From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Elliott, Robert (Server Storage)" Subject: RE: [PATCH 1/2] Use sdev_scsi2lun for SCSI parallel drivers Date: Fri, 4 Jul 2014 20:14:28 +0000 Message-ID: <94D0CD8314A33A4D9D801C0FE68B402958B86718@G9W0745.americas.hpqcorp.net> References: <1404474875-109997-1-git-send-email-hare@suse.de> <1404474875-109997-2-git-send-email-hare@suse.de> <53B70404.9080303@interlog.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Return-path: Received: from g4t3427.houston.hp.com ([15.201.208.55]:52293 "EHLO g4t3427.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752107AbaGDUSm convert rfc822-to-8bit (ORCPT ); Fri, 4 Jul 2014 16:18:42 -0400 In-Reply-To: <53B70404.9080303@interlog.com> Content-Language: en-US Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "dgilbert@interlog.com" , Hannes Reinecke , James Bottomley Cc: Christoph Hellwig , "linux-scsi@vger.kernel.org" > -----Original Message----- > From: linux-scsi-owner@vger.kernel.org [mailto:linux-scsi- > owner@vger.kernel.org] On Behalf Of Douglas Gilbert > Sent: Friday, 04 July, 2014 2:44 PM > To: Hannes Reinecke; James Bottomley > Cc: Christoph Hellwig; linux-scsi@vger.kernel.org > Subject: Re: [PATCH 1/2] Use sdev_scsi2lun for SCSI parallel drivers > > On 14-07-04 07:54 AM, Hannes Reinecke wrote: > > SCSI-2 defines only up to 256 LUNs with a flat namespace. > > My SCSI-2 draft (revision 10b from August 1989) only has > 3 bit LUNs placed in byte 1 of the command block, in the top > 3 bits. There are also things called LUNTARs and LUNTRNs > at the message level. > > 8 bit LUNs do ring a distant bell, perhaps after SCSI-2? > > Doug Gilbert The hierarchical LUN structures have some limited size LUN subfields: * the peripheral device addressing method includes an 8-bit TARGET OR LUN subfield, which specifies an 8-bit LUN at the current level (if the BUS IDENTIFIER field is 0) * the logical unit addressing method has a 5-bit LUN subfield --- Rob Elliott HP Server Storage