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=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 24031 invoked from network); 12 Aug 2022 18:53:20 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 12 Aug 2022 18:53:20 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 1B8B740246; Sat, 13 Aug 2022 04:52:57 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tuhs.org; s=dkim; t=1660330377; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-owner:list-unsubscribe:list-subscribe:list-post; bh=SGLUXWuwLh/7K7Yaz3iUU6XxCF60Jamr0VVlN0HYQ9U=; b=CiQqjSfZ8MdtRWYTNX+DUnbfy8UkoUSCXyEsyoQcHImtPpPwFlKSva3Gdvgdi6/sNexcpB c7yb5c9mgl6MD7ZHTJe98+y+8ABnUYVQkzpppPAyFVHB8r2F/KdAwmh7ah/4Jqw+j5DXwq /dKpuz+BqCoE3YteoG21NG4fj/5Ju1s= Received: from mail-4325.protonmail.ch (mail-4325.protonmail.ch [185.70.43.25]) by minnie.tuhs.org (Postfix) with ESMTPS id 0E89140123 for ; Sat, 13 Aug 2022 04:52:50 +1000 (AEST) Date: Fri, 12 Aug 2022 18:52:41 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1660330367; x=1660589567; bh=SGLUXWuwLh/7K7Yaz3iUU6XxCF60Jamr0VVlN0HYQ9U=; h=Date:To:From:Cc:Reply-To:Subject:Message-ID:Feedback-ID:From:To: Cc:Date:Subject:Reply-To:Feedback-ID:Message-ID; b=u/fzZATiP+0Uy25+NRHhWGBVCqrBsXOt4UfbrI6bAIrME7x0ir+RhD1K2PDaBMtqO I5M1sHx713BSsivzmzJMilh4cRmP6o3gGdGv6UTRcRmtUYgPM3kTBg5PfGyrX0nGI0 yVRKu3lDYScWhEkSn2Hq08u3Zi2vH1ST/5LYA25HevyUnY2T2XqF7tRfnt4c8G7j6R 97JK37SvekuhrVJcwMlBlsOTbsEb5GofOMOc3IjJuwxDNdqJqg3GCDsM8tNQVns7qe RGzQueV48gu5cJBIi5ks2BRfLb4qNfgyYwkLeRKW4EMI+dYkluOtzAx9K/FthIBKFu b7t9h+MVogyaA== To: Warner Losh Message-ID: Feedback-ID: 35591162:user:proton MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Message-ID-Hash: SSH4JH4EQ67YADWBY3NAGRYB7642SRJA X-Message-ID-Hash: SSH4JH4EQ67YADWBY3NAGRYB7642SRJA X-MailFrom: segaloco@protonmail.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: Jonathan Gray , The Eunuchs Hysterical Society , Paul Ruizendaal X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] SysIII and SysV Feature Lineage (was: Documents for UNIX Collections) List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: segaloco via TUHS Reply-To: segaloco Thread fork as we're drifting from documentation research specifically. One matter that keeps coming to mind for me is the formal history of the ru= nlevel-based init system.=C2=A0 It isn't in Research obviously, nor was it = in PWB.=C2=A0 The first time it shows up in the wild is System III, but thi= s version is slightly different than what was in CB-UNIX at the time, which= is what eventually wound up in System V. The pressing question is whether the version in System III represents an ea= rlier borrowing from CB or if perhaps the runlevel init started in USG, got= bumped over to CB and improved, then that improved version came back to su= pported UNIX in 5.0. As for the notable differences: SysIII init allows for runlevels 1-9.=C2=A0 It will call /etc/rc with the c= urrent state, the prior state, and the number of times the current state ha= s been entered.=C2=A0 If the script is called for instance due to a powerfa= ilure, then the current state is passed suffixed with an 'x'.=C2=A0 The ini= ttab entries are in a different format: state:id:flags:process Where state is the runlevel, id is a two-character identifier, flags can be= either 'c' (like respawn) or 'o' (like off I think). No flag then indicat= es to run once. Flags 't' or 'k' will terminate or kill a process before i= t is started again if a given runlevel is entered and it is already running= . This of course is in contrast to SysV init which instead offers runlevels 0= -6 as well as a, b, and c. Init itself can be called with runlevels S|s or= Q|q additionally and these act as calls to enter single user mode or rerun= the current init state if I'm understanding correctly. Neither S nor Q op= tions appear to be valid for the inittab runlevel. Init tab entries here a= re: id:rstate:action:process Where id and rstate are essentially just the same fields from SysIII swappe= d. Action replaces the flags field with the more well known respawn, wait,= once, initdefault, etc. behaviors. All in all, different enough that inittabs between the two wouldn't be comp= atible. SysV also includes the telinit command which appears to be able to= handle those a, b, and c runlevels. Anywho, that's my understanding of the init changes, with the pertinent que= stion remaining whether the SysIII-style init ultimately started from the s= ame place as SysV, or if the general design idea was there between USG and = CB, and they got to a similar answer from different directions. Colon-deli= mited /etc files aren't uncommon, so while unlikely, it could be entirely p= ossible the two inittab formats arose relatively independently, but the tru= th remains obscure in my mind at least. I don't really blame Research for = not picking up this init system, it seems like there were a few parallel st= reams of development around the turn of the 80s, and the easier answer was = probably to just stay the course. I seem to recall reading in a thread som= ewhere Rob Pike discussing the resistance in the Research group regarding s= ucking up each and every little feature USG tried to promulgate as standard= , and this init system got specific mention. - Matt G.