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=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 6ff1a714 for ; Mon, 24 Jun 2019 16:22:26 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 5ADC79BCCE; Tue, 25 Jun 2019 02:22:25 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 3C3BA9BC47; Tue, 25 Jun 2019 02:21:54 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="iePhLyfV"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 30DAE9BC44; Tue, 25 Jun 2019 02:21:51 +1000 (AEST) Received: from mail-oi1-f169.google.com (mail-oi1-f169.google.com [209.85.167.169]) by minnie.tuhs.org (Postfix) with ESMTPS id 976F59BC43 for ; Tue, 25 Jun 2019 02:21:50 +1000 (AEST) Received: by mail-oi1-f169.google.com with SMTP id w7so10210369oic.3 for ; Mon, 24 Jun 2019 09:21:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=f4aKcmJm/SuiX2oq2vrr87qdqJ0udM5b8loUp8gg/Pg=; b=iePhLyfVNFgeckEVYdb+D5iU1FVkAqznb8eiP6eJKdi6Qec5oKL++kZwrKlorbQ4uQ CWGWeGqVQV5Eqj1qKOHVrTJkLf/nRAv3qszTjkzNkBtM85g/5Dlk2wfLAR9M4/bswQcX l2bCC3FxPjTekTESuboc7eoT0tdFKK82Wg82GZIHihkFZcliVb4WevPHh1v2eCQVQTec gVTxxPxFW+whxRqUySbvr2Iic1FRvNxD1vtQmhZctZqfNGsEfD/OCNKEEYLrTQk5W9Gm J23eLFmBPQzQkoyIyHwQsh/dhABv1mHs1fkIaWcGmwI0wG4h/VJgRW5qz5B8uqkXGqpI xYAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=f4aKcmJm/SuiX2oq2vrr87qdqJ0udM5b8loUp8gg/Pg=; b=dHv7mdVFlf1rRoVJJFPfyLNNmC72xGMFKVwK5G50R3dOwQR9KxaEfK+A18Scs9nCxu fMC5naMTUnkMX37GYbjMxdAMOOGikSoCE07YKeHHv3NswWANZ7IErJEuh8rG+x26p0q7 VlAqUmpZ1kWdECirTPsMGoubrgmRTwVy1iEHHsZU5pmiQLM3kCQyWNHX542204n8ydmT DTadzek5aO/+EVmu0Zc77XX3+8SL1ZHTj5Zz5JtskeowOFmvtok4HGmWeYjS8VUacwPz 7h7f58zJ9iSGRgsbfH53Cy5TSzrS8fXM/6CyFd1FmCYmtzDo2xZtFGuvQOfII4pTP0aQ O7yA== X-Gm-Message-State: APjAAAUgxjBEt2VYyjCuqNaSrHssS2bI1CGe3unEsVGtkf/2hmHTBlAM L/vdinQ+rkCpdWcgUhcVftT5HTpOihQ1eLR7GLo8Hz6F X-Google-Smtp-Source: APXvYqyrPRvZ3IuYUak3JXmxdzcAE7TPDR+PBiiBF8i8KoJupq0cU9OVckfXGkROV09kznNz02/6YTIdywIhxvxhCfQ= X-Received: by 2002:aca:ed50:: with SMTP id l77mr210332oih.157.1561393309666; Mon, 24 Jun 2019 09:21:49 -0700 (PDT) MIME-Version: 1.0 References: <20190622181719.E10E918C0B4@mercury.lcs.mit.edu> In-Reply-To: <20190622181719.E10E918C0B4@mercury.lcs.mit.edu> From: ron minnich Date: Mon, 24 Jun 2019 09:21:37 -0700 Message-ID: To: Noel Chiappa Content-Type: text/plain; charset="UTF-8" Subject: Re: [TUHS] Any oldtimers remember anything about the KS11 on the -11/20? 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 main list Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" just double checking, in case the odd.html had a typo: it was a KS11, not a KT11-B? Is there any chance there was an error in recollection? ron On Sat, Jun 22, 2019 at 11:18 AM Noel Chiappa wrote: > > This is an appeal to the few really-old-timers (i.e. who used the PDP-11/20 > version of Unix) on the list to see if they remember _anything_ of the KS11 > memory mapping unit used on that machine. > > Next to nothing is known of the KS11. Dennis' page "Odd Comments and Strange > Doings in Unix": > > https://www.bell-labs.com/usr/dmr/www/odd.html > > has a story involving it (at the end), and that is all I've ever been able > to find out about it. > > I don't expect documentation, but I am hoping someone will remember > _basically_ what it did. My original guess as to its functionality, from that > page, was that it's not part of the CPU, but a UNIBUS device, placed between > the UNIBUS leaving the CPU, and the rest of the the bus, which perhaps mapped > addresses around (and definitely limited user access to I/O page addresses). > > It might also have mapped part of the UNIBUS space which the -11/20 CPU _can_ > see (i.e. in the 0-56KB range) up to UNIBUS higher addresses, where 'extra' > memory is configured - but that's just a guess; but it is an example of the > kind of info I'd like to find out about it - just the briefest of high-level > descriptions would be an improvement on what little we have now! > > On re-reading that page, I see it apparently supported some sort of > user/kernel mode distinction, which might have require a tie-in to the > CPU. (But not necessarily; if there was a flop in the KS11 which stored the > 'CPU mode' bit, it might be automatically cleared on all interrupts. Not sure > how it would have handled traps, though.) > > Even extremely dim memories will be an improvement on the blank canvas we > have now! > > Noel