From owner-freebsd-scsi Sun Feb 22 10:55:51 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA24089 for freebsd-scsi-outgoing; Sun, 22 Feb 1998 10:55:51 -0800 (PST) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from gaia.coppe.ufrj.br (cisigw.coppe.ufrj.br [146.164.5.200]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA24082 for ; Sun, 22 Feb 1998 10:55:49 -0800 (PST) (envelope-from jonny@coppe.ufrj.br) Received: (from jonny@localhost) by gaia.coppe.ufrj.br (8.8.8/8.8.8) id QAA07114; Sun, 22 Feb 1998 16:55:26 -0200 (EDT) (envelope-from jonny) From: Joao Carlos Mendes Luis Message-Id: <199802221855.QAA07114@gaia.coppe.ufrj.br> Subject: Re: very slow scsi performance In-Reply-To: <199802182318.QAA01242@pluto.plutotech.com> from "Justin T. Gibbs" at "Feb 18, 98 04:15:35 pm" To: gibbs@plutotech.com (Justin T. Gibbs) Date: Sun, 22 Feb 1998 16:55:26 -0200 (EDT) Cc: tom@sdf.com, gibbs@plutotech.com, weeteck@eecs.umich.edu, freebsd-scsi@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL32 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org #define quoting(Justin T. Gibbs) // The problems that have been reported against many IBM drives stem from // the fact that the DQUE bit is set on many OEM models. The current SCSI // system does not look at the control mode page to see this, attempts to // perform tagged queuing operation anyway, and fails miserably. The IBM // drives are behaving completely within the bounds of the SCSI spec. CAM // handles this "problem" by honoring the DQUE bit assuming that the user // knows what they are doing. Is this one of these ? ahc0 rev 0 int a irq 12 on pci0:10 ahc0: aic7880 Wide Channel, SCSI Id=7, 16 SCBs (ahc0:0:0): "IBM XP34300W !z 81K1" type 0 fixed SCSI 2 sd0(ahc0:0:0): Direct-Access 4303MB (8813870 512 byte sectors) sd0(ahc0:0:0): with 3907 cyls, 20 heads, and an average 112 sectors/track I had to disable tagged queeing with this disk. One thing I dislike in this drive is that it is an OEM Quantum disk, and my experience with Quantum is not good at all. Jonny -- Joao Carlos Mendes Luis jonny@gta.ufrj.br +55 21 290-4698 jonny@coppe.ufrj.br Universidade Federal do Rio de Janeiro UFRJ/COPPE/CISI PGP fingerprint: 29 C0 50 B9 B6 3E 58 F2 83 5F E3 26 BF 0F EA 67 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message