svn commit: r293037 - head/etc/ntp
Cy Schubert
cy at FreeBSD.org
Fri Jan 1 11:57:33 UTC 2016
Author: cy
Date: Fri Jan 1 11:57:32 2016
New Revision: 293037
URL: https://svnweb.freebsd.org/changeset/base/293037
Log:
Update leap-seconds to latest. This will satisfy the ntpd leap-second
version check.
Obtained from: ftp://tycho.usno.navy.mil/pub/ntp/.
See also: http://www.iers.org/SharedDocs/News/EN/BulletinC.html
Modified:
head/etc/ntp/leap-seconds
Modified: head/etc/ntp/leap-seconds
==============================================================================
--- head/etc/ntp/leap-seconds Fri Jan 1 11:19:32 2016 (r293036)
+++ head/etc/ntp/leap-seconds Fri Jan 1 11:57:32 2016 (r293037)
@@ -1,119 +1,221 @@
#
# $FreeBSD$
#
-# ATOMIC TIME.
-# The Coordinated Universal Time (UTC) is the reference time scale derived
-# from The "Temps Atomique International" (TAI) calculated by the Bureau
-# International des Poids et Mesures (BIPM) using a worldwide network of atomic
-# clocks. UTC differs from TAI by an integer number of seconds; it is the basis
-# of all activities in the world.
-#
-#
-# ASTRONOMICAL TIME (UT1) is the time scale based on the rate of rotation of the earth.
-# It is now mainly derived from Very Long Baseline Interferometry (VLBI). The various
-# irregular fluctuations progressively detected in the rotation rate of the Earth lead
-# in 1972 to the replacement of UT1 by UTC as the reference time scale.
-#
-#
-# LEAP SECOND
-# Atomic clocks are more stable than the rate of the earth rotatiob since the later
-# undergoes a full range of geophysical perturbations at various time scales (lunisolar
-# and core-mantle torques,atmospheric and oceanic effetcs, ...)
-# Leap seconds are needed to keep the two time scales in agreement, i.e. UT1-UTC smaller
-# than 0.9 second. So, when necessary a "leap second" is introduced in UTC.
-# Since the adoption of this system in 1972 it has been necessary to add 26 seconds to UTC,
-# firstly due to the initial choice of the value of the second (1/86400 mean solar day of
-# the year 1820) and secondly to the general slowing down of the Earth's rotation. It is
-# theorically possible to have a negative leap second (a second removed from UTC), but so far,
-# all leap seconds have been positive (a second has been added to UTC). Based on what we know about the earth's rotation,
-# it is unlikely that we will ever have a negative leap second.
-#
-#
-# HISTORY
-# The first leap second was added on June 30, 1972. Until 2000, it was necessary in average to add a leap second at a rate
-# of 1 to 2 years. Since 2000, due to the fact that the earth rate of rotation is accelerating, leap seconds are introduced
-# with an average frequency of 3 to 4 years.
-#
-#
-# RESPONSABILITY OF THE DECISION TO INTRODUCE A LEAP SECOND IN UTC
-# The decision to introduce a leap second in UTC is the responsibility of the Earth Orientation Center of
-# the International Earth Rotation and reference System Service (IERS). This center is located at Paris
-# Observatory. According to international agreements, leap second date have to occur at fixed date :
-# first preference is given to the end of December and June, and second preference at the end of March
-# and September. Since the system was introduced in 1972, only dates in June and December were used.
-#
-# Questions or comments to:
-# Daniel Gambis, daniel.gambis at obspm.fr
-# Christian Bizouard: christian.bizouard at obspm.fr
-# Earth orientation Center of the IERS
-# Paris Observatory, France
-#
-#
-#
-# VALIDITY OF THE FILE
-# It is important to express the validity of the file. These next two dates are
-# given in units of seconds since 1900.0.
-#
-# 1) Last update of the file.
-#
-# Updated through IERS Bulletin C (ftp://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat)
-#
-# The following line shows the last update of this file in NTP timestamp:
-#
-#$ 3645216000
-#
-# 2) Expiration date of the file given on a semi-annual basis: last June or last December
-#
-# File expires on 28 December 2015
-#
-# Expire date in NTP timestamp:
-#
-#@ 3660249600
-#
-#
-# LIST OF LEAP SECONDS
-# NTP timestamp (X parameter) is the number of seconds since 1900.0
-#
-# MJD: The Modified Julian Day number. MJD = X/86400 + 15020
-#
-# DTAI: The difference DTAI= TAI-UTC in units of seconds
-# It is the quantity to add to UTC to get the time in TAI
-#
-# Day Month Year : epoch in clear
-#
-#NTP Time DTAI Day Month Year
-#
-2272060800 10 # 1 Jan 1972
-2287785600 11 # 1 Jul 1972
-2303683200 12 # 1 Jan 1973
-2335219200 13 # 1 Jan 1974
-2366755200 14 # 1 Jan 1975
-2398291200 15 # 1 Jan 1976
-2429913600 16 # 1 Jan 1977
-2461449600 17 # 1 Jan 1978
-2492985600 18 # 1 Jan 1979
-2524521600 19 # 1 Jan 1980
-2571782400 20 # 1 Jul 1981
-2603318400 21 # 1 Jul 1982
-2634854400 22 # 1 Jul 1983
-2698012800 23 # 1 Jul 1985
-2776982400 24 # 1 Jan 1988
-2840140800 25 # 1 Jan 1990
-2871676800 26 # 1 Jan 1991
-2918937600 27 # 1 Jul 1992
-2950473600 28 # 1 Jul 1993
-2982009600 29 # 1 Jul 1994
-3029443200 30 # 1 Jan 1996
-3076704000 31 # 1 Jul 1997
-3124137600 32 # 1 Jan 1999
-3345062400 33 # 1 Jan 2006
-3439756800 34 # 1 Jan 2009
-3550089600 35 # 1 Jul 2012
-3644697600 36 # 1 Jul 2015
-#
-# In order to verify the integrity of this file, a hash code
-# has been generated. For more information how to use
-# this hash code, please consult the README file under the
-# 'sha' repertory.
