From owner-freebsd-arch@FreeBSD.ORG Tue Jan 4 17:31:59 2011 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id F107C1065674; Tue, 4 Jan 2011 17:31:58 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id 2BCB28FC14; Tue, 4 Jan 2011 17:31:57 +0000 (UTC) Received: from [127.0.0.1] (pooker.samsco.org [168.103.85.57]) (authenticated bits=0) by pooker.samsco.org (8.14.4/8.14.4) with ESMTP id p04GtV5b077020; Tue, 4 Jan 2011 09:55:32 -0700 (MST) (envelope-from scottl@samsco.org) Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: text/plain; charset=us-ascii From: Scott Long In-Reply-To: <85271.1294128867@critter.freebsd.dk> Date: Tue, 4 Jan 2011 09:55:31 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: References: <85271.1294128867@critter.freebsd.dk> To: Poul-Henning Kamp X-Mailer: Apple Mail (2.1082) X-Spam-Status: No, score=-50.0 required=3.8 tests=ALL_TRUSTED, T_RP_MATCHES_RCVD autolearn=unavailable version=3.3.0 X-Spam-Checker-Version: SpamAssassin 3.3.0 (2010-01-18) on pooker.samsco.org Cc: arch@freebsd.org, Alfred Perlstein , Garrett Cooper Subject: Re: Linux kernel compatability X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Jan 2011 17:31:59 -0000 On Jan 4, 2011, at 1:14 AM, Poul-Henning Kamp wrote: > In message , Jeff Roberson = writes: >=20 >> Also, linux likes to change things very rapidly. Not to mention a = lot of=20 >> their APIs go against the grain on BSD and we would not find them=20 >> aesthetically or architecturally pleasing. >=20 > Absolutely. >=20 > But we, as a project, must also weigh the cost of our sensibilities > and preferences, against how much work we must expend to uphold them. >=20 I have mixed feelings about Jeff's shim layer. On the plus side, I = think that there's value to emulation without copying. On the negative = side, I agree with ALexander's concern that it's a large chuck of code = to be maintained. Emulation isn't a bad thing. It allows IHV's as well = as individual developers to take baby steps with getting familiar with = FreeBSD. It lowers the barrier to entry. The ones who aren't going = to put in the effort to making the leap from "emulation" to "native" = likely aren't going to take the leap with going from "nothing" to = "native" either. I understand the argument that it will coddle people = into using just the emulation and not the native interfaces, thus = degrading the value of the native interfaces. I'm just not sure how = much I believe that in my experience. I recall years ago Matt Jacob mentioning with some concern that the = project seemed to be aimed at creating a "FreeSolaris" of sorts; many of = the architectural decisions seemed to be based on the argument that = Solaris was doing it, so FreeBSD should too. That's fine, and there's a = certain amount of comfort in following an arguably decent architectural = standard like Solaris, though I understand what I believed to be Matt's = point about retaining some identity and exploring new paths rather than = just following old paths. In my not so humble opinion, Linux is not an architectural model to be = envied or copied, regardless of how pragmatic it might seem. Sure, = gratuitous differences can be argued against, but there are a lot of = fundamental architectural things that linux succeed at purely by brute = force of will, and nothing more. FreeBSD should be careful to not envy = that model. I think that there's a lot less value in both the long and = short terms in a "FreeLinux" than in a "FreeSolaris", and neither are = all that good in the long term. Having an emulation gives people a lower barrier to entry and some = stepping stones to getting comfortable with FreeBSD. It gives them a = series of achievable goals with costs and benefits at each step that can = be weighed. Aiming at simply evolving the native interfaces to be like = linux simply means that FreeBSD becomes a poor copy of linux with = nothing else under the surface to set it apart or create an attraction. Scott