From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 22347 invoked from network); 10 Feb 2021 03:54:14 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 10 Feb 2021 03:54:14 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 92FCA95034; Wed, 10 Feb 2021 13:54:12 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 3516794F1B; Wed, 10 Feb 2021 13:53:51 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="RgnXBeg0"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id E8C4894F1B; Wed, 10 Feb 2021 13:53:48 +1000 (AEST) Received: from mail-io1-f51.google.com (mail-io1-f51.google.com [209.85.166.51]) by minnie.tuhs.org (Postfix) with ESMTPS id 6F75B94F19 for ; Wed, 10 Feb 2021 13:53:48 +1000 (AEST) Received: by mail-io1-f51.google.com with SMTP id n14so519142iog.3 for ; Tue, 09 Feb 2021 19:53:48 -0800 (PST) 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=K2iOlokOEl/ePslHfEYTlXVB+2v4SFjY64txJpaaYRk=; b=RgnXBeg0Ge1mEpmefxtcD11NBejHQ9KG0ww0e0HjY4HWkJD+s9ODlOdToB8PBb57NZ WZQtNeFGRF+/V6rDGN7OVilcft1j70mJJFJg67nREXAiA84GSgSZWfnpoiWG8DFvQ4pF 5MJ/4wIXI4SlAoAPLFHLKQ/Wz0/euAUKpby2RmoapyxALmP+HEJIVu1GfaNEnouxC3Ao OO/WYHCYrPAYLjX05lTfqyLCLXbuzSPPTjacUe43xDm+GBrrCKYB2aFfjXFaYDYUbPzb IFx52nIvIeSVgDpfUxqHRhYHdtIxnn4BehKKeeIhiY6DMVKnRwY1asgEzohwdeEGkWZb pNDA== 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=K2iOlokOEl/ePslHfEYTlXVB+2v4SFjY64txJpaaYRk=; b=bN/7PzqudCrz0aeaxOTB0t1fI/scNEQBL7Txs6uK5yBN3vFgbHDpvtHwfTW+wxNPbn FF9dCocNq18QfJmkB8u3yl0JPxhAxZJNT2Yta8UMwWPxemnGRNHbvwUZvp7Un2TgHh5G c83Youxpk3/EFMliKWFe5Bjs9F2aOx4mbeKULLVi7BfhFN5zpphU9+PE2GodHxXrxlg0 +p6UuWrOzHC6uhztCRL/8C63+TS9yuCSAvvQ1ToecoNYno+e+NqKchT4S3vQVXmh48zw hpUyFORF9zJ6K94+b5iMTT5HGWP0iahZffZMmoBjo7b1KV2EZINhlFxtWhmKJXNuwpmS E2tw== X-Gm-Message-State: AOAM531ywz58499RZOlXY7uwLtcahW4ZRTtt99dzKntnrEqTeouFd9R8 5UPHNuNXjxE0AOFFdB8P7AXwGVrAY1g6pg+XpYQBpmAh X-Google-Smtp-Source: ABdhPJwA83ru6IBKZlRZXPkHQQX29tD/d3z986NgjMn0CbxzV2cPtpxJ7jj/zSsTokOsdGpaH+CNSor7zx9wYwuMnwk= X-Received: by 2002:a6b:f708:: with SMTP id k8mr795731iog.187.1612929227744; Tue, 09 Feb 2021 19:53:47 -0800 (PST) MIME-Version: 1.0 Received: by 2002:ad5:48a1:0:0:0:0:0 with HTTP; Tue, 9 Feb 2021 19:53:47 -0800 (PST) In-Reply-To: <20210210014123.GS13701@mcvoy.com> References: <202102091900.119J0Gv9850825@darkstar.fourwinds.com> <20210210014123.GS13701@mcvoy.com> From: Andrew Warkentin Date: Tue, 9 Feb 2021 20:53:47 -0700 Message-ID: To: tuhs@minnie.tuhs.org Content-Type: text/plain; charset="UTF-8" Subject: Re: [TUHS] Macs and future unix derivatives X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 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" On 2/9/21, Larry McVoy wrote: > > The problem space that kernels address these days include SMP, NUMA, > and all sorts of other stuff. I'm not sure I could understand the Linux > kernel even if I were in my prime. It's a harder space, you need to > know a lot more, be skilled at a lot more. > > My take is we're old dudes yearning for the days when everything > was simple. Remember when out of order wasn't a thing? Yeah, me too, > I gave up on trying to debug kernels when kadb couldn't tell me what I > was looking at. > > --lm > Pure microkernels with indirect message destinations (i.e. not thread IDs) can simplify things somewhat with regards to multiprocessing, since almost all OS subsystems are just regular processes that run in their own contexts and can structure their threads as they please, as opposed to being kernel subsystems that have to deal with the concurrency issues that arise from the possibility of being called from any process context. The microkernel still has to deal with being called in any context, but it can use simpler mechanisms for dealing with concurrency than a monolithic kernel would because processes don't stay in kernel mode for nearly as long as they can in a monolithic kernel.