSO.4.58.0811110912010.1290@cass03>



On Tue, 11 Nov 2008, Poul-Henning Kamp wrote:

> In message <Pine.GSO.4.58.0811101411590.27878 at cass03>, Peter Bunclark writes:
>
> >> Couldn't the opposite argument be made:  The majority of users don't care
> >> a hoot about time (ref: flashing 12:00 everywhere) and therefore the
> >
> >Don't be ridiculous, everybody cares about missing a bus or a favourite TV
> >show.
>
> You are not thinking clearly here.

I thought quite clearly about what you actually wrote.

>
> People do care about agreeing with the busdriver and the TV station,
> about what time it is.
>
>
> They do not care about the absolute numerical state of time relative
> to earth rotation as long as it is within a couple of hours.

This is a different statement to your original one.

Pete.

From phk at phk.freebsd.dk  Tue Nov 11 04:17:21 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 11 Nov 2008 09:17:21 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Mon, 10 Nov 2008 22:23:36 MST."
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu> 
Message-ID: <74553.1226395041@critter.freebsd.dk>



There is one requirement you do not seem to even think about, much less
mention:

	The limited human intelligence.

As we saw a couple of years ago, the 400 year leap-year role is slightly
above the level of complexity humans can deal with, a significant
fraction of "people who should have known" didn't.

Daylight savings time is borderline, but thanks to the implementation
between two non-workdays, fallout is mostly contained to social
embarrasment.

Another smart feature of DST is the fact that UTC is unaffected so
intelligently designed software only see DST as a representational
problem and not a problem of timekeeping.

Leap seconds fail the IQ compatibility test on so many levels that
it is unnecessary to reiterate them here.

So further requirements for The New Time Order are:

	Ia) Without steps.
or
	Ib) Have steps that are sufficient large to be noticed, and
	   they must fall at times where the fall-out from mistakes
	   is reduced.

and
	II) Not require human intervention for automatic systems to
	    perform timekeeping on the fundamental timescale.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From dot at dotat.at  Tue Nov 11 07:05:18 2008
From: dot at dotat.at (Tony Finch)
Date: Tue, 11 Nov 2008 12:05:18 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <74553.1226395041@critter.freebsd.dk>
References: <74553.1226395041@critter.freebsd.dk>
Message-ID: <alpine.LSU.2.00.0811111200170.23184@hermes-1.csi.cam.ac.uk>

On Tue, 11 Nov 2008, Poul-Henning Kamp wrote:
>
> There is one requirement you do not seem to even think about, much less
> mention:
>
> 	The limited human intelligence.
>
> As we saw a couple of years ago, the 400 year leap-year role is slightly
> above the level of complexity humans can deal with, a significant
> fraction of "people who should have known" didn't.

I did think of that, but we've just been discussing some much more complex
examples of arithmetic calendars. I couldn't argue that there had been a
historical trend towards simplicity as well as predictability. But I agree
that simplicity is an important requirement.

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FISHER: SOUTHWEST BECOMING CYCLONIC THEN NORTHWEST 5 TO 7, DECREASING 4 FOR A
TIME. MODERATE OR ROUGH. SQUALLY SHOWERS. MODERATE OR GOOD.

From dot at dotat.at  Tue Nov 11 08:08:44 2008
From: dot at dotat.at (Tony Finch)
Date: Tue, 11 Nov 2008 13:08:44 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
Message-ID: <alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>

On Mon, 10 Nov 2008, Rob Seaman wrote:
> Tony Finch wrote:
>
> > While we are taking a historical view of calendars, it's probably worth
> > observing how past problems similar to the current situation have been
> > resolved. UTC is an observational calendar, and over history these have
> > almost always been replaced with arithmetic calendars: this eliminates
> > problems of communication from the observers who determine the calendar to
> > its users, gives users more independence and allows them to make more
> > accurate plans for the future, at the cost of a smallish error that makes
> > future dates drift away from the events they were previously attached to.
>
> Words like "smallish" are to be avoided when writing requirements.
> Fundamentally your assertion is still that nobody but astronomers will
> notice, right?  So how might this be characterized in specific terms?
> That will give us something to grapple with.

I deliberately chose a vague word there because the size of the error is
an important point of discussion. It's another area where requirements
change over time. 365.25 days in a year was good enough for Julius Caesar,
but not for Pope Gregory.

For civil time we have some weird double-think going on, with subsecond
precision for universal time, but hours of error for most locations'
civil time. Clearly the "smallish" error (of civil time vs. local mean
or apparent solar time) for civil purposes can be comparatively large,
but for navigation and astronomy it must be as small as possible.

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 like your observational/arithmetic formalism -

Not mine! I got it from a post to this list by Zefram on 1st June 2006.

> - although I might draw different conclusions.  The thing about
> calendars is that the observational aspect is quantized - today is
> today, tomorrow is tomorrow.

Yes, but it is only precise when averaged over long periods of time, that
is, you can count days this way but not minutes. This problem also applies
to other observations such as the new moon or the spring equinox. The lack
of precision (and, for many observational calendars, variability depending
on location) leads to unpredictability: you can count months or years
accurately but your day numbering may be off. Hence we used mean time in
preference to apparent time, and we use arithmetic calendars in preference
to observational ones.

> What is this human factors requirement?

Predictability.

> Adi Stav wrote:
> >
> > Have there been suggestions, indeed, for such a predictable SI-second-
> > based calendar that synchronizes with the Earth's rotation?
>
> Well, that is the UTC that we have.

No, it isn't predictable.

Tony.


PS.

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. At a given
moment, therefore, the time is different in different places. The hour at
which a court is fixed to sit means prima facie the hour at the locality
where the particular court is to sit, and not Greenwich mean time [2].

[1] See para 216 post.

[2] Curtis v March (1858) 3 H & N 866, where failure to appear in court
in Dorchester, when the judge took his seat at 10 a.m. (according to
Greenwich mean time) constituted no default, since according to the local
time it was some minutes short of 10 a.m. This situation could not arise
today, since Greenwich mean time is now applied by statute: see para 216
post.

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]. Regard must be had to this rule in applying the
numerous statutes [3] in which certain hours of the day are specified
within which acts may or may not be done. It is apprehended that
Greenwich, and not local, time must be considered in fixing the hour or
day of an event with regard to which provision is made in an instrument
such as a policy of insurance, and that on the other hand the statutory
rule should not be applied in a case where the instrument was executed or
the event was expected to happen or did happen in a foreign country [4].

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].

[1] Ie subject to the Summer Time Act 1972 s 3: see para 217 post.

[2] See the Interpretation Act 1978 ss 9, 23(3), Sch 2 paras 1, 6; and
evidence vol 17(1) (Reissue) para 569; but see also R v Logan [1957] 2 QB
589, [1957] 2 All ER 688, C-MAC, where it was held that a statute said to
commence on 1 January came into force on the day which was 1 January in
the particular place where the Act had to be applied.

[3] Eg the Marriage Act 1949 s 4 (hours for solemnisation of marriages:
see matrimonial law vol 29(3) (Reissue) para 85); the Licensing Act 1964 s
59 (as amended), s 60 (as amended) (sale and consumption of liquor except
during permitted hours: see intoxicating liquor vol 26 (2004 Reissue)
paras 289 et seq).

[4] See R v Logan [1957] 2 QB 589, [1957] 2 All ER 688, C-MAC.

[5] See para 213 ante. [which says a day is midnight-to-midnight, or any
period of 24h, or sunrise-to-sunset, depending on context]

[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.

217. Summer time.

[gives the start and end of the period of summer time]

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].

Wherever any reference to a point of time occurs in any enactment, Order
in Council, order, regulation, rule, byelaw, deed, notice or other
document whatsoever, the time referred to is, during the period of summer
time, deemed, with certain exceptions, to be the time fixed for general
purposes under the Summer Time Act 1972 [4].

[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).

[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.

[3] See ibid ss 1(1), 2(1)(b). As to Greenwich mean time see para 216 ante.

[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.
For the purposes of the Police and Criminal Evidence Act 1984 s 69, errors
in the time or date of such print-outs caused by the Intoximeter device
recording Greenwich mean time during British summer time which do not
affect any material aspect of the document produced do not render the
document inadmissible as evidence: DPP v McKeown [1997] 1 All ER 737,
[1997] 1 WLR 295; DPP v Horswill (2 July 1997, unreported). Nothing in the
Summer Time Act 1972 affects the use of Greenwich mean time for the
purposes of astronomy, meteorology or navigation, or affects the
construction of any document mentioning or referring to a point of time in
connection with any of those purposes: s 3(2).

["by Order in Council" is the way the British Government issues
regulations under the authority of an existing statute. Statutes
are enacted by Parliament, but Orders in Council are not.]


-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FAIR ISLE FAEROES: NORTHEASTERLY BACKING NORTHWESTERLY 5 TO 7, OCCASIONALLY
GALE 8 AT FIRST, DECREASING 4 IN FAEROES LATER. ROUGH OR VERY ROUGH DECREASING
MODERATE OR ROUGH. RAIN OR SQUALLY SHOWERS. MODERATE OR GOOD.

From phk at phk.freebsd.dk  Tue Nov 11 08:14:10 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 11 Nov 2008 13:14:10 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 12:05:18 GMT."
	<alpine.LSU.2.00.0811111200170.23184@hermes-1.csi.cam.ac.uk> 
Message-ID: <89735.1226409250@critter.freebsd.dk>

In message <alpine.LSU.2.00.0811111200170.23184 at hermes-1.csi.cam.ac.uk>, Tony F
inch writes:

>> As we saw a couple of years ago, the 400 year leap-year role is slightly
>> above the level of complexity humans can deal with, a significant
>> fraction of "people who should have known" didn't.
>
>I did think of that, but we've just been discussing some much more complex
>examples of arithmetic calendars. I couldn't argue that there had been a
>historical trend towards simplicity as well as predictability. But I agree
>that simplicity is an important requirement.

I think we have to qualify predictability here, and it ties into
simplicity somewhat.

If we have "permanent predictability", as for leap years, then utter
simplicity is less important, because the rules, semicomplex or
not, can be encoded once and for all, and it is perfectly fair to
ridicule anybody who gets it wrong, having had a generation or
more of notice.

If we only have "temporaray predictability", ie: we predict the
outcome for some particular timehorizon, as currently with leap
seconds, or with the Ramadan depending on who spots the moon first,
then simplicty comes very much to the foreground.

If nothing else because a public awareness campaign must be carried
out, and you really don't want to newspaper adds to say things like
"Adjust your timekeeping according these trignometric formul?".

The fact that a large fraction of people, at least in countries
where the "spring forward, fall back" mnemonic sentence does not
translate, have trouble figuring out which way to adjust their
clocks on DST changes, should be a stern reminder that the general
population, and by inference, a lot of computer programmers, are
horribly incompetent when it comes to timekeeping.

Another issue is that exception rules should not trigger so seldom
that people forget about them.

Again the 400 year rule is exhibit number 1, and exhibit number two
could be how Sweden failed to follow their own established rules,
trying to recover from the old to the new calendar.

And exhibit number three could be the Indonesia Tsunami.

Most people have, at one point or another in their life, been told
that the correct response, if the water suddenly disappears from the
beach, is to run like hell inland.  But since most people never
experience this in real life, they don't when they should.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From sla at ucolick.org  Tue Nov 11 13:00:03 2008
From: sla at ucolick.org (Steve Allen)
Date: Tue, 11 Nov 2008 10:00:03 -0800
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <74553.1226395041@critter.freebsd.dk>
References: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<74553.1226395041@critter.freebsd.dk>
Message-ID: <20081111180003.GA26971@ucolick.org>

On Tue 2008-11-11T09:17:21 +0000, Poul-Henning Kamp hath writ:
>       The limited human intelligence.

I agree with the point, but I might qualify it better, as with the
tsunami response, to say: limited cognition of any given set of
individuals at any given point in their development, not an inherent
limit so much as one based on practical experience and teaching
and research.

But getting back to civil time that sort of limit produces these
two very disparate interpretations of what Hugo Chavez did in
Venezuela last year:

Venezuela's new time is officially with respect to the
Greenwich meridian
http://www.tsj.gov.ve/gaceta/noviembre/271107/271107-38819-01.html
and other documents make it explicit that the legal time is kept
by their naval observatory and that it is mean solar time.

The US DoS got the wording translated correctly
http://www.tsj.gov.ve/gaceta/noviembre/271107/271107-38819-01.html

But Denmark performed an interesting substitution
http://www.gkcaracas.um.dk/da/menu/Eksportraadgivning/Markedsmuligheder/Landeinformation/Time/

Whereas I'll admit this is likely one aspect of limited human
cognition -- the failure to recognize a significant difference
between UTC and GMT, with effort it could be interpreted to
say that Denmark expects that UTC and GMT will remain
indistinguishable.

Here's an interesting point.  Nobody misinterprets GPS time.
Nobody tries to extrapolate it backwards and make algorithms
about proleptic GPS time.  That's because GPS time simply
did not exist prior to 1980-01-06.  Nobody can screw it up
because GPS time is exactly and only what the US military
wants it to be.

But there are lots of examples of systems which try to assign meaning
to proleptic UTC, proleptic POSIX time, MS Windows time, .NET time, etc.
Proleptic interpretation of UTC is horribly broken with lots of
disagreeing algorithms even only for the late 20th century.

One of the best ways to limit the kinds of mistakes that limited
human cognition makes is to put the toys out of their reach.

I still assert that the safest means of going forward is for ITU-R to
wash their hands of UTC and say

    We don't care what you do with UTC, and we can't get the rest of
    the world to agree on whether or not UTC should change.  But we
    are sure that the machines of the world need a broadcast and
    internet time scale which increments predictably.  We're going to
    follow the advice of the Torino conference and call it Temps
    International (TI), and it will start being brodacast around 2022.
    If somebody wants to keep on maintaining UTC that's fine, but not
    us.

That is the sort of thing that is within the purview of the princes of
ITU-R.  Other princes will certainly keep on decreeing changes to the
civil time of various jurisdictions, and zoneinfo will handle that.
And if some other princes at BIPM and IERS want to maintain UTC with
leap seconds then they can do that, and zoneinfo can handle them too.
I hope BIPM and IERS will do that.

And if that happens then POSIX can make a very clear statment about
the interpretation of time_t.  They can just admit that the
interpretation before the UTC/TI cutover is a bit fuzzy, but point out
that the interpretation after the UTC/TI cutover is clearly defined.

One of the requirements of this process is to distinguish between
things that are not necessarily the same, between different things
that are only the same because of a convention created by ancestors
who had their own limited cognition.

Nothing requires that the broadcast/internet time scale be called UTC.
They are different things.  This was pointed out 5 years ago in Torino.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From phk at phk.freebsd.dk  Tue Nov 11 13:53:14 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 11 Nov 2008 18:53:14 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 10:00:03 PST."
	<20081111180003.GA26971@ucolick.org> 
Message-ID: <43950.1226429594@critter.freebsd.dk>

In message <20081111180003.GA26971 at ucolick.org>, Steve Allen writes:

>But Denmark performed an interesting substitution
>http://www.gkcaracas.um.dk/da/menu/Eksportraadgivning/Markedsmuligheder/Landeinformation/Time/
>
>Whereas I'll admit this is likely one aspect of limited human
>cognition -- the failure to recognize a significant difference
>between UTC and GMT, with effort it could be interpreted to
>say that Denmark expects that UTC and GMT will remain
>indistinguishable.

