From owner-freebsd-scsi Mon Jan 22 19:48:19 2001 Delivered-To: freebsd-scsi@freebsd.org Received: from demai05.mw.mediaone.net (demai05.mw.mediaone.net [24.131.1.56]) by hub.freebsd.org (Postfix) with ESMTP id 5113F37B400 for ; Mon, 22 Jan 2001 19:48:02 -0800 (PST) Received: from ian.batcave.com (nic-131-c233-239.mw.mediaone.net [24.131.233.239]) by demai05.mw.mediaone.net (8.8.7/8.8.7) with SMTP id WAA07846 for ; Mon, 22 Jan 2001 22:48:01 -0500 (EST) From: Ian Cartwright Reply-To: icartwright@mediaone.net To: freebsd-scsi@freebsd.org Subject: SCSI Speed Question Date: Mon, 22 Jan 2001 22:48:01 -0500 X-Mailer: KMail [version 1.1.99] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Message-Id: <01012222480104.00373@ian.batcave.com> Content-Transfer-Encoding: 8bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I have a question about the speed of my SCSI devices, especially under FreeBSD. I currently have an Adaptec 2940U/w Fast/Wide controller with two Compaq Fast/Wide hard disks, and Toshiba SCSI II cdrom and an HP SCSI II DAT Drive. My question is, is this the optimum configuration to support the highest transfer rate for my hard disks? Does the SCSI bus run at the speed of the slowest device on the bus or can I run it in asynchronous mode? If I can run in async mode, how do I tell FreeBSD to do it? I guess that's more than one question... ;-) In case it helps, here's the info camcontrol gave me: >camcontrol inquiry 0:0 pass0: Fixed Direct Access SCSI-2 device pass0: 40.000MB/s transfers (20.000MHz, offset 8, 16bit), Tagged Queueing Enabled >camcontrol inquiry 0:1 pass1: Fixed Direct Access SCSI-2 device pass1: 40.000MB/s transfers (20.000MHz, offset 8, 16bit), Tagged Queueing Enabled >camcontrol inquiry 0:2 pass2: Removable CD-ROM SCSI-2 device pass2: 10.000MB/s transfers (10.000MHz, offset 8) >camcontrol inquiry 0:6 pass3: Removable Sequential Access SCSI-2 device pass3: 10.000MB/s transfers (10.000MHz, offset 15) Cheers Ian Cartwright BTW: I am not subscribed to the FreeBSD SCSI mailing list so please send responses directly to me... Thanks. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message