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, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 11839 invoked from network); 16 Sep 2020 05:29:47 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 16 Sep 2020 05:29:47 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 597B99CB8A; Wed, 16 Sep 2020 15:29:43 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 4724D9C73F; Wed, 16 Sep 2020 15:29:06 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 054529C73F; Wed, 16 Sep 2020 15:29:04 +1000 (AEST) X-Greylist: delayed 429 seconds by postgrey-1.36 at minnie.tuhs.org; Wed, 16 Sep 2020 15:29:03 AEST Received: from lb1-smtp-cloud9.xs4all.net (lb1-smtp-cloud9.xs4all.net [194.109.24.22]) by minnie.tuhs.org (Postfix) with ESMTPS id 3B7459C6B1 for ; Wed, 16 Sep 2020 15:29:03 +1000 (AEST) Received: from cust-27e06a8f ([IPv6:fc0c:c122:908c:cb8e:3cc1:64e8:cd54:9bbd]) by smtp-cloud9.xs4all.net with ESMTPA id IPt8kLxMWXgwIIPt9kn3eP; Wed, 16 Sep 2020 07:21:51 +0200 Received: from arno by mail.ancienthardware.org with local (Exim 4.94) (envelope-from ) id 1kIPt7-0006Q7-Lm; Wed, 16 Sep 2020 07:21:49 +0200 Date: Wed, 16 Sep 2020 07:21:49 +0200 From: Arno Griffioen To: tuhs@tuhs.org Message-ID: <20200916052149.GH3311@ancienthardware.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CMAE-Envelope: MS4wfOTvhRLXIkI0bDaAC4RiLlZ7te+eOZQmYNRKDhV7yKyBj8ZLPKkUAplzK3R08ZqQ0gl9DhUVn+0qvIvsN6hwy1VUXxYKKC/gk+2tp5VBNNOcQZDKv7gk /DmchEextGrw8rgTkiVw3863GrxtoAyqdzd0NgyUK7S63uQ8IsArNR4aPnE2wU/e/2iiR2TAVo0P3JinVuFmMUZOXFcEfoXqgqvaZFzU1XTK35CzcsTSVqCL gpJ6yrHarEybDnobU7QM8g== Subject: Re: [TUHS] Historical sources for 68010 + 68451 systems? 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, Sep 15, 2020 at 04:28:36PM -0700, Chris Hanson wrote: > I have an MVME121 that I’d like to run some stuff on. I’m planning what I’ll > need to do to port MINIX 1.5 but since this has a 68451 segmented MMU, I’d > like to actually make use of it. Quite doable to adapt MINIX to this. Did a similar thing ages ago while still in school on a 68010 machine (not really VME, but similar card-cage setup) that had a custom MMU built from some SRAM and some control logic on it. Used MINIX 1.1 at the time though.. Only had 1MB physical RAM and the MMU could provide a virtual address space of 4MB. Initially ported MINIX to the machine 'as is' from the ST version and then modified the MINIX kernel to allow it to use the 4MB virtual space and such. Because of the bare-bones MMU design it had some interesting quirks that made it a good learning experience at the time. (and some very odd serial chips for the terminals that had their own 'interesting' behaviour but that's a different story..) Originally the machine did have a real SVR2 UNIX running on it, but sadly it was binary-only, so apart from some dis-assembly of bootstrap bits to learn how to get MINIX to start on this machine it was not very useful. > I figure at minimum I could have several segments set up to enforce > protections and a stable per-process address space, but it’d be good to > have an example. Yup. You may run into some of the shortcuts in the MINIX kernel when you start doing MMU work though, especially if you want to separate the kernel 'processes' as well. For performance the microkernel architecture of MINIX was violated in a few spots, mostly around FS and MM, where one kernel process would/could modify another's memory without going through the message passing mechanism. Introduce an MMU and that kinda breaks and needs some cleaning up ;) As MINIX later on did get a 386 port and cleanups/fixes that may now be a non-issue on 1.5. Another option would be Linux/m68k and perhaps starting on the 'nommu' version that runs on basic 68000's too and seeing how much functionality could be used from the 68451 to enhance it. Some of the Coldfire CPU's have similar limited MMU's that are supported for some functions of basic memory protection in the 'nommu' tree. As far as real UNIX sources go.. SUN2's were 68010's too although AFAIK with a custom SUN designed MMU logic? Perhaps some old sources available in that corner though. Bye, Arno.