From owner-freebsd-current@FreeBSD.ORG Wed Aug 10 11:41:01 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CA38416A420 for ; Wed, 10 Aug 2005 11:41:01 +0000 (GMT) (envelope-from momtchil.momtchev@netasq.com) Received: from smtp.netasq.com (netasq.netasq.com [213.30.137.178]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1525243D60 for ; Wed, 10 Aug 2005 11:40:59 +0000 (GMT) (envelope-from momtchil.momtchev@netasq.com) Received: from [10.2.0.3] (f1000c001440400601.netasq.com [10.0.0.126]) by smtp.netasq.com (Postfix) with ESMTP id 0753243C18; Wed, 10 Aug 2005 13:37:36 +0200 (CEST) From: Momtchil Momtchev Organization: NETASQ To: freebsd-current@freebsd.org, Bsderss Date: Wed, 10 Aug 2005 13:42:14 +0200 User-Agent: KMail/1.8.1 References: <20050810084015.40585.qmail@web54409.mail.yahoo.com> In-Reply-To: <20050810084015.40585.qmail@web54409.mail.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508101342.15211.momtchil.momtchev@netasq.com> Cc: Subject: Re: RTCoreBSD X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Aug 2005 11:41:01 -0000 On Wednesday 10 August 2005 10:40, Bsderss wrote: > Hi, > > I found this real-time OS based on BSD: > http://www.sdcsystems.com/realtime-linux.htm#rtcorebsd > > I m wondering what technology they used to make > FreeBSD as a real-time OS. I thought kqueue/kevent is > a key component? any comment? > No, kqueue/kevent is not realtime, as the whole FreeBSD kernel doesn't support hard real-time scheduling. In order to have hard real-time scheduling you should have a fully preemtible kernel, which schedules and preempts everything (even interrupt handlers). The RTCoreBSD uses a two-kernel approach with a real-time microkernel which runs the FreeBSD kernel as a process, providing a virtual interrupt controller. The real-time processes run directly on the microkernel and can't directly use the FreeBSD kernel services. -- -- Momtchil Momtchev R&D Engineer Netasq - Secure Internet Connectivity http://www.netasq.com Tel : +33 320 619 742 Fax : +33 320 619 639