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=-0.8 required=5.0 tests=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 f56d0b5c for ; Tue, 21 Jan 2020 21:33:21 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 2DF8B9C218; Wed, 22 Jan 2020 07:33:20 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 6BD1C9C1FF; Wed, 22 Jan 2020 07:32:58 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id A62DA9C1FF; Wed, 22 Jan 2020 07:32:56 +1000 (AEST) Received: from clarinet.employees.org (clarinet.employees.org [198.137.202.74]) by minnie.tuhs.org (Postfix) with ESMTPS id B97C79C14A for ; Wed, 22 Jan 2020 07:32:52 +1000 (AEST) Received: by clarinet.employees.org (Postfix, from userid 1736) id 9A3274E11B1B; Tue, 21 Jan 2020 21:32:51 +0000 (UTC) Date: Tue, 21 Jan 2020 21:32:51 +0000 From: Derek Fawcus To: The Unix Heritage Society mailing list Message-ID: <20200121213251.GA25322@clarinet.employees.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: [TUHS] Onyx (was Re: Unix on Zilog Z8000?) 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 Tue, Jan 21, 2020 at 01:28:14PM -0500, Clem Cole wrote: > The Onyx box redated all the 68K and later Intel or other systems. That was a fun bit of grubbing around courtesy of a bitsavers mirror (https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/onyx/). It seems they started with a board based upon the non-segmented Z8002 and only later switched to using the segmented Z8001. In the initial board, they created their own MMU: Page 6 of: https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/onyx/c8002/Onyx_C8002_Brochure.pdf Memory Management Controller: The Memory Management Controller (MMC) enables the C8002 to perform address translation, memory block protection, and separation of instruction and data spaces. Sixteen independent map sets are implemented, with each map set consisting of an instruction map and a data map. Within each map there are 32 page registers. Each page register relocates and validates a 2K byte page. The MMC generates a 20 bit address allowing the C8002 to access up to one Mbyte of physical memory. So I'd guess the MMC was actually programed through I/O instuctions to io space, and hence preserved the necessary protection domains. Cute. I've had a background interest in the Z8000 (triggered by reading a Z80000 datasheet around 87/88), and always though about using the segmented rather than unsegmented device. The following has a bit more info about the version of System III ported to their boxes: https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/onyx/c8002/UNIX_3.0.3_Software_Release_Notice_May83.pdf DF