From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: ioctls, etc. (was Re: [PATCH 1/4] sas: add flag for locally attached PHYs) Date: Sat, 22 Oct 2005 18:19:43 +0100 Message-ID: <20051022171943.GA7546@infradead.org> References: <4359440E.2050702@pobox.com> <43595275.1000308@adaptec.com> <435959BE.5040101@pobox.com> <43595CA6.9010802@adaptec.com> <43596070.3090902@pobox.com> <43596859.3020801@adaptec.com> <43596F16.7000606@pobox.com> <435A1793.1050805@s5r6.in-berlin.de> <20051022105815.GB3027@infradead.org> <1129994910.6286.21.camel@sipan.sipan.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1129994910.6286.21.camel@sipan.sipan.org> Sender: linux-kernel-owner@vger.kernel.org To: Sergey Panov Cc: Christoph Hellwig , Stefan Richter , linux-scsi@vger.kernel.org, Linux Kernel , Jeff Garzik , Luben Tuikov , andrew.patterson@hp.com, Christoph Hellwig , "Moore, Eric Dean" , jejb@steeleye.com, Linus Torvalds List-Id: linux-scsi@vger.kernel.org On Sat, Oct 22, 2005 at 11:28:30AM -0400, Sergey Panov wrote: > It is a mistake to think that you can not do a big rework and keep SCSI > sub-system stable. You just have to make sure the OLD way is supported > for as log as it is needed. No. Rewriting something from scratch is horrible engineering practice. It's impossible to very huge changes, small incremental changes OTOH allow easier planning, easier calculation of the risks and cost and most import better test coverage. There's nothing specific to scsi or linux kernel code about it. It'd suggest you read: http://www.joelonsoftware.com/articles/fog0000000069.html or various similar articles. Full scale rewrites almost never work out.