From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261425AbVFAP0Y (ORCPT ); Wed, 1 Jun 2005 11:26:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261435AbVFAPYw (ORCPT ); Wed, 1 Jun 2005 11:24:52 -0400 Received: from opersys.com ([64.40.108.71]:46098 "EHLO www.opersys.com") by vger.kernel.org with ESMTP id S261433AbVFAPXU (ORCPT ); Wed, 1 Jun 2005 11:23:20 -0400 Message-ID: <429DD533.6080407@opersys.com> Date: Wed, 01 Jun 2005 11:33:07 -0400 From: Karim Yaghmour Reply-To: karim@opersys.com Organization: Opersys inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040805 Netscape/7.2 X-Accept-Language: en-us, en, fr, fr-be, fr-ca, fr-fr MIME-Version: 1.0 To: Andrea Arcangeli CC: Esben Nielsen , Ingo Molnar , Paulo Marques , "Paul E. McKenney" , James Bruce , Nick Piggin , "Bill Huey (hui)" , Andi Kleen , Sven-Thorsten Dietrich , dwalker@mvista.com, hch@infradead.org, akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: RT patch acceptance References: <20050601143202.GI5413@g5.random> <20050601150527.GL5413@g5.random> In-Reply-To: <20050601150527.GL5413@g5.random> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea, I've been involved with understanding/fighting this patent for a very long time. I must have read it at least a dozen times. To the best of my understanding as a non-lawyer, I don't see how PREEMPT_RT could fall as being covered by it. Andrea Arcangeli wrote: > The patent text goes like this "providing a software emulator to disable > and enable interrupts from the general purpose operating system; > > marking interrupts as "soft disabled" and not "soft enabled" in response > to requests from the general purpose operating system to disable > interrupts; ". What you are refering to is claim #7. The text does resemble this, but it's in a wider context of all the other statements within that claim, the main part being what I quoted earlier. Now in regards to emulating interrupts in a general purpose OS, then this has been done many times over prior to the patent. Here's one readily available example in the Unix world: http://www.usenix.org/publications/library/proceedings/micro93/stodolsky.html Please drop this one Andrea. Karim -- Author, Speaker, Developer, Consultant Pushing Embedded and Real-Time Linux Systems Beyond the Limits http://www.opersys.com || karim@opersys.com || 1-866-677-4546