From owner-freebsd-hackers@FreeBSD.ORG Wed Apr 9 16:32:57 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CD9DC37B401 for ; Wed, 9 Apr 2003 16:32:57 -0700 (PDT) Received: from heron.mail.pas.earthlink.net (heron.mail.pas.earthlink.net [207.217.120.189]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2F8F143F85 for ; Wed, 9 Apr 2003 16:32:57 -0700 (PDT) (envelope-from tlambert2@mindspring.com) Received: from pool0163.cvx22-bradley.dialup.earthlink.net ([209.179.198.163] helo=mindspring.com) by heron.mail.pas.earthlink.net with asmtp (SSLv3:RC4-MD5:128) (Exim 3.33 #1) id 193P3d-0004Bz-00; Wed, 09 Apr 2003 16:32:46 -0700 Message-ID: <3E94AD3C.B17D2751@mindspring.com> Date: Wed, 09 Apr 2003 16:31:08 -0700 From: Terry Lambert X-Mailer: Mozilla 4.79 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Harti Brandt References: <20030409114957.GN83126@cicely9.cicely.de> <20030409160038.B658@beagle.fokus.fraunhofer.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-ELNK-Trace: b1a02af9316fbb217a47c185c03b154d40683398e744b8a4cf36e443737f32ee34e000bc8dd2c47ba2d4e88014a4647c350badd9bab72f9c350badd9bab72f9c cc: hackers@freebsd.org cc: ticso@cicely.de Subject: Re: realtime problem X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Apr 2003 23:32:58 -0000 Harti Brandt wrote: > On Wed, 9 Apr 2003, Bernd Walter wrote: > BW>Well it's wishfull to have non failures on my requirements, but if it > BW>does fail once it is detectable and it only costs a small amount of > BW>money - noone will die because of it. > BW>If I would need garantied 100% acuracy, then I would spend the money > BW>into a microcontroller to do the job. > BW>In fact I need it for the programming impulse on writing EPROMs and > BW>GALs. > BW>GALs are the devices which may need a 1ms programming impulse, but I > BW>don't know if there are really devices on the maket which use 1ms. > BW>EPROMS are not very sensible on the programming length. > BW>I really hate that available burners need DOS or Windows. > > So that is really not a classical real-time problem. The above should > work. I still recommoned shoving HZ up by over a factor of 10, and the quantum down by a factor of at least 5 less than the precision required. That will (almost) guaranteed that you are always in a loose ballpark around your 1mS deadline, which should be less than 500uS. You may lose out once in a while, but it shouldn't bee too often (I assume the thing's not going to be exposed to the Internet ;^)). -- Terry