From owner-freebsd-questions@FreeBSD.ORG Mon Jan 16 06:14:26 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1CB3D106566B for ; Mon, 16 Jan 2012 06:14:26 +0000 (UTC) (envelope-from jhs@berklix.com) Received: from tower.berklix.org (tower.berklix.org [83.236.223.114]) by mx1.freebsd.org (Postfix) with ESMTP id B23248FC12 for ; Mon, 16 Jan 2012 06:14:25 +0000 (UTC) Received: from mart.js.berklix.net (p5DCBFFEF.dip.t-dialin.net [93.203.255.239]) (authenticated bits=0) by tower.berklix.org (8.14.2/8.14.2) with ESMTP id q0G6EAOp027325; Mon, 16 Jan 2012 06:14:11 GMT (envelope-from jhs@berklix.com) Received: from fire.js.berklix.net (fire.js.berklix.net [192.168.91.41]) by mart.js.berklix.net (8.14.3/8.14.3) with ESMTP id q0G6E9Wg098940; Mon, 16 Jan 2012 07:14:12 +0100 (CET) (envelope-from jhs@berklix.com) Received: from fire.js.berklix.net (localhost [127.0.0.1]) by fire.js.berklix.net (8.14.4/8.14.4) with ESMTP id q0G6DvjH012679; Mon, 16 Jan 2012 07:14:03 +0100 (CET) (envelope-from jhs@fire.js.berklix.net) Message-Id: <201201160614.q0G6DvjH012679@fire.js.berklix.net> To: "Conrad J. Sabatier" From: "Julian H. Stacey" Organization: http://www.berklix.com BSD Unix Linux Consultancy, Munich Germany User-agent: EXMH on FreeBSD http://www.berklix.com/free/ X-URL: http://www.berklix.com In-reply-to: Your message "Sun, 15 Jan 2012 19:13:34 CST." <20120115191334.385bd3eb@cox.net> Date: Mon, 16 Jan 2012 07:13:57 +0100 Sender: jhs@berklix.com Cc: freebsd-questions@freebsd.org Subject: Re: COMPAT_* kernel config options -- some housecleaning overdue? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Jan 2012 06:14:26 -0000 Hi, "Conrad J. Sabatier" wrote: > I've been wondering for a while now about the accuracy of some of the > comments in /sys/conf/NOTES re: the various COMPAT_* options, and now, > with 9.0-RELEASE already out the door and 10.0-CURRENT as the current > development branch, it seems even more relevant to ask just how > necessary or useful some of these options are anymore. > > Let me preface the following by saying that I just recently built a > 10.0-CURRENT kernel with no COMPAT_* options besides COMPAT_FREEBSD32 > and COMPAT_LINUX32, and everything seems to be working just fine (yes, > including Linux emulation). > > First and foremost, the comment re: COMPAT_43: "You probably do NOT > want to remove this as much current code still relies on the 4.3 > emulation." This might not be just refering to code runing on FreeBSD, but perhaps also code running on older other legacy net machines ? I suspect I may have needed it to talk to eg my Symmetric 375 (a 4.2BSD Bill Jollitz product pre 386BSD pre FreeBSD http://www.berklix.com/~jhs/symmetric/ ) (Not that I put that comment in), it might be an ifdef that allows adaptive detection of logic low & high for TCP broadcast address ? Whatever, searching & updated comments on what they all do would be nice. Feel free to search the source with find & grep & use send-pr to update the comments, would be useful :-) cd /usr/src vi -c/COMPAT_43TTY `find . -type f -exec grep -l COMPAT_43TTY {} \;` dmesg .... > This would appear to no longer be true. And similarly, > how relevant or viable is COMPAT_43TTY anymore? Why would one want to > use this? To support legacy code/ apps. Warning "There be dragons" as it says on old maps ;-) ie tty in Unix has traditionaly been a complex place to mess around, personaly I'd stear clear & leave it to those willing to futz about with tty :-). > I suspect that neither of these options has any real effect > anymore and both may, in fact, be essentially NOOPs. How close to the > real picture is that? > > It is my understanding that, on 64-bit platforms, COMPAT_FREEBSD32 > *is* necessary if COMPAT_LINUX32 is enabled, which seems perfectly > reasonable. However, the comment accompanying COMPAT_LINUX32 states > that COMPAT_43 is also required, which simply is not true. > And speaking of Linux compatibility, we still have an erroneous reference to > COMPAT_LINUX instead of COMPAT_LINUX32 accompanying 'device tdfx'. dmesg then > Then, of course, there are the various COMPAT_FREEBSD[4-7] options, > each accompanied by a comment which merely states the obvious but > offers no real clue as to whether or not any of them are actually > necessary. was mentioned on another list in last few days > I don't know, this whole COMPAT area just seems really messy to me -- > disorganized, unclearly documented and probably suffering from no small > amount of bit rot and neglect. I really do think it's time for some > cleaning up. > > Hope I didn't ruffle any feathers, but I just hate this type of gray > fuzziness. Clarification (maybe even some deprecation?) seems to be in > order here. Yup, certainly needs clearer comments ... find ... grep ... vi ... dmesg :-) Cheers, Julian -- Julian Stacey, BSD Unix Linux C Sys Eng Consultants Munich http://berklix.com Reply below not above, cumulative like a play script, & indent with "> ". Format: Plain text. Not HTML, multipart/alternative, base64, quoted-printable.