Re: [LEAPSECS] one second tolerance
On Thu, 10 Feb 2011, Michael Deckers wrote: > >Which evidently wasn't worth it. I've heard objections against >the notation on the grounds that letter suffixes like A and B >are used in the military, where they denote fixed time zones >(Alpha for UTC + 1 h, Bravo for UTC + 2 h, ...). Which amusingly is the exact opposite of the Danish notation :-) Tony. -- f.anthony.n.finchhttp://dotat.at/ HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7, DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR ROUGH. RAIN THEN FAIR. GOOD. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On 2011-02-10 20:42, Poul-Henning Kamp wrote about the Danish summer time law: Yes, one interesting detail here is the use of the word "klokketiden" which literally means "(Church-)Bell-Time", but which most people would understand as "clock-time" This word first appears in 1946 in the first law to introduce DST in Denmark, and _presumably_, but we cannot know for sure, this was meant to distinguish "clock time" from "solar time": http://ordnet.dk/ods/ordbog?query=klokketid Very interesting indeed! "klokketiden" also shows up in web sites of Greenland and Norway (bokmål). I do not know enough Danish -- could it have a function similar to the (US) English wall clock time? He continued about the use of suffixes 'A' and 'B' to distinguish between the "repeated" datetimes that occur when a civil time scale is set back from summer time to winter time: I have only ever seen it once, and that was my own doing: When we ran into this, We tried to see if we could fit the 'A/B' designator on the receipt printed by the automatic gas-pumps without using another line of text. We couldn't and since we could not have a special print format during that one hour a day, compliance would have used 138km more paper per year. Which evidently wasn't worth it. I've heard objections against the notation on the grounds that letter suffixes like A and B are used in the military, where they denote fixed time zones (Alpha for UTC + 1 h, Bravo for UTC + 2 h, ...). Thanks. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
In message <4d544a0e.4020...@yahoo.com>, Michael Deckers writes: > >> In Denmark the law used to say that you have to suffix the >> timestamp with 'A' and 'B' during these two hours. > >Interesting. That notation still seems to be legal, see >[http://www.retsinformation.dk/Forms/R0710.aspx?id=22064]. Yes, one interesting detail here is the use of the word "klokketiden" which literally means "(Church-)Bell-Time", but which most people would understand as "clock-time" This word first appears in 1946 in the first law to introduce DST in Denmark, and _presumably_, but we cannot know for sure, this was meant to distinguish "clock time" from "solar time": http://ordnet.dk/ods/ordbog?query=klokketid >However, I have never seen that notation being applied in >practice in Germany, not even by the PTB. Has it ever been >used on a perceivable level in Denmark? I have only ever seen it once, and that was my own doing: When we ran into this, We tried to see if we could fit the 'A/B' designator on the receipt printed by the automatic gas-pumps without using another line of text. We couldn't and since we could not have a special print format during that one hour a day, compliance would have used 138km more paper per year. -- 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] one second tolerance
On 2011-02-09, Poul-Henning Kamp wrote: In Denmark the law used to say that you have to suffix the timestamp with 'A' and 'B' during these two hours. Interesting. That notation still seems to be legal, see [http://www.retsinformation.dk/Forms/R0710.aspx?id=22064]. In Germany, the law allows for a similar notation but does not require it. The notation is both more general (a separate token is applied before and after the discontinuity, this works not just at the end of a whole hour or minute), and potentially less confusing than the notation of ITU-R 460 with second field values >= 60. However, I have never seen that notation being applied in practice in Germany, not even by the PTB. Has it ever been used on a perceivable level in Denmark? Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On Wed 2011/02/09 08:56:21 -, Ian Batten wrote in a message to: Leap Second Discussion List >Microsoft Exchange meeting invitations say things like >"GMT: London, Edinburgh, Lisbon", and then contain local timestamps >corrected for daylight savings. They do that all year round. >Whatever the timezone in London is in July, one thing it certainly >_isn't_ is GMT. They mean "clock on the wall time in places where >the civil time is UTC or UT1 during the winter". Extra fun will Microsoft gets it wrong? Never! Surely it must be user error. Regards, Mark Calabretta ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On Wed 2011/02/09 08:48:28 -, "Poul-Henning Kamp" wrote in a message to: Leap Second Discussion List >>>during the autumn >>>change, a hour is repeated. So as far as a clock ticking civil time is >>>concerned, you have 0100 through 0200 twice, once a year. Events >>>stamped 0130.01 and 0130.02 could be an hour and a second apart. > >In Denmark the law used to say that you have to suffix the timestamp >with 'A' and 'B' during these two hours. Bully for the Danish parliament for exhibiting a bit of nous. >When we did automatic pumps at the oilcompany I worked at, we decided >that we would just refund any complaint during those two ours and >if that turned into abuse, we would just close the pumps for >maintenance instead. The oil company (was it BP by any chance?) apparently decided it could cut corners at the service station. Hopefully it did not adopt such a blasé attitude at the refinery or oil rig. Regards, Mark Calabretta ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On Wed 