From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: SCSI vs SATA considerations Date: Sun, 09 May 2004 12:25:37 +1000 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <409D96A1.7000500@torque.net> References: <200405071455.i47EtBB18653@www.watkins-home.com> <409D2C56.7B7BEE7E@danbbs.dk> 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 bunyip.cc.uq.edu.au ([130.102.2.1]:24849 "EHLO bunyip.cc.uq.edu.au") by vger.kernel.org with ESMTP id S264262AbUEIC2H (ORCPT ); Sat, 8 May 2004 22:28:07 -0400 In-Reply-To: <409D2C56.7B7BEE7E@danbbs.dk> List-Id: linux-scsi@vger.kernel.org To: monz@danbbs.dk Cc: Guy , Linux-scsi Mogens Valentin wrote: > Guy wrote: > >>Check the jumpers on the disk. Most have a force SE jumper, that would >>limit you to 40M/s. >>Also, anything else on the SCSI bus? If so, if 1 device is SE the bus >>must be SE, which would limit you to 40M/s. > > > No other devices on the scsi bus. > The SE jumper is not installed. Tried with/without - once had an older > IBM scsi disk where the docs had the definition on one pin reverted :- > I had it jumpered as ID2; making it ID0, for some reason it properly > negotiates as a 160 device, at 80MHz, of cause. > I still get only 34.4 MB/s, though (misspelled the speed in first post). > Tried forcing 80MB/s, disabling domain validation, and forcing > termination on the 29160, no change. > > Been thinking if IBM at some point sold some DDYS's as pure UW 40MB/s > disks, to satisfy the market... > > Out of ideas, except flashing the controller. Latest BIOS should do some > BIOS optimizations and device order stuff, whatever that means. Mogens, Perhaps you could try sg_rbuf in the sg3_utils package (see http://www.torque.net/sg ). sg_rbuf uses the READ BUFFER SCSI command and on most disks (e.g. recent seagate and fujitsu) sources data out of the disk cache quickly. The best figure that I have seen is about 110 MB/sec on a U160 bus when the streaming performance of the disk was about half that figure. IBM transferred their disk business to Hitachi (joint venture?) a few years back. BTW recent press releases from maxtor and fujitsu claim 100 MB/sec streaming performance on the U320 bus for (soon to be released) 15k rpm disks. Doug Gilbert