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 18016 invoked from network); 2 May 2022 16:31:14 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 2 May 2022 16:31:14 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id C0F179D471; Tue, 3 May 2022 02:31:12 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id DEF149D431; Tue, 3 May 2022 02:29:08 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id E04969D431; Tue, 3 May 2022 02:29:06 +1000 (AEST) Received: from mcvoy.com (mcvoy.com [192.169.23.250]) by minnie.tuhs.org (Postfix) with ESMTPS id 6400D9CE23 for ; Tue, 3 May 2022 02:29:06 +1000 (AEST) Received: by mcvoy.com (Postfix, from userid 3546) id D436E35E0A7; Mon, 2 May 2022 09:29:05 -0700 (PDT) Date: Mon, 2 May 2022 09:29:05 -0700 From: Larry McVoy To: Bakul Shah Message-ID: <20220502162905.GJ24237@mcvoy.com> References: <9EB92333-42A7-401E-A273-D35A681B02A5@iitbombay.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9EB92333-42A7-401E-A273-D35A681B02A5@iitbombay.org> User-Agent: Mutt/1.5.24 (2015-08-30) Subject: Re: [TUHS] First Unix-like OSes not derived from AT&T code? 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" On Mon, May 02, 2022 at 09:16:40AM -0700, Bakul Shah wrote: > On May 2, 2022, at 8:43 AM, Clem Cole wrote: > > > > Thoth Thucks.... [Kelly Booth gave me one of these tee's years go]. > > > > Mike Malcolm did not try to clone UNIX - for one thing, it was in B [which Steve Johnson has spread the gospel of same on his sabbatical). It was not until the Thoth rewrite that became QNX that they tried to ensure all of the Unix behaviors and APIs. Mike was certainly had an influence by UNIX and IIRC his thesis and the Thoth papers reference/compare it. > > IIRC Gordon Bell and Dan Dodge worked with Thoth as students but QNX is not derived from it. I ran across QNX at a contract job in 1986 or so[1]. Back then it fit in 8KB. IIRC the original few versions were mostly written in assembly language or had substantial portions in assembly while most of Thoth was written in C[2]. The original QNX was basically a message passing microkernel. Unix APIs came in much later. I was friends with Dan Hildebrandt, one of the 3 people allowed to commit changes to the microkernel in the 1990's. That history seems pretty accurate though Dan told me the commonly used microkernel code fit in 4K of instruction cache, I don't recall what it needed in the data cache. Dan told me they were very careful to not let that bloat, I remember him saying "the instruction cache needs to have space for user code". A refreshing point of view, especially since I was living in "I measured it, it's only 1% slower" AKA "death by a thousand paper cuts".