2011/02/09 08:40:42 -, "Clive D.W. Feather" wrote in a message to: Leap Second Discussion List >> Not if the timestamps are properly labelled with the timezone, >> preferably specified as an offset, which distinguishes between >> DST and non-DST. > > I'm at a loss as to what you find so amusing in the above. The idea that timestamps would be labelled with the timezone? Or that the timezone would be expressed as an offset? If it's such a far-fetched notion (your mailer seems to be able to do it), the idea of leaping timezones rather than seconds would seem to be asking for trouble so far as interpreting historical timestamps is concerned. Regards, Mark Calabretta ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On 02/09/2011 01:56, Ian Batten wrote: Timestamping financial events to 1s resolution opens up the whole "is UK legal time UT1 or UTC?" question again, too. These regulations are from FINRA which is a US regulatory company. The timestamps already were required to have 1s resolution. This requirement is for the clocks to have less than 1s drift from NIST during the course of the trading day. The weird 'Eastern Military Time' is preserved from prior versions of the OATS specification which are on the FINRA web site. Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On 02/08/2011 23:54, Mark Calabretta wrote: On Wed 2011/02/09 06:25:25 -, Ian Batten wrote in a message to: Tom Van Baak, Leap Second Discussion List Although that mandates access to a continuously reliable source of DST changeover dates and offsets. It also opens the interesting question of what timestamps mean in a non-monotonic timescale: during the autumn change, a hour is repeated. So as far as a clock ticking civil time is concerned, you have 0100 through 0200 twice, once a year. Events stamped 0130.01 and 0130.02 could be an hour and a second apart. Not if the timestamps are properly labelled with the timezone, preferably specified as an offset, which distinguishes between DST and non-DST. I think the view is that there's no trading going on in the missing hour as the exchanges are closed then. Whether this is, in fact, true in the future remains to be seen. After seeing this last night, I also contacted some friends that I have where I helped setup a timing system that I talked here about here a while ago. I asked them about this and their insistence to me about the millisecond level timestamps. There were two reasons for them. (1) they use them as internal controls for auditing (which is what I'd confused for external controls: they match them against their own systems which are sync to the submillisecond level so large deltas between the indicate problems) and (2) they are used by their algorithms for future trading purposes. My friend was surprised that they didn't mandate tighter requirements, since most traders would easily be able to comply (since most trading firms already have highly synchronized clocks which helps to drive some of their trading algorithms). The trading aspect of time drove the requirements, since from it they can make more money than they can without synchronized clocks. Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
Clive D.W. Feather wrote: > Tony Finch said: > >> As far as I can tell from a brief look at the document, the accurate >> timestamp requirement applies to trading data, and they don't trade when >> there is a DST change or when leap seconds occur. >> > > Does it say that, or are you guessing? > > DST changes tend to be outside trading hours, but leap seconds happen at > 16:00 local time in California. And is there no out-of-hours trading? > > And New Year's Eve isn't a bank holiday in many (any?) places, is it? ian ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
>> As far as I can tell from a brief look at the document, the accurate >> timestamp requirement applies to trading data, and they don't trade when >> there is a DST change or when leap seconds occur. > > Does it say that, or are you guessing? > > DST changes tend to be outside trading hours, but leap seconds happen at > 16:00 local time in California. And is there no out-of-hours trading? Having scanned the document, it appears to assume 24/7 trading. For example, on page 199 it says that an event at 06:00 on Saturday has to be reported by 08:00 on Tuesday. There's a specific mention of an event at 03:59:59. -- 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] one second tolerance
Tony Finch said: > As far as I can tell from a brief look at the document, the accurate > timestamp requirement applies to trading data, and they don't trade when > there is a DST change or when leap seconds occur. Does it say that, or are you guessing? DST changes tend to be outside trading hours, but leap seconds happen at 16:00 local time in California. And is there no out-of-hours trading? -- 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] one second tolerance
On Wed, 9 Feb 2011, Ian Batten wrote: > > Extra fun will ensue if England moves to full-time daylight saving or to > WET, both of which have a non-zero chance of happening, while Scotland > remain on their existing arrangements, which also has a non-zero chance. You mean CET. (We are currently on WET. > Timestamping financial events to 1s resolution opens up the whole "is UK > legal time UT1 or UTC?" question again, too. Not really, since a particluar market can specify which reference clock its traders must use. Having said that, I had a brief look at the rules of the London Stock Exchange which says in rule 3040 in the "off order book trading rules": "Member firms shall submit the exact date and time of when a trade is agreed to the nearest second" - but it doesn't specify any reference clock. Tony. -- f.anthony.n.finchhttp://dotat.at/ HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7, DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR ROUGH. RAIN THEN FAIR. GOOD. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On Wed, 9 Feb 2011, Ian Batten wrote: > > It also opens the interesting question of what timestamps mean in a > non-monotonic timescale: during the autumn change, a hour is repeated. > So as far as a clock ticking civil time is concerned, you have 0100 > through 0200 twice, once a year. Events stamped 0130.01 and 0130.02 > could be an hour and a second apart. As far as I can tell from a brief look at the document, the accurate timestamp requirement applies to trading data, and they don't trade when there is a DST change or when leap seconds occur. Tony. -- f.anthony.n.finchhttp://dotat.at/ HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7, DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR ROUGH. RAIN THEN FAIR. GOOD. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
Ian Batten said: > Microsoft Exchange meeting invitations say things like "GMT: London, > Edinburgh, Lisbon", and then contain local timestamps corrected for daylight > savings. [...] Yes, I'd forgotten that one. Given that half of my team are now based in Bangalore and the other half in Cambridge, much hilarity ensues from time to time as one or the other turns up at the wrong time for a video conference. I can't wait to see what happens at the end of March. -- 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] one second tolerance
On 9 Feb 2011, at 08:40, Clive D.W. Feather wrote: > Mark Calabretta said: >> Not if the timestamps are properly labelled with the timezone, >> preferably specified as an offset, which distinguishes between >> DST and non-DST. > > > > I was involved in a murder case where the police investigated the wrong > person because they hadn't realized the difference between UTC and BST. > What makes you think that financial lawyers will think of it. Microsoft Exchange meeting invitations say things like "GMT: London, Edinburgh, Lisbon", and then contain local timestamps corrected for daylight savings. They do that all year round. Whatever the timezone in London is in July, one thing it certainly _isn't_ is GMT. They mean "clock on the wall time in places where the civil time is UTC or UT1 during the winter". Extra fun will ensue if England moves to full-time daylight saving or to WET, both of which have a non-zero chance of happening, while Scotland remain on their existing arrangements, which also has a non-zero chance. Timestamping financial events to 1s resolution opens up the whole "is UK legal time UT1 or UTC?" question again, too. ian ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
In message , Mark Calabretta writes: >>during the autumn >>change, a hour is repeated. So as far as a clock ticking civil time is >>concerned, you have 0100 through 0200 twice, once a year. Events >>stamped 0130.01 and 0130.02 could be an hour and a second apart. In Denmark the law used to say that you have to suffix the timestamp with 'A' and 'B' during these two hours. When we did automatic pumps at the oilcompany I worked at, we decided that we would just refund any complaint during those two ours and if that turned into abuse, we would just close the pumps for maintenance instead. -- 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] one second tolerance
Mark Calabretta said: > Not if the timestamps are properly labelled with the timezone, > preferably specified as an offset, which distinguishes between > DST and non-DST. I was involved in a murder case where the police investigated the wrong person because they hadn't realized the difference between UTC and BST. What makes you think that financial lawyers will think of it. -- 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] one second tolerance
On Wed 2011/02/09 06:25:25 -, Ian Batten wrote in a message to: Tom Van Baak , Leap Second Discussion List >Although that mandates access to a continuously reliable source of DST >changeover dates and offsets. It also opens the interesting question >of what timestamps mean in a non-monotonic timescale: during the autumn >change, a hour is repeated. So as far as a clock ticking civil time is >concerned, you have 0100 through 0200 twice, once a year. Events >stamped 0130.01 and 0130.02 could be an hour and a second apart. Not if the timestamps are properly labelled with the timezone, preferably specified as an offset, which distinguishes between DST and non-DST. Regards, Mark Calabretta ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
On 9 Feb 2011, at 03:31, Tom Van Baak wrote: >> Note that they require "Eastern Military (24 hour clock) Time", not UTC. > > Do these really differ fundamentally? > I'm assuming you can subtract 5 hours (or 4 for DST) by hand. Although that mandates access to a continuously reliable source of DST changeover dates and offsets. It also opens the interesting question of what timestamps mean in a non-monotonic timescale: during the autumn change, a hour is repeated. So as far as a clock ticking civil time is concerned, you have 0100 through 0200 twice, once a year. Events stamped 0130.01 and 0130.02 could be an hour and a second apart. ian ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] one second tolerance
Note that they require "Eastern Military (24 hour clock) Time", not UTC. Do these really differ fundamentally? I'm assuming you can subtract 5 hours (or 4 for DST) by hand. Note that they assert the existence of "the" NIST atomic clock as if there were only one. They're ok. There is only one NIST clock. US legal time is based on UTC(NIST). How they actually calculate this at the ns level is not relevant outside of the halls of NIST. Yes, most of you know they have multiple atomic frequency standards but the product that they disseminate is one "clock": UTC(NIST). /tvb ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs