From owner-freebsd-questions@FreeBSD.ORG Mon Jul 20 12:53:57 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 11003106564A for ; Mon, 20 Jul 2009 12:53:57 +0000 (UTC) (envelope-from mahlerrd@yahoo.com) Received: from web51007.mail.re2.yahoo.com (web51007.mail.re2.yahoo.com [206.190.38.138]) by mx1.freebsd.org (Postfix) with SMTP id C07C08FC21 for ; Mon, 20 Jul 2009 12:53:56 +0000 (UTC) (envelope-from mahlerrd@yahoo.com) Received: (qmail 57875 invoked by uid 60001); 20 Jul 2009 12:53:55 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1248094435; bh=PXY0+hwJIUrCp521B4RHIw9C8l0NtEqIvuemOo1nwB8=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=aA6VlEYioxR0vptKunaS3zv17bQPmSJuHUnsj7BbXAxE8M5fGELs2oMohjG1/AEB4B6z5lvA/eUDT54TLDBpVbRe5T4uzJ/bQFRGED/qKP6OyR+vQGIOm9df1Chb6NX6PSAwAeS3pXm+rRVUomAAf90KTYT2+zk1KgM57zATkDk= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=0Y4OF8BhA7jcJk7/vDl9RPMsi0B62eCa+LZwmEx4Ry0ZVAPL6M4nSN2h9Ixt1hPNR7kvSgcE3I7HSm8l+3ggKlD/IQkp4Gt8ddbYqmTYcq6Js+czYpZan3zqwS7AVCiMzMBjQWj4B+ehYdasIB0OoNQoHnKVmYof+/xe3q/6ml4=; Message-ID: <829991.56927.qm@web51007.mail.re2.yahoo.com> X-YMail-OSG: RiI_jQQVM1li1WmszxHh3FKC7k2L_YPTNz16zJnanZuDW5Q7._PNJMt1lBHoTPwmC.r6Nug40YVeDBWb.GTz9QoZkfhN_DvVjDWJ4wv9bMXguLy_ZvprixdvEcE.plS9Ftz3BixKbKDxRMQ7cC4e9H.f5BKoARFrHKmyGxJAnoKJ4m0f27pZMLMFd_tLq6T8y8DBG6gM83CEb9S1oDrjgRJIfA1hH0xleUGV2zGIeXB_NB4apWyme3hHCQo1nh2LKRUAtmPqssbfzkqf9H6chZE_xaiDpP_AhcEr93ou60yptETznroV5HkisboYEtHjTXiEaK0sQfcZSXEgxNrSyphDBGI0ehG7 Received: from [74.40.57.42] by web51007.mail.re2.yahoo.com via HTTP; Mon, 20 Jul 2009 05:53:55 PDT X-Mailer: YahooMailClassic/5.4.17 YahooMailWebService/0.7.289.15 Date: Mon, 20 Jul 2009 05:53:55 -0700 (PDT) From: Richard Mahlerwein To: freebsd-questions@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable 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: mahlerrd@yahoo.com List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Jul 2009 12:53:57 -0000 > From: Polytropon =0A> Subject: Re: Odd behavior after i= nstalling a tape drive=0A> To: "Tim Judd" =0A> Cc: mahler= rd@yahoo.com, freebsd-questions@freebsd.org=0A> Date: Monday, July 20, 2009= , 12:22 AM=0A> On Sun, 19 Jul 2009 21:43:29 -0600,=0A> Tim Judd =0A> wrote:=0A> > I'm no expert on tape drives either, but I was sur= e=0A> that "losing a=0A> > SCSI device" is a bad thing for SCSI -- think of= it as=0A> an IDE drive.=0A> > you don't just go pulling power or data from= a=0A> running, booted=0A> > computer.=0A> =0A> With SCSI, "hot plug" is us= ually not that problematic as=0A> with=0A> "modern" ATA and SATA on the PC.= Anyway, using=0A> =0A> =A0=A0=A0 # camcontrol stop =0A> =0A> before = switching off or detaching a SCSI component is often=0A> a=0A> good idea.= =0A> =0A> =0A> =0A> > All the devices in a computer are on, stays on, until= =0A> the system shuts down.=0A> =0A> SCSI allows you to have "internal devi= ces" outside the=0A> computer,=0A> connected with a cable. In principle, it= doesn't even=0A> matter if=0A> a hard disk is inside the computer or outsi= de, same for=0A> optical=0A> disc drives, tape drives, and even scanners. "= Hot plug" has=0A> always=0A> been a nice feature of SCSI, even 10 or more y= ears ago,=0A> where=0A> you couldn't imagine something similar in the PC wo= rld.=0A> =0A> =0A> =0A> > The PTY/SCSI subject of your email should be=0A> = unrelated, but a abruptly=0A> > missing device is never a positive outcome = for an=0A> OS.=A0 Think about the=0A> > old "removing a mounted USB drive = =3D panic" issue we've=0A> dealt with for=0A> > years.=0A> =0A> Or /dev/mem= : device disappeared. :-)=0A> =0A> =0A> =0A> > I am questioning your reason= ing behind turning off a=0A> tape drive on a=0A> > live system.=A0 I would = never recommend that.=0A> =0A> As I said, if you do it "the SCSI way", it's= completely=0A> unproblematic.=0A> =0A> =0A> =0A> =0A> -- =0A> Polytropon= =0A> From Magdeburg, Germany=0A> Happy FreeBSD user since 4.0=0A> Andra moi= ennepe, Mousa, ...=0A> =0A=0AThanks! I'll do that in the future - I was g= etting the idea that since camcontrol *includes* a "stop" command I should = have done that before pulling the power anyway. :)=0A=0AI still don't know= if the two items were related in any way, but I'm not really that worried = about it unless it happens again - or at least more than once in a blue moo= n.=0A=0AI'll have a bit of time this week to test taking it down and back u= p a few times the "correct" way and see if it exhibits any of the same beha= vior. =0A=0AThanks again!=0A=0A-Rich=0A=0A=0A=0A