One of the reasons the implementation of the suppression of leap seconds
was placed so far in the future is that GLONASS is said to rely on the
current implementation of UTC. I wonder, if the international authorities
decided to suppress a negative leap second but Russia decided that GLONASS
h
daylight saving time and let people work out a schedule they decide is the
best compromise between summer and winter.
Gerard Ashton
On Tue, Nov 15, 2022 at 5:27 AM Poul-Henning Kamp
wrote:
>
> Clive D.W. Feather writes:
>
> > Stick with what people are used to, which is (
If you want to go all the way back, Sumerian clay tablets arranged numbers
in a grid that looked a lot like a modern spreadsheet, and one unit in a
given column was equivalent to 60 units in the column immediately to the
right.
-Original Message-
From: LEAPSECS
Of course Brooks Harris is free to define proleptic UTC any way he pleases
within the confines of a document he has control over, including a post to
this mailing list. But I think the term proleptic UTC, outside the
confines of a document that gives it a proprietary definition, could mean a
and time of day at quasi-Greenwich, where each day consists of exactly
86,400 SI seconds?
Gerard Ashton
-Original Message-
From: LEAPSECS [mailto:leapsecs-boun...@leapsecond.com] On Behalf Of Steve
Allen
Sent: Wednesday, October 15, 2014 11:07 AM
To: Leap Second Discussion List
Subject
Steffen Nurpmeso wrote:
This approach would satisfy all parties: humans can continue to enjoy the
cultural achievement of a clock that exactly describes their home planet,
and engineers can use TAI for satisfying airplane schedule calculations for
businessmen.
Businessmen can keep whatever time
Sorry, but I disagree with Tony Finch. The time period from June 30, 2012,
7:59:60 to June 30, 2012, 8:00:00, Eastern Daylight Time, did occur in the
United States and any end user requiring such precision was legally obliged
to observe it.
-Original Message-
From: LEAPSECS
I think lots of contracts for the use of computers where time matters, such
as online auction sites, contain language that the parties agree to use the
time as maintained on a particular computer system, such as the electronic
auction site's computers.
-Original Message-
From: LEAPSECS
Tony Finch wrote
Right, and this is good for many purposes, e.g. recording times of events
now or in the past. However for events in the future (meetings etc.) you
need to record a time and a place, because the UTC offset and time zone
rules are not predictable.
Even better, local time can be
ISO 8601 is expensive; I obtained a copy before they started making it hard
to find copies on the web. The wording of the standard is convoluted. Does
anyone know if there is a highly-reputable, readable description of the
standard that explains the extent to which the various choices are
In US law (see http://www.law.cornell.edu/uscode/text/15/260a ) the time
observed in each time zone is referred to as the standard time, even when
the time is advanced during the summer. Obviously the language of the law
differs from common usage.
Gerry Ashton
We all know that Greenwich Mean Time is commonly used to describe UTC,
UT1, and various similar time scales. Please check if I have estimated
correctly.
-The easternmost point of the London district of Greenwich is a the
intersection of two roads, Maze Hill and Charlton Way. The coordinates are
This link was embedded in a newsletter to American amateur radio operators:
http://transition.fcc.gov/Daily_Releases/Daily_Business/2014/db0128/DA-14-88
A2.pdf
Instructions for commenting are provided here:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-14-88A1.pdf
Gerard Ashton
employ in searches.
Gerard Ashton
-Original Message-
From: leapsecs-boun...@leapsecond.com
[mailto:leapsecs-boun...@leapsecond.com] On Behalf Of Daniel R. Tobias
Sent: Sunday, January 19, 2014 10:35 AM
To: Leap Second Discussion List
Subject: Re: [LEAPSECS] Future time
On 18 Jan 2014 at 19
considered all these scenarios?
Gerard Ashton
PS: (I'm fudging the minutes due to imperfect memory) Dispatched on an
ambulance call at 2:30 AM. Returned to quarters 2:15 AM.
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E. G. Richards in Mapping Time: The Calendar and its History mentions the
church was leary of negative numbers, and Hindu-Arabic numerals. He suggests
one possible reason being that most of the people who could do arithmetic
with Roman numerals were clergy, and they didn't want to lose their
I think Matsakis's post illustrates an important point: who is in charge?
Since no authority is in clear control of the definition of the Julian and
Gregorian calendars, no authority is in a position to demand that December
31, 2000, be regarded as the last day of the 20th century. In the absence
a fixed duration in SI seconds and use the
2011 value, the Gregorian calendar will be off by a day in about 3000 years.
