From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: Task Sets in SCSI and Linux Date: Wed, 08 May 2002 11:34:40 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <200205081634.g48GYe304381@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: (from root@localhost) by pogo.mtv1.steeleye.com (8.9.3/8.9.3) id JAA05661 for ; Wed, 8 May 2002 09:34:45 -0700 In-Reply-To: Message from Michael Heinz of "Wed, 08 May 2002 10:54:48 EDT." <8B024BD9-6293-11D6-B607-0003934B22FE@infiniconsys.com> List-Id: linux-scsi@vger.kernel.org To: Michael Heinz Cc: linux-scsi@vger.kernel.org mheinz@infiniconsys.com said: > From perusing the source code it appears to me that the Linux SCSI > layers do not take advantage of SCSI task sets. Is that correct? Could you elaborate on what you mean by "task set"? SCSI 3 defines a task simply as "work to be performed by the logical unit in the form of a command or a group of linked commands". This basically means the I_T_L or I_T_L_Q nexus of scsi2, however scsi3 expands this for multi-ported devices. "task set" usually just means the outstanding tasks on a given logical unit, and as such it's really a target concept although the initiator must know how to track outstanding tasks correctly. If by "take advantage of SCSI task sets" you mean use tagged tasks to get multiple outstanding tasks on a logical unit, the answer is yes but it depends on the low level driver implementation. James Bottomley