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,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 8944 invoked from network); 1 May 2021 10:09:33 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 1 May 2021 10:09:33 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 93D429C1D7; Sat, 1 May 2021 20:09:29 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id A6F0D9BD01; Sat, 1 May 2021 20:08:16 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=planet.nl header.i=@planet.nl header.b="Q1Zz8bVi"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id B71C49BD01; Sat, 1 May 2021 20:08:07 +1000 (AEST) Received: from cpsmtpb-ews01.kpnxchange.com (cpsmtpb-ews01.kpnxchange.com [213.75.39.4]) by minnie.tuhs.org (Postfix) with ESMTP id 628CD9BCFF for ; Sat, 1 May 2021 20:08:00 +1000 (AEST) Received: from cpsps-ews06.kpnxchange.com ([10.94.84.173]) by cpsmtpb-ews01.kpnxchange.com with Microsoft SMTPSVC(8.5.9600.16384); Sat, 1 May 2021 12:07:56 +0200 X-Brand: 7abm2Q== X-KPN-SpamVerdict: e1=0;e2=0;e3=0;e4=;e6=(e1=10;e3=10;e2=11;e4=10;e6=1 0);EVW:White;BM:NotScanned;FinalVerdict:Clean X-CMAE-Analysis: v=2.4 cv=Ypls+6UX c=1 sm=1 tr=0 ts=608d287c cx=a_idp_e a=LO2mTXPAMClkaqVt2RTykg==:117 a=soxbC+bCkqwFbqeW/W/r+Q==:17 a=x1i13A_MHe4A:10 a=IkcTkHD0fZMA:10 a=5FLXtPjwQuUA:10 a=YQ40WqKhAAAA:20 a=9vBhAPF6326573MzeIoA:9 a=QEXdDO2ut3YA:10 a=tf1YDX3pA6yNhKSqw0sB:22 X-CM-AcctID: kpn@feedback.cloudmark.com Received: from smtp.kpnmail.nl ([195.121.84.12]) by cpsps-ews06.kpnxchange.com over TLS secured channel with Microsoft SMTPSVC(8.5.9600.16384); Sat, 1 May 2021 12:07:55 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=planet.nl; s=planet01; h=to:date:message-id:subject:mime-version:content-type:from; bh=BUMidEvyoDKcHMr4xl0M8SrLy6iv7sJbLmCdE4Z3SJM=; b=Q1Zz8bViT3+Juw7JpM9rnPLRyz6ahnOOT/Ax6IUZ9nrWb+qpNUNZI53bfeRQ+/2LxJKRqUU1b/KHR ibQmIjK9tNTUHgOShHySDFoiyy5duT5TzyBgTMQGvkSTXC0AsOWLN1yCeKWydUi2JN4R3UBlCxwnHT xZFgD5M8ivzlq1FQ= X-KPN-VerifiedSender: Yes X-CMASSUN: 33|4qc5hMrEGolYs5SF/disHhz6oRM2tssVBB3oUqzKVVwi3JOOQe9kxTBGaDgdIrX dEsUS8VGuTuFowKcNdIjXrw== X-Originating-IP: 80.101.112.122 Received: from mba1.fritz.box (sqlite.xs4all.nl [80.101.112.122]) by smtp.kpnmail.nl (Halon) with ESMTPSA id 18f372fe-aa65-11eb-baae-00505699772e; Sat, 01 May 2021 12:07:56 +0200 (CEST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.7\)) Message-Id: <61A97237-FBF7-4401-8971-266CE8E4A010@planet.nl> Date: Sat, 1 May 2021 12:07:54 +0200 To: TUHS main list X-Mailer: Apple Mail (2.3445.9.7) X-OriginalArrivalTime: 01 May 2021 10:07:55.0850 (UTC) FILETIME=[DB1482A0:01D73E71] X-RcptDomain: minnie.tuhs.org Subject: [TUHS] Evolution of Unix (demand) paging 1980-1985 X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Paul Ruizendaal via TUHS Reply-To: Paul Ruizendaal Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" As an offshoot of looking more closely at 32V, SysIII and 8th Edition I = got interested in how each managed memory. I=E2=80=99ve not deep-dived into the code yet, but from cursory = inspection and searching past posts on this list, I get to the following = summary: - As has been documented widely, 32V essentially retained the V7 = swapping architecture, merely increasing the maximum process size a bit = versus the PDP-11 version. - SysIII appears to have retained this, just cleaning up the source code = a bit. I assume that all the V7/SysIII derivatives of the early 80=E2=80=99= s were swapping systems. - John Reiser further developed 32V memory management into a (reportedly = elegant) demand paging system in 1980-1981, but this code appears lost. - 3BSD/4BSD/4.1BSD developed 32V memory management into a full demand = paging setup as well. This code base was dominant in the 1980-1985 era. - 8th Edition pulled in the BSD VM code and is essentially identical to = that in 4.1BSD. This choice was made because it was not a research = interest and using a maintained code base freed up scarce time. - SysV R1 appears to have retained the SysIII memory system. - SysV R2 (floating about on the net, eg. here = https://github.com/ryanwoodsmall/oldsysv) seems to have used a new = implementation. Questions: Is that about correct, or am I missing major elements? Several places mention that there was also a setup that was still = swapping in nature, but did not require allocations in core to be = contiguous (=E2=80=9Cscatter paging=E2=80=9D). Did this get used much in = the era? At first glance, the SysV R2 code seems shorter and cleaner than the = early BSD code (~2000 vs. ~3000 sloc). Is this implementation perhaps a = derivative of John Reiser=E2=80=99s work?=