Whether it is reasonable to suppose any decision about leap seconds will
endure for 3000 years is another issue.
Gerard Ashton
progress to the same degree. UT1 is
satisfactory for most event
recording and planning purposes.
Gerard Ashton
-Original Message-
From: leapsecs-boun...@leapsecond.com
[mailto:leapsecs-boun...@leapsecond.com] On Behalf Of Harlan Stenn
Sent: Wednesday, May 08, 2013 10:36 PM
To: Leap Second
by running a fake
leap second into a test system
that is sitting in a lab doing nothing but keep time. But a realistic test
requires that the system under test
be running a load as similar as possible to production systems.
Gerard Ashton
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?
Will the people in charge of the new group of vulnerable systems be any more
trustworthy than those in charge of the systems that failed?
Gerard Ashton
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that this time it is medium-precision systems that failed; the
coarse systems like Windows desktop systems that invoke their NTP client
once a week did fine, and did fine when interfacing with medium-precision
systems if the medium-precision systems were operating at all.
Gerard Ashton
-Original Message
The list often discusses the fact that astronomers need UT1. Does anyone
know astronomer's requirement for pointing accuracy. Does anyone know of a
document that discusses how astronomers receive ΔUT1 and incorporate it in
telescope pointing systems. (For telescope, read any astronomical
] On Behalf Of Steve Allen
Sent: Friday, June 08, 2012 9:58 AM
To: Leap Second Discussion List
Subject: Re: [LEAPSECS] Telescope pointing
On 2012 Jun 8, at 04:32, Gerard Ashton wrote:
The list often discusses the fact that astronomers need UT1. Does
anyone know astronomer's requirement for pointing
So summarizing what I find in Steve's paper, and only concerning the
pointing of the telescope and not the reporting results from the scope,
large telescopes with guidance systems from the 1970s and 1980s have a guide
camera field of view of 3 arcminutes, or a bit more. So if the telescope was
Using the USA as an example, the constitutional provision giving the federal
government
authority over standards of weight and measure arguably gives it authority
over time-of-day.
Their success in regulating time zones and legal recognition of UTC as the
basis of time
tends to confirm this
offsets or boundaries.
This suggest a desire for an algorithm that accepts as input a latitude
and longitude of a point of interest, and a set of boundaries, and
determines which of the regions the point of interest falls in. Does
anyone know of such an algorithm?
Gerard Ashton
.
This will make certain time computations quite intricate.
Representing the time as a simple floating point number may
lead to unexpected results.
Gerard Ashton
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On 1/21/2012 9:13 AM, Poul-Henning Kamp wrote:
In message4f1ac413.1010...@comcast.net, Gerard Ashton writes:
Consider US eastern daylight time, June 30, 2012.
[...]
This will make certain time computations quite intricate.
Representing the time as a simple floating point number may
lead
For the smallest time resolution required, we might suppose that at some
point in the
future there might be a need to account for transmission delay from one part
of a computer to another. The smallest location that I can imagine being of
interest even in a future computer is the diameter of a
would be to
subtract the transmission delay from the first-received
server to the server that decides who won. It's difficult to predict
what applications might require awareness of much
shorter transmission delays.
Gerard Ashton
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device.
Gerard Ashton
On 1/20/2012 2:18 PM, Michael Sokolov wrote:
Steve Allens...@ucolick.org wrote:
TAI can be derived from UTC, GPS and other broadcast timescales, so
availability is fine.
Indications have been that BIPM will disagree violently with that
statement.
And what's wrong
Please check my reasoning:
The westernmost point of the London Borough of Greenwich appears to
be at the intersection of the A200 and Deptford Church Street, which
is west longitude 0° 1' 24. That corresponds to 5.6 seconds of time.
Assuming the last possible leap second is in 2017, and that
On 1/10/2012 12:06 PM, Ian Batten wrote:
But unfortunately, UK civil time does not include a DST indicator
Is there a law or rule that specifies how UK civil time ought to be written?
Where can we examine the law or rule to see if there is a DST indicator
or not?
If there is no rule, how is
On 1/9/2012 10:55 AM, Ian Batten wrote:
pace all the bizarre claims about bear hunting
There are a number of laws and rules related to sunset and sunrise,
including hunting, turning headlights on
in automobiles, and being present in parks. No reliable evidence has
been presented as to
On 1/9/2012 3:14 PM, Ian Batten wrote:
And you do this not by looking up sunset in an almanac, a newspaper, a website,
but by performing a calculation that relies on UTC-plus-leapseconds? Could you
give me more detail of this?
