Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-17 03:35 AM, Tony Finch wrote: Clive D.W. Feather cl...@davros.org wrote: Brooks Harris said: Wikipedia (not always an authoritative source) Standard time http://en.wikipedia.org/wiki/Standard_time states: Where daylight saving time is used, the term standard time typically refers to the time without the offset for daylight saving time.. That is consistent with my understanding of Standard time. But not mine. standard time is to be contrasted with local time. Both GMT and BST are standard time in the UK. That isn't the contrast in ISO 8601. It says: 2.1.16 local time locally applicable time of day such as standard time of day, or a non-UTC based time of day The relevant distinction is from the late 1800s, between local mean solar time and time based on a standard meridian, as in railway time. So ISO 8601 is right that summer time is also a standard time (in this sense) even though the North American terminology that distinguishes between (original) standard time and daylight saving time is clearer. Tony. The WORLD MAP OF TIME ZONES published by the UK Hydrographic Office uses the standard plus daylight convention. STANDARD TIME ZONES Corrected to April 2012 Zone boundaries are approximate Daylight Saving Time (Summer Time), usually one hour in advance of Standard Time, is kept in some places Map outline © Mountain High Maps Compiled by HM Nautical Almanac Office http://www.ukho.gov.uk/HMNAO/HMNAODocs/Wmtz120424.pdf -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
Warner Losh i...@bsdimp.com wrote: Moving to atomic time doesn't undo 4500 years of timekeeping tradition. In fact, it restores the tradition of all minutes being the same length. That is a relatively recent tradition compared to 4500 years :-) Tony. -- f.anthony.n.finch d...@dotat.at http://dotat.at/ Irish Sea: Southeast 6 to gale 8, veering south 5 or 6. Slight or moderate, occasionally rough. Rain or showers. Moderate or good. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
Tony Finch said: But not mine. standard time is to be contrasted with local time. Both GMT and BST are standard time in the UK. The relevant distinction is from the late 1800s, between local mean solar time and time based on a standard meridian, as in railway time. Right. But to be honest, I don't hear either term used very often in the UK, where we (almost) only have one time zone. -- Clive D.W. Feather | If you lie to the compiler, Email: cl...@davros.org | it will get its revenge. Web: http://www.davros.org | - Henry Spencer Mobile: +44 7973 377646 ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Definition of Standard time - Brooks Harris
It seems the meaning of the term Standard time in common-use and in POSIX is in conflict with the definitions in ISO 8601 and IEC 60050-111. Wikipedia (not always an authoritative source) Standard time http://en.wikipedia.org/wiki/Standard_time states: Where daylight saving time is used, the term standard time typically refers to the time without the offset for daylight saving time.. That is consistent with my understanding of Standard time. POSIX doesn't seem to explicitly state this, but the logic of the TZ environment and functions are consistent with this definition. But ISO 8601 and IEC 60050-111 say standard time may include time shifts for winter time and summer time: In ISO 8601 2.1.14 standard time time scale derived from coordinated universal time, UTC, by a time shift established in a given location by the competent authority [IEC 60050-111] NOTE This time shift may be varied in the course of a year. 2.1.15 standard time of day quantitative expression marking an instant within a calendar day by the duration elapsed after midnight in the local standard time [IEC 60050-111] NOTE Standard time of day is called “clock time” in IEC 60050-111. In IEC 60050-111 --- 111-16-16 standard time time scale derived from coordinated universal time, UTC, by a time shift established in a given location by the competent authority NOTE Examples are Central European Time (CET), Central European Summer Time (CEST), Pacific Standard Time (PST), Japanese Standard Time (JST), etc. 111-16-17 clock time quantitative expression marking an instant within a calendar day by the duration elapsed after midnight in the local standard time NOTE Usually, clock time is represented by the number of hours elapsed after midnight, the number of minutes elapsed after the last full hour, and, if necessary, the number of seconds elapsed after the last full minute, possibly with decimal parts of a second. Examples of the standardized representation (see ISO 8601) are 09:01; 09:01:12; 09:01:12,23. --- Is my interpretation correct? Can anyone shed light on how and why ISO 8601 and IEC 60050-111 are in conflict with common use and POSIX and how this may have come about? -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-16 01:28 AM, John Hawkinson wrote: This is not a real conflict. The standards you cite do not say standard time, they say things like standard time scale which is parsed as (STANDARD (TIME SCALE)) not ((STANDARD TIME) SCALE). etc. Ah, they are defining standard time, standard time of day, and clock time. The note on ISO 8601, 2.1.14 standard time says NOTE This time shift may be varied in the course of a year. The note on