From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Kastrup Subject: Re: preempt rt in commercial use Date: Wed, 15 Sep 2010 18:20:40 +0200 Message-ID: <877hinhtbb.fsf@lola.goethe.zz> References: <20100914094411.GB10841@pengutronix.de> <4C8F8500.5070002@theptrgroup.com> <201009141830.03206@zigzag.lvk.cs.msu.su> <4C8F8B79.1010300@theptrgroup.com> <4C8FF52E.1030407@us.ibm.com> <4C907A51.1050305@steinhoff.de> <4C90D392.8040808@us.ibm.com> <87k4mnhv9h.fsf@lola.goethe.zz> <4C90EE26.8060003@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain To: linux-rt-users@vger.kernel.org Return-path: Received: from lo.gmane.org ([80.91.229.12]:60481 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753402Ab0IOQUz (ORCPT ); Wed, 15 Sep 2010 12:20:55 -0400 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1Ovuj5-00011Y-2A for linux-rt-users@vger.kernel.org; Wed, 15 Sep 2010 18:20:51 +0200 Received: from p508edc0b.dip.t-dialin.net ([80.142.220.11]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 15 Sep 2010 18:20:51 +0200 Received: from dak by p508edc0b.dip.t-dialin.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 15 Sep 2010 18:20:51 +0200 Sender: linux-rt-users-owner@vger.kernel.org List-ID: Nivedita Singhvi writes: > David Kastrup wrote: >> >> It does not matter whether one system can run circles around the >> other one as long as any given circle can't be guaranteed to complete >> in a specified amount of time. > > Right -- but the point was, any HW system can fail, too (very, very > low statistically speaking, but still not 0%). So no system is > impervious to all sources of breakage. A hardware failure means that the system is in violation of the system design. A soft realtime failure means that reality is in violation of the system design. You can't shift the blame to another department by claiming that a mistake could have happened there as well. -- David Kastrup