...
No one has yet provided even the beginnings of the
If the proposed change goes through, we will need a new term, perhaps
proleptic UTC2017, for
post-2017 UTC extended backwards by subtracting as many minutes of 60 SI
seconds as desired.
Gerry Ashton
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I don't think the original poster had this in mind, but there is a
Revised Julian Calendar which is described
in Wikipedia, and is equivalent to the Gregorian Calendar until AD 2800.
It has been adopted by
some Orthodox churches. It was defined at a church meeting in the 1920s
(before the
Although statements of birthdays are seldom accompanied by explicit
statements of the
time zone, the place of birth is usually available so the time zone can
be reconstructed.
As for what is recorded on a birth certificate, there is no telling what
might be recorded;
there are more than 14,000
A question that arose at the Wikipedia Leap second article is what is
the voting procedure
for the 2012 Radiocommuication Assembly? What percent must vote in the
affirmative?
Is it the required percent of member states, member states present, or
member states
that vote (where an abstention is
is possible that day.
Gerard Ashton
On 10/1/2011 5:16 AM, Paul Sheer wrote:
I am busy implementing some heartbeat monitoring code between two
machines. The spec calls for a 1 second recovery.
Basically if I get no heartbeats for 1 full second then I should
consider the peer system to have failed
It would be OK if
- the heartbeats occur much more frequently than 1 per second
- the 1 second without a heartbeat criteria is arbitrary, and causing
a false alarm because the actual period without a heartbeat is,
for example, 998 ms.
Gerard Ashton
On 10/1/2011 12:23 PM, Paul Sheer wrote
calculations, and timepieces, to satisfy the hunter who doesn't want
to get caught. Then there is the question of the hunter who
wishes to voluntarily obey the rules, even if he/she was sure
of not getting caught. I expect minute precision would suffice
for the conscientious hunter.
Gerard Ashton
On 9/21/2011 7:59 AM, Daniel R. Tobias wrote:
On 21 Sep 2011 at 7:53, Ian Batten wrote:
hunting sunrise, hunting sunset, hunting daylight and hunting
night all return zero hits.
I don't really think that the presence or absence of enforced
penalties for failing to precisely adhere to
hunting hours to the
time of the offense could be contained
on a tape recording of the trial, perhaps never having been put in text
form.
Of course, if there is a search strategy I'm overlooking, feel free to
point it out.
Gerard Ashton
___
LEAPSECS
On 9/18/2011 7:02 PM, Tom Van Baak wrote:
This may or may not be a boundary condition. The fundamental
system engineering problem is that there are two different types
of time, two kinds of clock.
Rob,
You keep saying this, but there's only one kind of clock and
one kind of time. When you
On 8/18/2011 4:30 AM, mike cook wrote:
Could this be a good argument for getting parking ticket offences
thrown out?
Under current rules, UTC is an approximation to mean solar time at some
meridian that passes through the grounds of the Royal Observatory,
Greenwich (although not
Wikipedia can be edited by almost anyone, but the regulars there will
look to
see if any change is supported by a citation to a reliable published
source, since there is
no mechanism to establish that a particular contributor has any relevant
qualifications. So a change is likely to stick, if
It is not necessary, at least in the case of WWV and WWVB, to have special
equipment beyond a short wave radio to decode DUT1. It can be done by
ear. Timings of sun and star observations can be done with a hand-operated
stop watch to a precision of 0.1 s, the same precision as DUT1. (Not
to say
On 2/21/2011 10:49 AM, Paul Sheer wrote, in part:
No, it's my own idea.
Hereby released to the world:
2010-02-21 09:40:27 -0600 L0024
I hereby name it timestamp L-format.
It solves the problem of absolutely specifying a future time where you
don't know how many leap seconds there will be
On 2/19/2011 10:24 AM, Joe Gwinn wrote, in part:
I have not been following the proposal in detail, but a key issue to
the POSIX community is that their timescale must be implementable in a
totally isolated machine, one having no GPS or internet access.
There are other requirements as well.
On 2/8/2011 6:42 AM, Tony Finch wrote:
On Mon, 7 Feb 2011, Rob Seaman wrote:
Tony Finch wrote:
the whole point of universal time is that it's the default timscale
for civil use and only specialists should need anything else.
Stephen should add this to the consensus building list.
Does that
On 2/8/2011 9:51 AM, Clive D.W. Feather wrote:
Gerard Ashton said:
A secular change to civil time that would be perceptible without the aid
of a clock has
never been introduced,
How about those places that moved timezone permanently.
