From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id f32110b0 for ; Tue, 27 Aug 2019 22:30:49 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 41E3B9BC47; Wed, 28 Aug 2019 08:30:48 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 0421D9BBFD; Wed, 28 Aug 2019 08:30:17 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=algebras-org.20150623.gappssmtp.com header.i=@algebras-org.20150623.gappssmtp.com header.b="LwuigWRH"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 840909BBFD; Wed, 28 Aug 2019 08:30:15 +1000 (AEST) Received: from mail-io1-f44.google.com (mail-io1-f44.google.com [209.85.166.44]) by minnie.tuhs.org (Postfix) with ESMTPS id DEAC09BBF7 for ; Wed, 28 Aug 2019 08:30:12 +1000 (AEST) Received: by mail-io1-f44.google.com with SMTP id t3so1748882ioj.12 for ; Tue, 27 Aug 2019 15:30:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=algebras-org.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=OkTyMt39drLxtr7/7uRmqIiOhrBRx1WW77md1iCikYw=; b=LwuigWRHCf6/9EOQgGQLHWr5vS7uOeD4DHxr953YzDkGhRU96Srxs15/iNo4poU5g/ jN+luJs8FMRAP1VZIa666hCSSkQvGcufy6DaO0lrR9nzW1c+36XS5/Suaw+ybsFrT0je vdZ7FvKevM65bIy75ozW9wllgIJDKq/zaD66IPtO49Vs34+qorY2em6eLqrhZ9u5ZPci P/+I4mU+hGtC7hK706XIvF0FKDAM0r3VimGtd45sWml6c65lmmrj4eZqcJy40fRytJxB AuUgx5W0/8IVjgeWQJusqqVUxcDd4kahLSz57nEfSWRHV6v9ZPkvCRnbzGOvbHtWPJq/ TkHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=OkTyMt39drLxtr7/7uRmqIiOhrBRx1WW77md1iCikYw=; b=Y4i+Cf/bUhX6UfpZWsWM14lyyqV4Wv+Qlfvx/5IzXLhzqpTnE+rasaUTlUouhoO4uA ThxkaGO+Va1mCEdHy8Nd/NqcJhHLm+3wN4hfzZmplpYrt/KIi9gEOzqArOtZqmbiJ8lu fyP8Iw+CJMALO001901rv3Fwl4Fu8uuG7jhEf4klf5d2AD5SZJOXxCnCB5gsXGetHj2K hmwsR+vzdVo4UQZUcNXKwFLdD4BmsVMMRhN83SLYu2JMs/WSr1oxR/OmzNiECHmyRfQv ePJqkd6EJHrUBXGYVqh3/SyFCPpUXfNZ9scWanEyonCTHx26QJ93JgWcVSK611QLnPgn T7tg== X-Gm-Message-State: APjAAAWNFUzKLaL77c+pR18O8WNF2WPD8mNRb4AoryynTh49+DpyDLGL jf2esE7I35rcuZ1klA+YOwlz936IihoV4HO9QG5zcvI8KLY= X-Google-Smtp-Source: APXvYqzmZsMtdh9uC4aEzgCmCNYelPDf39KN/0+0xd/07NtciGSDpq7Nk4KmYYS1s9SZCgPopc4ES2htqs6n8aIRtpE= X-Received: by 2002:a05:6638:105:: with SMTP id x5mr1242520jao.43.1566945012071; Tue, 27 Aug 2019 15:30:12 -0700 (PDT) MIME-Version: 1.0 References: <13c5c36e-c84d-e020-d09e-51c8c502dc6d@kilonet.net> <75a32043-4830-ba04-ee0f-023c5f5ade3f@gmail.com> <20190827003013.GS13570@mcvoy.com> <312b39a1-2944-100f-55e0-fc65b504d43d@kilonet.net> <20190827024511.GU13570@mcvoy.com> <20190827145556.GD13570@mcvoy.com> In-Reply-To: <20190827145556.GD13570@mcvoy.com> From: George Michaelson Date: Wed, 28 Aug 2019 08:30:01 +1000 Message-ID: To: Larry McVoy Content-Type: text/plain; charset="UTF-8" Subject: Re: [TUHS] If not Linux, then what? 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: , Cc: TUHS main list Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" BSD, but with the original STREAMS semantics, not sockets. DARPA did us no favours accepting sockets in place of simple file I/O semantics for networks. Newcastle connection put the namespace into /.../remote-part/path/to/thing which I felt was also good. So for me, 7 -> BSD -> got worse for some values of worse On Wed, Aug 28, 2019 at 12:56 AM Larry McVoy wrote: > > On Mon, Aug 26, 2019 at 11:14:45PM -0400, Arthur Krewat wrote: > > On 8/26/2019 10:45 PM, Larry McVoy wrote: > > > Which was that the page cache is > > >*the* cache. There is nothing else. > > Yeah, I re-read what you wrote a few times after I replied, and realized > > what you meant ... eventually ;) > > I might be making too big of a deal about it. mmap semantics mattered > a lot when SMPs first showed up and main memory was small. It meant > that you could have multiple CPUs seeing and working on the same chunk > of data at the same time. > > It's very similar to way that IOMMUs are exposed to user space these > days, enabling virtual machines direct access to the I/O devices. > > ZFS breaks that model, the data is all in the ARC and if you mmap > it they have to bcopy the data out of the ARC, into the page cache > and now they have a consistency problem, you could modify stuff > via mmap or write and they have to manage that. > > That consistency problem is the main reason that Sun almost completely > killed the buffer cache (it still was used for inodes and directories > but that was it). That consistency problem is a pain in the rear, > all sorts of race conditions and it tended to bit rot. > > Jeff and Bill are smart people so I suspect they got it right but I'm > still stunned that they took such an architecturally bad approach. > And even more stunned that the oversight people approved it. There > is zero chance that the Sun I worked at would have allowed that. > > --lm