Date: Mon, 20 Jul 2009 06:22:49 +0200 From: Polytropon <freebsd@edvax.de> To: Tim Judd <tajudd@gmail.com> Cc: freebsd-questions@freebsd.org, mahlerrd@yahoo.com Subject: Re: Odd behavior after installing a tape drive Message-ID: <20090720062249.3b8cea82.freebsd@edvax.de> In-Reply-To: <ade45ae90907192043w13889a3dx6fdb7a5b58001c60@mail.gmail.com> References: <195035.41847.qm@web51008.mail.re2.yahoo.com> <ade45ae90907192043w13889a3dx6fdb7a5b58001c60@mail.gmail.com>
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On Sun, 19 Jul 2009 21:43:29 -0600, Tim Judd <tajudd@gmail.com> 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 <unit> 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, ...
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