We're talking about the country where legal time is mean solar time
of 15E, but DST is defined relative to GMT, what level of correctness
do you expect the state department give a south-american countrys
press-announcements about something as booring as time ?

>But there are lots of examples of systems which try to assign meaning
>to proleptic UTC, proleptic POSIX time, MS Windows time, .NET time, etc.
>Proleptic interpretation of UTC is horribly broken with lots of
>disagreeing algorithms even only for the late 20th century.
>
>One of the best ways to limit the kinds of mistakes that limited
>human cognition makes is to put the toys out of their reach.

I don't think you can avoid this on any civil timescale, the average
journalist cannot resist calculating "that Alexander The Great
died on a Thursday" if they are out of intelligent reporting to do.

>I still assert that the safest means of going forward is for ITU-R to
>wash their hands of UTC and say
>
>    We don't care what you do with UTC, and we can't get the rest of
>    the world to agree on whether or not UTC should change.[...]

This doesn't solve any problems for anybody.

Since computers (mostly, se Denmark above) run on legal time, and
legal time is linked to UTC, then it certainly does not solve the
issue of computers not coping with leap seconds.

It adds a timescale, but we have plenty of those already, only
I can't see anybody using this one for anything

And that is the crux of the matter:  The millions of computers in
the world are stuck with UTC, until such time as all the governments
enact laws that says otherwise.

Any relief from the leap second madness therefor has to happen
on the UTC timescale to have any effect.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From seaman at noao.edu  Tue Nov 11 16:28:06 2008
From: seaman at noao.edu (Rob Seaman)
Date: Tue, 11 Nov 2008 14:28:06 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081111180003.GA26971@ucolick.org>
References: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<74553.1226395041@critter.freebsd.dk>
	<20081111180003.GA26971@ucolick.org>
Message-ID: <FEAB8686-08F1-48B2-A436-F892C3F29075@noao.edu>

Poul-Henning Kamp hath writ:

> The limited human intelligence.

I think the word you are looking for is innocence or naivete or  
perhaps simple ignorance, not "limited intelligence".  The technical  
laity manage to navigate quite complex aspects of society, presuming  
the details haven't been obscured from their view.

> It adds a timescale, but we have plenty of those already, only I  
> can't see anybody using this one for anything
>
> And that is the crux of the matter:  The millions of computers in  
> the world are stuck with UTC, until such time as all the governments  
> enact laws that says otherwise.
>
> Any relief from the leap second madness therefor has to happen on  
> the UTC timescale to have any effect.

If there is a lack of imagination here, it is on the part of the  
scientists and engineers.  A dearth of imagination to understand the  
full breadth of the problem of civil timekeeping, and a dearth in  
understanding the range of possible solutions.

Rob Seaman
NOAO


From phk at phk.freebsd.dk  Tue Nov 11 17:03:44 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 11 Nov 2008 22:03:44 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 14:28:06 MST."
	<FEAB8686-08F1-48B2-A436-F892C3F29075@noao.edu> 
Message-ID: <85936.1226441024@critter.freebsd.dk>

In message <FEAB8686-08F1-48B2-A436-F892C3F29075 at noao.edu>, Rob Seaman writes:
>Poul-Henning Kamp hath writ:
>
>> The limited human intelligence.
>
>I think the word you are looking for is innocence or naivete or  
>perhaps simple ignorance, not "limited intelligence".

No, actually the word I am looking for is intelligence, and I think
central to both the problem and the solution.

There are only so much nitty-gritty detail a brain can retain and
recall at relevant moments, and the scientific consensus is that
it correlates very strongly with the general "g", as long as you
control for cases of Asbergers, Autism etc.

Most people are in overflow mode when it comes to details, constantly
loosing non-memorable bits of history, which way you set the clock
on DST and your wifes birthday.  This is why people use personal
organizers, FiloFax'es, etc.

It has never been expressed better than by Ed J. Djikstra in
his classic "Programming considered as a human activity":

http://www.cs.utexas.edu/users/EWD/transcriptions/EWD01xx/EWD117.html

	"My own feelings are perhaps best described by saying that
	I am perfectly aware that there is no Royal Road to
	Mathematics, in other words, that I have only a very small
	head and must live with it."

People who make it to our level of professional achievement, is way
above average in this particular respect.

Most of us can quote pointless details and minutae of rules, each
in our subject domain, until the birds drop roasted from the sky.
Quite a large fraction of us being helped by a tendency towards
Asbergers.

But that does not give us a mandate to make the world the rest of
the population lives in, so complex that they cannot cope with it.

Quite the contrary: the burden is on us to make life simple for
the simple, and save the complexity for those who can deal with it.

(Shakespeares observation on lawyers is in no little part
driven by this observation)

In that respect, both the pre-leap rubberseconds and the leap
seconds were very sensible ways to deal with the issue at hand
back in those days:  The number of people who had to care about
those adjustments where very very few, you could expect them
all to get the memo, and they all had "Phd" after their names.

And that is also why I think the proposal to just stop putting
leap-seconds in UTC is so eminently sensible:

It moves the problem back to people with "Phd" after their names,
primarily astronomers and the engineers who run the telescopes
and satellite antenn?.

The "leap-hour" solution, as ugly as it is, has repeatedly been
proven a perfectly adequate way to address the issue of earth
orientation relative to civil time, mostly by politicians who muck
about with timezones for no good reason, but entirely fail to make
their jurisdictions descend into (further) uncivilized chaos as a
result.

>If there is a lack of imagination here, it is on the part of the  
>scientists and engineers.  A dearth of imagination to understand the  
>full breadth of the problem of civil timekeeping, and a dearth in  
>understanding the range of possible solutions.

If there is a lack of realism anywhere, it is on the part of the
astronomers, who think that you can hold a highbrow meeting or two,
and demote a planet (which everybody loves because of the Mickey
Mouse connection) to "some random celestial rock status" and believe
that changing IT systems and the national laws of all nations is
equally effortless.

I don't care how many new timescales you want to invent for people
with Phd after their names, the only timescale that matters to
99.9999...% of this planets population is UTC, and that is the one
we have to find a workable solution for leapseconds in.

The solution can take three forms:

   1. No leap seconds.
	Solves the civil issue, but is an embuggerance for the Phds.

   2. Regular leapseconds.
	Helps nobody.

   3. Much longer warning about leap seconds.
	Might be workable for both parties.

Pick your poison.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From mike-leapsecs at pedantic.org  Tue Nov 11 18:02:11 2008
From: mike-leapsecs at pedantic.org (Michael Thorpe)
Date: Tue, 11 Nov 2008 15:02:11 -0800
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <85936.1226441024@critter.freebsd.dk>
References: <FEAB8686-08F1-48B2-A436-F892C3F29075@noao.edu>
	<85936.1226441024@critter.freebsd.dk>
Message-ID: <20081111230211.GJ5886@pedantic.org>

On 2008-11-11 22:03:44, Poul-Henning Kamp wrote:
>I don't care how many new timescales you want to invent for people
>with Phd after their names, the only timescale that matters to
>99.9999...% of this planets population is UTC, and that is the one
>we have to find a workable solution for leapseconds in.

I must respectfully disagree.  The timescale used by 99.9999% of this
planet's population is, for lack of a better term, most akin to "sloppy
GMT".  Most people keep track of time through wall clocks, wristwatches,
the clock on their car's dashboard, etc.  None of these are precision
timepieces; they cannot distinguish between UTC and GMT, nor stay
accurate enough to make leap seconds a concern.  Most people go about
their lives quite happy to be within a few minutes of what other people
consider to be "the time".

These "general purpose" timepieces (watches, etc.) fall into two
categories: those that synchronize with some sort of broadcast time,
and those that don't (and will drift until reset manually).  The latter
category is of no concern for anyone debating leap seconds, as those
devices are generally going to be inherently off by more than a second
or two.  The former category of devices is the only one that matters at
this level of detail.  Even then, many auto-synchronizing devices (e.g.,
people's computers) may gain or lose a few seconds between
synchronizations without anyone really caring.

The distinction between "GMT", "UTC with leap seconds", "UTC without leap
seconds", and "what does my $10 wristwatch say" doesn't even exist for the
99.9999% of the planet's population that doesn't deal with high-precision
time.  If you want to keep things simple for most people, the end solution
needs to have some kind of "general time" or "basic time".  This "basic
time" scale should have exactly 60 seconds in every minute, regardless of
whether leap seconds exist or not.  Any self-synchronizing clock can
amortize that extra second over whatever time period it wants (say, the
next 24 hours, which would be GMT-like 86400 "rubber seconds" per day),
and 99.9999% of the world won't notice.

When you start talking about "leap hours", then you're forcibly causing
that 99.9999% to care about something that, arguably, they shouldn't have
to.  For most people, dealing with leap seconds means doing nothing, while
dealing with a leap hour means doing something.

Now, about that 0.0001% of the world that cares about accuracy to a global
timescale to within 1 second?  That's a very complex topic (witness this
mailing list's continuing discussion, which has only scratched the surface
so far), and not one I can add much to at this time.  But I do agree with
Mr. Kamp that the 99.9999% need a simple solution; I only disagree insofar
as to state that the simple solution for that 99.9999% is much simpler
than he claims.

-- 
Michael Thorpe

From phk at phk.freebsd.dk  Tue Nov 11 18:12:15 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Tue, 11 Nov 2008 23:12:15 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 15:02:11 PST."
	<20081111230211.GJ5886@pedantic.org> 
Message-ID: <86269.1226445135@critter.freebsd.dk>

In message <20081111230211.GJ5886 at pedantic.org>, Michael Thorpe writes:

>On 2008-11-11 22:03:44, Poul-Henning Kamp wrote:
>>I don't care how many new timescales you want to invent for people
>>with Phd after their names, the only timescale that matters to
>>99.9999...% of this planets population is UTC, and that is the one
>>we have to find a workable solution for leapseconds in.
>
>I must respectfully disagree.  The timescale used by 99.9999% of this
>planet's population is, for lack of a better term, most akin to "sloppy
>GMT". 

These people are bound by national laws that say "UTC"[1], even
if they are not very good at implementing it.

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.

Furthermore, most of these systems are coded by people who couldn't
tell a time scale from a postal scale without the aid of a picture.

The fact that people are sloppy with their implementation of UTC,
is only relevant as far as leap seconds has become a problem because
the implementations have gotten increasingly better at it.

Poul-Henning


[1] Or more or less confused versions thereof, such as "GMT".

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From seaman at noao.edu  Tue Nov 11 18:33:46 2008
From: seaman at noao.edu (Rob Seaman)
Date: Tue, 11 Nov 2008 16:33:46 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <85936.1226441024@critter.freebsd.dk>
References: <85936.1226441024@critter.freebsd.dk>
Message-ID: <1036CB00-CB83-4F7F-B2CB-C1CF78DB6CEA@noao.edu>

Poul-Henning Kamp wrote:

> No, actually the word I am looking for is intelligence, and I think
> central to both the problem and the solution.
>
> There are only so much nitty-gritty detail a brain can retain and
> recall at relevant moments, and the scientific consensus is that
> it correlates very strongly with the general "g", as long as you
> control for cases of Asbergers, Autism etc.

I'd recommend Gould's "Mismeasure of Man" over the crap science in the  
"Bell Curve".  Also Howard Gardner.  Binet never made extreme claims  
about IQ; these are a later abuse of what was originally a simple  
instrument to help children in need of special attention.

> But that does not give us a mandate to make the world the rest of
> the population lives in, so complex that they cannot cope with it.

...but it is the world that is complex.  As with a lot of other  
technology issues, the question is how best to match impedances.  You  
can't sweep the intrinsic complexity under the rug.

> Quite the contrary: the burden is on us to make life simple for
> the simple, and save the complexity for those who can deal with it.

"The simple"?!?  Please.  If you want to follow this line of argument,  
maybe start with "Zen and the Art of Motorcycle Maintenance".

Maybe I'll write an essay explaining the need for both solar time and  
interval time in terms of Julian Jaynes' "Origin of Consciousness in  
the Breakdown of the Bicameral Mind".  Right brain?  Solar time.  Left  
brain?  Interval.  Human consciousness and institutions sit at the  
intersection of the two.

Suggesting that people are too stupid to deserve a clock that keeps  
proper time is no less absurd.

...or maybe time would be better spent actually accumulating use cases  
and requirements for civil timekeeping in the 21st century?  This is  
the responsibility of those who would change the status quo.  The rest  
of us have been kept busy just trying to fend off precipitous and  
hasty decision-making.

> The "leap-hour" solution, as ugly as it is, has repeatedly been
> proven a perfectly adequate way to address the issue of earth
> orientation relative to civil time, mostly by politicians who muck
> about with timezones for no good reason, but entirely fail to make
> their jurisdictions descend into (further) uncivilized chaos as a
> result.

Leap hours have never been tried and there numerous reasons to be  
skeptical they could work.  I won't belabor why these are different  
than daylight saving time adjustments or standard time zones.  Read  
the archives.

> If there is a lack of realism anywhere, it is on the part of the
> astronomers,

A reminder that the astronomers are also among the true power users of  
atomic timescales.

Civil time just happens to be (obviously) a flavor of mean solar  
time.  For instance, all the timekeeping policy options suggested in  
the original "GPS World" article were variations on ways to cheat a  
bit (just a few milliseconds per day) on mean solar time.

> I don't care how many new timescales you want to invent for people
> with Phd after their names, the only timescale that matters to
> 99.9999...% of this planets population is UTC, and that is the one
> we have to find a workable solution for leapseconds in.

We have a workable solution.  The best way to make the case that it is  
time for a change is to follow well known system engineering  
principles and compile new requirements.

Surely by now we all recognize that these informal mailing list  
discussions aren't going to convince the other side.

>   3. Much longer warning about leap seconds.
> 	Might be workable for both parties.

Ok - so that makes three proposed solutions for the trade-off matrix.   
The status quo is one such (and should always be included in such  
trade-offs).  The other is Allen's zoneinfo suggestion.  I'm sure  
there are more.

Continue compiling a coherent, complete and self-consistent set of  
requirements and we can get around to testing the various options.  In  
the mean time we'll be arguing about system requirements, not about  
entrenched positions or differing sociological or philosophical  
stances.  The work invested in uncovering requirements will be well  
invested whatever solution is ultimately developed.

> Pick your poison.

That's the goal of system engineering.  The ITU could call any random  
member of INCOSE and would receive advice to follow system engineering  
best practices in contemplating any change to UTC.
>


Why is this controversial?

Rob

From phk at phk.freebsd.dk  Tue Nov 11 19:09:03 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 00:09:03 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 23:12:15 GMT."
	<86269.1226445135@critter.freebsd.dk> 
Message-ID: <86523.1226448543@critter.freebsd.dk>

In message <86269.1226445135 at critter.freebsd.dk>, "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/leapsecs at rom.usno.navy.mil/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=an&subtype=ca&htmlfid=897/ENUS294-152&appname=isource&language=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
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From phk at phk.freebsd.dk  Tue Nov 11 20:12:58 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 01:12:58 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 16:33:46 MST."
	<1036CB00-CB83-4F7F-B2CB-C1CF78DB6CEA@noao.edu> 
Message-ID: <86911.1226452378@critter.freebsd.dk>

In message <1036CB00-CB83-4F7F-B2CB-C1CF78DB6CEA at noao.edu>, Rob Seaman writes:


>Continue compiling a coherent, complete and self-consistent set of  
>requirements and we can get around to testing the various options.


