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 26609 invoked from network); 16 Dec 2023 19:44:51 -0000 Received: from minnie.tuhs.org (2600:3c01:e000:146::1) by inbox.vuxu.org with ESMTPUTF8; 16 Dec 2023 19:44:51 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 3695243EAC; Sun, 17 Dec 2023 05:44:50 +1000 (AEST) Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by minnie.tuhs.org (Postfix) with ESMTPS id 033CD43EAB for ; Sun, 17 Dec 2023 05:44:46 +1000 (AEST) Received: by mail-pg1-x52f.google.com with SMTP id 41be03b00d2f7-5cd82917ecfso384665a12.0 for ; Sat, 16 Dec 2023 11:44:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702755885; x=1703360685; darn=tuhs.org; h=to:subject:message-id:date:from:references:in-reply-to:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=/C3wnC3XaXByKhOlaZSu+W8q1uHOP6aBVUEXypVcwuo=; b=jkKXsq4qoEx3wy1t3X/Lh7R1DP31C9U3fjdW4qnMdD2Wg3cTo86NCuGFBNSCiHnwkg VK4Btq3r1k84bg//d7UavFSuLUFdcUqBb2x4H1T5Nhdqd0dupMxdhwGl3KZQLXzVuluH Da16y8Jpvl+VojgVU2M6DcURNDpi0yr5HfidYtNcmcHhlaqC4W0IZch1MBzZWrNVtcbz 7yn2R/Rxf9veJd9+oxlfe1ojmIjkgdnSXOa7vxULFVv9/HqWhVuBylQr4MutZgbm7uh+ NeEewKw16bQWkB+VYaDAfQHSEI9rgyThGlgQvKXenabBbXO0xxtCn5GD886BWZ2w61Rr KzCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702755885; x=1703360685; h=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=/C3wnC3XaXByKhOlaZSu+W8q1uHOP6aBVUEXypVcwuo=; b=nvYSCztjdHy0dZ0JY30ebbXdqATTctZrdq1NT1S+/CIDKBsPhxMnoqJfdbgULdtodx LMy+T13mIlYtN8JbFHSNDCFH27OVL6antUoBRYBCFO0ZJMsqb1ZzjERO1keYxVTmLym5 m+TFitK3npOG37ImaC5RGrtbwnI/KWLWkNDSuG6JgxRYf9eBzDeUrWkxD2XKSuEGhGhD bDHbxeiafd/v8zUdMiRwqXH9XRZBDJU1PsFgJTVxXHXuquVbOqQcrT6c6w5Qs3YLwXpY d+1bZGp/GbjHP5hdrk1wCP5sj2/EtSzncgenBRdbfG1Sj6webRk1+7RQ7hg6/pKSSFHX Kf0Q== X-Gm-Message-State: AOJu0YxLTwwFgD1zqUpaAl7j0s0k6YUwonsS3c59UReY8JjoHBHZOpHq +7thHYiDPk63dcfIn8yCuTyefUFAlG0J1MGFO2VexwLI X-Google-Smtp-Source: AGHT+IHon2joNCpnZm9LYUAaPYKSIi/X+9Ab0TWUslDdZ57Nl28RexEAbd4gUoIK/ThxTFCQeoVCSDgXrq87AE9PyUQ= X-Received: by 2002:a05:6a20:244d:b0:190:9181:7d6d with SMTP id t13-20020a056a20244d00b0019091817d6dmr16452036pzc.83.1702755885011; Sat, 16 Dec 2023 11:44:45 -0800 (PST) MIME-Version: 1.0 Received: by 2002:a05:6a10:234f:b0:526:f191:393 with HTTP; Sat, 16 Dec 2023 11:44:44 -0800 (PST) In-Reply-To: References: <20231214232935.802BB18C08F@mercury.lcs.mit.edu> <4416CB1B-CDE2-42DA-92F2-33284DB6093F@iitbombay.org> From: Paul Winalski Date: Sat, 16 Dec 2023 14:44:44 -0500 Message-ID: To: coff@tuhs.org Content-Type: text/plain; charset="UTF-8" Message-ID-Hash: F3IN4FIX7PQ2K6JX3VL6WT6S2EKXK52L X-Message-ID-Hash: F3IN4FIX7PQ2K6JX3VL6WT6S2EKXK52L 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 X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [COFF] Re: Terminology query - 'system process'? List-Id: Computer Old Farts Forum Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: IBM's OS/360 did not have the modern "process" concept using virtual memory to implement a thread of control with its own, separate address space. Instead they had the concept of threads of control associated with contiguous segments of physical memory called "partitions". You had either a pre-defined set of partitions (OS MFT, multiprogramming with a fixed number of tasks) or the OS allocated partitions on-the-fly as needed for the current mix of jobs (OS/MVT, multiprogramming with a variable number of tasks). OS/VS1, OS/VS2 SVS, and DOS/VS for System/370 operated in the same way, except there was a single virtual address space, usually much larger than physical memory, that was partitioned up. DOS/360 ran one job at a time. DOS/VS had up to 5 partititions: BG (background), and P1-P4. Scheduling in DOS/VS was strictly preemptive, in the order P1, P2, P3, P4, BG. P1 got control whenever it was ready to run. If P1 was stalled, P2 was scheduled, then P3 through BG, which only got to run whenever the higher-priority jobs were stalled. The most sophisticated (and resource-hogging) version of OS/VS was OS/VS MVS (multiple virtual storages) which implemented the modern concept of each partition (process) getting its own, separate 0-based address space. Some of these partitions might be allocated to privileged tasks, most notably the spooling system such as HASP (Houston Automatic Spooling Priorithy), which was developed by IBM contractors working at NASA's Houston space facility in the mid-1960s. HASP provided both spooling and remote job entry services and ran at least partly in partition (i.e., user process) context. DOS/360 had a kernel (supervisor, in IBM-speak) enhancement called POWER that provided spooling capability. DOS/VS had POWER/VS, which ran in a separate partition (typically P1, the highest priority). VAX/VMS (and its successor OpenVMS) had a few privileged user-mode processes to perform system tasks. Two of these processes were OPCOM (provides communication with the operator at the operator's console) and JOB CONTROL (provides spooling and batch job services). I think OPCOM runs entirely in user mode. JOB CONTROL may have some routines that execute in kernel mode. These system processes are similar to daemons in Unix. -Paul W.