From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [Scst-devel] Fwd: Re: linuxcon 2010... Date: Wed, 25 Aug 2010 18:20:26 -0400 Message-ID: <201008251820.27293.konrad@darnok.org> References: <594039.74663.qm@web111905.mail.gq1.yahoo.com> <4C73DA15.2010207@vlnb.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from andromeda.dapyr.net ([206.212.254.10]:35871 "EHLO andromeda.dapyr.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748Ab0HYWVc (ORCPT ); Wed, 25 Aug 2010 18:21:32 -0400 In-Reply-To: Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Chris Weiss Cc: Vladislav Bolkhovitin , James Bottomley , Mike Christie , linux-scsi@vger.kernel.org, Chetan Loke , linux-kernel@vger.kernel.org, scst-devel On Tuesday 24 August 2010 10:51:04 Chris Weiss wrote: > On Tue, Aug 24, 2010 at 9:41 AM, Vladislav Bolkhovitin wrote: > > James Bottomley, on 08/22/2010 12:43 AM wrote: > >> Interface re-use (or at least ABI compatibility) is the whole point, > >> it's what makes the solution a drop in replacement. > > > > I see now. You want ABI compatibility to keep the "contract" that no > > kernel changes can break applications binary compatibility for unlimited > > time. > > ok now I'm confused, or maybe I'm not understanding ABI correctly, or > maybe you guys are using it in a way that is inconsistent with popular You are thinking of the KABI. That changes per each release except if you buy a vendor product. Red Hat for example keeps an KABI symbol list where they guarantee that those parameters, structures ,etc will never change. John Masters wrote a nice paper about how they solved this: http://dup.et.redhat.com/presentations/DriverUpdateProgramTechnical.pdf I don't have experience with other vendors. In terms of ABI, think ioctl calls and its a parameters. They are suppose to stay the same for long long durations. > convention. As a VMware user, I have experienced fully that the > kernel ABI changes in various places with every release. VMwares > drivers have to be constantly updated to match changes in kernel > function parameters and even what functions are available. > > I've also experienced it with scsi cards, dsl modems, and other 3rd > party drivers. It's the one big downside to developing for the Linux > kernel, the ABI is /always/ changing. > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html