The most important requirement is obviously that the proposed
change, can possibly be made to happen.

Using the most lenient standard of review we can, we assume that a
"scientifically perfect" solution is found.

By "scienfically perfect" we obviously do not assume that "we will
stabilize the Earths rotation", but a solution that works inside
the bounds of our geophysical knowledge and models of the physical
reality.

Likewise, the solution is not a technological magicians trick,
such as "perfect atomic clocks surgically connected to our brains
right after birth" or "all devices must be on the internet" etc.

In other words, we assume a solution that, through one or more time
scales, caters to the various needs of humanity, along with such
rules and observational frameworks that will be required for the
conversion between these time scales.

We totally disregard small details such as naming, chosen tolerances,
and thresholds, assuming that the best possible choices have been
in all such matters.


Under this hypothetical scenario, please flesh out this sequence
of events:

    A.  Rob Seaman announces the scientifically perfect NewTime to
        the world.

    [ Please fill in what happens here ]

    H.  Scientists, all over, generally applaud this as sensible.
	(With the usual small, but loud, fraction of emeriti who
	grumble on general principles of age, and are revered but
	not necessarily listened to, for the very same reason.)

    [ Please fill in what happens here ]

    N.  NewTime becomes the legal basis of civil timekeeping in all
	of USA & EU.
	[please insert realistic year this could happen]

    [ Please fill in what happens here ]

    Z.  NewTime is implemented on 99% of all USA & EU based IT
        systems which react according to what time it is.
	[please insert realistic year this could happen]


Having done that, please address the probability that the entire
plan will be derailed by:

    ?.  Computer consultants estimate the cost of implementation
	of NewTime in legacy systems to $BIGNUM, and offer the
	alternative of just dropping leapseconds from UTC as a
	virtually no-cost change.

This event which can be assumed to happen right after A and
certainly long before N.


Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From sla at ucolick.org  Tue Nov 11 20:44:46 2008
From: sla at ucolick.org (Steve Allen)
Date: Tue, 11 Nov 2008 17:44:46 -0800
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <86911.1226452378@critter.freebsd.dk>
References: <1036CB00-CB83-4F7F-B2CB-C1CF78DB6CEA@noao.edu>
	<86911.1226452378@critter.freebsd.dk>
Message-ID: <20081112014446.GA30364@ucolick.org>

On Wed 2008-11-12T01:12:58 +0000, Poul-Henning Kamp hath writ:
> The most important requirement is obviously that the proposed
> change, can possibly be made to happen.

The operational systems will not notice if the name of the
broadcast/internet time scale changes.  The operational systems will
work just fine without leaps -- even better than with leaps.

BIPM has already offered to deprecate TAI in favor of a time scale
offset by the integer number of seconds in a leap-free broadcast time
scale, so there won't be more time scales, just an international
atomic one synched with UT in around 2022 instead of 1958.

The humans will adapt to the name change, even getting it fixed in
most documents and ancillary software long before the difference
between TI and UT gets to a few seconds.

This goes doubly so because something with the simple rules of TI is
so simple that the ITU-R's inabilty to provide an openly published
standard describing TI is not a problem.
BIPM can describe their new TI, and ITU-R can just say they're using
that.
IERS can publish how leap seconds are added to create UTC, and they
can openly publish that.

CCIR was able to decree a change to UTC in 1970 because there was no
official document describing what UTC was, and no operational systems
making use of it.  That's just not the case anymore.

Yes, it has to be something that can be made to happen -- politically.
The operational systems, the technical aspects, are not the stumbling
block.  The stumbling is coming from things like "we only need one
time zone" People's Republic of China suddenly taking the same
position as the UK and objecting to any change to UTC by WP7A.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From seaman at noao.edu  Tue Nov 11 20:47:28 2008
From: seaman at noao.edu (Rob Seaman)
Date: Tue, 11 Nov 2008 18:47:28 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <86911.1226452378@critter.freebsd.dk>
References: <86911.1226452378@critter.freebsd.dk>
Message-ID: <67561FDB-4FA2-4084-943D-973310B60795@noao.edu>

Recall that the U.S. has just been through a two year ordeal of an  
election in which the technique you just demonstrated of setting up a  
strawman opponent, just to knock it down, has been a daily  
occurrence.  I've never asserted any position even vaguely similar to  
what you say.

Meanwhile, the astronomers in this conversation have repeatedly  
demonstrated the willingness to consider new options, cf. the  
possibility of extending/stabilizing leap second scheduling, or of  
implementing TI via zoneinfo.  In general, we're not supporters of  
leap seconds so much as of mean solar time.

Meanwhile, the cabal pressing the eradication of leap seconds has  
chosen to not participate in this mailing list for nine years running,  
leaving the support of this option on the list to folks who are  
certainly not privy to the cabal's inner machinations.

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.

I reject your assertion out of hand that proper system engineering  
would cost more than wasting nine years (and counting) on a unilateral  
pursuit of the fantasy position that solar time is a disposable  
commodity.  It is very telling that every time I mention best practice  
system engineering, the response is more panic stricken than when I  
wax poetic on astronomical issues.

Rob Seaman
NOAO
--

On Nov 11, 2008, at 6:12 PM, Poul-Henning Kamp wrote:

> In message <1036CB00-CB83-4F7F-B2CB-C1CF78DB6CEA at noao.edu>, Rob  
> Seaman writes:
>
>
>> Continue compiling a coherent, complete and self-consistent set of
>> requirements and we can get around to testing the various options.
>
>
> The most important requirement is obviously that the proposed
> change, can possibly be made to happen.
>
> Using the most lenient standard of review we can, we assume that a
> "scientifically perfect" solution is found.
>
> By "scienfically perfect" we obviously do not assume that "we will
> stabilize the Earths rotation", but a solution that works inside
> the bounds of our geophysical knowledge and models of the physical
> reality.
>
> Likewise, the solution is not a technological magicians trick,
> such as "perfect atomic clocks surgically connected to our brains
> right after birth" or "all devices must be on the internet" etc.
>
> In other words, we assume a solution that, through one or more time
> scales, caters to the various needs of humanity, along with such
> rules and observational frameworks that will be required for the
> conversion between these time scales.
>
> We totally disregard small details such as naming, chosen tolerances,
> and thresholds, assuming that the best possible choices have been
> in all such matters.
>
>
> Under this hypothetical scenario, please flesh out this sequence
> of events:
>
>    A.  Rob Seaman announces the scientifically perfect NewTime to
>        the world.
>
>    [ Please fill in what happens here ]
>
>    H.  Scientists, all over, generally applaud this as sensible.
> 	(With the usual small, but loud, fraction of emeriti who
> 	grumble on general principles of age, and are revered but
> 	not necessarily listened to, for the very same reason.)
>
>    [ Please fill in what happens here ]
>
>    N.  NewTime becomes the legal basis of civil timekeeping in all
> 	of USA & EU.
> 	[please insert realistic year this could happen]
>
>    [ Please fill in what happens here ]
>
>    Z.  NewTime is implemented on 99% of all USA & EU based IT
>        systems which react according to what time it is.
> 	[please insert realistic year this could happen]
>
>
> Having done that, please address the probability that the entire
> plan will be derailed by:
>
>    ?.  Computer consultants estimate the cost of implementation
> 	of NewTime in legacy systems to $BIGNUM, and offer the
> 	alternative of just dropping leapseconds from UTC as a
> 	virtually no-cost change.
>
> This event which can be assumed to happen right after A and
> certainly long before N.
>
>
> Poul-Henning
>
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | 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 at leapsecond.com
> http://six.pairlist.net/mailman/listinfo/leapsecs


From cowan at ccil.org  Tue Nov 11 23:48:21 2008
From: cowan at ccil.org (John Cowan)
Date: Tue, 11 Nov 2008 23:48:21 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <67561FDB-4FA2-4084-943D-973310B60795@noao.edu>
References: <86911.1226452378@critter.freebsd.dk>
	<67561FDB-4FA2-4084-943D-973310B60795@noao.edu>
Message-ID: <20081112044821.GD23706@mercury.ccil.org>

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.                    cowan at ccil.org
But then they don't really grind their gears, either;   
        they only obey the laws of physics.  --Unknown

From adi at stav.org.il  Wed Nov 12 01:09:23 2008
From: adi at stav.org.il (Adi Stav)
Date: Wed, 12 Nov 2008 08:09:23 +0200
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
Message-ID: <20081112060923.GC5965@stav.org.il>

On Mon, Nov 10, 2008 at 10:23:36PM -0700, Rob Seaman wrote:
> Adi Stav wrote:
>
>> On Mon, Nov 10, 2008 at 04:13:25PM +0000, 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?
>
>
> Well, that is the UTC that we have.  Two timescales, earth orientation  
> and interval.  Compromise a little on the SI part and a little on the  
> solar day part to jigger these two things into a single standard.

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.

From seaman at noao.edu  Wed Nov 12 02:08:11 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 00:08:11 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112044821.GD23706@mercury.ccil.org>
References: <86911.1226452378@critter.freebsd.dk>
	<67561FDB-4FA2-4084-943D-973310B60795@noao.edu>
	<20081112044821.GD23706@mercury.ccil.org>
Message-ID: <F2A54D51-65ED-42DB-8912-51D8C949F619@noao.edu>

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


From clive at demon.net  Wed Nov 12 04:04:31 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Wed, 12 Nov 2008 09:04:31 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
Message-ID: <20081112090431.GA34814@finch-staff-1.thus.net>

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 delivered to the charterers at 2100 hours UTC 8th February 2004,
    loaded a cargo in New Orleans, discharged at Tartous and was re-delivered
    at 1130 hours UTC 13th March 2004. Thus the vessel's employment lasted
    only 33 days 12 hours 31 minutes, ie 1 day 11 hours 29 minutes short of
    the minimum 35 days' duration guaranteed by the charterers.

> ["by Order in Council" is the way the British Government issues
> regulations under the authority of an existing statute. Statutes
> are enacted by Parliament, but Orders in Council are not.]

Actually, it is more normal to use Statutory Instruments, which may be
debated briefly by Parliament but are never amended in the process of
passing them.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From phk at phk.freebsd.dk  Wed Nov 12 04:19:38 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 09:19:38 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 17:44:46 PST."
	<20081112014446.GA30364@ucolick.org> 
Message-ID: <88423.1226481578@critter.freebsd.dk>

In message <20081112014446.GA30364 at ucolick.org>, Steve Allen writes:
>On Wed 2008-11-12T01:12:58 +0000, Poul-Henning Kamp hath writ:

>The humans will adapt to the name change, even getting it fixed in
>most documents and ancillary software long before the difference
>between TI and UT gets to a few seconds.

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.

>Yes, it has to be something that can be made to happen -- politically.
>The operational systems, the technical aspects, are not the stumbling
>block.  The stumbling is coming from things like "we only need one
>time zone" People's Republic of China suddenly taking the same
>position as the UK and objecting to any change to UTC by WP7A.

I think it is safe to say, that adding a new timescale will not
result in its widespread adoption.

The other thing I find ironic by the TI proposal, is that the
timescale named "Universal" is only fit for this planet, whereas
the one called "International" is much better suited for other
planets.

Details like that tend to make historical persons look pretty silly.

Poul-Henning


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From phk at phk.freebsd.dk  Wed Nov 12 04:27:31 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 09:27:31 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Tue, 11 Nov 2008 18:47:28 MST."
	<67561FDB-4FA2-4084-943D-973310B60795@noao.edu> 
Message-ID: <88461.1226482051@critter.freebsd.dk>

In message <67561FDB-4FA2-4084-943D-973310B60795 at noao.edu>, Rob Seaman writes:

>Meanwhile, the astronomers in this conversation have repeatedly  
>demonstrated the willingness to consider new options, [...]

... as long as they get things their way.

None of the proposals from your hand have addressed the problems
of the other party, without adding equally huge problems.

Just take the naming:  You insist that astronomers get to keep
the "UTC" name, despite the fact that this is embedded in far
more legal documents than astronomy papers.

>Meanwhile, the cabal pressing the eradication of leap seconds has  
>chosen to not participate in this mailing list for nine years running,  
>leaving the support of this option on the list to folks who are  
>certainly not privy to the cabal's inner machinations.

I can fully agree.

I have a hard time blaming them however, reading the archives would
not give them reason to think they would gain anything by spending
time here.

>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.

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.

>It is very telling that every time I mention best practice  
>system engineering, the response is more panic stricken than when I  
>wax poetic on astronomical issues.

Best practice system engineering is a very bad method for tackling
legal problems.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From clive at demon.net  Wed Nov 12 04:44:22 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Wed, 12 Nov 2008 09:44:22 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <89735.1226409250@critter.freebsd.dk>
References: <alpine.LSU.2.00.0811111200170.23184@hermes-1.csi.cam.ac.uk>
	<89735.1226409250@critter.freebsd.dk>
Message-ID: <20081112094422.GA40833@finch-staff-1.thus.net>

Poul-Henning Kamp said:
> Another issue is that exception rules should not trigger so seldom
> that people forget about them.
> 
> Again the 400 year rule is exhibit number 1, and exhibit number two
> could be how Sweden failed to follow their own established rules,
> trying to recover from the old to the new calendar.

With two-bis being the misinterpretation of "every four years" in the
Julian calendar, so that Feb 29th was added every *three* years for some
time (Wikipedia suggests the most likely sequence was 44, 41, 38, 35, 32,
29, 26, 23, 20, 17, 14, 11, 8 BC, then a hiatus to correct the problem,
then AD 4, 8, 12 etc.).

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From clive at demon.net  Wed Nov 12 04:46:56 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Wed, 12 Nov 2008 09:46:56 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081111180003.GA26971@ucolick.org>
References: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<74553.1226395041@critter.freebsd.dk>
	<20081111180003.GA26971@ucolick.org>
Message-ID: <20081112094656.GB40833@finch-staff-1.thus.net>

Steve Allen said:
> Here's an interesting point.  Nobody misinterprets GPS time.
> Nobody tries to extrapolate it backwards and make algorithms
> about proleptic GPS time.  That's because GPS time simply
> did not exist prior to 1980-01-06.  Nobody can screw it up
> because GPS time is exactly and only what the US military
> wants it to be.

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.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From seaman at noao.edu  Wed Nov 12 08:22:09 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 06:22:09 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112094656.GB40833@finch-staff-1.thus.net>
References: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<74553.1226395041@critter.freebsd.dk>
	<20081111180003.GA26971@ucolick.org>
	<20081112094656.GB40833@finch-staff-1.thus.net>
Message-ID: <6443144D-7935-43B7-98A8-729DCBFE5824@noao.edu>

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?

From seaman at noao.edu  Wed Nov 12 08:30:57 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 06:30:57 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112090431.GA34814@finch-staff-1.thus.net>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
	<20081112090431.GA34814@finch-staff-1.thus.net>
Message-ID: <1CF841CB-D4BB-4EF0-A556-0C6EEA9C5EEA@noao.edu>

Clive D.W. Feather wrote:

> 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.

Not too surprising.  There are plenty of everyday (there's that word  
"day" again) issues that are left similarly undefined for later  
interpretation in a court by judge or jury.

In colloquial use (what will often be applied), sunrise will be when  
the Sun (meaning its photosphere) is first visible from some location,  
ie., "dawn's early light".  Sunset will be when the light vanishes.

For other court cases, this might better align with astronomical  
twilight - was any light whatsoever still present from the previous or  
succeeding day.  In that case, the sun will still be several degrees  
below the horizon.

Rarely will sunrise and sunset be defined in terms of an ensemble of  
atomic clocks with no reference to the actual possibility of light.

No matter how carefully worded, every law permits differing  
interpretations.

Rob


From seaman at noao.edu  Wed Nov 12 09:48:24 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 07:48:24 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <1CF841CB-D4BB-4EF0-A556-0C6EEA9C5EEA@noao.edu>
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com>
	<61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
	<20081112090431.GA34814@finch-staff-1.thus.net>
	<1CF841CB-D4BB-4EF0-A556-0C6EEA9C5EEA@noao.edu>
Message-ID: <CB191BA7-489E-407F-926A-BA4C924DD037@noao.edu>

On Nov 12, 2008, at 6:30 AM, Rob Seaman wrote:

> "dawn's early light"

This better fits twilight.  Perhaps "crack of dawn"?


From dot at dotat.at  Wed Nov 12 10:02:26 2008
From: dot at dotat.at (Tony Finch)
Date: Wed, 12 Nov 2008 15:02:26 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <6443144D-7935-43B7-98A8-729DCBFE5824@noao.edu>
References: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<74553.1226395041@critter.freebsd.dk>
	<20081111180003.GA26971@ucolick.org>
	<20081112094656.GB40833@finch-staff-1.thus.net>
	<6443144D-7935-43B7-98A8-729DCBFE5824@noao.edu>
Message-ID: <alpine.LSU.2.00.0811121500220.30582@hermes-1.csi.cam.ac.uk>

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  <dot at dotat.at>  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.

From seaman at noao.edu  Wed Nov 12 11:06:03 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 09:06:03 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <88423.1226481578@critter.freebsd.dk>
References: <88423.1226481578@critter.freebsd.dk>
Message-ID: <79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu>

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


From cowan at ccil.org  Wed Nov 12 11:06:30 2008
From: cowan at ccil.org (John Cowan)
Date: Wed, 12 Nov 2008 11:06:30 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112090431.GA34814@finch-staff-1.thus.net>
References: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
	<20081112090431.GA34814@finch-staff-1.thus.net>
Message-ID: <20081112160629.GG23706@mercury.ccil.org>

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                 cowan at ccil.org
    Then you generally can
Make the same stupid point seem profound!           --Jonathan Robie

From phk at phk.freebsd.dk  Wed Nov 12 11:11:42 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 16:11:42 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 09:06:03 MST."
	<79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu> 
Message-ID: <4379.1226506302@critter.freebsd.dk>

In message <79C80FD0-71B0-4A2B-B8AB-29DB8160B197 at noao.edu>, 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
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From clive at demon.net  Wed Nov 12 11:18:58 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Wed, 12 Nov 2008 16:18:58 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112160629.GG23706@mercury.ccil.org>
References: <20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
	<20081112090431.GA34814@finch-staff-1.thus.net>
	<20081112160629.GG23706@mercury.ccil.org>
Message-ID: <20081112161858.GA69859@finch-staff-1.thus.net>

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:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From psb at ast.cam.ac.uk  Wed Nov 12 11:30:05 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Wed, 12 Nov 2008 16:30:05 +0000 (GMT)
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <4379.1226506302@critter.freebsd.dk>
References: <4379.1226506302@critter.freebsd.dk>
Message-ID: <Pine.GSO.4.58.0811121629040.5480@cass03>



On Wed, 12 Nov 2008, Poul-Henning Kamp wrote:

> In message <79C80FD0-71B0-4A2B-B8AB-29DB8160B197 at noao.edu>, 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.


From seaman at noao.edu  Wed Nov 12 11:52:15 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 09:52:15 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <4379.1226506302@critter.freebsd.dk>
References: <4379.1226506302@critter.freebsd.dk>
Message-ID: <9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC@noao.edu>

Poul-Henning Kamp wrote:

> And illegal on many systems, including all USGOV owned and operated  
> systems.

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

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://six.pairlist.net/pipermail/leapsecs/attachments/20081112/0d9fbe68/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: goofyback.jpg
Type: image/jpeg
Size: 16611 bytes
Desc: not available
Url : <http://six.pairlist.net/pipermail/leapsecs/attachments/20081112/0d9fbe68/attachment-0001.jpg>

From dot at dotat.at  Wed Nov 12 12:03:11 2008
From: dot at dotat.at (Tony Finch)
Date: Wed, 12 Nov 2008 17:03:11 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu>
References: <88423.1226481578@critter.freebsd.dk>
	<79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu>
Message-ID: <alpine.LSU.2.00.0811121642130.30582@hermes-1.csi.cam.ac.uk>

On Wed, 12 Nov 2008, Rob Seaman 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.

If you simply do that then civil time will de facto diverge from UT, since
nobody will be applying the TI-UTC offset to the time broadcasts.

Remember that (as previously discussed on this list) you can't simply
redefine time_t to be TI and fix up the difference using zoneinfo. This is
because plenty of software doesn't use zoneinfo for time computations, and
instead relies on the POSIX specification that time_t is roughly UT.

You have for many years been able to configure the tz code (and therefore
many unix systems) to run with time_t following TAI and with the TAI-UTC
fixup in the zoneinfo code, just like the proposed TI setup. No-one runs
it this way because it isn't conforming and therefore isn't compatible
with a lot of code.

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FORTIES CROMARTY FORTH TYNE DOGGER: NORTHWEST 4 OR 5, OCCASIONALLY 6 AT FIRST,
BACKING SOUTHWEST 5 TO 7 LATER. MODERATE. SHOWERS THEN RAIN. MODERATE OR GOOD.

From ashtongj at comcast.net  Wed Nov 12 12:06:30 2008
From: ashtongj at comcast.net (Gerard Ashton)
Date: Wed, 12 Nov 2008 12:06:30 -0500
Subject: [LEAPSECS] Synchronization requirement
Message-ID: <19DFB33ADA1F4F8482FE40479067637F@grendel>

There have been requests on this list to gather requirements
for civil time keeping. I would like to suggest one. Anyone
who has ever participated in an EBay auction will have noticed
that all the savvy bidders wait to the very end to submit bids.
However, mismatches between the bidder's clock and EBay's clock
could cause some of these bidders to miss the bidding deadline.
I doubt this is an isolated example; my intuition is that there
are and will be many such instances where there are advantages
to waiting until a deadline approaches before acting.

It would be futile to try to regulate this at the microsecond
or nanosecond level. But I think a real requirement exists
that a person operating a keyboard or mouse be able to depend
on the civil time-of-day to within human reaction time,
which is often taken to be 0.1 s. This would make the current
civil time definitions inadequate, because at least one country,
the UK, specifies Greenwich Mean Time as their basis of civil time
and failed to address proposals to clarify whether this means
UT1 or UTC. Let me summarize my requirement:

   The legal definition of time shall be sufficiently
   unambiguous that those with adequate equipment will
   be able to determine the correct time to an accuracy
   of 0.1 s or better.

Such a requirement would also put those who require better
time accuracy that they are outside the realm of legally
defined time and need to negotiate an agreement with their
partners.

Gerry Ashton


From seaman at noao.edu  Wed Nov 12 12:20:54 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 10:20:54 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <alpine.LSU.2.00.0811121642130.30582@hermes-1.csi.cam.ac.uk>
References: <88423.1226481578@critter.freebsd.dk>
	<79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu>
	<alpine.LSU.2.00.0811121642130.30582@hermes-1.csi.cam.ac.uk>
Message-ID: <13E34B42-C887-45FA-B66C-73A5EC7AB80F@noao.edu>

Tony Finch wrote:

> On Wed, 12 Nov 2008, Rob Seaman 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.
>
> If you simply do that then civil time will de facto diverge from UT,  
> since
> nobody will be applying the TI-UTC offset to the time broadcasts.

No, the realization of civil time will diverge from UT until bad  
engineering is fixed in the fullness of time.

Everybody agrees we can cheat mean solar time for many purposes for  
some number of years.  For those purposes that need correct UT  
behavior immediately (meaning correct UTC behavior as your use of both  
terms neatly illustrates), more aggressive pressure will be applied to  
find appropriate mechanisms - whether zoneinfo or not - to recover  
UTC.  Other systems will follow as the distinction between TI and UTC  
grows.

However, the initial transition to TI simply requires cutting a ribbon  
with big scissors and declaring it to now be so.  I'm a bit perplexed  
at how astronomers are at fault if we don't consider such options and  
are still at fault if we do.

> Remember that (as previously discussed on this list) you can't simply
> redefine time_t to be TI and fix up the difference using zoneinfo.  
> This is
> because plenty of software doesn't use zoneinfo for time  
> computations, and
> instead relies on the POSIX specification that time_t is roughly UT.

Depends on the meaning of "fix up".  I would take it to mean actually  
using technology in an appropriate fashion.

Are people really convinced by the argument that badly implemented  
systems should determine policy?

> You have for many years been able to configure the tz code (and  
> therefore
> many unix systems) to run with time_t following TAI and with the TAI- 
> UTC
> fixup in the zoneinfo code, just like the proposed TI setup. No-one  
> runs
> it this way because it isn't conforming and therefore isn't compatible
> with a lot of code.

If the solution we're discussing came to pass through the fullness of  
time and the application of systems engineering best practices, then  
such usage would become conforming and the balance of code  
compatibility would shift.

As the consensus in Torino recognized, TI is one of the more gentle  
transitions to pursue.

For the ITU to win, why must UTC lose?

Rob

From phk at phk.freebsd.dk  Wed Nov 12 12:29:21 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 17:29:21 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 16:30:05 GMT."
	<Pine.GSO.4.58.0811121629040.5480@cass03> 
Message-ID: <4810.1226510961@critter.freebsd.dk>

In message <Pine.GSO.4.58.0811121629040.5480 at cass03>, Peter Bunclark writes:


>> 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?

That's the funny thing, isn't it ?

As long as you run the system on the buggy POSIX definition of UTC,
and that obviously entails using a UTC source as your reference, it
doesn't matter how lousy your timekeeping is.

But the second you use a non-UTC reference, your are in violation
of FIPS151-2, even if that makes you more precise, timewise.

As one of your supreme court judges said during arguments last year:
words matter, especially in legal texts.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From phk at phk.freebsd.dk  Wed Nov 12 12:34:25 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 17:34:25 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 09:52:15 MST."
	<9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC@noao.edu> 
Message-ID: <4851.1226511265@critter.freebsd.dk>

In message <9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC at noao.edu>, Rob Seaman writes:

>Poul-Henning Kamp wrote:
>
>> And illegal on many systems, including all USGOV owned and operated  
>> systems.
>
>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.

No, ITU does not have treaty status, you are supposed to follow their
recommedations and standards, unless there is specific national
regulation.

FIPS-151-2 overrides both STD-C and POSIX for instance.

>Also, is it truly illegal for computers to keep time two different  
>ways?

FIPS-151-2 compliant systems would be noncompliant if they did.

>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.

Most people, and certainly NIST, view this as the local computer
"running UTC time", despite the fact that it does not run on the
"UTC timescale" in the strictly scientific meaning of the words.

>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.

I thought USA went out of their way some years back, to make it
clear that the relevant secretary (of commerce ?) decided what
US timekeeping was and that it certainly had nothing to do with GMT ?

Or was that laying the ground for US unlateral action on leap-seconds ?

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From phk at phk.freebsd.dk  Wed Nov 12 12:36:41 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 17:36:41 +0000
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: Your message of "Wed, 12 Nov 2008 12:06:30 EST."
	<19DFB33ADA1F4F8482FE40479067637F@grendel> 
Message-ID: <4868.1226511401@critter.freebsd.dk>

In message <19DFB33ADA1F4F8482FE40479067637F at grendel>, "Gerard Ashton" writes:

>There have been requests on this list to gather requirements
>for civil time keeping. I would like to suggest one. Anyone
>who has ever participated in an EBay auction will have noticed
>that all the savvy bidders wait to the very end to submit bids.

Savy auction houses deal with such behaviour by not closing the
auction "while bidding is ongoing", typically implementing a
30 second wait after the most recent bid before closing.

Why eBay doesn't have always been a mystery to me, people would
statistically get better prices if they did.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From dot at dotat.at  Wed Nov 12 13:08:24 2008
From: dot at dotat.at (Tony Finch)
Date: Wed, 12 Nov 2008 18:08:24 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <13E34B42-C887-45FA-B66C-73A5EC7AB80F@noao.edu>
References: <88423.1226481578@critter.freebsd.dk>
	<79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu>
	<alpine.LSU.2.00.0811121642130.30582@hermes-1.csi.cam.ac.uk>
	<13E34B42-C887-45FA-B66C-73A5EC7AB80F@noao.edu>
Message-ID: <alpine.LSU.2.00.0811121757500.30582@hermes-1.csi.cam.ac.uk>

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  <dot at dotat.at>  http://dotat.at/
SOLE: WEST OR SOUTHWEST 4 OR 5. ROUGH BECOMING MODERATE. RAIN OR DRIZZLE. GOOD
BECOMING MODERATE OR POOR.

From dot at dotat.at  Wed Nov 12 13:12:00 2008
From: dot at dotat.at (Tony Finch)
Date: Wed, 12 Nov 2008 18:12:00 +0000
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <4868.1226511401@critter.freebsd.dk>
References: <4868.1226511401@critter.freebsd.dk>
Message-ID: <alpine.LSU.2.00.0811121811350.30582@hermes-1.csi.cam.ac.uk>

On Wed, 12 Nov 2008, Poul-Henning Kamp wrote:
>
> Savy auction houses deal with such behaviour by not closing the
> auction "while bidding is ongoing", typically implementing a
> 30 second wait after the most recent bid before closing.
> Why eBay doesn't have always been a mystery to me, people would
> statistically get better prices if they did.

They'd never be able to close any auctions :-)

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
FORTIES: NORTHWEST 4 OR 5 BACKING SOUTHWEST 5 TO 7. MODERATE, OCCASIONALLY
ROUGH LATER. SHOWERS THEN RAIN. MODERATE OR GOOD.

From sla at ucolick.org  Wed Nov 12 13:26:40 2008
From: sla at ucolick.org (Steve Allen)
Date: Wed, 12 Nov 2008 10:26:40 -0800
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <alpine.LSU.2.00.0811121757500.30582@hermes-1.csi.cam.ac.uk>
References: <88423.1226481578@critter.freebsd.dk>
	<79C80FD0-71B0-4A2B-B8AB-29DB8160B197@noao.edu>
	<alpine.LSU.2.00.0811121642130.30582@hermes-1.csi.cam.ac.uk>
	<13E34B42-C887-45FA-B66C-73A5EC7AB80F@noao.edu>
	<alpine.LSU.2.00.0811121757500.30582@hermes-1.csi.cam.ac.uk>
Message-ID: <20081112182640.GA1934@ucolick.org>

Standards and laws are commonly disregarded, especially when those
ignore the practicalities of reality.

