From owner-freebsd-questions@FreeBSD.ORG Mon Jul 20 04:22:57 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1B29D1065672 for ; Mon, 20 Jul 2009 04:22:57 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from mx02.qsc.de (mx02.qsc.de [213.148.130.14]) by mx1.freebsd.org (Postfix) with ESMTP id CD3F38FC19 for ; Mon, 20 Jul 2009 04:22:56 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from r55.edvax.de (port-92-195-64-14.dynamic.qsc.de [92.195.64.14]) by mx02.qsc.de (Postfix) with ESMTP id 2FEA424A74; Mon, 20 Jul 2009 06:22:55 +0200 (CEST) Received: from r55.edvax.de (localhost [127.0.0.1]) by r55.edvax.de (8.14.2/8.14.2) with SMTP id n6K4Mn2r002463; Mon, 20 Jul 2009 06:22:49 +0200 (CEST) (envelope-from freebsd@edvax.de) Date: Mon, 20 Jul 2009 06:22:49 +0200 From: Polytropon To: Tim Judd Message-Id: <20090720062249.3b8cea82.freebsd@edvax.de> In-Reply-To: References: <195035.41847.qm@web51008.mail.re2.yahoo.com> Organization: EDVAX X-Mailer: Sylpheed 2.4.7 (GTK+ 2.12.1; i386-portbld-freebsd7.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org, mahlerrd@yahoo.com Subject: Re: Odd behavior after installing a tape drive X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Polytropon List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Jul 2009 04:22:57 -0000 On Sun, 19 Jul 2009 21:43:29 -0600, Tim Judd wrote: > I'm no expert on tape drives either, but I was sure that "losing a > SCSI device" is a bad thing for SCSI -- think of it as an IDE drive. > you don't just go pulling power or data from a running, booted > computer. With SCSI, "hot plug" is usually not that problematic as with "modern" ATA and SATA on the PC. Anyway, using # camcontrol stop before switching off or detaching a SCSI component is often a good idea. > All the devices in a computer are on, stays on, until the system shuts down. SCSI allows you to have "internal devices" outside the computer, connected with a cable. In principle, it doesn't even matter if a hard disk is inside the computer or outside, same for optical disc drives, tape drives, and even scanners. "Hot plug" has always been a nice feature of SCSI, even 10 or more years ago, where you couldn't imagine something similar in the PC world. > The PTY/SCSI subject of your email should be unrelated, but a abruptly > missing device is never a positive outcome for an OS. Think about the > old "removing a mounted USB drive = panic" issue we've dealt with for > years. Or /dev/mem: device disappeared. :-) > I am questioning your reasoning behind turning off a tape drive on a > live system. I would never recommend that. As I said, if you do it "the SCSI way", it's completely unproblematic. -- Polytropon >From Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...