IEC 60050-111, 111-16-16 standard time (that ISO 8601 references) says NOTE Examples are Central European Time (CET), Central European Summer Time (CEST), Pacific Standard Time (PST), Japanese Standard Time (JST), etc. That includes *both* CET and CEST. The note on ISO 8601, 2.1.15 standard time of day says NOTE Standard time of day is called clock time in IEC 60050-111. And IEC 60050-111, 111-16-17 clock time describes time as indicated for local standard time It seems pretty clear they mean standard time may include summer time. That really *is* in conflict with common use, isn't it? This comes up in context of attempting to write a definition of standard time as understood in common use (and POSIX, and such). You'd like to reach to ISO 8601 for the definition, and there you discover this conflict. ISO 8601 is an important standard. Besides its famous description of representation is also defines what its representing (Basic concepts, Time Units, Gregorian calendar). But it is silent on daylight savings. It describes representation of Local time and the difference from UTC, and local time is defined in 2.1.16 - local time - locally applicable time of day such as standard time of day, or a non-UTC based time of day It can't, or doesn't, distinguish between New York standard time 12:00:00-05:00 and New York daylight time 12:00:00-04:00. Standard time in 8601 really is in conflict with common use, I think. -Brooks Not optimal but so little in life is. --jh...@mit.edu John Hawkinson +1 617 797 0250 Brooks Harris bro...@edlmax.com wrote on Sun, 16 Feb 2014 at 01:23:23 -0800 in 5300838b.8030...@edlmax.com: Date: Sun, 16 Feb 2014 01:23:23 -0800 From: Brooks Harris bro...@edlmax.com To: Leap Second Discussion List leapsecs@leapsecond.com Subject: [LEAPSECS] Definition of Standard time - Brooks Harris X-Virus-Check-By: mailwash27.pair.com X-TCPREMOTEIP: 76.176.132.16 X-Authenticated-UID: bro...@edlmax.com Message-ID: 5300838b.8030...@edlmax.com Reply-To: Leap Second Discussion List leapsecs@leapsecond.com Sender: leapsecs-boun...@leapsecond.com It seems the meaning of the term Standard time in common-use and in POSIX is in conflict with the definitions in ISO 8601 and IEC 60050-111. Wikipedia (not always an authoritative source) Standard time http://en.wikipedia.org/wiki/Standard_time states: Where daylight saving time is used, the term standard time typically refers to the time without the offset for daylight saving time.. That is consistent with my understanding of Standard time. POSIX doesn't seem to explicitly state this, but the logic of the TZ environment and functions are consistent with this definition. But ISO 8601 and IEC 60050-111 say standard time may include time shifts for winter time and summer time: In ISO 8601 2.1.14 standard time time scale derived from coordinated universal time, UTC, by a time shift established in a given location by the competent authority [IEC 60050-111] NOTE This time shift may be varied in the course of a year. 2.1.15 standard time of day quantitative expression marking an instant within a calendar day by the duration elapsed after midnight in the local standard time [IEC 60050-111] NOTE Standard time of day is called ?clock time? in IEC 60050-111. In IEC 60050-111 --- 111-16-16 standard time time scale derived from coordinated universal time, UTC, by a time shift established in a given location by the competent authority NOTE Examples are Central European Time (CET), Central European Summer Time (CEST), Pacific Standard Time (PST), Japanese Standard Time (JST), etc. 111-16-17 clock time quantitative expression marking an instant within a calendar day by the duration elapsed after midnight in the local standard time NOTE Usually, clock time is represented by the number of hours elapsed after midnight, the number of minutes elapsed after the last full hour, and, if necessary, the number of seconds elapsed after the last full minute, possibly with decimal parts of a second. Examples of the standardized representation (see ISO 8601) are 09:01; 09:01:12; 09:01:12,23. --- Is my interpretation correct? Can anyone shed light on how and why ISO 8601 and IEC 60050-111 are in conflict with common use and POSIX and how this may have come about? -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
In message 5300838b.8030...@edlmax.com, Brooks Harris writes: It seems the meaning of the term Standard time in common-use and in POSIX is in conflict with the definitions in ISO 8601 and IEC 60050-111. It seems to me that a term like Standard time is so vague and fuzzy that we should naturally expect people to use it carelessly and without any formal definition. Sort of like RS-232... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@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@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On Feb 16, 2014, at 4:30 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 5300838b.8030...