From owner-sc22wg5+sc22wg5-dom8=www.open-std.org@open-std.org Fri Apr 5 23:11:28 2013 Return-Path: X-Original-To: sc22wg5-dom8 Delivered-To: sc22wg5-dom8@www.open-std.org Received: by www.open-std.org (Postfix, from userid 521) id DD1C635698B; Fri, 5 Apr 2013 23:11:28 +0200 (CEST) Delivered-To: sc22wg5@open-std.org Received: from exprod6og123.obsmtp.com (exprod6og123.obsmtp.com [64.18.1.241]) by www.open-std.org (Postfix) with ESMTP id 2BCC635698B for ; Fri, 5 Apr 2013 23:11:24 +0200 (CEST) Received: from CFWEX01.americas.cray.com ([136.162.34.11]) (using TLSv1) by exprod6ob123.postini.com ([64.18.5.12]) with SMTP ID DSNKUV89+ypu5WZ2IT2ZTIA4mnPKkVGEMmni@postini.com; Fri, 05 Apr 2013 14:11:27 PDT Received: from fortran.us.cray.com (172.31.19.200) by CFWEX01.americas.cray.com (172.30.88.25) with Microsoft SMTP Server id 14.2.342.3; Fri, 5 Apr 2013 16:03:44 -0500 Message-ID: <515F3CB6.7010101@cray.com> Date: Fri, 5 Apr 2013 16:05:58 -0500 From: Bill Long Reply-To: Organization: Cray Inc. User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:17.0) Gecko/20130328 Thunderbird/17.0.5 MIME-Version: 1.0 To: sc22wg5 Subject: Re: (j3.2006) (SC22WG5.4947) [ukfortran] AW: WG5 ballot on first draft TS 18508, Additional Parallel Features in Fortran (Update) References: <20130329104945.2C28A356BB3@www.open-std.org> <20130329232930.A368A356DC2@www.open-std.org> <20130330091839.AC044356A50@www.open-std.org> In-Reply-To: <20130330091839.AC044356A50@www.open-std.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-sc22wg5@open-std.org Precedence: bulk On 3/30/13 4:18 AM, N.M. Maclaren wrote: > There is no support in most hardware for most reductions or, indeed, > most of modern Fortran. We shouldn't be adopting a C/C++ mindset and > imagining that the primary purpose of a high-level language is to give > the programmer access to the hardware facilities. Fortran has lasted Well, the purpose of C is exactly to give the programmer access to the hardware facilities. You need that to write device drivers and OS kernels. > over more variations in those than most people can believe! Fortran has lasted because it continues to provide a portable means for compiling (mainly scientific or mathematical) source code into executable files that perform well on current hardware. The key is that Fortran has evolved with the hardware changes to keep relevant. When some hardware-specific operation vanishes (think arithmetic IF) for long enough, we (at least sometimes) relegate the corresponding Fortran construct to the deleted heap. On the other hand, we adopt whole new parts (all of clause 14, for example) in response to evolution in hardware. Users will continue to want the high performance that keeps Fortran relevant, and if the hardware changes, vendors will be pressed to add language features that can be translated to use that new capability. If these are not standardized as language features, we loose portability, which is one of the main goals. To some extent, we need to anticipate future hardware trends (usually not that hard to do), because the time lag between a feature proposal and widespread availability in a compiler is years. Cheers, Bill > > > Regards, > Nick Maclaren. -- Bill Long longb@cray.com Fortran Technical Support & voice: 651-605-9024 Bioinformatics Software Development fax: 651-605-9142 Cray Inc./Cray Plaza, Suite 210/380 Jackson St./St. Paul, MN 55101