A single permanent time zone change is not a secular
Poul-Henning Kamp wrote:
History has shown that very few, if any, governments have been unable
to carry through their more or less well thought out policies in this
area.
Well, it can be difficult to identify government policies; various
office holders and agencies tend to scurry about
Sovereign states have some degree of control over civil time; the
remaining control is
in the control of individuals, either through personal whims or
voluntary collective
action. The IAU, ITU, BIPM, ISO, and all the rest do not have control
over civil timekeeping
because the weights and
On 2/7/2011 2:49 PM, Tony Finch wrote:
On Mon, 7 Feb 2011, Finkleman, Dave wrote:
This discussion exposes the fact that we don't all have to work in the
same reference frame or time system - as long as we understand what we
are using and make it clear to users.
Though the whole point of
On 2/3/2011 9:00 AM, Clive D.W. Feather wrote:
Warner Losh said:
SI
- the SI-second is a standardised unit of measurement
- the SI-second is currently defined as a fixed number of transitions
of a caesium atom
- the current definition of the SI-second was ratified in 1967
Agreed. I'd also add
Change and add:
s- the solar-day is a commonly used unit of measurement/s
u- TAI and parallel time scales have been defined so that in modern
times the difference between
an atomic day and a solar day is not perceptible without the aid of
timepieces. Popular acceptance
of atomic days as a
On 2/2/2011 11:47 AM, Stephen Colebourne wrote:
Statements so far - disgree or add please (in particular something on
UT1/UT/etc as I will only get it wrong...):
General:
- the terms seconds, minutes, hours and days are overloaded, thus
pedantic and explicit terms are used here
SI
- the
On 2/2/2011 1:44 PM, Stephen Colebourne wrote:
You're reading more into the statement than is intended by trying to
interpret them as a time-scale or clock. I'm defining a unit of
SI-based-minute that is a multiple of 60 of the unit SI-second. No
more no less.
I think when trying to list
According to the 2008 edition of the NIST Special Publication 811, page
8, day, hour, and minute are not part of the SI but are accepted by
the CIPM, and thus by this Guide, for use with the SI. So I guess that
makes them CIPMFUWSI days, hours, and minutes.
Gerry Ashton
The point below should be
* definition: UTC-1972-day - a duration of 86399, 86400, or 86401 seconds.
On 2/2/2011 8:50 PM, Stephen Colebourne wrote:
* definition: UTC-1972-day - a duration either 86400 SI-seconds or
86401 SI-seconds long
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It may not have been your intention, but from now on I will hear whatever
you type in a particular accent.
Gerry Ashton
On 2/1/2011 5:09 AM, Poul-Henning Kamp wrote:
In messagee1pkcow-0005fn...@grus.atnf.csiro.au, Mark Calabretta writes:
OK Tom, I'm prepared to accept those odds. I'll give
On 2/1/2011 3:24 PM, Michael Deckers wrote, in part:
On 2011-02-01 11:35, Poul-Henning Kamp wrote:
How could the unpredictable difference TAI - UTC be a
problem if everybody (including every computer) just kept UTC?
Michael Deckers.
___
On 1/29/2011 3:27 AM, Stephen Colebourne wrote, in part:
It is my opinion, coming from an open source background, that if the
body currently defining leap seconds stops doing so with less than
100% consensus, then the leap second defining process would be forked.
Some other person/body/open
I suggest the following replacement for parts of the the Instant
description. I offer the replacement because the wording of
UTC-SLS clearly only applies after 1 January 1972, and that
scale should be regarded as undefined prior to that date.
This is the Javadoc for Instant, the most widely used
I suggest that UT, as a concept, can be extended as far back as the
location of Greenwich
can be discerned, even if it was known by some other name. I suggest
that encompass all
recorded history. Since UT1 was originally defined as a function of
sidereal time and the function was created by
When it comes to finding a standard to smooth UTC in order to hide leap
seconds for purposes of the Java Instant class, I would be tempted to
find a computer architecture that handles leap seconds properly, and
propose a standard that can be implemented as easily as possible on that
-second precision
without needing sub-second accuracy.
Gerard Ashton
On 1/28/2011 3:42 PM, Tom Van Baak wrote, in part:
I partly ask because for the class of users who are willing to be
close enough to UTC (say within 1 second), there are no leap
second issues, ever. This covers most users
On 1/28/2011 5:47 PM, Rob Seaman wrote (in part):
Civil time is based on the synodic day. Interval timekeeping requires a
different timescale. Pretending one is the other is not a requirement.
