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 autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 3102 invoked from network); 28 Nov 2022 16:31:40 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 28 Nov 2022 16:31:40 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 90E2041BC8; Tue, 29 Nov 2022 02:31:32 +1000 (AEST) Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) by minnie.tuhs.org (Postfix) with ESMTPS id 16EC34010B for ; Tue, 29 Nov 2022 02:31:28 +1000 (AEST) Received: by mail-wm1-f49.google.com with SMTP id t4so8886248wmj.5 for ; Mon, 28 Nov 2022 08:31:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=o0JK7zE25Zl5zfH3Y/ABu7R8PLBBg8D/4UqarZx0O08=; b=f08EPdPLA/1QVPWCP4ed9p2o2NKGuJTtTNY0vhIJ/24T7waoUOPPn/8ML9A+arnOzX 92rNdxcEpf+8D3ByZ+bImKpw3M4+Iq2J1U5FspfW1yqF/soRIISOrFXm8kj+V5chBy0P VCdmZEvo6VmztdO3Nmg19OSD6mgGsPDoDxtbxJTmScP7Rqi3jS+M486AmRxlxrsWOMZ1 JXoQBUwREcSdmiRRMLxXlVoyf8VkAvtT4j8jNviioQGMBg/i8qe+xvspzHsBfbgeOzbS bLolpKoDkKvbHadMijHFGq5TKAL6cpekw0fOhOvMmZPIbmrO+y6W6nezkII3sha3sYRC eLXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=o0JK7zE25Zl5zfH3Y/ABu7R8PLBBg8D/4UqarZx0O08=; b=OKhtxX+IFBI8JjdU3gzaqq+6kuHXTUP+i3vyAOEbPsNstT2/3piFx0bitVj7x9UyDj GBgxiFkPBtOPmLx2f2mPFhdCcIngW0IB5SmwV/19Tbf2fvIXcCKWUeQAgICY3v1mVZQ3 fnI4AJu2wkV+rtNm3+1jl4xgCSkssCzeiharTk60bS5YM8YRiaxoZhrVkRRjIMLnL9F9 QFC23nCdDLShR3bsntnU2zr3MKC0rdTiEcPyT2w6JCnzhA0VWrVbPvxIZT8McWD8UmRq JRY4f/Uu/1laXQ915Ik52+sEoStikKKh8e29rYqUwmwQd2YxBt7MUvuc3aanEYWieugs a/+Q== X-Gm-Message-State: ANoB5ploIPgdzjlZ6XI4ODddfSzGCk9CuqnzHsxLUGIdySiYPFOB57qF MAYqaWweS+2/9lPiMAH/pkiEGV63IlX4O+8il6voHE/S X-Google-Smtp-Source: AA0mqf5pTBdhFjSjaxv6etgrdEiWRkM5OOKPzrhJ+N/C+w+F1krd23ziSpKNaiZBaypvH7GO6dU5gtbp8HHRxtDUjv8= X-Received: by 2002:a05:600c:d7:b0:3cf:c95e:450f with SMTP id u23-20020a05600c00d700b003cfc95e450fmr26651820wmm.17.1669653026539; Mon, 28 Nov 2022 08:30:26 -0800 (PST) MIME-Version: 1.0 Received: by 2002:a05:600c:4ec8:0:0:0:0 with HTTP; Mon, 28 Nov 2022 08:30:25 -0800 (PST) In-Reply-To: References: <7C8CADAB-65AA-4841-AFA1-569A9651E56D@planet.nl> From: Paul Winalski Date: Mon, 28 Nov 2022 11:30:25 -0500 Message-ID: To: Clem Cole Content-Type: text/plain; charset="UTF-8" Message-ID-Hash: KFI3FJLFNEPRZYGZ2KVA4ZSQTXD26WVT X-Message-ID-Hash: KFI3FJLFNEPRZYGZ2KVA4ZSQTXD26WVT X-MailFrom: paul.winalski@gmail.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: Paul Ruizendaal , The Eunuchs Hysterical Society X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Early multiprocessor Unix List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 11/28/22, Clem Cole wrote: > > A few years later (1980), Goble's work became the Purdue Vax [ > https://en.wikipedia.org/wiki/George_H._Goble] - which used a master-slave > configuration. He spliced a second 780 CPU onto the SMB SBI (Synchronous Backplane Interconnect), the data bus for the 11/780. The KA780 CPU plugged into it, as did the memory controller, the UBA (UNIBUS adapter), the MBA (MASSBUS adapter), and the CI (Computer Interconnect, the high-speed network used for VAXcluster communication). > and, with some > interesting work, allowed the second CPU to run user code. This was > extremely effective for their usage case -- timesharing of students. Normally only one KA780 CPU was attached to the SBI, but there was nothing physical or electronic to prevent plugging in a second one. IIRC there were a couple of places in the 11/780 microcode that assumed there was only one CPU on the SBI, but that was easily tweaked. DEC productized the two-processor asymmetric multiprocessor configuration as the VAX-11/782. The software development tools group that I worked in was one of the two beta test sites for the 782 (the other was MIT). I was the system manager for that machine. Ours ran VMS, of course, not Unix, but with the same idea that only user mode code was scheduled to run on the second processor. All I/O and kernel mode code was done on the primary. It scaled pretty well for compute-intensive loads. It actually ran slower than a single processor under high I/O loads, though, and it gave no advantage to real-time workloads. I don't know if Ultrix ever supported the 11/782. The product had a rather short lifetime, as it was soon superseded by VAX models that were designed for symmetric multiprocessing from the ground up, and full SMP support had been implemented in VMS and Ultrix. -Paul W.