@edlmax.com, Brooks Harris writes: It seems the meaning of the term Standard time in common-use and in POSIX is in conflict with the definitions in ISO 8601 and IEC 60050-111. It seems to me that a term like Standard time is so vague and fuzzy that we should naturally expect people to use it carelessly and without any formal definition. Universal Time brings clarity to the timescale underlying the idiosyncrasies of the standard timezone system. Universal Time is the modern version of Greenwich Mean Time that flowed naturally from establishing the prime meridian that anchors the timezone system spatially as UT does temporally. It seems a strange position for the precision timekeeping community to take, that Coordinated Universal Time should be replaced by perpetual ad hoc uncoordinated unstandardized local adjustments to a vague and fuzzy, careless and informal system that will have been deliberately unmoored from the solid common standards of both mean solar time and prime meridian. Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-16 03:30 AM, Poul-Henning Kamp wrote: In message 5300838b.8030...@edlmax.com, Brooks Harris writes: It seems the meaning of the term Standard time in common-use and in POSIX is in conflict with the definitions in ISO 8601 and IEC 60050-111. It seems to me that a term like Standard time is so vague and fuzzy that we should naturally expect people to use it carelessly and without any formal definition. 8601 defines many thing very well - Basic concepts, Time Units, Gregorian calendar, and generally, the text representations. But it is silent on daylight Savings or summer time (but mentioned in some notes) and the representation of Local time and the difference from UTC cannot distinguish standard time from daylight time. I wonder why they avoid making clear definitions of Standard time and Daylight? Is it because previous precedent had already confused the meanings of the terms, or maybe because they emanate from the Western world and can't be agreed on internationally? Or something else? -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On Sun 2014-02-16T09:07:11 -0800, Brooks Harris hath writ: I wonder why they avoid making clear definitions of Standard time and Daylight? Is it because previous precedent had already confused the meanings of the terms, or maybe because they emanate from the Western world and can't be agreed on internationally? Or something else? These are questions better posed in the context of the tz mail list. In that list there exist examples where the pronouncements of impending (or sometimes already implemented) time changes are accompanied by words where the bureaucrats in charge show that they believe there is some sort of international scheme for time zones. Apparently nobody told them that there are no rules and that they can choose any offset they like and any dates of changes that they like. I would not be surprised if the ISO folks found that in many jurisdictions there is no statutory basis for the summer/daylight terminology, so no source of clear definitions. -- Steve Allen s...@ucolick.orgWGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165Lat +36.99855 1156 High StreetVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-16 09:22 AM, Steve Allen wrote: On Sun 2014-02-16T09:07:11 -0800, Brooks Harris hath writ: I wonder why they avoid making clear definitions of Standard time and Daylight? Is it because previous precedent had already confused the meanings of the terms, or maybe because they emanate from the Western world and can't be agreed on internationally? Or something else? These are questions better posed in the context of the tz mail list. Perhaps. But it revolves around UTC. In that list there exist examples where the pronouncements of impending (or sometimes already implemented) time changes are accompanied by words where the bureaucrats in charge show that they believe there is some sort of international scheme for time zones. Apparently nobody told them that there are no rules and that they can choose any offset they like and any dates of changes that they like. I think bureaucrats in charge would be relieved and pleased if the *where* an international scheme for time zones. After all, time-keeping is fundamental to commerce and culture in general. Most governments are going to want to interact with the world in cooperative ways where time is concerned. They are also now dependent on computers and software implementations of time. In may respects, its the behavior of computers that define the common use of timekeeping. And its with computers where many of the interoperability problems originate. So maybe there's now an opportunity for some standards body to create a comprehensive and rigorous standard that spanned UTC to local time. I would not be surprised if the ISO folks found that in many jurisdictions there is no statutory basis for the summer/daylight terminology, so no source of clear definitions. Sure. But some, like the US, do have reasonably complete definitions (even if they change details unexpectedly). Many follow that example in the hopes of being compatible. Clear definitions won't come from governments - they need to originate with the experts in the timekeeping community. Only a comprehensive plan which aims to fix the obvious and well known problems is going to head off the kill Leap Seconds movement. I tried to explore how that might be started and was blown to bits. OK, if not me, who's going to try? Or will we just roll over and watch 4500 years of timekeeping tradition evaporate? -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
