Re: Predictable Internet Time

Nico Williams <nico@cryptonector.com> Wed, 29 March 2017 15:56 UTC

Return-Path: <nico@cryptonector.com>
X-Original-To: ietf@ietfa.amsl.com
Delivered-To: ietf@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id AE1E5126B6D for <ietf@ietfa.amsl.com>; Wed, 29 Mar 2017 08:56:55 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.796
X-Spam-Level:
X-Spam-Status: No, score=-4.796 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-2.796] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cryptonector.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XTlQQCOLa8d0 for <ietf@ietfa.amsl.com>; Wed, 29 Mar 2017 08:56:53 -0700 (PDT)
Received: from homiemail-a31.g.dreamhost.com (sub4.mail.dreamhost.com [69.163.253.135]) (using TLSv1.1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D561712953C for <ietf@ietf.org>; Wed, 29 Mar 2017 08:56:53 -0700 (PDT)
Received: from homiemail-a31.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a31.g.dreamhost.com (Postfix) with ESMTP id 5E69E1406B1A; Wed, 29 Mar 2017 08:56:53 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=cryptonector.com; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=cryptonector.com; bh=t0Mmq3zonHgtdK oVD/ZTPYwn0Xg=; b=ya6EdFFACUIL18ZxJ7siHDEYx/eoKrjRnR/CrkYw84PyVb jrR+wV0TTaZjaPyhn84DgVCMHOZhAgE8OddirHhpxb1ZORLZ6kH4JZSNuR1oy+Dn xoTjxcwobhNsNyR4YHToovMz7I9jekCjoWeL+G0RZIopz+cJFRknQF4Zk8HGE=
Received: from localhost (cpe-70-123-158-140.austin.res.rr.com [70.123.158.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: nico@cryptonector.com) by homiemail-a31.g.dreamhost.com (Postfix) with ESMTPSA id 132ED1406B0A; Wed, 29 Mar 2017 08:56:53 -0700 (PDT)
Date: Wed, 29 Mar 2017 10:56:50 -0500
From: Nico Williams <nico@cryptonector.com>
To: Harald Alvestrand <harald@alvestrand.no>
Cc: ietf@ietf.org
Subject: Re: Predictable Internet Time
Message-ID: <20170329155649.GS7490@localhost>
References: <m1cOYZ6-0000FAC@stereo.hq.phicoh.net> <bf1a0b49-6f76-1ec8-0a70-bfff9be40c16@alvestrand.no>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <bf1a0b49-6f76-1ec8-0a70-bfff9be40c16@alvestrand.no>
User-Agent: Mutt/1.5.24 (2015-08-30)
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf/Y2kVwcopRcsJ8AHcrF29zYZUg4s>
X-BeenThere: ietf@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: IETF-Discussion <ietf.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ietf>, <mailto:ietf-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ietf/>
List-Post: <mailto:ietf@ietf.org>
List-Help: <mailto:ietf-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ietf>, <mailto:ietf-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 29 Mar 2017 15:56:56 -0000

On Wed, Jan 04, 2017 at 09:49:35AM +0100, Harald Alvestrand wrote:
> FWIW, the W3C has switched to defining time inside a Web page in two
> segments:
> - Page load time, which is UTC-derived (POSIX time extended to
> milliseconds), and can jump when the system clock is reset
> - Events related to the page load time, which has floating-point
> representation, and is guaranteed to be monotonic.

But aren't these relative times (intervals)?  As long as they are short
enough, distinctions between UTC, TAI, local, and smeared time will make
little difference most of the time.  (Naturally, using local time might
cause a page load time to appear to be negative, or over an hour, around
daylight savings switch overs, or if one is moving across timezones,
thus "most of the time".)