Rob
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I was talking to the IT manager for a town in Connecticut, USA. I asked
if town residents could pay taxes and fees online. He said they could. I
asked how they knew if a deadline had been met and whether late
penalties should be added. He said that the town officials were lenient,
and if the
The ball dropping in Times Square illustrates an exacerbation of
something that has always been true. It is not possible in the USA, now
that digital TV is pervasive, to broadcast a truly live event. The
ball must drop with an accuracy of about 1 second to satisfy a million
people who are
In this list, various time problems that people have learned to live
with without really solving are sometimes mentioned, in order to put the
leap second problem into perspective. I would like to mention one more.
A company has its employees fill out a time sheet on a computer (or
There have been allusions to computer systems other than POSIX which
recognize leap seconds. I thought I would point out a partial example of
one.
The z/Architecture Principles of Operation (descendant of the
System/370) explains in chapter 4 the operation of the time of day clock.
The
The idea that consumer grade WWVB receivers will become obsolete
supposes that legal time will be a fixed (except for daylight savings
time) offset from UTC, and UTC continues to include leap seconds. If
WWVB were to broadcast the proposed TI instead of UTC, the old receivers
would display
Poul-Henning Kamp made some inquiries about how quickly Rob could review
code. I suggest this question misses a few important items.
1. Documentation. If the documentation for any given system claims UTC
agrees with UT1 or GMT within 0.9 s, there is the danger that some
programmer who only
If ISO does publish a standard, I hope they distribute it better than
they did ISO 8601. In that case, they made it absurdly expensive, and
then published a free summary of it on their website claiming it was the
best way to write dates, but left out so many important details that
anyone who
On 12/10/2010 10:15 AM, Peter Vince wrote:
Hello Paul,
I'd be interested if you have some examples of of Y2K bugs that
were fixed before they became a problem. In my very limited
experience, I wasn't affected by any, nor aware of them.
Peter
On 10 December 2010 01:55, Paul
One effect I recall from the Y2K prevention effort actually relates to
29 February 2000. There was considerable discussion among programmers as
to whether that date existed or not, and there was enough disagreement
among the computer language manuals and the like that programmers lost
I find it remarkable that one group of time users chose a
particular time dissemination mode (GPS) and made the typical
array of poor decisions / errors with software. They also
create a rather arbitrary demand of obtaining correct UTC
within 5 minutes of installing hardware that has been
sitting
Oasis will soon present for public review eNotarization Markup Language
(ENML)
Version 1.0 which is a proposed standard to represent a notarized document
in
XML. It is available in several formats at
http://www.oasis-open.org/committees/documents.php?wg_abbrev=legalxml-enotar
y
One of the
Perhaps a link to the PDF version will work better:
http://www.oasis-open.org/committees/download.php/31222/ENML-1.0-Specificati
on.pdf
-Original Message-
From: leapsecs-boun...@leapsecond.com
[mailto:leapsecs-boun...@leapsecond.com] On Behalf Of Rob Seaman
Sent: Tuesday, February 17,
Rob Seaman wrote in part:
Creating an ID that is guaranteed unique is not a trivial task,
especially if (as one suspects is true here) a central server is out
of the question.
I'm not familiar with the details of OID, but in general, it would be
desireable to have the option to
Rob Seaman wrote in part:
Actually, there is a failure of the current scheme in the document. A
notary is per country/state pair. But about a third of the U.S.
states and presumably many provinces in other countries are split by
timezones
Notaries are usually allowed to
Given that UTC did not exist in its present form (and as described
in ISO 8601:2004, that is, with leap seconds) until 1 January 1972,
and
given that the ISO 8601:2004 standard states [Z] is used as UTC
designator.
(p. 12)
is it fair to conclude that it is improper to use the Z designator for
I asked is it fair to conclude that it is improper to use the 'Z'
designator for any
date/time in the ISO 8601 format prior to 1 January 1972?
Poul-Henning Kamp replied No. 'Zulu Time' is much older than 1972 and the
'Z'
designator goes waaay back.
I must disagree with that reasoning. The
Rob Seaman wrote:
Gerard Ashton wrote:
Similarly, within ISO 8601, Z designates UTC and any meaning it
may have had for most of the 20th century outside that standard is
irrelevant.
I don't know if I agree with the latter part of the sentence since Z
retains usage outside of ISO 8601
An addition to the list set forth by M. Warner is surveyors
who use star or sun sightings to establish precise directions
of lines (to an accuracy of less than one arcminute). Although
some surveyors do this with GPS, many surveyors do not because
of the expense of the equipment (about two orders
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