From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: Lun 0 Date: Mon, 21 Oct 2002 12:18:57 -0400 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20021021161857.GB28914@redhat.com> References: <3DB421F8.438FF804@patni.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3DB421F8.438FF804@patni.com> To: MShetty Cc: linux-scsi , linux-raid List-Id: linux-raid.ids On Mon, Oct 21, 2002 at 09:19:12PM +0530, MShetty wrote: > Hi, > > Thanks a lot for all the replies > > A piece of code I am reading, sends the Inquiry cmd to lun 0 first and then to > the actual lun to be probed. As only SCSI devices have the concept of luns... I > think the 1st probe to lun 0 is to check if it is a SCSI device but... on 2nd > thought the same can be inferred by probing for lun n. No. SCSI devices, if present on a given target, must have something on LUN 0. That item on LUN 0 doesn't have to be online, but it has to exist and respond to the INQUIRY command. LUNs > 0 need not exist. > I have read something which says that some devices may mess up if probed for > luns > 0. Is this true ?? Yes. Absolutely. Lots of CD-ROM drives will hard lock when you try and probe for LUNs > 0. -- Doug Ledford 919-754-3700 x44233 Red Hat, Inc. 1801 Varsity Dr. Raleigh, NC 27606