+# In the following text, the symbol '#' introduces
+# a comment, which continues from that symbol until
+# the end of the line. A plain comment line has a
+# whitespace character following the comment indicator.
+# There are also special comment lines defined below.
+# A special comment will always have a non-whitespace
+# character in column 2.
+#
+# A blank line should be ignored.
+#
+# The following table shows the corrections that must
+# be applied to compute International Atomic Time (TAI)
+# from the Coordinated Universal Time (UTC) values that
+# are transmitted by almost all time services.
+#
+# The first column shows an epoch as a number of seconds
+# since 1900.0 and the second column shows the number of
+# seconds that must be added to UTC to compute TAI for
+# any timestamp at or after that epoch. The value on
+# each line is valid from the indicated initial instant
+# until the epoch given on the next one or indefinitely
+# into the future if there is no next line.
+# (The comment on each line shows the representation of
+# the corresponding initial epoch in the usual
+# day-month-year format. The epoch always begins at
+# 00:00:00 UTC on the indicated day. See Note 5 below.)
+#
+# Important notes:
+#
+# 1. Coordinated Universal Time (UTC) is often referred to
+# as Greenwich Mean Time (GMT). The GMT time scale is no
+# longer used, and the use of GMT to designate UTC is
+# discouraged.
+#
+# 2. The UTC time scale is realized by many national
+# laboratories and timing centers. Each laboratory
+# identifies its realization with its name: Thus
+# UTC(NIST), UTC(USNO), etc. The differences among
+# these different realizations are typically on the
+# order of a few nanoseconds (i.e., 0.000 000 00x s)
+# and can be ignored for many purposes. These differences
+# are tabulated in Circular T, which is published monthly
+# by the International Bureau of Weights and Measures
+# (BIPM). See www.bipm.fr for more information.
+#
+# 3. The current defintion of the relationship between UTC
+# and TAI dates from 1 January 1972. A number of different
+# time scales were in use before than epoch, and it can be
+# quite difficult to compute precise timestamps and time
+# intervals in those "prehistoric" days. For more information,
+# consult:
+#
+# The Explanatory Supplement to the Astronomical
+# Ephemeris.
+# or
+# Terry Quinn, "The BIPM and the Accurate Measurement
+# of Time," Proc. of the IEEE, Vol. 79, pp. 894-905,
+# July, 1991.
+#
+# 4. The insertion of leap seconds into UTC is currently the
+# responsibility of the International Earth Rotation Service,
+# which is located at the Paris Observatory:
+#
+# Central Bureau of IERS
+# 61, Avenue de l'Observatoire
+# 75014 Paris, France.
+#
+# Leap seconds are announced by the IERS in its Bulletin C
+#
+# See hpiers.obspm.fr or www.iers.org for more details.
+#
+# All national laboratories and timing centers use the
+# data from the BIPM and the IERS to construct their
+# local realizations of UTC.
+#
+# Although the definition also includes the possibility
+# of dropping seconds ("negative" leap seconds), this has
+# never been done and is unlikely to be necessary in the
+# foreseeable future.
+#
+# 5. If your system keeps time as the number of seconds since
+# some epoch (e.g., NTP timestamps), then the algorithm for
+# assigning a UTC time stamp to an event that happens during a positive
+# leap second is not well defined. The official name of that leap
+# second is 23:59:60, but there is no way of representing that time
+# in these systems.
+# Many systems of this type effectively stop the system clock for
+# one second during the leap second and use a time that is equivalent
+# to 23:59:59 UTC twice. For these systems, the corresponding TAI
+# timestamp would be obtained by advancing to the next entry in the
+# following table when the time equivalent to 23:59:59 UTC
+# is used for the second time. Thus the leap second which
+# occurred on 30 June 1972 at 23:59:59 UTC would have TAI
+# timestamps computed as follows:
+#
+# ...
+# 30 June 1972 23:59:59 (2287785599, first time): TAI= UTC + 10 seconds
+# 30 June 1972 23:59:60 (2287785599,second time): TAI= UTC + 11 seconds
+# 1 July 1972 00:00:00 (2287785600) TAI= UTC + 11 seconds
+# ...
+#
+# If your system realizes the leap second by repeating 00:00:00 UTC twice
+# (this is possible but not usual), then the advance to the next entry
+# in the table must occur the second time that a time equivlent to
+# 00:00:00 UTC is used. Thus, using the same example as above:
+#
+# ...
+# 30 June 1972 23:59:59 (2287785599): TAI= UTC + 10 seconds
+# 30 June 1972 23:59:60 (2287785600, first time): TAI= UTC + 10 seconds
+# 1 July 1972 00:00:00 (2287785600,second time): TAI= UTC + 11 seconds
+# ...
+#
+# in both cases the use of timestamps based on TAI produces a smooth
+# time scale with no discontinuity in the time interval.
+#
+# This complexity would not be needed for negative leap seconds (if they
+# are ever used). The UTC time would skip 23:59:59 and advance from
+# 23:59:58 to 00:00:00 in that case. The TAI offset would decrease by
+# 1 second at the same instant. This is a much easier situation to deal
+# with, since the difficulty of unambiguously representing the epoch
+# during the leap second does not arise.
+#
+# Questions or comments to:
+# Jeff Prillaman
+# Time Service Department
+# US Naval Observatory
+# Washington, DC
+# jeffrey.prillaman at usno.navy.mil
+#
+# Last Update of leap second values: 31 Dec 2015
+#
+# The following line shows this last update date in NTP timestamp
+# format. This is the date on which the most recent change to
+# the leap second data was added to the file. This line can
+# be identified by the unique pair of characters in the first two
+# columns as shown below.
+#
+#$ 3660508800
+#
+# The data in this file will be updated periodically as new leap
+# seconds are announced. In addition to being entered on the line
+# above, the update time (in NTP format) will be added to the basic
+# file name leap-seconds to form the name leap-seconds.<NTP TIME>.
+# In addition, the generic name leap-seconds.list will always point to
+# the most recent version of the file.
+#
+# This update procedure will be performed only when a new leap second
+# is announced.
+#
+# The following entry specifies the expiration date of the data
+# in this file in units of seconds since 1900.0. This expiration date
+# will be changed at least twice per year whether or not a new leap
+# second is announced. These semi-annual changes will be made no
+# later than 1 June and 1 December of each year to indicate what
+# action (if any) is to be taken on 30 June and 31 December,
+# respectively. (These are the customary effective dates for new
+# leap seconds.) This expiration date will be identified by a
+# unique pair of characters in columns 1 and 2 as shown below.
+# In the unlikely event that a leap second is announced with an
+# effective date other than 30 June or 31 December, then this
+# file will be edited to include that leap second as soon as it is
+# announced or at least one month before the effective date
+# (whichever is later).
+# If an announcement by the IERS specifies that no leap second is
+# scheduled, then only the expiration date of the file will
+# be advanced to show that the information in the file is still
+# current -- the update time stamp, the data and the name of the file
+# will not change.
+#
+# Updated through IERS Bulletin C 50
+# File expires on: 1 Jun 2016
+#
+#@ 3673728000
+#
+2272060800 10 # 1 Jan 1972
+2287785600 11 # 1 Jul 1972
+2303683200 12 # 1 Jan 1973
+2335219200 13 # 1 Jan 1974
+2366755200 14 # 1 Jan 1975
+2398291200 15 # 1 Jan 1976
+2429913600 16 # 1 Jan 1977
+2461449600 17 # 1 Jan 1978
+2492985600 18 # 1 Jan 1979
+2524521600 19 # 1 Jan 1980
+2571782400 20 # 1 Jul 1981
+2603318400 21 # 1 Jul 1982
+2634854400 22 # 1 Jul 1983
+2698012800 23 # 1 Jul 1985
+2776982400 24 # 1 Jan 1988
+2840140800 25 # 1 Jan 1990
+2871676800 26 # 1 Jan 1991
+2918937600 27 # 1 Jul 1992
+2950473600 28 # 1 Jul 1993
+2982009600 29 # 1 Jul 1994
+3029443200 30 # 1 Jan 1996
+3076704000 31 # 1 Jul 1997
+3124137600 32 # 1 Jan 1999
+3345062400 33 # 1 Jan 2006
+3439756800 34 # 1 Jan 2009
+3550089600 35 # 1 Jul 2012
+3644697600 36 # 1 Jul 2015
+#
+# the following special comment contains the
+# hash value of the data in this file computed
+# use the secure hash algorithm as specified
+# by FIPS 180-1. See the files in ~/sha for
+# the details of how this hash value is
+# computed. Note that the hash computation
+# ignores comments and whitespace characters
+# in data lines. It includes the NTP values
+# of both the last modification time and the
+# expiration time of the file, but not the
+# white space on those lines.
+# the hash line is also ignored in the
+# computation.
+#
+#h 44a44c49 35b22601 a9c7054c 8c56cf57 9b6f6ed5
#
-#h 620ba8af 37900668 95ac09ba d77640f9 6fd75493
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