From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luben Tuikov Subject: Re: SATA Drive Information (vs hdparm -i)? Date: Fri, 23 Sep 2005 10:22:47 -0400 Message-ID: <43340FB7.3080708@adaptec.com> References: <7744a2840509221206254d2109@mail.gmail.com> <43334AFF.8010901@torque.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from magic.adaptec.com ([216.52.22.17]:50818 "EHLO magic.adaptec.com") by vger.kernel.org with ESMTP id S1751016AbVIWOW5 (ORCPT ); Fri, 23 Sep 2005 10:22:57 -0400 In-Reply-To: <43334AFF.8010901@torque.net> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: dougg@torque.net Cc: Richard Bollinger , linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org On 09/22/05 20:23, Douglas Gilbert wrote: > However an improved "sdparm -i" is not what you seem to be > asking for. Most of the above information is derived from > the response to the IDENTIFY [PACKET] DEVICE ATA command. > There seems to be two options for providing this: > 1) libata to implement ioctls like HDIO_GET_IDENTITY > 2) libata to implement SCSI ATA Translation [SAT] > facilities such as: > a) the ATA Information VPD page > b) SCSI ATA pass through commands > c) MODE SELECT SCSI command > > Option 1) is the simplest but it requires that the SAT layer > is on the host computer [as it is in the case of libata]. > Hopefully external USB and Firewire storage enclosures will > be enhanced to support the [draft] SAT standard and in > that case the SAT layer will be in the enclosure. SATA > disks [and S-ATAPI devices] in a SAS fabric may either > tunnel through the SAS fabric [via SAS Tunnelling Protocol > [STP]] or have a SAT layer in the fabric [typically in the > enclosure holding the disks]. There will be no SAT layer in a SAS fabric. STP is just that, a _tunneling_ protocol. Thus, either in Option 1, or Option 2 if you want to present the device to SCSI Core as a SCSI Device you need SAT somewhere below SCSI Core (on the host). In general, lower (hardware) layers want to do the _absolute_ minimum as far as their function is concerned. Thus, for example, you can expect an incomplete USB/IEEE1394 SAT layer on the device. > Only the STP route allows for option 1) . Option 2 as well: you'll just treat the device as SCSI and SAT will emulate as much as possible. Luben