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 ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On Feb 16, 2014, at 11:20 AM, Brooks Harris wrote: Only a comprehensive plan which aims to fix the obvious and well known problems is going to head off the kill Leap Seconds movement. I think the momentum and general conservatism of the powers that be will do more to kill the plan than any other comprehensive plan. the status quo is powerful enough and works well enough that people are unwilling to risk a change. Or will we just roll over and watch 4500 years of timekeeping tradition evaporate? The kill the leap second stuff doesn't kill 4500 years of timekeeping tradition. Leap seconds broke with tradition my making minutes longer than 60s. It accepted there's an error between the time in London and the time we coordinate on and that's OK. The leap second moved one step away from the sun by averaging out the noise into discrete steps. Moving to atomic time doesn't undo 4500 years of timekeeping tradition. In fact, it restores the tradition of all minutes being the same length. In many ways, it is the next logical step in moving away from being beholden to the wobbles of the rock we live on by increasing the error we accept and providing a way for civil time to sync to the sun that leverages the current mechanism that civil time uses to sync to the sun. After talking here, though, it is clear the time isn't right for this move... Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-16 10:32 AM, Gerard Ashton wrote: 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. Sure enough. Oh dear. -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-16 10:39 AM, Warner Losh wrote: On Feb 16, 2014, at 11:20 AM, Brooks Harris wrote: Only a comprehensive plan which aims to fix the obvious and well known problems is going to head off the kill Leap Seconds movement. I think the momentum and general conservatism of the powers that be will do more to kill the plan than any other comprehensive plan. the status quo is powerful enough and works well enough that people are unwilling to risk a change. Maybe. But we're still left with vague and difficult implementations that have known problems. Or will we just roll over and watch 4500 years of timekeeping tradition evaporate? The kill the leap second stuff doesn't kill 4500 years of timekeeping tradition. Leap seconds broke with tradition my making minutes longer than 60s. It accepted there's an error between the time in London and the time we coordinate on and that's OK. The leap second moved one step away from the sun by averaging out the noise into discrete steps. Right. Well I see it slightly differently. For centuries timekeeping sought to align the observed positions to some absolute time reference, long recognizing the days length didn't divide into a year. Pope Gregory (partly) fixed that. Then when atomic clocks could keep very accurate time and astronomical observations were extremely precise we were finally in a position to quantify the difference between absolute time and observed rotational position. Integral seconds (Leap Seconds) was deemed accurate enough to solve the problem for general purposes. So I see UTC as the latest and greatest version of 4500 years of timekeeping tradition. Moving to atomic time doesn't undo 4500 years of timekeeping tradition. In fact, it restores the tradition of all minutes being the same length. I think it abandons the long sought goal of aligning civil time to the position of the Sun. The tradition of all minutes being the same length was the best anybody could do. Everyone knew it wasn't exactly right. UTC solved that. -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
There are many timekeeping traditions across many cultures. For most, the move to mean time and the implementation of hours of uniform length were the breaks from tradition. A good demonstration of this is Japanese clocks before and after 1873. During Pope Gregory's life, there were many different ways of reckoning hours--Italian hours, Nuremberg hours, French hours, and canonical hours. For many clocks of that period--particularly the complicated guild masterpiece clocks, sidereal time and astrology for purposes of calculating natal charts was as important as solar time. Our time system is not a product of tradition but relatively recent choices. Yet, since the history of timekeeping tends to be told in terms of the techniques and technologies that were adopted rather than those that were discarded, it looks like there is great historical depth and tradition to our current system. If one takes into account all the timekeeping techniques and preferences that have fallen by the wayside, then the only traditions seem to be ongoing discussions and arguments about how to reckon time. In that sense, the leap second debate, not leap seconds, is traditional. Cheers, Kevin From: leapsecs-boun...@leapsecond.com [leapsecs-boun...@leapsecond.com] on behalf of Brooks Harris [bro...