From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [linux-iscsi-devel] Re: [PATCH RFC] replace ioctl for sysfs take 2 Date: Thu, 09 Sep 2004 10:40:04 +1000 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <413FA664.6050009@torque.net> References: <20040907210520.0251476C56@isis.visi.com> <413E6F8F.3020008@torque.net> <20040908073843.7dbcddb6.rddunlap@osdl.org> Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from borg.st.net.au ([65.23.158.22]:17134 "EHLO borg.st.net.au") by vger.kernel.org with ESMTP id S269247AbUIIAlE (ORCPT ); Wed, 8 Sep 2004 20:41:04 -0400 In-Reply-To: <20040908073843.7dbcddb6.rddunlap@osdl.org> List-Id: linux-scsi@vger.kernel.org To: "Randy.Dunlap" Cc: sferris@acm.org, James.Bottomley@SteelEye.com, mikenc@us.ibm.com, michaelc@cs.wisc.edu, willy@debian.org, hch@lst.de, surekhap@cisco.com, linux-scsi@vger.kernel.org Randy.Dunlap wrote: > On Wed, 08 Sep 2004 12:33:51 +1000 Douglas Gilbert wrote: > > | Scott M. Ferris wrote: > | > | > > | > Should all drivers that currently use one host for each SCSI initiator > | > device, and a channel for each initiator port on each device, be > | > modified to use a host for each initiator port? > | > > | > Documentation/scsi/scsi_mid_low_api.txt says that a host corresponds > | > to a SCSI initiator device. Could someone change that to say SCSI > | > initiator port instead, since that seems to be the new goal? > | > | Scott, > | Yes, I can change that if we all agree. Randy Dunlap asked me some > | time back to define what was meant by a "linux SCSI host" and that > | was the best I could come up with at the time. > > Sorry to be dense here, but what is an "initiator port" in this context? > Is it a physical connector or something else? A logical connector? > (whatever that means) Probably the best place to start is the diagram at http://www.t10.org under the "Architecture" tab near the top of the left hand pane. The focus of that diagram is the Architectural Model (SAM) of which http://www.t10.org/ftp/t10/drafts/sam3/sam3r13.pdf is the latest available draft. The transports are along the bottom of that diagram and the command sets are along the top. The concepts of initiator, target, port and delivery subsystems are defined (abstractly) in SAM-3. It then falls to the various transports (e.g. FCP, iSCSI and SPI) to put "meat" on these abstractions and add some of their own terms (e.g. "logical connector" from iSCSI). Transports that are not exclusively used by SCSI command sets (e.g. iSCSI uses IP) come with their own architectural models and jargon. SCSI has been around for over 20 years (see wikipedia.org) and for the first 15 years was synonymous with the "SCSI Parallel Interface" (SPI) but that is no longer the case. That change has been very slow getting out to the wider technical community (as reflected by the SCSI entry in wikipedia.org) > | > | A few related matters: > | > | Steven Fairchild dropped a proposal for SAS storage management > > "dropped" as in dropped (oh, as in deleted) or as in "added", "put", > or "placed" ? Seems to be "added"... Sorry, just sloppy usage. Authors put proposals on that site for comment. Doug Gilbert