September 2019 - tz - lists.iana.org

Re: [tz] [PROPOSED] Improve leapseconds support
by Chris Woodbury Sept. 10, 2019

Sept. 10, 2019

The following has been kicking around my "Handling_Leapseconds directory for more than a year. It is a complete replacement for the current "leapseconds.awk". It uses the NTP timestamp *data* rather than the *comments* at the end of each leap-second datum from the leap-seconds.list file. I found it again today and finished the changes needed to use Dennis' sstamp_to_ymdhMs() AWK function. I've incorporated some AT&T UNIX programming style changes (which I learned back in the dark ages), too. I'm sure Paul will re-arrange it whichever way he wants before (or even if) it makes it into the TZ distribution. # -=*< This file is in the public domain !! >*=- # Generate zic LEAP commands from an NIST format 'leap-seconds.list'. BEGIN { print "# This file is in the public domain\n" print "# Allowance for leap-seconds added to each time zone file.\n" print "# This script generates zic \"Leap\" directives from public-domain data" print "# in the NIST format leap-seconds.list file (originally created for the" print "# Network Time Protocol (NTP) daemon by Judah Levine). Find it at:\n" print "# <ftp://ftp.nist.gov/pub/time/leap-seconds.list>" print "# -or- <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>\n" print "# For more info about the leap-seconds.list file, please see:\n" print "# The NTP Timescale and Leap Seconds by Prof. David L. Mills." print "# <https://www.eecis.udel.edu/~mills/leap.html>.\n" print "# The rules for leap-seconds are specified in Annex 1 (Time scales) of:\n" print "# \"Standard-frequency and time-signal emissions\"" print "# International Telecommunication Union -" print "# Radiocommunication Sector Recommendation (ITU-R) TF.460-6 (02/2002)\n" print "# <https://www.itu.int/rec/R-REC-TF.460-6-200202-I/>\n" print "# which is incorporated by reference in the [ITU] Radio Regulations.\n" print "# The International Earth Rotation and Reference Systems Service (IERS)" print "# periodically uses leap seconds to keep UTC to within 0.9 s of UT1" print "# (which is a proxy for the earth's angular orientation in space)" print "# and publishes leap-second data in a copyrighted file" print "# <https://hpiers.obspm.fr/iers/bul/bulc/Leap_Second.dat>." print "# USNO also has a comprehensive uncopyrighted list of leap-seconds at:" print "# <ftp://199.211.133.23/ser7/leapsec.dat> (AKA maia.usno.navy.mil)" print "# Also see: Coordinated Universal Time and the leap second by Judah Levine" print "# URSI Radio Sci Bull. 2016;89(4):30-6. doi:10.23919/URSIRSB.2016.7909995" print "# <https://ieeexplore.ieee.org/document/7909995>.\n" print "# There were no leap-seconds before 1972, as no official mechanism existed" print "# accounting for the discrepancy between atomic time (TAI) and UT1." print "# All leap-seconds are Stationary (S) at the given UTC time.\n" print "# The correction (+ or -) is made at the given time, so lines" print "# will typically look like:\n" print "# Leap YEAR MON DAY 23:59:60 + S" print "# - or -" print "# Leap YEAR MON DAY 23:59:59 - S\n" monthabbr[ 1] = "Jan" ; monthabbr[ 2] = "Feb" ; monthabbr[ 3] = "Mar" monthabbr[ 4] = "Apr" ; monthabbr[ 5] = "May" ; monthabbr[ 6] = "Jun" monthabbr[ 7] = "Jul" ; monthabbr[ 8] = "Aug" ; monthabbr[ 9] = "Sep" monthabbr[10] = "Oct" ; monthabbr[11] = "Nov" ; monthabbr[12] = "Dec" # In case the input has CRLF form a la NIST RS = "\r?\n" old_TAI_minus_UTC = int( 0 ) # This variable should be initialize !! sstamp_init() # Init function } # Note: maintaining case, spacing or punctuation can # not be depended upon when humans are involved... /^#[ \t]*[Uu]pdated through[ \t:]*/ || /^#[ \t]*[Ff]ile expires on[ \t:]*/ { last_lines = last_lines $0 "\n" } /^#[$][ \t]/ { updated = strtonum( $2 ) } # Save update NTP timestamp /^#[@][ \t]/ { expires = strtonum( $2 ) } # Save expiry NTP timestamp /^[ \t]*#/ { next } { NTP_timestamp = int( $1 ) # NTP epoch timestamp TAI_minus_UTC = int( $2 ) # delta T if ( old_TAI_minus_UTC ) { if ( old_TAI_minus_UTC < TAI_minus_UTC ) { sign = "23:59:60\t+" } else { sign = "23:59:59\t-" } sstamp_to_ymdhMs( NTP_timestamp - 1, ss_NTP ) # Note minus one !! printf "Leap\t%d\t%s\t%d\t%s\tS\n", ss_y, monthabbr[ ss_m ], ss_d, sign } old_TAI_minus_UTC = TAI_minus_UTC } END { # The difference between the NTP and POSIX epochs is 70 years # (including 17 leap days), each 24 hours of 60 minutes of 60 # seconds each. epoch_minus_NTP = ((1970 - 1900) * 365 + 17) * 24 * 60 * 60 print "" print "# POSIX timestamps for the data in this file:" sstamp_to_ymdhMs( updated, ss_NTP ) printf "# Updated: %s (%02d %s %d)\n", ( updated - epoch_minus_NTP ), ss_d, monthabbr[ ss_m ], ss_y sstamp_to_ymdhMs( expires, ss_NTP ) printf "# Expires: %s (%02d %s %d)\n", ( expires - epoch_minus_NTP ), ss_d, monthabbr[ ss_m ], ss_y printf "\n%s", last_lines } # Contributed by # # Dennis Ferguson <dennis.c.ferguson(a)gmail.com> on Sun, 14 Oct 2018 21:56:57 -0700 # # sstamp_to_ymdhMs() - convert (NTP, POSIX) seconds stamp to date and time # # Call as: # # sstamp_to_ymdhMs( sstamp, epoch_days ) # # where: # # sstamp - is a seconds timestamp, e.g. POSIX or NTP # epoch_days - is the timestamp epoch in (proleptic Gregorian) days since # 1 Mar 1600. ss_NTP is appropriate for a NTP sstamp, ss_POSIX # for a Unix sstamp. # # On return the following variables are set based on sstamp: # # ss_y - calendar year for the sstamp (e.g. 2016) # ss_m - month of the year (1-January to 12-December) # ss_d - day of the month # ss_h - hour (0-23) # ss_M - minute (0-59) # ss_s - second (0-59) # ss_w - day of week (0-Sunday to 6-Saturday) # # The function # # sstamp_init() # # should be called prior to using sstamp_to_ymdhMs(). # # The calendar computation part of this starts with a count of days since # March 1, 1600 (in a proleptic Gregorian calendar) and computes a ymd # date with days of the month numbered 0-30, months (March-February) numbered # 0-11 and years which run from March-February. The last four lines of code # in the function convert the date to a conventional day of month (1-31), # month (1-12, January-December) and Gregorian year. # # In the alternate calendar a year starts at March 1 and ends after the last # day of February. A quad-year starts on March 1 of a year evenly divisible # by 4 and ends after the last day of February 4 years later. A century # starts on and ends before March 1 in a year evenly divisible by 100 # (i.e. 1600, 1900, 2100). A quad-century starts on and ends before March 1 # in years divisible by 400 (1600, 2000, 2400). Given this the magic constants # used here are: # # days per year = 365 # days per quad-year = 1461 = (365 * 4) + 1 # days per century = 36524 = (1461 * 25) - 1 # days per quad-century = 146097 = (36524 * 4) + 1 # weekday (0-Sunday 6-Saturday) of first day of quad-century = 3 (Wednesday) # # Note that while the number of days in a quad-century is a constant the # number of days in each of the other time periods can vary by 1. In all # these cases, however, the variation is in the last day of the time period # (there might or might not be a February 29) where it is easy to deal with. # # The three standard day_epochs are: # # ss_MJD = 94493 # ss_NTP = 109513 # ss_POSIX = 135080 function sstamp_init(){ ss_mon_days[ 1] = 31 ss_mon_days[ 2] = 61 ss_mon_days[ 3] = 92 ss_mon_days[ 4] = 122 ss_mon_days[ 5] = 153 ss_mon_days[ 6] = 184 ss_mon_days[ 7] = 214 ss_mon_days[ 8] = 245 ss_mon_days[ 9] = 275 ss_mon_days[10] = 306 ss_mon_days[11] = 337 ss_NTP = 109513 ss_POSIX = 135080 } function sstamp_to_ymdhMs( sstamp, epoch_days, ss_qcent, ss_cent, ss_qyr, ss_yr ){ ss_s = sstamp % 86400 # isolate hms ss_h = int( ss_s / 3600 ) ss_s %= 3600 ss_M = int( ss_s / 60 ) ss_s %= 60 ss_d = int( sstamp / 86400 ) + epoch_days # select epoch ss_qcent = int( ss_d / 146097 ) ss_y = 1600 + ss_qcent * 400 ss_d -= ss_qcent * 146097 ss_w = ( ss_d + 3 ) % 7 ss_cent = int( ss_d / 36524 ) if (ss_cent == 4) { ss_cent = 3 } ss_d -= ss_cent * 36524 ss_y += ss_cent * 100 ss_qyr = int( ss_d / 1461 ) ss_y += ss_qyr * 4 ss_d -= ss_qyr * 1461 ss_yr = int(ss_d / 365) if ( ss_yr == 4 ) { ss_yr = 3 } ss_d -= ss_yr * 365 ss_y += ss_yr for ( ss_m = 11 ; ss_m > 0 ; ss_m-- ){ if( ss_d >= ss_mon_days[ss_m] ){ ss_d -= ss_mon_days[ss_m] ; break ; } } # convert to conventional calendar ss_d += 1; if (ss_m > 9) { ss_m -= 9 ; ss_y++ } else { ss_m += 3 } }

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Add ISO Phonetic and Letter Time Zone Links to etcetera
by Brian Inglis Sept. 9, 2019

Sept. 9, 2019

Suggest adding ISO Phonetic and Letter time zone names, used in military and other organizations, in the Etc directory, linked to the existing Etc/GMT[-/+n] time zones, created from the etcetera data file, as shown in the attached file (suffixed .txt for reader convenience). If there are any concerns about adding them into Etc, they could be added to a new ISO, Letter, Phonetic, Mil, Military, or other directory. Note that Etc/Zulu is already created as a Link from Etc/UTC, the names India and Quebec do not already exist in any directories, while America/Lima (Peru) already exists. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised.