Worrying about the effect on the documentation aspects of deployed
systems did not stop the CCIR from declaring a change to leap seconds
in 1970.

During the 1960s the CCIR was recommending that broadcast time be GMT,
but the US NBS broadcast the local time of the transmitters until 1967.

The legal time of the US was unequivocally established as based on GMT
in 1966, but the US NBS was already using what was called UTC and
started calling their broadcasts UTC in 1974.

If the broadcast/internet time scale is to be changed, I want to see
it changed in a way that is operationally better -- and as immune as
possible to misinterpretation.  Too many aspects about the name UTC
are tainted with practices that are confused and misinformed.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From phk at phk.freebsd.dk  Wed Nov 12 13:34:19 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 18:34:19 +0000
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: Your message of "Wed, 12 Nov 2008 18:12:00 GMT."
	<alpine.LSU.2.00.0811121811350.30582@hermes-1.csi.cam.ac.uk> 
Message-ID: <5353.1226514859@critter.freebsd.dk>

In message <alpine.LSU.2.00.0811121811350.30582 at hermes-1.csi.cam.ac.uk>, Tony F
inch writes:
>On Wed, 12 Nov 2008, Poul-Henning Kamp wrote:
>>
>> Savy auction houses deal with such behaviour by not closing the
>> auction "while bidding is ongoing", typically implementing a
>> 30 second wait after the most recent bid before closing.
>> Why eBay doesn't have always been a mystery to me, people would
>> statistically get better prices if they did.
>
>They'd never be able to close any auctions :-)

They would, it works fine in most real-life auction houses.  This is
why you have the famous 

	going once...
	going twice...
	third time anybody ?
	sold to the man next to the woman who clearly isn't his wife...

sort of stuff at art auctions

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From ch at murgatroid.com  Wed Nov 12 13:34:27 2008
From: ch at murgatroid.com (christopher hoover)
Date: Wed, 12 Nov 2008 10:34:27 -0800
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <19DFB33ADA1F4F8482FE40479067637F@grendel>
References: <19DFB33ADA1F4F8482FE40479067637F@grendel>
Message-ID: <002001c944f5$4b98c830$e2ca5890$@com>

Gerry Ashton wrote:
> There have been requests on this list to gather requirements
> for civil time keeping. I would like to suggest one. Anyone
>
> Let me summarize my requirement:
> 
>    The legal definition of time shall be sufficiently
>    unambiguous that those with adequate equipment will
>    be able to determine the correct time to an accuracy
>    of 0.1 s or better.

This might make sense for situations involving a small number of parties,
say closing escrow in a real estate transaction, but it will be entirely
insufficient when large number of parties are involved or if the transaction
interarrival rate is of the same order.

Consider orders and quotes for securities.  A lot of orders and still more
(3-10x) quotes happen in 0.1 s.     The S.E.C does not allow you to
"shuffle" those about within a 0.1 s window.     Cf. [1].     

-ch


[1] http://en.wikipedia.org/wiki/RegNMS 



From phk at phk.freebsd.dk  Wed Nov 12 13:35:58 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 18:35:58 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 10:26:40 PST."
	<20081112182640.GA1934@ucolick.org> 
Message-ID: <5378.1226514958@critter.freebsd.dk>

In message <20081112182640.GA1934 at ucolick.org>, Steve Allen writes:

>Standards and laws are commonly disregarded, especially when those
>ignore the practicalities of reality.
>
>Worrying about the effect on the documentation aspects of deployed
>systems did not stop the CCIR from declaring a change to leap seconds
>in 1970.

I doubt you can get people to apply 1970-style quality assurance
in ISO9000 mandated organizations like telcos etc.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From cowan at ccil.org  Wed Nov 12 13:37:53 2008
From: cowan at ccil.org (John Cowan)
Date: Wed, 12 Nov 2008 13:37:53 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC@noao.edu>
References: <4379.1226506302@critter.freebsd.dk>
	<9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC@noao.edu>
Message-ID: <20081112183753.GC13292@mercury.ccil.org>

Rob Seaman scripsit:

> 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.

Even if it were a treaty rather than an IGO, treaties are not typically
self-executing: national legislation is usually required to implement them.

-- 
A rabbi whose congregation doesn't want         John Cowan
to drive him out of town isn't a rabbi,         http://www.ccil.org/~cowan
and a rabbi who lets them do it                 cowan at ccil.org
isn't a man.    --Jewish saying

From ashtongj at comcast.net  Wed Nov 12 13:53:10 2008
From: ashtongj at comcast.net (Gerard Ashton)
Date: Wed, 12 Nov 2008 13:53:10 -0500
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <002001c944f5$4b98c830$e2ca5890$@com>
Message-ID: <A22FDE6ABFB846E8911B0E396FDD0809@grendel>

I'm just stating a requirement. I leave open the possibility that other
requirements might be more stringent, thus making
my requirement redundant.

Gerry Ashton

-----Original Message-----
From: leapsecs-bounces at leapsecond.com
[mailto:leapsecs-bounces at leapsecond.com] On Behalf Of christopher hoover
Sent: Wednesday, November 12, 2008 1:34 PM
To: 'Leap Second Discussion List'
Subject: Re: [LEAPSECS] Synchronization requirement


Gerry Ashton wrote:
> There have been requests on this list to gather requirements
> for civil time keeping. I would like to suggest one. Anyone
>
> Let me summarize my requirement:
> 
>    The legal definition of time shall be sufficiently
>    unambiguous that those with adequate equipment will
>    be able to determine the correct time to an accuracy
>    of 0.1 s or better.

This might make sense for situations involving a small number of parties,
say closing escrow in a real estate transaction, but it will be entirely
insufficient when large number of parties are involved or if the transaction
interarrival rate is of the same order.

Consider orders and quotes for securities.  A lot of orders and still more
(3-10x) quotes happen in 0.1 s.     The S.E.C does not allow you to
"shuffle" those about within a 0.1 s window.     Cf. [1].     

-ch


[1] http://en.wikipedia.org/wiki/RegNMS 


_______________________________________________
LEAPSECS mailing list
LEAPSECS at leapsecond.com
http://six.pairlist.net/mailman/listinfo/leapsecs


From cowan at ccil.org  Wed Nov 12 13:56:05 2008
From: cowan at ccil.org (John Cowan)
Date: Wed, 12 Nov 2008 13:56:05 -0500
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <5353.1226514859@critter.freebsd.dk>
References: <alpine.LSU.2.00.0811121811350.30582@hermes-1.csi.cam.ac.uk>
	<5353.1226514859@critter.freebsd.dk>
Message-ID: <20081112185605.GD13292@mercury.ccil.org>

Poul-Henning Kamp scripsit:

> >They'd never be able to close any auctions :-)
> 
> They would, it works fine in most real-life auction houses.  

Real-life auction rooms don't routinely have tens of active bidders
for a particular item.  Waiting does not scale.

-- 
MEET US AT POINT ORANGE AT MIDNIGHT BRING YOUR DUCK OR PREPARE TO FACE WUGGUMS
John Cowan      cowan at ccil.org      http://www.ccil.org/~cowan

From psb at ast.cam.ac.uk  Wed Nov 12 13:57:06 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Wed, 12 Nov 2008 18:57:06 +0000 (GMT)
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <19DFB33ADA1F4F8482FE40479067637F@grendel>
References: <19DFB33ADA1F4F8482FE40479067637F@grendel>
Message-ID: <Pine.GSO.4.58.0811121847230.5901@cass03>



On Wed, 12 Nov 2008, Gerard Ashton wrote:

> There have been requests on this list to gather requirements
> for civil time keeping. I would like to suggest one. Anyone
> who has ever participated in an EBay auction will have noticed
> that all the savvy bidders wait to the very end to submit bids.

Sometime it does feel like we're going round and round:

On Fri, 5 Aug 2005, Tom Van Baak wrote:

> Things are more precise now; trains in Japan
> or Europe, synchronized traffic lights, TV show
> times, TiVo, 911 calls, ATM withdrawls, top of
> the hour radio broadcasts, stock and currency
> transactions, and such. My favorite example is
> eBay. It seems we are now in a world pushing
> an accuracy level of 1 second. (though, there
> are plenty of farmers who just need to know
> what day Spring begins)
>

> But I think a real requirement exists
> that a person operating a keyboard or mouse be able to depend
> on the civil time-of-day to within human reaction time,
> which is often taken to be 0.1 s.
>
>    The legal definition of time shall be sufficiently
>    unambiguous that those with adequate equipment will
>    be able to determine the correct time to an accuracy
>    of 0.1 s or better.
>

Sort of what I was getting at with human perception, but not so specific:

On Sun, 9 Nov 2008, Peter Bunclark wrote:
>
> So a User requirement might be:
> The rythms of life, including the orbits of the earth and the moon,
> the rotation of the earth, and convenient sub-divisions of the rotation
> down to nearly  the limit of human perception, shall be expressed in
> a single monotonic calendar.
>

Pete.

From phk at phk.freebsd.dk  Wed Nov 12 13:58:22 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Wed, 12 Nov 2008 18:58:22 +0000
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: Your message of "Wed, 12 Nov 2008 13:56:05 EST."
	<20081112185605.GD13292@mercury.ccil.org> 
Message-ID: <5477.1226516302@critter.freebsd.dk>

In message <20081112185605.GD13292 at mercury.ccil.org>, John Cowan writes:
>Poul-Henning Kamp scripsit:
>
>> >They'd never be able to close any auctions :-)
>> 
>> They would, it works fine in most real-life auction houses.  
>
>Real-life auction rooms don't routinely have tens of active bidders
>for a particular item.  Waiting does not scale.

It sure does, bidding stops automatically when the maximum attainable
price is reached.

Sniper bids is an attempt at buying the object at a price lower than
that, by preventing other bidders from revising their bids, thus
circumventing the purpose of the auction: to establish the highest
mutually agreeable price.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From clive at demon.net  Wed Nov 12 14:12:02 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Wed, 12 Nov 2008 19:12:02 +0000
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <19DFB33ADA1F4F8482FE40479067637F@grendel>
References: <19DFB33ADA1F4F8482FE40479067637F@grendel>
Message-ID: <20081112191202.GB80464@finch-staff-1.thus.net>

Gerard Ashton said:
> This would make the current
> civil time definitions inadequate, because at least one country,
> the UK, specifies Greenwich Mean Time as their basis of civil time
> and failed to address proposals to clarify whether this means
> UT1 or UTC.

You fail to understand what they are. Greenwich Mean Time is a very clearly
specified thing - it is solar mean time at Greenwich. You can debate
whether it means UT0, UT1, or UT2, but it is clearly not UTC. And I don't
believe the choice of 0, 1, or 2 is significant.

[Query: I'm not clear what the maximum difference is between UT0 measured
at Greenwich and UT1, but as I understand it |UT1-UT2| < 0.04s. Is that
right?]

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From ashtongj at comcast.net  Wed Nov 12 14:38:17 2008
From: ashtongj at comcast.net (Gerard Ashton)
Date: Wed, 12 Nov 2008 14:38:17 -0500
Subject: [LEAPSECS] Synchronization requirement
In-Reply-To: <20081112191202.GB80464@finch-staff-1.thus.net>
Message-ID: <F13D445C60F34AE8A0671B96C9AA8C60@grendel>

I consider the matter of whether for civil time-keeping purposes,
GMT is, or is not, UTC, is unresolved until the highest court in
the UK rules on a case where the difference is important. Courts
sometimes pay more attention to conduct than words, and I gather
that most clocks in the UK are set according to radio clocks
and then used for civil time-keeping. That course of conduct
might establish UTC as the basis of civil time, notwithstanding
any words written in any law.

Gerry Ashton

-----Original Message-----
From: leapsecs-bounces at leapsecond.com
[mailto:leapsecs-bounces at leapsecond.com] On Behalf Of Clive D.W. Feather
Sent: Wednesday, November 12, 2008 2:12 PM
To: Leap Second Discussion List
Subject: Re: [LEAPSECS] Synchronization requirement


Gerard Ashton said:
> This would make the current
> civil time definitions inadequate, because at least one country,
> the UK, specifies Greenwich Mean Time as their basis of civil time
> and failed to address proposals to clarify whether this means
> UT1 or UTC.

You fail to understand what they are. Greenwich Mean Time is a very clearly
specified thing - it is solar mean time at Greenwich. You can debate
whether it means UT0, UT1, or UT2, but it is clearly not UTC. And I don't
believe the choice of 0, 1, or 2 is significant.

[Query: I'm not clear what the maximum difference is between UT0 measured
at Greenwich and UT1, but as I understand it |UT1-UT2| < 0.04s. Is that
right?]

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | 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 at leapsecond.com
http://six.pairlist.net/mailman/listinfo/leapsecs


From seaman at noao.edu  Wed Nov 12 16:36:27 2008
From: seaman at noao.edu (Rob Seaman)
Date: Wed, 12 Nov 2008 14:36:27 -0700
Subject: [LEAPSECS] stack overflow
Message-ID: <4763DA55-0CF7-4C46-B45C-9B67D809F892@noao.edu>

Just back from the dentist and can't possibly spare the time to read  
all the intervening messages with the attention they deserve, so I'll  
just recommend (highly!) the book I'm currently reading:

	"The Stuff of Thought", by Steven Pinker

And pass on a lovely quote from Immanuel Kant that gives name,  
"Cleaving the Air", to chapter 4 from the book:

	"The light dove, cleaving the air in her free flight, and feeling its  
resistance, might imagine that its flight would be still easier in  
empty space."

In short, we are better off for the challenges presented us by "the  
surly bonds of Earth".  (A familiar phrase quoted during Gemini and  
Apollo, from the sonnet "High Flight" by John Gillespie Magee, Jr.   
Magee died at the age of 19 during WWII in a mid-air collision.)

A kite doesn't fly in spite of its string - it flies because of it.

Rob Seaman
NOAO
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://six.pairlist.net/pipermail/leapsecs/attachments/20081112/801e8062/attachment.htm>

From cowan at ccil.org  Wed Nov 12 17:58:28 2008
From: cowan at ccil.org (John Cowan)
Date: Wed, 12 Nov 2008 17:58:28 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112094422.GA40833@finch-staff-1.thus.net>
References: <alpine.LSU.2.00.0811111200170.23184@hermes-1.csi.cam.ac.uk>
	<89735.1226409250@critter.freebsd.dk>
	<20081112094422.GA40833@finch-staff-1.thus.net>
Message-ID: <20081112225827.GF13292@mercury.ccil.org>

Clive D.W. Feather scripsit:

> With two-bis being the misinterpretation of "every four years" in the
> Julian calendar, so that Feb 29th was added every *three* years for some
> time (Wikipedia suggests the most likely sequence was 44, 41, 38, 35, 32,
> 29, 26, 23, 20, 17, 14, 11, 8 BC, then a hiatus to correct the problem,
> then AD 4, 8, 12 etc.).

A natural mistake for the Romans, who seem to have made such fencepost
errors a convention:  their eight-day market week was called the
"nundinae", from "novem diem", and although December 31 was sensibly
"the day before the kalends of January", December 30 was "the third day
before the kalends of January", and so on back.

