Re: Predictable Internet Time

Eliot Lear <> Tue, 03 January 2017 06:43 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 9D153129432 for <>; Mon, 2 Jan 2017 22:43:30 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -17.622
X-Spam-Status: No, score=-17.622 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_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RP_MATCHES_RCVD=-3.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id SVjVpHTQIkrm for <>; Mon, 2 Jan 2017 22:43:29 -0800 (PST)
Received: from ( []) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id EC6F6129434 for <>; Mon, 2 Jan 2017 22:43:28 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;;; l=3552; q=dns/txt; s=iport; t=1483425809; x=1484635409; h=subject:to:references:cc:from:message-id:date: mime-version:in-reply-to; bh=a1G+zNVy+noqkxW+ArpmTMuCK6zkK/ssixKEsDGb9nY=; b=cnFgJC3K9VYQfJynx5zxkcqlvXZJO7A1z79ErL8IDZXB/24AReDrDODL klKXPCJlm/8IRl34vSJ432TIv2BzYGZTLgX/+/qgzMEIbm30BVGLB/mFM Upstr2PGROHjG0wU5VTrXdVMuPOMVnFVsYXNZCpPnqal/Hut7JRVxYmz0 A=;
X-Files: signature.asc : 481
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-AV: E=Sophos;i="5.33,451,1477958400"; d="asc'?scan'208";a="648450483"
Received: from (HELO ([]) by with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jan 2017 06:43:07 +0000
Received: from [] ([]) by (8.14.5/8.14.5) with ESMTP id v036h65m020236; Tue, 3 Jan 2017 06:43:06 GMT
Subject: Re: Predictable Internet Time
To: Patrik Fältström <>, Joe Touch <>
References: <> <> <> <> <>
From: Eliot Lear <>
Message-ID: <>
Date: Tue, 03 Jan 2017 07:43:05 +0100
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.6.0
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="jgL0qW7DlXlmrs0ncgFppogh54nwrnWN3"
Archived-At: <>
Cc: Phillip Hallam-Baker <>, IETF Discussion Mailing List <>
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: IETF-Discussion <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 03 Jan 2017 06:43:30 -0000

Good morning, Patrik,

On 1/3/17 7:29 AM, Patrik Fältström wrote:
> I think personally, as long as we do have leap seconds:
> - we should have the leap second information available somewhere in clear machine readable format. Some suggestions exists, including encoding it in A-records in DNS ;-)
> - we should look at having the time since epoch really be the number of SI-seconds since the epoch
> - we should have translation between number of seconds and UTC take leap seconds into account

The TZDB at IANA contains the file "leapseconds" which is machine
readable, and provides a history of all leapseconds.  This provides you
the 1st and 3rd of your requirements.
> - we should fix the code that do not accept 61 seconds in a minute
> Now, we can also say we should stop having leap seconds, but I feel that is a _different_ matter and different discussion. I am myself not clear over what is the correct thing regarding leap seconds.
> What I am sure of is that I think most of the problems we have is because of bad programming (including in old UNIX days the priorities although correct at the time have continued to let the time_t definition continue to be wrong).

I'm of two minds as well.  On the one hand, the current system makes it
quite easy to do the wrong thing, and that's not good.  There are
utility functions such as pytz's normalize() and localize() functions
that people just don't know about, for instance.  On the other hand,
it's not just leap seconds.  It's timezones in general, it's DST
transitions, etc.  Getting rid of leap seconds only marginally improves
things, and gets really philosophical really quickly...