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=MAILING_LIST_MULTI, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 1734 invoked from network); 31 Dec 2023 17:39:15 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 31 Dec 2023 17:39:15 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 1B9CD43DE3; Mon, 1 Jan 2024 03:39:11 +1000 (AEST) Received: from freefriends.org (frenzy.freefriends.org [198.99.81.75]) by minnie.tuhs.org (Postfix) with ESMTPS id 7C26A43DE1 for ; Mon, 1 Jan 2024 03:39:05 +1000 (AEST) X-Envelope-From: arnold@skeeve.com Received: from freefriends.org (localhost [127.0.0.1]) by freefriends.org (8.14.7/8.14.7) with ESMTP id 3BVHctQ5018337 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 31 Dec 2023 10:38:55 -0700 Received: (from arnold@localhost) by freefriends.org (8.14.7/8.14.7/Submit) id 3BVHctA1018336; Sun, 31 Dec 2023 10:38:55 -0700 From: arnold@skeeve.com Message-Id: <202312311738.3BVHctA1018336@freefriends.org> X-Authentication-Warning: frenzy.freefriends.org: arnold set sender to arnold@skeeve.com using -f Date: Sun, 31 Dec 2023 10:38:55 -0700 To: tuhs@tuhs.org, gtaylor@tnetconsulting.net References: <6470c59f-a1e5-418f-803d-76bcd761f530@tnetconsulting.net> In-Reply-To: <6470c59f-a1e5-418f-803d-76bcd761f530@tnetconsulting.net> User-Agent: Heirloom mailx 12.5 7/5/10 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID-Hash: XRVDN5NQ7OHCBQWS2EKLU6KJLJNZB5Q5 X-Message-ID-Hash: XRVDN5NQ7OHCBQWS2EKLU6KJLJNZB5Q5 X-MailFrom: arnold@skeeve.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Question about BSD disklabel history List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: The different overlapping partitions predates disk labels. Up to and including 4.3 BSD, to change the size of partitions on a particular disk, you had to recompile the kernel. They were that way so that if you had multiple disks, you could use one for root + swap + some thing small and use another whole disk for a single filesystem. It was also helpful, if you had the drives, to nightly dd your real root to the "a" partition on another, identical drive, so that you could boot the backup root in an emergency. I don't remember for sure, but I think that Ultrix may have been the first BSD-style system to have disk labels, followed by some version of SunOS. All of that is way in the distant past though: mid- to late 80's. I am guessing that the original conventions date back to V7 or 32V, but one would have to go looking at code to be sure. HTH, Arnold Grant Taylor via TUHS wrote: > Hi, > > I've found myself wondering about partitions inside of BSD disk labels. > > Specifically, when and where was the convention that "a" is root, "b" is > swap, etc? > > I also understand the "c" partition to be the entire disk, unless it > isn't, at which point it's the entire slice (BIOS / MBR partition) > containing the BSD disklabel and "d" is the entire disk. > > I also found something last night that indicated that OpenBSD uses disk > labels somewhat differently than FreeBSD. > > Aside: This is one of the dangers of wondering how something curious > came to be and why it came to be when working on 10-15 year old FreeBSD > systems. > > > > -- > Grant. . . .