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_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FROM,MAILING_LIST_MULTI, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 22467 invoked from network); 26 Jul 2023 14:38:24 -0000 Received: from minnie.tuhs.org (2600:3c01:e000:146::1) by inbox.vuxu.org with ESMTPUTF8; 26 Jul 2023 14:38:24 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id C741341091; Thu, 27 Jul 2023 00:38:20 +1000 (AEST) Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by minnie.tuhs.org (Postfix) with ESMTPS id 25E2640B8E for ; Thu, 27 Jul 2023 00:38:06 +1000 (AEST) Received: by mail-pl1-x631.google.com with SMTP id d9443c01a7336-1b8b4748fe4so39818585ad.1 for ; Wed, 26 Jul 2023 07:38:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690382285; x=1690987085; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=GKCT2NHI3Xm5j77qlmKKZ7tKoL2kogpKHwIkxk8lUb4=; b=jFWNLmOyvyIPAj1o/hyrPI3ezf+eQrAobHfnF0OzO0NDsBYV1gHP5VA3l1mqoWXmdY EL/qrEh8sEoavF5ZYCkK/bNJTi+mh/l0ObPjS5AvuikZDIjvNGlAqu+XFfV9bjf/tR81 ZZFeGeP/3b8tRbzEvz4Z28Fo5/hXwxNI8cQCCKbJ61RQgOFPM7eP/8QIkHgKnLbz8quA GOuYAUMEOOuIm0zXD5Olf4kQJ5K3AFv3J1muC3dXFKOp1pmVAGIh5evSLaM85xx3lzLh qk6KDXNO1AeUAYMnZgue6M19mFvOYbjg3qh7quBnX7Tzad1+VOSyXJzdhByb/yWb7BEK Kthw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690382285; x=1690987085; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=GKCT2NHI3Xm5j77qlmKKZ7tKoL2kogpKHwIkxk8lUb4=; b=NkgoqTn6S4wVqrXV9T44mMTrbxzPDEI0r+ZdteuJ6N1/3cl6aySM27SJxDfGssKxyE CHvxWuPj7cvAbPpnVGbw6LU0PNIB/TYztKgzVOiZWtpHjaLX1IvWryE36Ilr/g+b7gxi 49uoLiFzKWsET9Qz66XKPa3ZuroxcpQwb2XTjeou0tkDWdAgOV7W3pgjAHsito3E3m6E CipZMcp3KKaF8TCKpFCD2lSmpmiIP48GU417nZnG3sDy/suS/yA1UORryKYnsm83mOsr B0DY8QNuvJZJjLnOYpXLIAKh44j4rSTkL/nSH/nft3UA7bDXsINAChF5XX6P8FHu7LHU bUZw== X-Gm-Message-State: ABy/qLZFRD7gZ6ouDfRwLfksAkZrSJVvMNYTWTO0lx2iR/GMn216nw/i Fbhlc+xVG5GRnCBtgJeO8++pUpCixsou0kPZUUo= X-Google-Smtp-Source: APBJJlGHtJ7yL3sGOmJxLVGlDXVAR1DQRwgylfNPum11sJ9M2ERLf/Vxz3NuJtRS+LmZkvmuqApAuDvA1xUUDXEfAvo= X-Received: by 2002:a17:90b:4c03:b0:267:f2f4:feb1 with SMTP id na3-20020a17090b4c0300b00267f2f4feb1mr1770426pjb.28.1690382285092; Wed, 26 Jul 2023 07:38:05 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a05:6a11:af19:b0:4c1:7ec0:eb04 with HTTP; Wed, 26 Jul 2023 07:38:04 -0700 (PDT) In-Reply-To: References: From: Paul Winalski Date: Wed, 26 Jul 2023 10:38:04 -0400 Message-ID: To: segaloco Content-Type: text/plain; charset="UTF-8" Message-ID-Hash: CEKAGJ5IALHX5BPEEJJMD4C7VX42E74J X-Message-ID-Hash: CEKAGJ5IALHX5BPEEJJMD4C7VX42E74J X-MailFrom: paul.winalski@gmail.com 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 CC: COFF X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [COFF] Re: What Happened to Interdata? List-Id: Computer Old Farts Forum Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 7/25/23, segaloco via COFF wrote: > Were Interdata machines > problematic in some sort of way, or was it merely fate, with more popular > minis from DEC simply spacing them out of the market? I suspect that Interdata had the same problem with their S/360 lookalikes that RCA did with theirs. If your business model is to provide a cheaper hardware alternative to IBM, your machine has to run IBM software, particularly the OS. When IBM did their pre-release of the S/370 specifications they deliberately left out key bits of the privileged architecture, such as the detailed bit layout of the PSW. Companies such as RCA and Interdata had make guesses while designing their S/370 lookalikes and in some cases they guessed wrong. RCA's Spectra 70 couldn't run IBM OS/VS or DOS/VS and that made it a total non-starter for most IBM commercial shops. I suspect Interdata ran into the same problem. Yes, they could design their own me-too operating systems, but they would always lag behind on new IBM OS features, on which critical IBM applications would depend. The IBM customer base knew this and stuck with genuine IBM. A lower price point wasn't enough to make up for the incompatibility. The advent of 32-bit minicomputers at the end of the 1970s brought down for good the IBM price umbrella under which Interdata and other lookalikes had been living. An example of how high that price umbrella had been: In 1978 my undergraduate alma mater was a true-blue IBM shop with a S/370 model 125 running batch, CICS, and a small BASIC timesharing system for the students. They'd outgrown the model 125. IBM's solution was to upgrade to a model 135. For the same price as the IBM processor upgrade, DEC was offering a complete VAX-11/780 system to run timesharing and other academic computing, with the S/370-125 devoted exclusively to the business side of things. The 11/780 was roughly equivalent in computing power to an IBM S/370-158--two models up from the 125. Buying the 11/780 was a complete no-brainer. IBM was forced to cut prices on the S/370 line, and that fatally destroyed Interdata's one advantage over true S/360/370. -Paul W.