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 autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 18427 invoked from network); 17 Sep 2021 21:22:14 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 17 Sep 2021 21:22:14 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 450409CAD0; Sat, 18 Sep 2021 07:22:11 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id A7EDC9CAB3; Sat, 18 Sep 2021 07:21:55 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id A82749CAB3; Sat, 18 Sep 2021 07:21:54 +1000 (AEST) Received: from mail.ultimate.com (mail.ultimate.com [104.225.1.121]) by minnie.tuhs.org (Postfix) with ESMTPS id 28CB19CAB2 for ; Sat, 18 Sep 2021 07:21:54 +1000 (AEST) Received: from ultimate.com (localhost [127.0.0.1]) by mail.ultimate.com (8.16.1/8.16.1) with ESMTPS id 18HLLmZ7061860 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Fri, 17 Sep 2021 17:21:48 -0400 (EDT) (envelope-from phil@ultimate.com) Received: (from phil@localhost) by ultimate.com (8.16.1/8.16.1/Submit) id 18HLLlB8061859; Fri, 17 Sep 2021 17:21:47 -0400 (EDT) (envelope-from phil) From: Phil Budne Message-Id: <202109172121.18HLLlB8061859@ultimate.com> Date: Fri, 17 Sep 2021 17:21:47 -0400 To: clemc@ccc.com, brantley@coraid.com References: <20210917153523.96CC618C0A6@mercury.lcs.mit.edu> <202109171828.18HISiR5057486@ultimate.com> In-Reply-To: User-Agent: Heirloom mailx 12.4 7/29/08 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: [TUHS] Unix for PDP11/20 w/o mmu or paging option 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@minnie.tuhs.org Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" I was commenting based on the Boot Procedures man page on pg 5 of the pdf at: https://www.bell-labs.com/usr/dmr/www/pdfs/man71.pdf on dmr's "Unix Manual, first edition" page: https://www.bell-labs.com/usr/dmr/www/1stEdman.html which makes no reference to the rk disk, but does talk about loading up initial files. The page for init (pdf p.11) mentions that the usr directory is mounted from the rk disk. The rf0 page (pdf p3) at https://www.bell-labs.com/usr/dmr/www/pdfs/man41.pdf says "writing is inherently very dangerous since a file system resides there" The description of seek on the special files really slapped me in the face for the first time! The tty page in the man41 file ever so slightly advances my theory that the interrupt character on the PDP-7 console (0176 or rather 0376) could have been generated by the "ALT MODE" key on the console Teletype. But regarding memory management, I foolishly put my foot in the gopher hole of assumption that the earliest kernel on hand required the mystery MMU, without verifying by reading the code, and forgetting that "editions" refer to dates the manual was published, and that the fragmentary fossil record that is the earliest surviving code (which was in a constant state of evolution) doesn't align with the manuals. Mea culpa, for adding any confusion!