From owner-sc22wg5+sc22wg5-dom8=www.open-std.org@open-std.org  Mon Apr  6 18:02:44 2015
Return-Path: <owner-sc22wg5+sc22wg5-dom8=www.open-std.org@open-std.org>
X-Original-To: sc22wg5-dom8
Delivered-To: sc22wg5-dom8@www.open-std.org
Received: by www.open-std.org (Postfix, from userid 521)
	id 8119D35862B; Mon,  6 Apr 2015 18:02:44 +0200 (CEST)
Delivered-To: sc22wg5@open-std.org
Received: from ppsw-32.csi.cam.ac.uk (ppsw-32.csi.cam.ac.uk [131.111.8.132])
	by www.open-std.org (Postfix) with ESMTP id 17A193582F1
	for <sc22wg5@open-std.org>; Mon,  6 Apr 2015 18:02:40 +0200 (CEST)
X-Cam-AntiVirus: no malware found
X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/
Received: from hermes-1.csi.cam.ac.uk ([131.111.8.51]:47720)
	by ppsw-32.csi.cam.ac.uk (smtp.hermes.cam.ac.uk [131.111.8.156]:25)
	with esmtpa (EXTERNAL:nmm1) id 1Yf9Tz-0005Dj-2K (Exim 4.82_3-c0e5623)
	(return-path <nmm1@hermes.cam.ac.uk>); Mon, 06 Apr 2015 17:02:39 +0100
Received: from prayer by hermes-1.csi.cam.ac.uk (hermes.cam.ac.uk)
	with local (PRAYER:nmm1) id 1Yf9Tz-0005zP-ME (Exim 4.72)
	(return-path <nmm1@hermes.cam.ac.uk>); Mon, 06 Apr 2015 17:02:39 +0100
Received: from [146.199.140.93] by old-webmail.hermes.cam.ac.uk
	with HTTP (Prayer-1.3.5); 06 Apr 2015 17:02:39 +0100
Date: 06 Apr 2015 17:02:39 +0100
From: "N.M. Maclaren" <nmm1@cam.ac.uk>
To: John Reid <John.Reid@stfc.ac.uk>
Cc: WG5 <sc22wg5@open-std.org>
Subject: Re: [ukfortran] (SC22WG5.5485) WG5 straw ballot on N2048
Message-ID: <Prayer.1.3.5.1504061702390.22883@hermes-1.csi.cam.ac.uk>
In-Reply-To: <20150406115029.C1CC69DB143@www.open-std.org>
References: <20150406115029.C1CC69DB143@www.open-std.org>
X-Mailer: Prayer v1.3.5
Mime-Version: 1.0
Content-Type: text/plain; format=flowed; charset=ISO-8859-1
Sender: owner-sc22wg5@open-std.org
Precedence: bulk

No, for the following reasons:

Not all objections in previous responses have been addressed (see
N2045 and the documents it points to).

We do not know if it is possible to specify a well-defined consistency
model for either events or collectives when called from within
functions.

We do not know if it is possible to specify the semantics of a complete
program if an image fails.

We do not know if it is possible to specify a consistency model for the
atomic operations that can be implemented with reasonable efficiency
without hardware or operating system assistance.

We know that there are differing views of the intent of all of those
features, and it is therefore vanishingly unlikely that progress on
integrating this TS into the main standard will be fast.

It is almost certain that, if we proceed according to the schedule,
the above aspects will differ between processors in ways that will
make it very hard to write portable, or even reliable, programs.

I would change my vote to abstain if this TS were not integrated into
the next version of the standard.


Regards,
Nick Maclaren.

