From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: tuhs-bounces@minnie.tuhs.org X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,HTML_FONT_LOW_CONTRAST, HTML_MESSAGE,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.1 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id b8883165 for ; Tue, 19 Jun 2018 12:59:38 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id DF73AA19FD; Tue, 19 Jun 2018 22:59:37 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 3EA39A19D6; Tue, 19 Jun 2018 22:59:11 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (1024-bit key; unprotected) header.d=ccc.com header.i=@ccc.com header.b=jetDVImd; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 6DD0DA19D5; Tue, 19 Jun 2018 22:59:09 +1000 (AEST) Received: from mail-it0-f41.google.com (mail-it0-f41.google.com [209.85.214.41]) by minnie.tuhs.org (Postfix) with ESMTPS id BD7B3A19D4 for ; Tue, 19 Jun 2018 22:59:08 +1000 (AEST) Received: by mail-it0-f41.google.com with SMTP id v83-v6so189185itc.3 for ; Tue, 19 Jun 2018 05:59:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ccc.com; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=WkaRYFoROSd9jJ0UcqbZMVAJRug2Te360z4ICQ29mTc=; b=jetDVImdQEAHZ/5v/HRiDCFh8gZHV3ILLPqPfZdA11iXbKqRW6HPTMw9/S+n5z1DhP Enl5IA/BiteEJ0RnmsXxuUCwy+U2KSyxvmZ0H+o3bumGoo8yCwCYPrfMwN39zfXjbsVU +/J4XBp27O9RHwb8EhJuIFx1uiKIV/LdtpUnc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=WkaRYFoROSd9jJ0UcqbZMVAJRug2Te360z4ICQ29mTc=; b=O4nSRmmKQo29+yqYeiK5dffxggOQy0PCGX7cnx/Y7MdQ3kQdKnvzgDkmIHNkzPWave UXJhxh/Em/myqD4A95oeTmzHpBvLDlo/I+cU36L64dfeyH24/ZMsIOTTLqpi85Af6oWX Imy5tr1MivhxzYn6SZyBaGOK19MLGm+IpeVq3ew24YjGpEl2+H1DlE6btQbgAQ0fjNkG rOWx9eODClCaonPCZhszmjnE0pNddi/wsTRQy7bHJkNvZZzv8BjRK3AcrJH1W14Xu3nI OYSu/9OCAtwY5gp0km3zAkHLeFoCk9Rdwc6QKvxO9hbtmJi10lXHeWf2FZqDaLZxV8tY GVug== X-Gm-Message-State: APt69E3IAsTiPuynTsNTfzQEuAsX/cpUO5NeQrSQgciw00PG7r3Wov/y qivZ/tiuhu6mLLW6ISmrWSmqx1144xW814T1qafPuw== X-Google-Smtp-Source: ADUXVKJz8XXqtEmvKKYM1cs31+gmGL4hdzlvzTR5x4LIaaP/wxdO1xZrfT700YUVpacJRchlZXw1FQ5dez3JyCowRFQ= X-Received: by 2002:a02:2710:: with SMTP id g16-v6mr13239884jaa.98.1529413147803; Tue, 19 Jun 2018 05:59:07 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a4f:ca8a:0:0:0:0:0 with HTTP; Tue, 19 Jun 2018 05:58:36 -0700 (PDT) In-Reply-To: <20180619122359.1525D18C084@mercury.lcs.mit.edu> References: <20180619122359.1525D18C084@mercury.lcs.mit.edu> From: Clem Cole Date: Tue, 19 Jun 2018 08:58:36 -0400 Message-ID: To: Noel Chiappa Content-Type: multipart/alternative; boundary="00000000000064688a056efe3f23" Subject: Re: [TUHS] core X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: The Eunuchs Hysterical Society Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --00000000000064688a056efe3f23 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Jun 19, 2018 at 8:23 AM, Noel Chiappa wrote: > > From: Doug McIlroy > > > Yet late in his life Forrester told me that the Whirlwind-connected > > invention he was most proud of was marginal testing > > Given the above, I'm totally gobsmacked to hear that. Margin testing was > important, yes, but not even remotely on the same quantum level as core. =E2=80=8BWow -- I had exactly the same reaction. To me, core was the se= cond most important invention (semiconductors switching being he first) for making computing practical. I was thinking that systems must have been really bad (worse than I knew) from a reliability stand point if he put marginal testing up there as more important than core. Like you, I thought core memory was pretty darned important. I never used a system that had Williams tubes, although we had one in storage so I knew what it looked like and knew how much more 'dense' core was compared to it. Which is pretty amazing still compare today. For the modern user, the IBM 360 a 1M core box (which we had 4) was made up of 4 19" relay racks, each was about 54" high and 24" deep. If you go to CMU Computer Photos from Chris Hausler =E2=80=8B and scroll down you can see some pictures of the old 360 (includi= ng a copy of me in them circa 75/76 in front of it) to gage the size). FWIW: I broke in with MECL which Motorola invented / developed for IBM for System 360 and it (and TTL) were the first logic families I learned with which to design. I remember the margin pots on the front of the 360 that we used when we were trying to find weak gates, which happened about ones every 10 days. The interesting part to me is that I'm suspect the PDP-10's and the Univac 1108 broke as often as the 360 did, but I have fewer memories of chasing problems with them. Probably because it was a less of an issue that was causing so many people to be disrupted by the 'down' time. =E1=90=A7 --00000000000064688a056efe3f23 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Tue, Jun 19, 2018 at 8:23 AM, Noel = Chiappa <jnc@mercury.lcs.mit.edu> wrote:
=C2= =A0 =C2=A0 > From: Doug McIlroy <doug@cs.dartmouth.edu>

=C2=A0 =C2=A0 > Yet late in his life Forrester told me that the Whirlwin= d-connected
=C2=A0 =C2=A0 > invention he was most proud of was marginal testing
<= /font>
Given the above, I'm totally gobsmacked = to hear that. Margin testing was
important, yes, but not even remotely on the same quantum level as core.
=E2=80=8BWo= w -- I had exactly the same reaction.=C2=A0 =C2=A0 =C2=A0To me, core was th= e second most important invention (semiconductors switching being he first)= for making computing practical.=C2=A0 =C2=A0I was thinking that systems mu= st have been really bad (worse than I knew) from a reliability stand point = if he put marginal testing up there as more important than core.=C2=A0=C2= =A0

Like you, I= thought core memory was pretty darned important.=C2=A0 I never used a syst= em that had Williams tubes, although we had one in storage so I knew what i= t looked like and knew how much more 'dense' core was compared to i= t.=C2=A0 =C2=A0Which is pretty amazing still compare today.=C2=A0 For the m= odern user, the IBM 360 a 1M core box (which we had 4) was made up of=C2=A0= 4 19" relay racks, each was about 54" high and 24" deep.=C2= =A0 =C2=A0 If you go to
CMU Computer Photos from Chris Hausler
=E2=80=8B and scroll down you can see some pictures of = the old 360 (including a copy of me in them circa 75/76 in front of it) to = gage the size).



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