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Time zone abbreviations
by Elena Sharovar Sept. 7, 2019

Sept. 7, 2019

Hi Iana Team, where can I find some explanation why in 2017a format changed from AST to +03? and the same happened in a lot of timezones (letter abbreviations changed to +03, +02, etc.) // 2016j Zone Asia/Riyadh 3:06:52 - LMT 1947 Mar 14 3:00 -* AST* // 2017a Zone Asia/Riyadh 3:06:52 - LMT 1947 Mar 14 3:00 - *+03* Thanks & Regards, Elena.

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Central America Time Zone?
by Rodolfo Quesada Zumbado Sept. 7, 2019

Sept. 7, 2019

Hello, I have one question/proposal. Recently I ran into a problem because my calendar shows the "America/Costa_Rica" time zone appointments as "Central Time", which seems to be the designation so far. However at the moment, I checked several sources about the current "Central Time" and it is currently UTC-05:00, whereas in "America/Costa_Rica" it is UTC-06:00. Here in Costa Rica we don't use the customary North American time zones (Pacific, Mountain, Central, Eastern), we just call it "the local time", as is the rest of Central America. We are very small countries so those designations doesn't make sense. I can drive from the Pacific coast to Caribbean/Atlantic coast through the mountains and the central valley in a few hours! :-) What would be the procedure to suggest an standardized "Central America" time zone? I just checked the tz database, and it shows America/Costa_Rica as designated with C%sT. Should it come from the local governmental science/tech departments? Is this related to ISO or other international organization? I have seen that Microsoft uses a "TZID=Central America Standard Time" which is more culturally sensitive and appropriate than using the other designations. Thanks for your time. -- Ing. Rodolfo Quesada Zumbado http://www.roqz.net roqz(a)roqz.net

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end of DST in occupied France October 1944
by Alois Treindl Sept. 7, 2019

Sept. 7, 2019

This is just a question to some well informed readers of this mailing list. Liberated France ended daylight saving time on 8 October 1944, 01:00, as represented in zone Europe/Paris. Eastern parts of France were still occupied by the German army at that time, and Germany ended DST in 1944 on 2 October 1922, 02:00s = 03:00, as represented in TZ by Europe/Berlin, rule C-Eur. For occupied France however, Shanks claims the end of DST on 3 Oct 1944 03:00. For all other countries in Europe on German time at that moment, Shanks holds that DST ended 2 October, like in Germany itself. I cannot find a source supporting Shanks' claim for the deviation in France. Does anyone have information supporting Shanks' claim?

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Typo fixes
by Tim Parenti Sept. 2, 2019

Sept. 2, 2019

Attached are a couple small typo fixes to recent commentary. -- Tim Parenti

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[PATCH] * southamerica: Modernize Magallanes comments.
by Paul Eggert Sept. 1, 2019

Sept. 1, 2019

--- southamerica | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/southamerica b/southamerica index 397a2cc..9b679c6 100644 --- a/southamerica +++ b/southamerica @@ -1230,14 +1230,8 @@ Zone America/Rio_Branco -4:31:12 - LMT 1914 # From Juan Correa (2016-12-04): # Magallanes region ... will keep DST (UTC -3) all year round.... # http://www.soychile.cl/Santiago/Sociedad/2016/12/04/433428/Bachelet-firmo-e… -# # From Deborah Goldsmith (2017-01-19): # http://www.diariooficial.interior.gob.cl/publicaciones/2017/01/17/41660/01/… -# From Paul Eggert (2017-01-19): -# The above says the Magallanes change expires 2019-05-11 at 24:00, -# so in theory, they will revert to -04/-03 after that, which means -# they will switch from -03 to -04 one hour after Santiago does that day. -# For now, assume that they will not revert. # From Juan Correa (2018-08-13): # As of moments ago, the Ministry of Energy in Chile has announced the new @@ -1258,6 +1252,11 @@ Zone America/Rio_Branco -4:31:12 - LMT 1914 # So we extend the new rules on Saturdays at 24:00 mainland time indefinitely. # From Juan Correa (2019-02-04): # http://www.diariooficial.interior.gob.cl/publicaciones/2018/11/23/42212/01/… +# From Paul Eggert (2019-09-01): +# The above says the Magallanes exception expires 2022-04-02 at 24:00, +# so in theory, they will revert to -04/-03 after that. +# For now, assume that they will not revert, +# since they have extended the expiration date once already. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Chile 1927 1931 - Sep 1 0:00 1:00 - -- 2.21.0

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