From owner-freebsd-questions@FreeBSD.ORG Mon Jan 16 01:13:46 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 8C15F106566C for ; Mon, 16 Jan 2012 01:13:46 +0000 (UTC) (envelope-from conrads@cox.net) Received: from eastrmfepo202.cox.net (eastrmfepo202.cox.net [68.230.241.217]) by mx1.freebsd.org (Postfix) with ESMTP id 2FC8B8FC14 for ; Mon, 16 Jan 2012 01:13:46 +0000 (UTC) Received: from eastrmimpo210.cox.net ([68.230.241.225]) by eastrmfepo202.cox.net (InterMail vM.8.01.04.00 201-2260-137-20101110) with ESMTP id <20120116011340.TZFC2803.eastrmfepo202.cox.net@eastrmimpo210.cox.net> for ; Sun, 15 Jan 2012 20:13:40 -0500 Received: from serene.no-ip.org ([98.164.86.55]) by eastrmimpo210.cox.net with bizsmtp id N1Df1i0081BeFqy021DggM; Sun, 15 Jan 2012 20:13:40 -0500 X-CT-Class: Clean X-CT-Score: 0.00 X-CT-RefID: str=0001.0A020209.4F1379C4.0063,ss=1,re=0.000,fgs=0 X-CT-Spam: 0 X-Authority-Analysis: v=1.1 cv=WviWdoU0ckN3JoXTgB1bhStvvqCbiPw70GMZghakpf0= c=1 sm=1 a=tMAdfNF9mhEA:10 a=G8Uczd0VNMoA:10 a=kj9zAlcOel0A:10 a=fdHYxQQoAueMHNSmXppgDg==:17 a=kviXuzpPAAAA:8 a=g-XFR-G7qGPC4Wpg8PkA:9 a=1mdAqHShcAlissu2rqkA:7 a=CjuIK1q_8ugA:10 a=4vB-4DCPJfMA:10 a=fdHYxQQoAueMHNSmXppgDg==:117 X-CM-Score: 0.00 Authentication-Results: cox.net; none Received: from cox.net (localhost [127.0.0.1]) by serene.no-ip.org (8.14.5/8.14.5) with ESMTP id q0G1Dd8l035676 for ; Sun, 15 Jan 2012 19:13:39 -0600 (CST) (envelope-from conrads@cox.net) Date: Sun, 15 Jan 2012 19:13:34 -0600 From: "Conrad J. Sabatier" To: freebsd-questions@FreeBSD.org Message-ID: <20120115191334.385bd3eb@cox.net> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.6; amd64-portbld-freebsd10.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Subject: 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 01:13:46 -0000 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 would appear to no longer be true. And similarly, how relevant or viable is COMPAT_43TTY anymore? Why would one want to use this? 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'. 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. 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. Thank you. -- Conrad J. Sabatier conrads@cox.net