From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: tuhs-bounces@minnie.tuhs.org X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.1 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 1308ac8e for ; Wed, 27 Jun 2018 15:31:27 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 75DBCA189C; Thu, 28 Jun 2018 01:31:26 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 618E6A1816; Thu, 28 Jun 2018 01:30:52 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=mq7Dc2xk; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 28031A1816; Thu, 28 Jun 2018 01:30:50 +1000 (AEST) Received: from mail-lf0-f53.google.com (mail-lf0-f53.google.com [209.85.215.53]) by minnie.tuhs.org (Postfix) with ESMTPS id 6D3DB9EDF1 for ; Thu, 28 Jun 2018 01:30:49 +1000 (AEST) Received: by mail-lf0-f53.google.com with SMTP id j26-v6so1876144lfb.11 for ; Wed, 27 Jun 2018 08:30:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=aN3uFowOrxSmi+iRd816qkojI0QcmiRDJNeTrKZx7IQ=; b=mq7Dc2xkjY/Qb7g1QYCmxkbXFxznE2NpwK5B3g1GvCK8JZiQDO+kPCmtp/YKZ2/V1z tYDryEknCECaL4ZCYRQsGExpICFNnuluVoOD/meon04kvGikmAowQJOtthK0b98TrJro uYSsfV09lmZeS01D2x/GaTbwWgqYfsQmfltt2zXE8bT4FFDk/kncv3axr2ztfsCA66R8 h8p5mGsRkqstDisFcL15c9oOIR+R6bFH0BQPNdniMljorgpBqgUeh/Dy6VjOwdrmJyYW da61y7x/o2tr/qW40gx02atHxUtbo+rbxev4EEpjrCaWImIR9meHVlLK5hgw30byZ33b TeyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=aN3uFowOrxSmi+iRd816qkojI0QcmiRDJNeTrKZx7IQ=; b=Rdg7YcNXQhN7HchMVsZztM+5ZS8UwHlWMDuyZdYZLkAXQ9gVxABOvdEPOocjP7tBlj JYZLUhMu39OeHLJJpEplr7NhAIcPnsMvE6PPIhZ3qCPvy2E9huBYqWIcOrrJZzXXoXtz /vh27MEJXMT6jPYRjpHXOJa0JwpYAtQCp7rE6sjPYmwsxw7yNCcjRMJNF44Z6eH37NaX v/J+CrUf+V1yWkIjs+AOV+/jsdu7xxb61DVW8FjneEmVjaG4zdoQM8Us9kdxDA3J0oNp Ch2/dCQAKdM7+CVbaT2BRE3YSGvAcqCeVeUHcBsBdIyIIzYGrE00Bb9GcwiKs1Q+6Wpk z4zg== X-Gm-Message-State: APt69E1gU/rshDnBuO4wC9+ouUYouj01AGjsI2o1H8NXl8vLFKUcnJLh sW874NzLKun+OUljIn/J7V1fZtHy5JqLa0wu6Zs= X-Google-Smtp-Source: AAOMgpfsu8OjYdUbgmk6mUPu2k6H1HIECQtNwnu9bMw7wvodiQpC6RqYIP2JpvwI6zIql31mO6A8SPoCimjv9mOi3eU= X-Received: by 2002:a19:d3c3:: with SMTP id k186-v6mr4753815lfg.62.1530113447582; Wed, 27 Jun 2018 08:30:47 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a2e:5c81:0:0:0:0:0 with HTTP; Wed, 27 Jun 2018 08:30:47 -0700 (PDT) In-Reply-To: References: <1f8043fd-e8d6-a5e6-5849-022d1a41f5bf@kilonet.net> <20180626215012.GE8150@mcvoy.com> From: Paul Winalski Date: Wed, 27 Jun 2018 11:30:47 -0400 Message-ID: To: TUHS main list Content-Type: text/plain; charset="UTF-8" Subject: Re: [TUHS] PDP-11 legacy, C, and modern architectures X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" What Clem said. Chisnall is right about C having been designed for a sequential-programming world. That's why Fortran (with array and other parallel/vector operations built in) rules in the HPTC parallel programming space. But I don't buy most of his arguments. Making parallel programming easy and natural has been an unsolved problem during my entire 30+ year career in designing software development tools. It's still an unsolved problem. Modern compiler technology helps to find the hidden parallelism in algorithms expressed sequentially, but I think the fundamental problem is that most human beings have great difficulty conceptualizing parallel algorithms. It's also always been true that to get maximum performance you have to somehow get close to the specific hardware you're using--either by explicitly programming for it, or by having a compiler do that for you. Note also that there have been extensions to C/C++ to support parallelism. Cilk, for example. -Paul W.