From owner-freebsd-scsi Fri Jun 7 9:19:34 2002 Delivered-To: freebsd-scsi@freebsd.org Received: from srv1.cosmo-project.de (srv1.cosmo-project.de [213.83.6.106]) by hub.freebsd.org (Postfix) with ESMTP id 49E0337B405 for ; Fri, 7 Jun 2002 09:19:29 -0700 (PDT) Received: from cicely5.cicely.de (cicely5.cicely.de [IPv6:3ffe:400:8d0:301:200:92ff:fe9b:20e7]) (authenticated bits=0) by srv1.cosmo-project.de (8.12.3/8.12.3) with ESMTP id g57GJKHc062996 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=OK); Fri, 7 Jun 2002 18:19:22 +0200 (CEST) (envelope-from ticso@cicely5.cicely.de) Received: from cicely5.cicely.de (localhost [IPv6:::1]) by cicely5.cicely.de (8.12.1/8.12.1) with ESMTP id g57GJLSA091506 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Fri, 7 Jun 2002 18:19:21 +0200 (CEST)?g (envelope-from ticso@cicely5.cicely.de) Received: (from ticso@localhost) by cicely5.cicely.de (8.12.1/8.12.1/Submit) id g57GJLYg091505; Fri, 7 Jun 2002 18:19:21 +0200 (CEST)?g (envelope-from ticso) Date: Fri, 7 Jun 2002 18:19:20 +0200 From: Bernd Walter To: Tom Samplonius Cc: ticso@cicely.de, Joao Pedras , freebsd-scsi@FreeBSD.ORG Subject: Re: sync cache Message-ID: <20020607161919.GO66505@cicely5.cicely.de> Reply-To: ticso@cicely.de References: <20020606110101.GU66505@cicely5.cicely.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.26i X-Operating-System: FreeBSD cicely5.cicely.de 5.0-CURRENT i386 Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Fri, Jun 07, 2002 at 08:08:45AM -0700, Tom Samplonius wrote: > > On Thu, 6 Jun 2002, Bernd Walter wrote: > > > Even if they do not need the command they should have implemented > > it as a nop. > > I don't think that is a good idea for a device to lie about what it > supports. The illegal command response is an appropriate response for an > unimplemented command, so OS knows that the command did not work. FreeBSD > simply logs it to the console, and it is harmless. If the device has nvram based cache it's completely legal to implement sync cache as a nop, as there realy is nothing to do. In short: it does not lie when doing it. And the OS/User knows it's save to power off. In the current situation noone really knows if there is unsave data. It *does* harm if I don't know when I can savely power down. > BTW, most SCSI-SCSI RAID boxes don't implement the cache flush command. Many RAID boxes have questionable command support. But that doesn't mean it's a good choice after all. They havn't thought about that simple command, which realy gives a bad taste. How could I beleave they have thought about the real critical commands? -- B.Walter COSMO-Project http://www.cosmo-project.de ticso@cicely.de Usergroup info@cosmo-project.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message