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=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 27483 invoked from network); 26 Sep 2023 23:32:49 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 26 Sep 2023 23:32:49 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id C962C407A6; Wed, 27 Sep 2023 09:32:43 +1000 (AEST) Received: from mail-ot1-x333.google.com (mail-ot1-x333.google.com [IPv6:2607:f8b0:4864:20::333]) by minnie.tuhs.org (Postfix) with ESMTPS id 95A87402A1 for ; Wed, 27 Sep 2023 09:32:35 +1000 (AEST) Received: by mail-ot1-x333.google.com with SMTP id 46e09a7af769-6c4e7951dddso3008760a34.1 for ; Tue, 26 Sep 2023 16:32:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=algebras-org.20230601.gappssmtp.com; s=20230601; t=1695771154; x=1696375954; darn=tuhs.org; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=4A58nzBPYYlDPBnuE1BMbRkR9wD3rlNIfzBIqjsoKNk=; b=Sed5JW5RMHqRAAnsge9Z0pGRTr1Y+prXu0bH9naD+8l8wJHgM0u4rcm40fbd6JmTGf gcl/09N+RqBNhagSCULmbixTppe31xOD2s/mPLKt31kIRtI3ipaROHZKyjJAqVXRyhjm eTJcshixZ+ho2eCeVmhhLiDKgtAsPeQ9lY2kZHm74sKXRmB/ZP5C0sqV/KdomUXTllty oopqGI/rrKOlB5et1O4RSk0XqD/fRq/a+pLE5xGxsr8HiFWY2INxbkGtQBOob1FQr5Oo h3T8k+eC3qtAqL4clM8m39HRgyXlFiEyTE+Q8g9+2X/yAHQceYX/ZMeXn+F/micYLFpV tLJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695771154; x=1696375954; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4A58nzBPYYlDPBnuE1BMbRkR9wD3rlNIfzBIqjsoKNk=; b=JW8102Z2NVaLLAL6JhGzm0q9EKpUZTi6j4a2+HNxedEjWjNvJAaIdblOmIHEdc1O3M CKY99SJkUihwSRWVf6DNpu+VElVMeCM+6oLTyjIYpNfLBnr4As5D2hzZFDig6/ooz5FH KS2W/xtuDbfVjaVcmBNDMo2aSY653Wa/GI3xYNO84AbYPWy1JBvAL4J4cezzUVfbHwqE za6Tl5IugqnjtAitxKtzgx0sRAf+qJUQjI7rRFzG82i5eRXytVHzDxSQ6frOzbrPgzHU /GmJS/ENoD3bcWWASA5sGV4KTSTCdbVcpzZj7r4WNy+8G5Gsb/wZUxauPsDkkR0+4uir 7RdA== X-Gm-Message-State: AOJu0YxrxZW/OSbz/SxFwHqnB//q/vZEsf6k3Frt0+v+/AnVhXjMzppQ PcwE4ZiHTWn/HtWZPyEYdnbJsUTJ9vpVaODrOCbRiX/1iUa4oZEUv7A= X-Google-Smtp-Source: AGHT+IFbtzzFikU8UMHqmGK71X9n/pbpUqn9EXar3FfbPulWF4UspZfhfQiZbl9gdaURwWiUk43bmnAElAy5YxZP2og= X-Received: by 2002:a9d:7f0c:0:b0:6c4:897a:31c4 with SMTP id j12-20020a9d7f0c000000b006c4897a31c4mr359647otq.29.1695771154668; Tue, 26 Sep 2023 16:32:34 -0700 (PDT) MIME-Version: 1.0 References: <39a754af-1a38-da96-379f-d5886fcd0fec@f4grx.net> In-Reply-To: From: George Michaelson Date: Wed, 27 Sep 2023 09:32:23 +1000 Message-ID: To: The Eunuchs Hysterical Society Content-Type: text/plain; charset="UTF-8" Message-ID-Hash: DKRMCVTFSS3AVAIZMCU4PVKBTMAG24IA X-Message-ID-Hash: DKRMCVTFSS3AVAIZMCU4PVKBTMAG24IA X-MailFrom: ggm@algebras.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: It may be obvious, certainly to anyone who owns the BSTL series (I don't. I read it in the library at uni), but would I be right in thinking the motivation behind "real time UNIX" was switching? It's the closest problem to Bell labs which demands time critical outcomes, the delay tolerance in circuit establishment and end-to-end telephony signaling was there, but it was finite. And, for capacity planning purposes being told a single unit of UNIX logic controlling a telephone switch could handle X call setup and tear-down events per second meant you could do the Erlang sums over customers call volumes and phone handset counts. The british digital switch experience in the System-X series Was GEC/Plessey, and ran CORAL which was the real time system they used to do MILSPEC stuff. It was explicitly fault tolerant design, lots of 2 and triple redundant componentry. -G