Re: [art] summary of updates - draft-time-touch

[Joe Touch <[e-mail]>]

Hi, all,

I've completed an update that rolls in the changes below as well as a
few other issues raised off-list.

Joe

A new version of I-D, draft-touch-time-02.txt
has been successfully submitted by Joe Touch and posted to the
IETF repository.

Name:		draft-touch-time
Revision:	02
Title:		Resolving Multiple Time Scales in the Internet
Document date:	2017-04-17
Group:		Individual Submission
Pages:		17
URL:            https://www.ietf.org/internet-drafts/draft-touch-time-02.txt
Status:         https://datatracker.ietf.org/doc/draft-touch-time/
Htmlized:       https://tools.ietf.org/html/draft-touch-time-02
Htmlized:       https://datatracker.ietf.org/doc/html/draft-touch-time-02
Diff:           https://www.ietf.org/rfcdiff?url2=draft-touch-time-02

Abstract:
   Internet systems use a variety of time scales, which can complicate
   time comparisons and calculations. This document explains these
   various ways of indicating time and explains how they can be used
   together safely. This document is intended as a companion to
   Internet time as discussed in RFC 3339.

                                                                    


On 3/29/2017 9:43 AM, Joe Touch wrote:
> Hi, all,
>
> So I have a set of things to update so far. Please let me know if I
> missed something. I will have an update out by the end of this week.
>
> I'm hoping this update can help us converge...
>
> Joe
> ---------
>
> - clarify TAI as a post-facto average
> - clarify prev definition of astronomical second as instantaneous:
>
> 1/31556925.9747 of the tropical year as of the instant
> 1900 January 0 at 12:00:00 Ephemeris Time.
>
> - clarify UT1 as a a measure of the orientation angle of the earth upon
> which international agreement bases the notion of calendar days.
> - consider cleaning up the UT definitions, noting mostly that UT1 is the
> only one in use (and not getting into the detail of UT0 and UT2)
> - clean up the POSIX definition (it's not solar; more like a local clock)
> - this is all at mean sea level (we're ignoring relativistic effects)
> - reminder that the POSIX "equation" is approximate
> - a light discussion about implementation issues (e.g., struct timeval
> vs struct tm vs. ISO 8601)
> - fix NTP epoch to 1900-01-01
> - clarify the two solar times as "apparent" vs "mean"
> - reminder that timers either end on a date or specify an interval
> - reminder that future times in UTC are indeterminate
> - UTC is known only into some future (e.g., a few months) that you know
> about scheduled leaps
> - earth rotation, not orbit, causes most of solar time variation
>
> One other thing that came up is the difference between "POSIX time"
> (previously called Unix time) and the POSIX time API. The API can access
> a variety of time scales, including UTC (e.g., when NTP is running), an
> emulation of UTC, an emulation of Unix time, or direct access to a
> monotonic counter (which may or may not be reset on reboot). I think
> this is Nico's issue with data types, and it's worth clarifying.
>
> -----