Draft profile of ISO 8601

Misha Wolf misha.wolf at reuters.com
Tue Jun 24 18:48:26 UTC 1997

Dan Connolly wrote:
> Misha Wolf wrote:
> > 2.  Date plus hours and minutes
> > -------------------------------
> > 
> > The format is one of: YYYY-MM-DDThh:mmZ
> >                       YYYY-MM-DDThh:mm+hh:mm
> >                       YYYY-MM-DDThh:mm-hh:mm
> A major benefit of using YYYY-MM-DD over the Internet
> traditional Tue, 30 Jan 1997... format is that string
> comparisons work for date comparisons; e.g. you don't
> have to go through heroics to sort log files by date.
> By including timezone stuff (+hh:mm), you lose that
> benefit.
> Is there some motivation for including +yy:mm that
> offsets this loss?

[Note: For "+yy:mm" read "+hh:mm"]

I'm not sure which of the following you are asking:

Q1. Why have time zone info?

Q2. Why not require that all dates/times be normalised to UTC when entered.

Answer to Q1: A time is only meaningful within a time zone.

Answers to Q2:

a)  I'm defining a profile with various options (this can be viewed as 
    a family of profiles), such that each adopting standard can choose 
    the appropriate options.  For many purposes, the actual time zone 
    is important.  PICS, for instance, requires the time zone.

b)  The normalisation to UTC can easily be done prior to date/time 
    collation/comparison.  It involves just an addition or subtraction.

Misha Wolf            Email: misha.wolf at reuters.com     85 Fleet Street
Standards Manager     Voice: +44 171 542 6722           London EC4P 4AJ
Reuters Limited       Fax  : +44 171 542 8314           UK


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