From owner-freebsd-questions@FreeBSD.ORG Wed Aug 10 12:12:42 2005 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0D71316A41F for ; Wed, 10 Aug 2005 12:12:42 +0000 (GMT) (envelope-from NKoch@demig.de) Received: from server.absolute-media.de (server.absolute-media.de [213.239.231.9]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8BC0E43D53 for ; Wed, 10 Aug 2005 12:12:41 +0000 (GMT) (envelope-from NKoch@demig.de) Received: from localhost (unknown [127.0.0.1]) by server.absolute-media.de (Postfix) with ESMTP id 239A78F16E; Wed, 10 Aug 2005 14:12:39 +0200 (CEST) Received: from server.absolute-media.de ([127.0.0.1]) by localhost (server [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 12431-05; Wed, 10 Aug 2005 14:12:34 +0200 (CEST) Received: from firewall.demig (p5083AD71.dip0.t-ipconnect.de [80.131.173.113]) by server.absolute-media.de (Postfix) with ESMTP id 46E628DDD2; Wed, 10 Aug 2005 14:12:34 +0200 (CEST) Received: from ws-ew-3 (ws-ew-3.w2kdemig [192.168.1.72]) by firewall.demig (8.13.4/8.13.4) with SMTP id j7AC65t8019666; Wed, 10 Aug 2005 14:06:05 +0200 (CEST) (envelope-from NKoch@demig.de) From: "Norbert Koch" To: "Bsderss" , Date: Wed, 10 Aug 2005 14:12:06 +0200 Message-ID: <000001c59da4$b9dd1b80$4801a8c0@ws-ew-3.W2KDEMIG> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <20050810091911.16996.qmail@web54404.mail.yahoo.com> X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2120.0 X-Virus-Scanned: by amavisd-new X-Virus-Scanned: by amavisd-new at absolute-media.de Cc: Subject: RE: RTCoreBSD X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Aug 2005 12:12:42 -0000 > > > 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? > > > > > > Thanks > > > Sam > > > > I think it's just that *old* rtlinux concept of > > having a hard real time kernel and running the > > operating system as some kind of an idle task > > above that. As far as I remember FSMLabs earlier > > press information talked about using NetBSD for > > that. > > > Does current version of FreeBSD uses real-time > scheduler at the kernel? If it does, which part of the > code (in /usr/src) contains those code? Depends on what you mean. FreeBSD is no rtos, but has rtprio(1). It allows to have fixed process priorities in contrast to the usual 'varying' unix priorites. But it is still possible for a high priority process to be blocked by a lower priority process entering a system call for a non-deterministic amount of time. This is at least so for 4.X, but may be less true for 6.X whith the kernel becoming more and more preemptable. Norbert