I also think adding precision of better than one second would be good.
If you're going to be using EDTF in a system already, it would be
good to also use the data type for system generated timestamps and
such (where you might want the finer level of precision). That way
you're using one datetime data type (the same one for system generated
times and for fuzzier (higher level) datetimes).
On Fri, Feb 15, 2013 at 5:47 AM, Edward C. Zimmermann <[log in to unmask]> wrote:
> Oh... Yes.. I speak up from fractional seconds! The second as time atom? 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
>> 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.
>> 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
>> > 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
>> > these formats are redundant and/or not very useful; to reduce the scope
>> > 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
>> > date and time format conventions in common use that are not included in
>> > 8601; it seems worthwhile to normalize these."
>> > And so, early drafts had quite a lot of features that did not make the
>> > 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?
>> > 09F159E636F2A03&Y=rden%40loc.gov>
>> > http://listserv.loc.gov/cgi-bin/wa?
>> > 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
>> > 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
>> > 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
> Umsatz-St-ID: DE130492967