From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: from minnie.tuhs.org (minnie.tuhs.org [50.116.15.146]) by inbox.vuxu.org (Postfix) with ESMTP id 276F0291C1 for ; Fri, 5 Jul 2024 23:38:18 +0200 (CEST) Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 5352243CB6; Sat, 6 Jul 2024 07:38:12 +1000 (AEST) Received: from gal.iecc.com (gal.iecc.com [IPv6:2001:470:1f07:1126:0:43:6f73:7461]) by minnie.tuhs.org (Postfix) with ESMTPS id E624343CA7 for ; Sat, 6 Jul 2024 07:38:06 +1000 (AEST) Received: (qmail 86300 invoked from network); 5 Jul 2024 21:38:05 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=iecc.com; h=date:message-id:from:to:cc:subject:in-reply-to:references:mime-version:content-type:content-transfer-encoding:cleverness; s=15119668867bd.k2407; bh=2VI+qwhQit/nyhgdJgmX3TLRh+3EQMyTy1jgQNIl1UU=; b=m0EQo04BNmP55VmKK8Ox8kEAJt4uhmewgJ0MccRfEN7wmpESDB8qEnViP2Okfomug9pTZknGLbbpznD3KB7r7qOuws5b56vhAJPySZKOp+/vLHCgEoUirNUkS4FwPgZLTuD06aeDhmiqrjOiLKZqqt9hDiFYv5RhCn89GEpF4ACmt8jMz3Sxm5ilVK/FF5doFRxh+qwhuJ1zvgkseWR9RvXikA4Oi0hhCJwzXiR9Ofitv6FXR2wyJr7GgTcX7dfgtiWKy+87R/kHstZxQr6goX2qCfy4yUCHQQTyOo882tLQ9KPMim7N8s8+MNVkSW1LHAJ8ty2r7NDURQI2VHv11g== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=taugh.com; h=date:message-id:from:to:cc:subject:in-reply-to:references:mime-version:content-type:content-transfer-encoding:cleverness; s=15119668867bd.k2407; bh=2VI+qwhQit/nyhgdJgmX3TLRh+3EQMyTy1jgQNIl1UU=; b=fKVom6/jak2BEZKraPm9xzczxZK/O3b+61/2sv3ympFBx741P8QFKOA9M9j9MnS8ii+5//yqxPO8ln6lVTmwpMW0qSlr55GI0EarxsUG8mRNIyPOhvPTbCir+B9TSVcI+LUYgEQBTZTqNuGunzRz3CxIpc6CTOLcg8FN4zBAVFbm2z7OtkofnvenD3Qp1LoSWLW3QsPhywNuzOuOpjePqLn+BBc3LHZEd4VwA7akSwejj2kPbd+wjyR5hUDh2JnjuAhVc5VZpxZmEDkE0BZOHNtisPJlQre5mLeOryNY0blZfYYS+hFc/gIRiG3wk8TbVS61E0e5t80/sjpOYwYL8Q== Received: from ary.qy ([IPv6:2001:470:1f07:1126::78:696d:6170]) by imap.iecc.com ([IPv6:2001:470:1f07:1126::78:696d:6170]) with ESMTPS (TLS1.3 ECDHE-RSA CHACHA20-POLY1305 AEAD) via TCP6; 05 Jul 2024 21:38:04 -0000 Received: by ary.qy (Postfix, from userid 501) id 550128EDF53C; Fri, 5 Jul 2024 17:38:03 -0400 (EDT) Date: 5 Jul 2024 17:38:03 -0400 Message-Id: <20240705213804.550128EDF53C@ary.qy> From: "John Levine" To: tuhs@tuhs.org In-Reply-To: Organization: Taughannock Networks References: X-Headerized: yes Cleverness: minimal Mime-Version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 8bit Message-ID-Hash: BO7LKE2KCSLIRAOCEU275LI65DNSOHNS X-Message-ID-Hash: BO7LKE2KCSLIRAOCEU275LI65DNSOHNS X-MailFrom: johnl@iecc.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tuhs.tuhs.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: peter.martin.yardley@gmail.com X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: mental architecture models, Anyone ever heard of teaching a case study of Initial Unix? List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: It appears that Peter Yardley said: >The DG Nova had a pretty nice architecture. 2 accumulators, 2 index registers, program counter, status register. No stack register tho. There was a micro processor version by Fairchild. It did, but it was word addressed which makes it an historical curiosity like its spiritual predecessors PDP-4/5/7/8/9. I also have a mental model of a PDP-11 but these days it's more a simplified 386 leaving out the dumb or useless stuff. I ignore the segments which are useless other than for 286 emulation, and some of the strange instructions like decimal adjust and the warty 8 and 16 bit registers. What's important is the memory model which on a 386 the way it was invariably set up was a flat 32 bit consistent little-endian byte addressed memory with a stack and reasonable addressing modes, and 4K pages for virtual memory. ARM should be OK too but I have to ask which ARM? There have been so many generations often not backward compatible.