-- 
John Cowan          http://www.ccil.org/~cowan        cowan at ccil.org
To say that Bilbo's breath was taken away is no description at all.  There are
no words left to express his staggerment, since Men changed the language that
they learned of elves in the days when all the world was wonderful. --The Hobbit

From cowan at ccil.org  Wed Nov 12 18:13:10 2008
From: cowan at ccil.org (John Cowan)
Date: Wed, 12 Nov 2008 18:13:10 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112161858.GA69859@finch-staff-1.thus.net>
References: <1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
	<20081112090431.GA34814@finch-staff-1.thus.net>
	<20081112160629.GG23706@mercury.ccil.org>
	<20081112161858.GA69859@finch-staff-1.thus.net>
Message-ID: <20081112231310.GG13292@mercury.ccil.org>

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.

Ahhhhh, yessss.  For anyone who's not following this, see A. P. Herbert's
_Uncommon Law_.

-- 
Mos Eisley spaceport.  You will never           John Cowan
see a more wretched hive of scum and            cowan at ccil.org
villainy --unless you watch the                http://www.ccil.org/~cowan
Jerry Springer Show.   --georgettesworld.com

From cowan at ccil.org  Wed Nov 12 18:13:44 2008
From: cowan at ccil.org (John Cowan)
Date: Wed, 12 Nov 2008 18:13:44 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <Pine.GSO.4.58.0811121629040.5480@cass03>
References: <4379.1226506302@critter.freebsd.dk>
	<Pine.GSO.4.58.0811121629040.5480@cass03>
Message-ID: <20081112231343.GH13292@mercury.ccil.org>

Peter Bunclark scripsit:

> 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?

Modern Windows boxes do indeed do NTP, or rather SNTP.

-- 
I don't know half of you half as well           John Cowan
as I should like, and I like less than half     cowan at ccil.org
of you half as well as you deserve.             http://www.ccil.org/~cowan
        --Bilbo

From greg.hennessy at cox.net  Wed Nov 12 20:18:13 2008
From: greg.hennessy at cox.net (Greg Hennessy)
Date: Wed, 12 Nov 2008 20:18:13 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <4379.1226506302@critter.freebsd.dk>
References: <4379.1226506302@critter.freebsd.dk>
Message-ID: <491B8055.4010306@cox.net>


>> The adoption of TI would be massive and immediate.
> 
> And illegal on many systems, including all USGOV owned and operated
> systems.

Are you sure you want to be commenting on what is and is not legal
on US computers when you post from a .dk address?




From jhardis at tcs.wap.org  Wed Nov 12 21:13:46 2008
From: jhardis at tcs.wap.org (Jonathan E. Hardis)
Date: Wed, 12 Nov 2008 21:13:46 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <4851.1226511265@critter.freebsd.dk>
References: <4851.1226511265@critter.freebsd.dk>
Message-ID: <p06230900c5412c3b1f60@[192.168.0.5]>

>In message <9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC at noao.edu>, Rob Seaman writes:
>
>I thought USA went out of their way some years back, to make it
>clear that the relevant secretary (of commerce ?) decided what
>US timekeeping was and that it certainly had nothing to do with GMT ?
>
>Or was that laying the ground for US unlateral action on leap-seconds ?

What you have in mind is Section 3013 of the 
America COMPETES Act 
http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=110_cong_public_laws&docid=f:publ069.110.pdf 
.  It made a number of "Technical Amendments," 
which say among other things,

"COORDINATED UNIVERSAL TIME DEFINED.-In this section,
the term 'Coordinated Universal Time' means the time scale maintained
through the General Conference of Weights and Measures
and interpreted or modified for the United States by the Secretary
of Commerce in coordination with the Secretary of the Navy.''.


The General Conference of Weights and Measures 
(in French, the Conf?rence G?n?rale des Poids et 
Mesures, CGPM) was established by the Treaty of 
the Meter, which the Senate ratified in 1878. 
Amendments to the Treaty were ratified by the 
Senate in 1923.  One can infer from this that the 
longstanding policy of the U.S. Government has 
been that it's a good thing if measurements are 
the same worldwide, and that decisions of the 
CGPM carry some weight.

If you're looking for hidden meanings in this 
wording you need only compare it to the wording 
on how the Metric System is defined in the U.S. 
(as SI) -- it's EXACTLY THE SAME.  This wording 
has been around in the law since the mid-1960's, 
a few years after SI was established.

In case you're wondering, the power of the 
Secretary of Commerce has been used to "interpret 
or modify" SI.  In the U.S., it's "meter" and 
"liter," not "metre" and "litre."


>In message <9EE85ED8-DCC8-4299-BF59-E1E322D8D1CC at noao.edu>, Rob Seaman writes:
>
>>Poul-Henning Kamp wrote:
>>
>>>  And illegal on many systems, including all USGOV owned and operated 
>>>  systems.
>>
>>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.
>
>No, ITU does not have treaty status, you are supposed to follow their
>recommedations and standards, unless there is specific national
>regulation.


The ITU is a U.N. agency.

It's really been amusing to read so many people 
say what is/was legal and what is/was not, on a 
whole variety of points.

Let's take a survey:

   * Who on this mailing list is a lawyer?

   * 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.)

Frankly, a lot of what I've been reading here 
sounds like it's really overreaching.  It's 
perfectly possible for precise legalities to be 
never determined because they never arise as a 
point of meaningful controversy.

    - Jonathan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://six.pairlist.net/pipermail/leapsecs/attachments/20081112/3f1697bf/attachment-0001.html>

From jsm at polyomino.org.uk  Wed Nov 12 21:47:16 2008
From: jsm at polyomino.org.uk (Joseph S. Myers)
Date: Thu, 13 Nov 2008 02:47:16 +0000 (UTC)
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <p06230900c5412c3b1f60@[192.168.0.5]>
References: <4851.1226511265@critter.freebsd.dk>
	<p06230900c5412c3b1f60@[192.168.0.5]>
Message-ID: <Pine.LNX.4.64.0811130232380.22077@digraph.polyomino.org.uk>

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
jsm at polyomino.org.uk

From mgy1912 at cox.net  Wed Nov 12 22:44:25 2008
From: mgy1912 at cox.net (Brian Garrett)
Date: Wed, 12 Nov 2008 19:44:25 -0800
Subject: [LEAPSECS] Synchronization requirement
References: <5477.1226516302@critter.freebsd.dk>
Message-ID: <921C6DF3C1C440BDAA5C5D8A36E8AC69@company48fcb68>


----- Original Message ----- 
From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
To: "Leap Second Discussion List" <leapsecs at leapsecond.com>
Sent: Wednesday, November 12, 2008 10:58 AM
Subject: Re: [LEAPSECS] Synchronization requirement


> In message <20081112185605.GD13292 at mercury.ccil.org>, John Cowan writes:
>>Poul-Henning Kamp scripsit:
>>
>>> >They'd never be able to close any auctions :-)
>>>
>>> They would, it works fine in most real-life auction houses.
>>
>>Real-life auction rooms don't routinely have tens of active bidders
>>for a particular item.  Waiting does not scale.
>
> It sure does, bidding stops automatically when the maximum attainable
> price is reached.
>
> Sniper bids is an attempt at buying the object at a price lower than
> that, by preventing other bidders from revising their bids, thus
> circumventing the purpose of the auction: to establish the highest
> mutually agreeable price.
>
> Poul-Henning
>
I was wondering when somebody was going to mention sniper bids.  These are 
automated and require reliable synchronization so as to get bids in at 
literally the very last second.  It would be easy to imagine a lawsuit filed 
regarding such a bid received at 23:59:59.xxx on New Year's Eve with a leap 
second underway.  Then, lawyers could easily split hairs over DUT1 and all 
that good stuff.  (And, such lawsuits had _better_ happen, if this subject 
is ever to be seen as anything but an academic wank-a-thon by Mr. and Ms. 
Average Citizen--in which case, we might actually get laws that reference 
civil time to actual timescales, instead of "mean solar time of 15 degrees 
east longitude" and the like.)


Brian Garrett 


From mgy1912 at cox.net  Wed Nov 12 22:51:45 2008
From: mgy1912 at cox.net (Brian Garrett)
Date: Wed, 12 Nov 2008 19:51:45 -0800
Subject: [LEAPSECS] The relation between calendars and leap seconds.
References: <mailman.27.1226163641.78129.leapsecs@leapsecond.com><61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net><20081109020827.GA4815@ucolick.org><1226196779.12771.11.camel@glastonbury><Pine.GSO.4.58.0811090857500.23237@cass03><alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk><Pine.GSO.4.58.0811101216410.27695@cass03><alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk><92833382-E016-495E-A505-86CC87ACBF23@noao.edu><alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk><20081112090431.GA34814@finch-staff-1.thus.net><1CF841CB-D4BB-4EF0-A556-0C6EEA9C5EEA@noao.edu>
	<CB191BA7-489E-407F-926A-BA4C924DD037@noao.edu>
Message-ID: <975A820773D94B9492CABA349D91D363@company48fcb68>


----- Original Message ----- 
From: "Rob Seaman" <seaman at noao.edu>
To: "Leap Second Discussion List" <leapsecs at leapsecond.com>
Sent: Wednesday, November 12, 2008 6:48 AM
Subject: 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"?
> 
At the third stroke, it will be 0dark:30, precisely  (beep, beep, beep)


Brian

From sla at ucolick.org  Thu Nov 13 01:50:35 2008
From: sla at ucolick.org (Steve Allen)
Date: Wed, 12 Nov 2008 22:50:35 -0800
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112090431.GA34814@finch-staff-1.thus.net>
References: <61767D4BE247724E8A1A8932B2B1B3DA06A5E9FB@emailwf1.jnpr.net>
	<20081109020827.GA4815@ucolick.org>
	<1226196779.12771.11.camel@glastonbury>
	<Pine.GSO.4.58.0811090857500.23237@cass03>
	<alpine.LSU.2.00.0811101155370.30582@hermes-1.csi.cam.ac.uk>
	<Pine.GSO.4.58.0811101216410.27695@cass03>
	<alpine.LSU.2.00.0811101504090.23184@hermes-1.csi.cam.ac.uk>
	<92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<alpine.LSU.2.00.0811111205210.23184@hermes-1.csi.cam.ac.uk>
	<20081112090431.GA34814@finch-staff-1.thus.net>
Message-ID: <20081113065035.GA8332@ucolick.org>

On Wed 2008-11-12T09:04:31 +0000, Clive D.W. Feather hath writ:
> My legal research has failed to find any definition in statute of "sunrise"
> and "sunset".

Sunset?
To quote from Buffy the Vampire Slayer "DoubleMeat Palace":
It's a process.

As seen in the following link, especially in the first two frames from
the same film strip in the 35 mm movie camera

http://www.ucolick.org/~sla/sunset/

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From seaman at noao.edu  Thu Nov 13 02:51:02 2008
From: seaman at noao.edu (Rob Seaman)
Date: Thu, 13 Nov 2008 00:51:02 -0700
Subject: [LEAPSECS] Synchronization requirement?
In-Reply-To: <921C6DF3C1C440BDAA5C5D8A36E8AC69@company48fcb68>
References: <5477.1226516302@critter.freebsd.dk>
	<921C6DF3C1C440BDAA5C5D8A36E8AC69@company48fcb68>
Message-ID: <89B6A754-57FA-44A4-8B1A-E972861629AB@noao.edu>

Brian Garrett wrote:

> I was wondering when somebody was going to mention sniper bids.   
> These are automated and require reliable synchronization so as to  
> get bids in at literally the very last second.
> [...]
> laws that reference civil time to actual timescales, instead of  
> "mean solar time of 15 degrees east longitude" and the like.)

I'm tempted to pen a defense of mean solar time as an "actual  
timescale".  What does "actual" mean, if not something that can be  
measured from first principles?

The real issue here, however, is transport of time signals, not their  
definition.  From an architectural standpoint, it isn't immediately  
clear that a special purpose timekeeping application like an online  
auction has a requirement for close synchronization with an external  
timescale, so much as a requirement for close synchronization among  
its own clients.  For example, a traditional auction takes place at  
some specific place and time, but once the auction starts for a  
particular lot, the bidders either physically present or participating  
by phone proxy are bound only by the cadences of the auctioneering  
process, not by an external clock.

A lot of the issues that we've discussed on this mailing list share an  
underlying etiology of choosing the wrong timescale for a particular  
application.  With civil timekeeping we might argue, for instance,  
over whether an inappropriate choice of timescale is being forced on  
one group or another.  But for many timekeeping applications, the key  
requirements are for relative, not absolute, synchronization.   
Overloading the project requirements by demanding tight compliance  
with some absolute standard may result in sacrificing performance  
elsewhere in the system.

To be more specific, there is nothing ebay can do to enforce that  
their customers have computers with properly set system clocks.  What  
ebay could do is build a dedicated NTP service into their system, and  
promulgate their own time signals tying their servers as tightly as  
needed to user client applications.  Whether ebay's clocks are then  
themselves tied to external time signals is a completely separate issue.

Which is all to say that it might benefit the larger discussion to  
question a few underlying assumptions, to vet and perhaps reject some  
premises.  I know why astronomers need access to universal time - it  
provides a utilitarian representation of Earth orientation metadata.   
Just so with navigation, tide tables, wind and weather and other  
diurnally tied phenomena.  We've also mentioned other legal, economic,  
political, etc. use cases for distributed timescales, diurnal or not.   
What are the use cases for tying widely disparate systems jointly  
together, however?

When there is an election, the public needs to know when the polls  
open and close.  Traders need to know when the stock market opens and  
closes.  Computer databases and code build tools need to interoperate  
across local or wide area networks.  But why do we assume that these  
several purposes need to be tied together?

Is this a requirement - or rather only a presumptive convenience?

Rob Seaman
NOAO


From phk at phk.freebsd.dk  Thu Nov 13 03:35:28 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Thu, 13 Nov 2008 08:35:28 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 18:13:44 EST."
	<20081112231343.GH13292@mercury.ccil.org> 
Message-ID: <8964.1226565328@critter.freebsd.dk>

In message <20081112231343.GH13292 at mercury.ccil.org>, John Cowan writes:
>Peter Bunclark scripsit:
>
>> 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?

No, because the do it according to POSIX, as mandated.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From phk at phk.freebsd.dk  Thu Nov 13 03:37:17 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Thu, 13 Nov 2008 08:37:17 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 20:18:13 EST."
	<491B8055.4010306@cox.net> 
Message-ID: <8976.1226565437@critter.freebsd.dk>

In message <491B8055.4010306 at cox.net>, Greg Hennessy writes:
>
>>> The adoption of TI would be massive and immediate.
>> 
>> And illegal on many systems, including all USGOV owned and operated
>> systems.
>
>Are you sure you want to be commenting on what is and is not legal
>on US computers when you post from a .dk address?

It might be a relevant detail that I have been in the operating
system business since 1992, and were both core team member and
release engineer for a couple of major FreeBSD releases.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From phk at phk.freebsd.dk  Thu Nov 13 03:49:28 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Thu, 13 Nov 2008 08:49:28 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Wed, 12 Nov 2008 21:13:46 EST."
	<p06230900c5412c3b1f60@[192.168.0.5]> 
Message-ID: <9028.1226566168@critter.freebsd.dk>

In message <p06230900c5412c3b1f60@[192.168.0.5]>, "Jonathan E. Hardis" writes:

>>I thought USA went out of their way some years back, to make it
>>clear that the relevant secretary (of commerce ?) decided what
>>US timekeeping was and that it certainly had nothing to do with GMT ?
>>
>>Or was that laying the ground for US unlateral action on leap-seconds ?
>
>What you have in mind is Section 3013 of the America COMPETES Act 

>and interpreted or modified for the United States by the Secretary
>of Commerce in coordination with the Secretary of the Navy.''.

