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=-1.0 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 16784 invoked from network); 28 Jul 2020 16:36:34 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 28 Jul 2020 16:36:34 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id B82FE9CAB1; Wed, 29 Jul 2020 02:36:31 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 84BEA9C8E4; Wed, 29 Jul 2020 02:35:19 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=messagingengine.com header.i=@messagingengine.com header.b="TulWxk7U"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 6BBEB9C8E4; Wed, 29 Jul 2020 02:35:16 +1000 (AEST) Received: from wforward2-smtp.messagingengine.com (wforward2-smtp.messagingengine.com [64.147.123.31]) by minnie.tuhs.org (Postfix) with ESMTPS id C98D29C8E2 for ; Wed, 29 Jul 2020 02:35:15 +1000 (AEST) Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailforward.west.internal (Postfix) with ESMTP id F35E4419 for ; Tue, 28 Jul 2020 12:35:14 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute2.internal (MEProxy); Tue, 28 Jul 2020 12:35:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; bh=0aQnxVEyY6OYSDzK/yJlvUu+rcgJFniJMzkwbqXWm AQ=; b=TulWxk7ULV57mvyxqXItHdgyM2Trlbz8CCiFVAkLmVUXWGvNlVjQFX9WH lCoxgVulW+C3Yfs2fhfXPcKLZWWtjOc9zdg/Pa4bDjqWpLtEHFs4Kz1BBfb0Pmme E9n7g2so36/70+xw3FmQ45w+dzKtOuQdfJlaGbAVoqjBzKbc7IC4MAZz71g2KpVQ ZFTd6fI6fEneAxEiXALHxkIFCCvdwl5j2Uc6IcZ2inbu9Xt5cQnocXRsXykWimJu iEI12m0T/p+XZxR1x025slwVAE1PLvAvXeSV32uf6TpuJTz/2KHZjRnQYJUi98Mu ABlxbo4v9NR1yU7wsJzd5qvyfGZUw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduiedriedvgddutddtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucgoufhushhpvggtthffohhmrghinhculdegledmne cujfgurheptggguffhjgffgffkfhfvofesthhqmhdthhdtjeenucfhrhhomhephghinhcu vfhrvggvshgvuceothhrvggvshgvsegrtghmrdhorhhgqeenucggtffrrghtthgvrhhnpe egieevkeegffekveduvedutddulefhvedvudeghfeftdettdehveelleelhffftdenucff ohhmrghinhepsghlohhgshhpohhtrdgtohhmnecukfhppedutdekrdegledrudehuddrud efleenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpeht rhgvvghsvgesrggtmhdrohhrgh X-ME-Proxy: Received: from cirocco.treese.org (pool-108-49-151-139.bstnma.fios.verizon.net [108.49.151.139]) by mail.messagingengine.com (Postfix) with ESMTPA id DDBFF3280060 for ; Tue, 28 Jul 2020 12:35:13 -0400 (EDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.15\)) From: Win Treese In-Reply-To: Date: Tue, 28 Jul 2020 12:35:13 -0400 X-Mao-Original-Outgoing-Id: 617646913.23332-960a4098bd04f0e0b47cebf6a3c4512c Content-Transfer-Encoding: quoted-printable Message-Id: <26006DA8-EF6D-42FC-8A11-E84447E6946A@acm.org> References: To: The Eunuchs Hysterical Society X-Mailer: Apple Mail (2.3445.104.15) Subject: Re: [TUHS] reboot(2) system call 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 Jul 28, 2020, at 12:06 AM, Dave Horsfall wrote: >=20 > On Mon, 27 Jul 2020, Warner Losh wrote: >=20 >> I've done some research for a friend about when the reboot() system = call was added, and how it related to the sync, sync, sync dance. = https://bsdimp.blogspot.com/2020/07/when-unix-learned-to-reboot2.html >> may be of interest. Please do let me know if I've gotten something = wrong... >=20 > Seems OK to me; I was taught never to use "sync; sync; sync" for = precisely those reasons (the buffers may not have time to flush etc, as = "sync" merely schedules the I/O, not cause it. This was summarized at MIT=E2=80=99s Project Athena in the mid-80s as: When thou shuttest down the system, thou shalt sync three times. No = more, no less. Three shall be the number of the syncing, and the number = of the syncing shall be three. Four times shalt thou not sync, neither = sync twice, except that thou proceedest to sync a third time. Five is = right out. - Win