Date: Fri, 7 Jun 2002 18:19:20 +0200 From: Bernd Walter <ticso@cicely5.cicely.de> To: Tom Samplonius <tom@sdf.com> Cc: ticso@cicely.de, Joao Pedras <jpedras@webvolution.net>, freebsd-scsi@FreeBSD.ORG Subject: Re: sync cache Message-ID: <20020607161919.GO66505@cicely5.cicely.de> In-Reply-To: <Pine.BSF.4.05.10206070806550.175-100000@misery.sdf.com> References: <20020606110101.GU66505@cicely5.cicely.de> <Pine.BSF.4.05.10206070806550.175-100000@misery.sdf.com>
next in thread | previous in thread | raw e-mail | index | archive | help
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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020607161919.GO66505>