@edlmax.com] Sent: Sunday, February 16, 2014 2:14 PM To: leapsecs@leapsecond.com Subject: Re: [LEAPSECS] Definition of Standard time - Brooks Harris On 2014-02-16 10:39 AM, Warner Losh wrote: On Feb 16, 2014, at 11:20 AM, Brooks Harris wrote: Only a comprehensive plan which aims to fix the obvious and well known problems is going to head off the kill Leap Seconds movement. I think the momentum and general conservatism of the powers that be will do more to kill the plan than any other comprehensive plan. the status quo is powerful enough and works well enough that people are unwilling to risk a change. Maybe. But we're still left with vague and difficult implementations that have known problems. Or will we just roll over and watch 4500 years of timekeeping tradition evaporate? The kill the leap second stuff doesn't kill 4500 years of timekeeping tradition. Leap seconds broke with tradition my making minutes longer than 60s. It accepted there's an error between the time in London and the time we coordinate on and that's OK. The leap second moved one step away from the sun by averaging out the noise into discrete steps. Right. Well I see it slightly differently. For centuries timekeeping sought to align the observed positions to some absolute time reference, long recognizing the days length didn't divide into a year. Pope Gregory (partly) fixed that. Then when atomic clocks could keep very accurate time and astronomical observations were extremely precise we were finally in a position to quantify the difference between absolute time and observed rotational position. Integral seconds (Leap Seconds) was deemed accurate enough to solve the problem for general purposes. So I see UTC as the latest and greatest version of 4500 years of timekeeping tradition. Moving to atomic time doesn't undo 4500 years of timekeeping tradition. In fact, it restores the tradition of all minutes being the same length. I think it abandons the long sought goal of aligning civil time to the position of the Sun. The tradition of all minutes being the same length was the best anybody could do. Everyone knew it wasn't exactly right. UTC solved that. -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
Brooks Harris said: Wikipedia (not always an authoritative source) Standard time http://en.wikipedia.org/wiki/Standard_time states: Where daylight saving time is used, the term standard time typically refers to the time without the offset for daylight saving time.. That is consistent with my understanding of Standard time. But not mine. standard time is to be contrasted with local time. Both GMT and BST are standard time in the UK. -- Clive D.W. Feather | If you lie to the compiler, Email: cl...@davros.org | it will get its revenge. Web: http://www.davros.org | - Henry Spencer Mobile: +44 7973 377646 ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On Feb 16, 2014, at 3:05 PM, Clive D.W. Feather cl...@davros.org wrote: Brooks Harris said: Where daylight saving time is used, the term standard time typically refers to the time without the offset for daylight saving time.. That is consistent with my understanding of Standard time. But not mine. standard time is to be contrasted with local time. Both GMT and BST are standard time in the UK. Interesting. My personal experience of what is typical usage in the U.S. and Chile would be the opposite. Local time almost universally means what the clock says right now (or said at the time in question). On the other hand, calling something standard time (e.g., Pacific Standard Time) never means daylight saving time, rather that is Pacific Daylight Time). Contrast EST, CST, MST and PST with EDT, CDT, MDT and PDT. Since Arizona (outside Navajo lands) never observes MDT, this is something we're sensitive to from having to shift schedules twice a year relative to everybody else in the country. The observatory also has telescopes and personnel in Chile, and the anti-correlated seasonal daylight saving time shifts from CLT to CLST are referred to similarly. (I'd welcome correction regarding differences in Spanish usage.) In the U.S. I've lived in MA, PA, WY and HI (which also doesn't observe DST) and usage was similar to what I describe: local time means what the clock says and standard time refers to the opposite of daylight saving time. It would be interesting to explore the usage in other locations and by various communities. And of course, only a minority of the world's population observe DST at any time of the year, so it might be moot to distinguish the two in places that don't. Anybody from Canada want to report on usage? There's a large overlap in timezones with the U.S., but as a member of the Commonwealth you might be expected to have usage derived from the U.K. Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Definition of Standard time - Brooks Harris
On 2014-02-16 02:05 PM, Clive D.W. Feather wrote: Brooks Harris said: Wikipedia (not always an authoritative source) Standard time http://en.wikipedia.org/wiki/Standard_time states: Where daylight saving time is used, the term standard time typically refers to the time without the offset for daylight saving time.. That is consistent with my understanding of Standard time. But not mine. standard time is to be contrasted with local time. Both GMT and BST are standard time in the UK. Ah. Well that may help explain why 8601 and 60050 treat it that way. Also, as per other email, actually the US Daylight law also says the same thing. But the law is not consistent with common use in the US. Meantime, POSIX treats std as fixed offset from UTC with dst active or not. Thats more like common use in US, as in Eastern Standard Time and Eastern Daylight Time. -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
