[LEAPSECS] LEAPSECS Digest, Vol 25, Issue 5

[M. Warner Losh]

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-----

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: Subject: LEAPSECS Digest, Vol 25, Issue 5

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: 

: 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)

: 

: 

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