Yes, somebody on this list made a big deal out of that :-)

>>>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.
>>
>>No, ITU does not have treaty status, you are supposed to follow their
>>recommedations and standards, unless there is specific national
>>regulation.
>
>The ITU is a U.N. agency.

Yes, but their recommendations and standards do not automatically
acquire treaty-status for that reason.

>   * 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.)

	"Absent case law, the law is what reasonable people interpret
	it to mean, case law only happens when some of them are not
	reasonable."

>Frankly, a lot of what I've been reading here 
>sounds like it's really overreaching.

You mean stuff like "Lets just ignore federal regulations and do things
the way we want to, they can fix the problems when they notice them."
(paraphrasing)

Yes, that would certainly be overreaching.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From psb at ast.cam.ac.uk  Thu Nov 13 04:13:10 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Thu, 13 Nov 2008 09:13:10 +0000 (GMT)
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081112231343.GH13292@mercury.ccil.org>
References: <4379.1226506302@critter.freebsd.dk>
	<Pine.GSO.4.58.0811121629040.5480@cass03>
	<20081112231343.GH13292@mercury.ccil.org>
Message-ID: <Pine.GSO.4.58.0811130908570.7594@cass03>



On Wed, 12 Nov 2008, John Cowan wrote:

> Peter Bunclark scripsit:
>
> > 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?
>
> Modern Windows boxes do indeed do NTP, or rather SNTP.

Yes, but only if you set them up, they sync once a day, if they're booted
at the scheduled time, and if they're not so firewalled they can't talk to
an NTP server. In between they free run, so at best the clock sawtooths.

Pete.

From nimh at pipe.nl  Thu Nov 13 04:17:10 2008
From: nimh at pipe.nl (Nero Imhard)
Date: Thu, 13 Nov 2008 10:17:10 +0100 (CET)
Subject: [LEAPSECS] Synchronization requirement?
In-Reply-To: <89B6A754-57FA-44A4-8B1A-E972861629AB@noao.edu>
References: <5477.1226516302@critter.freebsd.dk>
	<921C6DF3C1C440BDAA5C5D8A36E8AC69@company48fcb68>
	<89B6A754-57FA-44A4-8B1A-E972861629AB@noao.edu>
Message-ID: <28528.87.249.99.109.1226567830.squirrel@webmail.wiggy.net>

> But why do we assume that these
> several purposes need to be tied together?

Because if we don't, we effectively require that each application
(purpose) explicitly defines (and - $deity forbid - possibly also
provides) a time scale. The whole idea behind a widely accepted
"universal" time is its universal usability.

N

From phk at phk.freebsd.dk  Thu Nov 13 04:38:13 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Thu, 13 Nov 2008 09:38:13 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Thu, 13 Nov 2008 09:13:10 GMT."
	<Pine.GSO.4.58.0811130908570.7594@cass03> 
Message-ID: <9393.1226569093@critter.freebsd.dk>

In message <Pine.GSO.4.58.0811130908570.7594 at cass03>, Peter Bunclark writes:
>
>
>On Wed, 12 Nov 2008, John Cowan wrote:
>
>> Peter Bunclark scripsit:
>>
>> > 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?
>>
>> Modern Windows boxes do indeed do NTP, or rather SNTP.
>
>Yes, but only if you set them up, they sync once a day, if they're booted
>at the scheduled time, and if they're not so firewalled they can't talk to
>an NTP server. In between they free run, so at best the clock sawtooths.

Neither POSIX nor FIPS-151-2 mandates that you run NTP and I know of
no other blanket requirement for this covering Federal systems.

The POSIX and FIPS-151-2 requirement is that you use UTC (with 86400
seconds per day), they doesn't say how good you have to be at it.

In other words: if you set your hourglass after your WWVB alarm
clock, and turn it over as required, all the way in the subway to
work, and then set the clock on www.cia.gov from it, then you are
in compliance.

If you set up a high quality radio-clock which steers your personal
office workstation in the Bureau of Tobacco, Arms & Alcohol to
within 1 microsecond of Robs "TI" timescale, then you are non-compliant,
*even* if TI == UTC at that point in time.

On the other hand, the Sarbanne-Oxley legislation had a lot of
$BIGCORP scrambling for timesynch of their systems because their
lawyers interpreted it to have an implicit requirement for traceability
to UTC time on all "relevant" computers.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From pete.forman at westerngeco.com  Thu Nov 13 04:47:19 2008
From: pete.forman at westerngeco.com (Pete Forman)
Date: Thu, 13 Nov 2008 09:47:19 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <alpine.LSU.2.00.0811121500220.30582@hermes-1.csi.cam.ac.uk>
References: <92833382-E016-495E-A505-86CC87ACBF23@noao.edu>
	<74553.1226395041@critter.freebsd.dk>
	<20081111180003.GA26971@ucolick.org>
	<20081112094656.GB40833@finch-staff-1.thus.net>
	<6443144D-7935-43B7-98A8-729DCBFE5824@noao.edu>
	<alpine.LSU.2.00.0811121500220.30582@hermes-1.csi.cam.ac.uk>
Message-ID: <7.0.1.0.2.20081113094014.04cd56d0@gatwick.westerngeco.slb.com>

At 2008-11-12 15:02 +0000, Tony Finch wrote:
>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.

That is not so.  The POSIX definition of Seconds Since the Epoch contains:
>If the year is <1970 or the value is negative, the relationship is undefined.

-- 
Pete Forman                -./\.-  Disclaimer: This post is originated
WesternGeco                  -./\.-   by myself and does not represent
pete.forman at westerngeco.com    -./\.-   the opinion of Schlumberger or
http://petef.22web.net           -./\.-   WesternGeco.


From greg.hennessy at cox.net  Thu Nov 13 07:31:09 2008
From: greg.hennessy at cox.net (Greg Hennessy)
Date: Thu, 13 Nov 2008 07:31:09 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <8976.1226565437@critter.freebsd.dk>
References: <8976.1226565437@critter.freebsd.dk>
Message-ID: <491C1E0D.8040305@cox.net>

Or it might not be relevant.

I actually purchase and set up computers
at a DoD agency (the Naval Observatory
as a matter of fact) and my opinion differs
from yours in some details.



Poul-Henning Kamp wrote:
> In message <491B8055.4010306 at cox.net>, Greg Hennessy writes:
>>>> The adoption of TI would be massive and immediate.
>>> And illegal on many systems, including all USGOV owned and operated
>>> systems.
>> Are you sure you want to be commenting on what is and is not legal
>> on US computers when you post from a .dk address?
> 
> It might be a relevant detail that I have been in the operating
> system business since 1992, and were both core team member and
> release engineer for a couple of major FreeBSD releases.
> 

From phk at phk.freebsd.dk  Thu Nov 13 07:36:57 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Thu, 13 Nov 2008 12:36:57 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Thu, 13 Nov 2008 07:31:09 EST."
	<491C1E0D.8040305@cox.net> 
Message-ID: <22959.1226579817@critter.freebsd.dk>

In message <491C1E0D.8040305 at cox.net>, Greg Hennessy writes:
>Or it might not be relevant.
>
>I actually purchase and set up computers
>at a DoD agency (the Naval Observatory
>as a matter of fact) and my opinion differs
>from yours in some details.

This is not meant as an accusation but I will note, in general,
that some person holding a particualr job is no guarantee that
applicable regulations gets followed.

I have no problem with you having a different opinion.

I do have a problem with you questioning my knowledge of the area.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From seaman at noao.edu  Thu Nov 13 09:07:33 2008
From: seaman at noao.edu (Rob Seaman)
Date: Thu, 13 Nov 2008 07:07:33 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <9393.1226569093@critter.freebsd.dk>
References: <9393.1226569093@critter.freebsd.dk>
Message-ID: <5B6C8982-5158-4921-BF39-DC957FA9B9D7@noao.edu>

Poul-Henning Kamp wrote:

> The POSIX and FIPS-151-2 requirement is that you use UTC (with 86400
> seconds per day), they doesn't say how good you have to be at it.
>
> In other words: if you set your hourglass after your WWVB alarm
> clock, and turn it over as required, all the way in the subway to
> work, and then set the clock on www.cia.gov from it, then you are
> in compliance.

Hmmm.  Forget about the details of the two main positions historically  
prevalent on this list.  Call them position "A" and position "B",  
rather than "leap seconds must die!" and "friend of mean solar time",  
respectively.

It occurs to me that I may not actually understand the underlying  
motivation for someone to hold position "A".  (We've been over and  
over the motivations behind position "B".)

I thought the motivation for holding position "A", was something like  
"commercial entities, especially those beholden to POSIX, throw a  
tizzy at each leap second".  I'm not here to debate the  
appropriateness of this motivation.  Rather, just - is this actually  
(more or less) it?

Because what you are saying here is the converse of that statement.   
The description above is not of commercial and personal systems that  
need highly regular time signals without interruption to intervening  
intervals.  The description above is simply of bending over backward  
to match some broken regulatory ("non-functional") requirement, no  
matter how irregular the timescale has to be.

Wouldn't time be better spent correcting the requirement?

> If you set up a high quality radio-clock which steers your personal
> office workstation in the Bureau of Tobacco, Arms & Alcohol to
> within 1 microsecond of Robs "TI" timescale, then you are non- 
> compliant,
> *even* if TI == UTC at that point in time.

Here's another of those strawman positions, set up just to be  
rhetorically knocked down.

It isn't my TI, of course, but rather the consensus of the only public  
meeting held on the topic.  I didn't attend that meeting.  In any  
event, I would have argued for some different name if nothing else.   
We're likely to be sued by the company that makes Beanie Babies :-)

> On the other hand, the Sarbanne-Oxley legislation had a lot of
> $BIGCORP scrambling for timesynch of their systems because their
> lawyers interpreted it to have an implicit requirement for  
> traceability
> to UTC time on all "relevant" computers.

System design by lawyer.  There's a recipe for success!

Rob Seaman
NOAO

From phk at phk.freebsd.dk  Thu Nov 13 09:37:36 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Thu, 13 Nov 2008 14:37:36 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Thu, 13 Nov 2008 07:07:33 MST."
	<5B6C8982-5158-4921-BF39-DC957FA9B9D7@noao.edu> 
Message-ID: <31367.1226587056@critter.freebsd.dk>

In message <5B6C8982-5158-4921-BF39-DC957FA9B9D7 at noao.edu>, Rob Seaman writes:
>Poul-Henning Kamp wrote:

>Here's another of those strawman positions, set up just to be  
>rhetorically knocked down.

Funny how anything that might impede your posistion is a strawman argument
whereas anything we say "you just don't understand".

No wonder the WP7A people stay away from here.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From nimh at pipe.nl  Thu Nov 13 14:34:41 2008
From: nimh at pipe.nl (Nero Imhard)
Date: Thu, 13 Nov 2008 20:34:41 +0100
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <5B6C8982-5158-4921-BF39-DC957FA9B9D7@noao.edu>
References: <9393.1226569093@critter.freebsd.dk>
	<5B6C8982-5158-4921-BF39-DC957FA9B9D7@noao.edu>
Message-ID: <70D63E00-7564-40ED-B4FC-8A0B7611C069@pipe.nl>


On 2008-11-13, at 15:07, Rob Seaman wrote:
>
> Hmmm.  Forget about the details of the two main positions  
> historically prevalent on this list.  Call them position "A" and  
> position "B", rather than "leap seconds must die!" and "friend of  
> mean solar time", respectively.

I read this list quite differently. The core of the ITU/UTC-issue  
seems to be whether it is appropriate/ethical/allowed to change the  
definition of a widely used existing time scale in mid-flight rather  
than construct new or use existing time scales according to whatever  
requirements you may have (and others may not have).

As I see it, the two main positions on this particular issue are X:  
"definitions may change" and Y: "are you silly?", but this is somewhat  
obscured by discussions about the merits of leap seconds (only natural  
for this list).

I don't need to care deeply about leap seconds to vehemenently oppose X.

N



From imp at bsdimp.com  Thu Nov 13 17:04:22 2008
From: imp at bsdimp.com (M. Warner Losh)
Date: Thu, 13 Nov 2008 15:04:22 -0700 (MST)
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <F2A54D51-65ED-42DB-8912-51D8C949F619@noao.edu>
References: <67561FDB-4FA2-4084-943D-973310B60795@noao.edu>
	<20081112044821.GD23706@mercury.ccil.org>
	<F2A54D51-65ED-42DB-8912-51D8C949F619@noao.edu>
Message-ID: <20081113.150422.-484491870.imp@bsdimp.com>

In message: <F2A54D51-65ED-42DB-8912-51D8C949F619 at noao.edu>
            Rob Seaman <seaman at noao.edu> writes:
: 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.

Yes.  But the times that I've proposed loosening DUT1 from +/- .9s (or
is it +/- 1.0s? today) to something like 10s so that you could account
for the long term trends of DUT1 and be able to predict out for 50
years with reasonable degrees of certainty, the details get shot down
by you, Mr. Seaman.  Or at least did in the early days of this debate.
The main practical effect of this would be that there'd be a 10x
increase in the error term for the uncorrected time, worst case, over
methods used today.  Already +/- 1s isn't anywhere near good enough to
aim larger telescopes with the precision necessary to do good science.
You need at least 1000x better numbers, which the better software
grabs off the net from published sources.  If DUT were to float, the
effect would be small.  Many of the DUT1 tables are published with
fixed columns, so the data format there would need to change...

Basically, your suggesting that the mean solar time remaining in sync
to earth's orientation be true, but with a longer averaging time than
we have today.

In reality, an extreme form of this is the leap hour.  It sets DUT1 to
be ~3000x looser than it is today, and extends the mean solar time to
be true on time scales measured in centuries rather than in terms of
decades.  There's really no difference between this and the other
proposals, except the size of the corrections that folks interested in
celestial positions will need to apply to their calculations.

None of these proposals, however, make UTC a mechanical calendar, or
UTC have a fixed radix.  It would still be an observational one, even
if the practical aspects of adjustment were made less burdensome.

At least the Gregorian calendar made the counting of the days totally
mechanical for the next 10k-100k years or so.  This is a far cry from
the counting of the seconds, which is mechanical for only on the order
of a year or two (worst case 6 months).

Warner

From clive at demon.net  Thu Nov 13 18:25:41 2008
From: clive at demon.net (Clive D.W. Feather)
Date: Thu, 13 Nov 2008 23:25:41 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <p06230900c5412c3b1f60@[192.168.0.5]>
References: <4851.1226511265@critter.freebsd.dk>
	<p06230900c5412c3b1f60@[192.168.0.5]>
Message-ID: <20081113232541.GA91396@finch-staff-1.thus.net>

Jonathan E. Hardis said:
> Let's take a survey:
> 
>   * Who on this mailing list is a lawyer?

Not me.

>   * Who can cite case law, where a court has had to decide an actual
>     controversy on timekeeping?

Me. I did so the other day. So have others (notably the case that defined
legal time as local solar time).


-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS - a Cable and Wireless business

From jhardis at tcs.wap.org  Thu Nov 13 21:31:54 2008
From: jhardis at tcs.wap.org (Jonathan E. Hardis)
Date: Thu, 13 Nov 2008 21:31:54 -0500
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <9393.1226569093@critter.freebsd.dk>
References: <9393.1226569093@critter.freebsd.dk>
Message-ID: <p06230901c54292430af6@[192.168.0.5]>

>The POSIX and FIPS-151-2 requirement is that you use UTC (with 86400
>seconds per day), they doesn't say how good you have to be at it.

Hey guys, I hate to spoil all of your fun, but FIPS 151-2 was 
WITHDRAWN eight years ago.

http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2000_register&docid=fr25fe00-39.pdf


   - Jonathan

From seaman at noao.edu  Thu Nov 13 22:42:01 2008
From: seaman at noao.edu (Rob Seaman)
Date: Thu, 13 Nov 2008 20:42:01 -0700
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: <20081113.150422.-484491870.imp@bsdimp.com>
References: <67561FDB-4FA2-4084-943D-973310B60795@noao.edu>
	<20081112044821.GD23706@mercury.ccil.org>
	<F2A54D51-65ED-42DB-8912-51D8C949F619@noao.edu>
	<20081113.150422.-484491870.imp@bsdimp.com>
Message-ID: <52B08CFE-F0B9-40BE-88E2-88CAABAA77BF@noao.edu>

M. Warner Losh wrote:

> Yes.  But the times that I've proposed loosening DUT1 from +/- .9s (or
> is it +/- 1.0s? today) to something like 10s so that you could account
> for the long term trends of DUT1 and be able to predict out for 50
> years with reasonable degrees of certainty, the details get shot down
> by you, Mr. Seaman.

What special powers do I really have to shoot proposals down?  Either  
a proposal can stand on its own merits or it can't.  In the former  
case, why does my opinion matter any more than your own?  If the  
latter case, I guess you're saying that I pointed out actual flaws in  
the logic.  If you want to make a case for relaxing the balance  
between DUT1 amplitude and scheduling horizon, go for it.

> In reality, an extreme form of this is the leap hour.  It sets DUT1 to
> be ~3000x looser than it is today, and extends the mean solar time to
> be true on time scales measured in centuries rather than in terms of
> decades.  There's really no difference between this and the other
> proposals, except the size of the corrections that folks interested in
> celestial positions will need to apply to their calculations.

The difference is that there is no coherent way to actually issue a  
leap hour.  These would not be the same thing as a DST adjustment.  A  
leap second happens at the same moment worldwide, so would a leap  
hour.  The only coherent way to do this is to make one really long  
minute, otherwise you would be interpolating the 25th hour in between  
different hours around the world.

Rob


From phk at phk.freebsd.dk  Fri Nov 14 03:37:50 2008
From: phk at phk.freebsd.dk (Poul-Henning Kamp)
Date: Fri, 14 Nov 2008 08:37:50 +0000
Subject: [LEAPSECS] The relation between calendars and leap seconds.
In-Reply-To: Your message of "Thu, 13 Nov 2008 21:31:54 EST."
	<p06230901c54292430af6@[192.168.0.5]> 
Message-ID: <46647.1226651870@critter.freebsd.dk>

In message <p06230901c54292430af6@[192.168.0.5]>, "Jonathan E. Hardis" writes:
>>The POSIX and FIPS-151-2 requirement is that you use UTC (with 86400
>>seconds per day), they doesn't say how good you have to be at it.
>
>Hey guys, I hate to spoil all of your fun, but FIPS 151-2 was 
>WITHDRAWN eight years ago.
>
>http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2000_register&docid=fr25fe00-39.pdf

Yes, and replaced with different requirements with just about exactly
the same content.

The problem was standards-political, basically The Open Group decided
on an economic model that called for all "certified UNIX" O/S's to
undergo regular (each release) expensive validations.

Open Source operating systems objected to being foreclosed on in this
manner, and as a result 151-2 was declared "obsolete" so that DoD could
deploy uncertified Linux and FreeBSD systems.

POSIX is still mandated, now you just have to look all over the place
for the requirement, for instance DISA COE.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

From psb at ast.cam.ac.uk  Fri Nov 14 04:43:37 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Fri, 14 Nov 2008 09:43:37 +0000 (GMT)
Subject: [LEAPSECS] UTC and Telescope Control.
In-Reply-To: <20081113.150422.-484491870.imp@bsdimp.com>
References: <67561FDB-4FA2-4084-943D-973310B60795@noao.edu>
	<20081112044821.GD23706@mercury.ccil.org>
	<F2A54D51-65ED-42DB-8912-51D8C949F619@noao.edu>
	<20081113.150422.-484491870.imp@bsdimp.com>
Message-ID: <Pine.GSO.4.58.0811140918260.3737@cass03>



On Thu, 13 Nov 2008, M. Warner Losh wrote:

> methods used today.  Already +/- 1s isn't anywhere near good enough to
> aim larger telescopes with the precision necessary to do good science.

I've been worrying for some time that we have been overstating the
telescope problem.

Prior to 1990 (very loosly) telescopes were built on an equatorial axis,
in which the polar axis is aligned parallel to earth's axis. Notionally,
they just need to be driven at a constant sidereal rate to track the
stars. After that, large telescopes were built on alt-azimuth axes,
basically like an overgrown theodolite, because computer technology made
the complex real-time axis control possible, and the mount was more
compact, less flexible, required smaller building == much cheaper.

Alt-az telescopes can't use UTC as an approximation to earth-rotation
angle, for .1 arcsec tracking you need hand-wavingley 1/150 second clock
accuracy.  So they always have to apply DUT1 (no matter how big it gets).

Equatorial telescopes get off a little lighter, because a clock error
amounts to a simple offset in the RA axis. Such telescopes also, because
of their vintage, often have axis encoders which don't initialise to a
precise zero point; so part of the nightly startup procedure tends to be
to acquire an unmistakeable bright star, centre it on the TV, and tell the
TCS to reset the zero point.  This removes both encoder and clock error.

The only related issue I've been able to find is at least one
user-interfaces which traps the operator from entering a DUT1 > 0.9s. So
there would be a cost in fixing telescope software; I think we should be
careful not to overstate it.

Pete.

From seaman at noao.edu  Fri Nov 14 11:50:59 2008
From: seaman at noao.edu (Rob Seaman)
Date: Fri, 14 Nov 2008 09:50:59 -0700
Subject: [LEAPSECS] Synchronization requirement?
In-Reply-To: <28528.87.249.99.109.1226567830.squirrel@webmail.wiggy.net>
References: <5477.1226516302@critter.freebsd.dk>
	<921C6DF3C1C440BDAA5C5D8A36E8AC69@company48fcb68>
	<89B6A754-57FA-44A4-8B1A-E972861629AB@noao.edu>
	<28528.87.249.99.109.1226567830.squirrel@webmail.wiggy.net>
Message-ID: <23D29C32-7C6A-4718-ADE4-4609B0D3DC8A@noao.edu>

My point was that some applications have requirements more tied to  
relative timekeeping, than to absolute timekeeping.  Universal  
usability (a rather loftier goal than I think anybody is actually  
pursuing) wouldn't imply that such a universally "usable" timescale is  
optimum for all purposes.  Conversely, there are many examples of  
using task defined timescale for some specific purpose - this says  
nothing about the design goals for a generally useful civil timescale.

In any event, the goal of system engineering is not to identify the  
optimum solution, but rather, a satisfactory solution.

Rob
--

On Nov 13, 2008, at 2:17 AM, Nero Imhard wrote:

>> But why do we assume that these
>> several purposes need to be tied together?
>
> Because if we don't, we effectively require that each application
> (purpose) explicitly defines (and - $deity forbid - possibly also
> provides) a time scale. The whole idea behind a widely accepted
> "universal" time is its universal usability.
>
> N
> _______________________________________________
> LEAPSECS mailing list
> LEAPSECS at leapsecond.com
> http://six.pairlist.net/mailman/listinfo/leapsecs


From sla at ucolick.org  Mon Nov 24 09:12:30 2008
From: sla at ucolick.org (Steve Allen)
Date: Mon, 24 Nov 2008 06:12:30 -0800
Subject: [LEAPSECS] leap second media coverage
Message-ID: <20081124141230.GA29996@ucolick.org>

Here's an article on the upcoming leap second

http://www.airspacemag.com/flight-today/One-More-Second.html

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From psb at ast.cam.ac.uk  Mon Nov 24 09:26:29 2008
From: psb at ast.cam.ac.uk (Peter Bunclark)
Date: Mon, 24 Nov 2008 14:26:29 +0000 (GMT)
Subject: [LEAPSECS] leap second media coverage
In-Reply-To: <20081124141230.GA29996@ucolick.org>
References: <20081124141230.GA29996@ucolick.org>
Message-ID: <Pine.GSO.4.58.0811241422190.15657@cass03>

Ah, glad to hear "Timekeepers in Greenwich, England, the location of a
world time standard..."

Would hate to think foreigners had got their hands on it.

Pete.

On Mon, 24 Nov 2008, Steve Allen wrote:

> Here's an article on the upcoming leap second
>
> http://www.airspacemag.com/flight-today/One-More-Second.html
>
> --
> Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
> UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
> University of California    Voice: +1 831 459 3046           Lng -122.06015
> Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m
> _______________________________________________
> LEAPSECS mailing list
> LEAPSECS at leapsecond.com
> http://six.pairlist.net/mailman/listinfo/leapsecs
>

From sla at ucolick.org  Mon Nov 24 09:59:07 2008
From: sla at ucolick.org (Steve Allen)
Date: Mon, 24 Nov 2008 06:59:07 -0800
Subject: [LEAPSECS] NYTimes OpEd
Message-ID: <20081124145907.GA30096@ucolick.org>

Also in the past week was this OpEd on Daylight/Summer Time
http://www.nytimes.com/2008/11/20/opinion/20kotchen.html

The content has prompted the blogosphere to begin saying Obama will
abolish daylight time even though there's no such evidence.

It's more interesting for the web2.0 commentary in which we
see that it's very hard to get people to agree on what they're
even talking about when they say time, and even when they do
their regional differences and personal makeup create a situation
where agreement is unlikely.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

From seaman at noao.edu  Mon Nov 24 11:32:30 2008
From: seaman at noao.edu (Rob Seaman)
Date: Mon, 24 Nov 2008 09:32:30 -0700
Subject: [LEAPSECS] leap second media coverage
In-Reply-To: <20081124141230.GA29996@ucolick.org>
References: <20081124141230.GA29996@ucolick.org>
Message-ID: <8AAA8597-D368-4464-860F-075545A49A72@noao.edu>

Steve Allen wrote:

> Here's an article on the upcoming leap second
>
> http://www.airspacemag.com/flight-today/One-More-Second.html

Hmmm.  The article is a bit more than the usual mix of banal truths,  
half-truths and untruths (but has those, too).  There is this  
observation:

	"The leap-second insertion may be the only human event that occurs  
simultaneously worldwide."

Can anybody think of any other candidates?  There are live TV  
broadcasts, but anybody from the U.S. Mountain time zone (and  
presumably from non-dominant time zones worldwide) can tell you that  
even supposedly live broadcasts are often delayed.  International live  
TV reaching a majority of countries must be rather rare.  Moon  
landing?  And can a broadcast from another world happen "worldwide"?

As far as a leap second itself, I'll resist exploring philosophical  
distinctions about whether a representational frame shift actually  
corresponds to an "event".

Rob Seaman
NOAO


From jhawk at MIT.EDU  Mon Nov 24 11:49:45 2008
From: jhawk at MIT.EDU (John Hawkinson)
Date: Mon, 24 Nov 2008 11:49:45 -0500
Subject: [LEAPSECS] leap second media coverage
In-Reply-To: <8AAA8597-D368-4464-860F-075545A49A72@noao.edu>
References: <20081124141230.GA29996@ucolick.org>
	<8AAA8597-D368-4464-860F-075545A49A72@noao.edu>
Message-ID: <20081124164945.GB15692@multics.mit.edu>

Rob Seaman <seaman at noao.edu> wrote on Mon, 24 Nov 2008
at 09:32:30 -0700 in <8AAA8597-D368-4464-860F-075545A49A72 at noao.edu>:

> 	"The leap-second insertion may be the only human event that occurs 
> simultaneously worldwide."
>
> Can anybody think of any other candidates?  There are live TV broadcasts, 
> but anybody from the U.S. Mountain time zone (and presumably from 
> non-dominant time zones worldwide) can tell you that even supposedly live 
> broadcasts are often delayed.

More pertinently, live network TV broadcasts can be delayed by
differing small numbers of seconds by the different affiliates
who actually execute the broadcast. (I gather this is even worse
with digital television.)

I suppose we'd have to define what we mean by "simultaneously."
Within 100ms? 10ms?

> As far as a leap second itself, I'll resist exploring philosophical 
> distinctions about whether a representational frame shift actually 
> corresponds to an "event".

Well, we need not ask, "if a clock reads 23:59:60 in a forrest..."
since we do have strong confidence that people are watching :)

--jhawk at mit.edu
  John Hawkinson


From seaman at noao.edu  Fri Nov 28 11:17:01 2008
From: seaman at noao.edu (Rob Seaman)
Date: Fri, 28 Nov 2008 09:17:01 -0700
Subject: [LEAPSECS] example requirements for time keeping
References: <20081128034709.GA31700@ucolick.org>
Message-ID: <DAD86BCF-1060-4FDE-945D-9ECB5C9C481D@noao.edu>

A little birdy pointed me to this discussion (note the three linked  
articles):

	http://fairhaven.typepad.com/my_weblog/2008/11/the-unixntp-real-world-compromise.html

This is a brief, but reasonable, analysis of broad timekeeping  
requirements for some healthcare scenarios.

A few comments:

1) Whatever the future status of international timekeeping standards,  
such analyses are required for pragmatic deployment of innumerable  
systems worldwide.  In particular, I like the author's discussion of  
scope (admin vs operating room, for instance).

1a) Eradicating leap seconds won't address most timekeeping issues in  
the least.

2) Requirements for an international standard should logically trace  
to requirements for the full ensemble of timekeeping users.  This  
ensemble is large (very) and diverse (very).

3) Note that they speculate on an acceptable solution, a variation on  
one of the timeslicing schemes that was discussed very early on this  
list.  The main point here is that the acceptability of a solution  
depends on the context.  (As a patient, though, I may have concerns  
about their timekeeping choices :-)

4) Any project is required to deal with standards as they are.  A  
standards effort, on the other hand, is about finding a satisfactory  
solution for a (weighted) average of all projects.  A lot of our  
disputes are really about asserting an acceptable weighting function.

That is, one position is that astronomical applications get a zero  
weighting because astronomers are - well - able to overcome bad  
standards, while (for instance) consumer electronics applications get  
a 100% weighting because corporate engineers are (willfully) ignorant  
of timekeeping issues.

I might assert that a successful strategy here would involve a  
somewhat more nuanced derivation of requirements.  In particular,  
ignorance of the issues also leaves one ignorant of potential hidden  
dependencies in the requirements.

(With the economy the way it is, one is also skeptical of corporate  
style decision-making at all levels.)

Rob Seaman
NOAO