LISTSERV mailing list manager LISTSERV 16.0

Help for DATETIME Archives


DATETIME Archives

DATETIME Archives


DATETIME@C4VLPLISTSERV01.LOC.GOV


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

DATETIME Home

DATETIME Home

DATETIME  February 2013

DATETIME February 2013

Subject:

Re: Precision better than one second

From:

"Byrd, Donald A." <[log in to unmask]>

Reply-To:

Discussion of the Developing Date/Time Standards <[log in to unmask]>

Date:

Fri, 15 Feb 2013 11:12:57 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (172 lines)

I'd say that the main tradeoffs involved in whether to add any feature 
to a standard are:
1. PRO: may make the standard potentially useful to more people
2. PRO OR CON: increase or decrease compatibility with existing standards
3. CON: make the standard more complex, so harder for programmers to 
handle and harder for users to understand
4. CON: harder to come up with syntax and semantics for

In this case, since we know some people really are using fractional 
seconds with ISO 8601, #2 definitely supports adding them to EDTF. #3 
and #4 are the arguments against, but #4 is a non-issue, since the 8601 
syntax is consistent with EDTF as it stands. And I think #3 is pretty 
weak. Speaking from many years of experience as a programmer, software 
architect, and user-interface designer, it's easy for a programmer to 
handle the 8601 syntax.

Overall, I think the balance is strongly in favor of adding fractional 
seconds back in.

--DAB


On Fri, 15 Feb 2013 11:47:03 +0100, "Edward C. Zimmermann" 
<[log in to unmask]> wrote:

> Oh... Yes.. I speak up from fractional seconds! The second as time atom? No-
> No.
>
> I think I was clear on my feeling about this. Did I not flood this list with
> more than one diatribe on units of time measurement, write about Babylonian
> Barleycorns or 1/72 time degree (actively used in Jewish time measures, which
> even has the concept of a "moment" as 1/76 a Barleycorn, eg. 5/114 sec.), TAI
> (caesium-133) and what's on the horizon..???
>
>
> On Thu, 14 Feb 2013 21:00:24 -0500, Byrd, Donald A. wrote
>> Thanks for the detailed explanation, Ray. I thought calling EDTF a
>> "profile" of 8601 just meant that redundant ways to represent the same
>> information would be removed; I didn't realize the scope of what could
>> be represented might be reduced. But I still have some questions.
>>
>> First, you said that no one spoke up for retaining fractional seconds,
>> but the first URL you give is a message from Edward Zimmermann in which
>> he says: "8601 uses hh:mm:ss.fff where fff are milliseconds.. Why not
>> hh:mm:ss
>> where ss are rational seconds. e.g. ss including decimal fractions
>> without restriction, e.g. allowing for times such as 12:21:44.5 and
>> 12:59:59.1001". So he _did_ speak up for fractional seconds! In fact,
>> he asked for any number of decimal places -- which is actually what
>> 8601 allows, not just milliseconds (i.e., exactly 3 decimal places),
>> according to two descriptions of it I have.
>>
>> And second, I have the impression that EDTF Level 0 can express
>> virtually everything 8601 can express _except_ fractional seconds
>> (though with fewer ways to express a lot of things). If I'm right, it
>> seems like a real mistake to remove fractional seconds in EDTF Level 0.
>> Especially since Levels 1 and 2 don't add them back in! Of course, as
>> you say, there will be a follow-up opportunity to propose more
>> features, but even so.
>>
>> --DAB
>>
>> On Thu, 14 Feb 2013 15:54:02 -0500, Ray Denenberg <[log in to unmask]> wrote:
>>
>> > Hi Don - Yes, maximum precision is one second. It wasn't always so, early
>> > drafts supported fraction of second in the same manner as ISO 8601.
>> >
>> > It was never the intention of this effort to fully support 8601. It tries
> to
>> > be a profile/extension of/to ISO 8601, As it says in the abstract:
>> >
>> > "ISO 8601 describes a large number of date/time formats. On one hand some
> of
>> > these formats are redundant and/or not very useful; to reduce the scope
> for
>> > error and the complexity of software, it seems worthwhile to restrict the
>> > supported formats to a smaller set. On the other hand, there are a number
> of
>> > date and time format conventions in common use that are not included in
> ISO
>> > 8601; it seems worthwhile to normalize these."
>> >
>> > And so, early drafts had quite a lot of features that did not make the
> cut.
>> > We went through a process of questioning each feature, and if nobody spoke
>> > up for a feature, it was removed.
>> >
>> >
>> > (For "fraction of a second", see
>> > <http://listserv.loc.gov/cgi-bin/wa?
> A2=ind1103&L=DATETIME&P=R5149&I=-3&X=048
>> > 09F159E636F2A03&Y=rden%40loc.gov>
>> > http://listserv.loc.gov/cgi-bin/wa?
> A2=ind1103&L=DATETIME&P=R5149&I=-3&X=0480
>> > 9F159E636F2A03&Y=rden%40loc.gov where I asked
>> >
>> >
>> > "For time, is hour:minute:second sufficient, or do we need to support
>> > fraction of a second?"
>> >
>> >
>> > Nobody responded, so it was removed.
>> >
>> >
>> > That's not to say that fraction of second is not a useful feature, it
> simply
>> > means that nobody who has participated in this round of the development of
>> > the spec found it useful.  There will be a follow-up opportunity to
> propose
>> > additional features.
>> >
>> >
>> > Ray
>> >
>> >
>> >
>> >> -----Original Message-----
>> >
>> >> From: Discussion of the Developing Date/Time Standards
>> >> [mailto:[log in to unmask]] On Behalf Of Byrd, Donald A.
>> >> Sent: Thursday, February 07, 2013 11:41 AM
>> >> To: [log in to unmask]
>> >> Subject: [DATETIME] Precision better than one second
>> >>
>> >> I may be blind, but as far as I can tell from both the text and the BNF,
>> >> EDTF's maximum precision is one second. OK, That's considerably more
>> >> limited than ISO 8601, which allows unlimited precision! For example,
>> >> "13:10:30,7" is 30.7 sec. after 13:10, with precision of 1/10 second. And
>> >> some people seem actually to be using 8601 with millisecond resolution --
>> >> for example, see the Joda.org website:
>> >
>> >>  <http://joda-time.sourceforge.net/cal_iso.html>
>> > http://joda-time.sourceforge.net/cal_iso.html .  I assume that this is
>> >
>> >> either my mistake or a mistake in the EDTF proposal? Surely it's not a
>> > good
>> >> idea to add any further limitations to 8601.
>> >
>> >>
>> >
>> >> --Don
>> >
>> >>
>> >
>> >>
>> >
>> >
>>
>> --
>> Donald Byrd
>> Woodrow Wilson Indiana Teaching Fellow
>> Adjunct Associate Professor of Informatics
>> Visiting Scientist, Research Technologies
>> Indiana University Bloomington
>
>
> --
>
> Edward C. Zimmermann, NONMONOTONIC LAB/BSn
> http://www.ibu.de/IB_Engine
> Umsatz-St-ID: DE130492967
>



--
Donald Byrd
Woodrow Wilson Indiana Teaching Fellow
Adjunct Associate Professor of Informatics
Visiting Scientist, Research Technologies
Indiana University Bloomington

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

August 2019
February 2019
December 2018
November 2018
October 2018
January 2018
August 2017
July 2017
June 2017
April 2017
March 2017
February 2017
August 2016
July 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
December 2014
November 2014
March 2014
September 2013
May 2013
February 2013
October 2012
September 2012
August 2012
May 2012
March 2012
December 2011
November 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
February 2010
January 2010
December 2009
November 2009

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager