Date: Tue, 31 Aug 1999 17:24:41 +0200 (CEST) From: Wilko Bulte <wilko@yedi.iaf.nl> To: syssgm@detir.qld.gov.au (Stephen McKay) Cc: freebsd-scsi@FreeBSD.ORG, syssgm@detir.qld.gov.au Subject: Re: SCSI surprise! (was: Softupdates reliability?) Message-ID: <199908311524.RAA53070@yedi.iaf.nl> In-Reply-To: <199908310952.TAA18445@nymph.detir.qld.gov.au> from Stephen McKay at "Aug 31, 1999 7:52:55 pm"
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As Stephen McKay wrote ... > On Monday, 30th August 1999, Wilko Bulte wrote: > >As Stephen McKay wrote ... > > > >> So, apart from being happy at having stable hardware again, I am intensely > >> curious about this. Why is a powered down SCSI device so nasty? For example, > > > >It is normally not so nasty. Did this particular device have the SCSI > >terminator? If so, the terminator needs +5V (terminator power aka TERMPWR) > >to function correctly. Some devices can be setup to take terminator power > >from the bus (generally supplied by the host adapter) or from the device > >they are installed on. > > > >I've run things with power-ed down devices without any ill effects. But > >always with external terminators, so not with the terminator on the device > >itself but on the bus cable. > > Just to be more clear about this: The SCSI cable has an active terminator > on the end, so no devices are terminated. The problem drive is not terminated > and functions just fine when powered up. It is in the middle of the chain. > I've had other powered-down-but-connected SCSI devices without trouble in > the past. Right. That is what I expect of a SCSI device ;-) > I'll check the drive more carefully tonight for "power terminator from BUS" > stuff to see if there is any possible silly stuff there. But I think the > fact is that sometimes it's not safe to just pull the power plug. Maybe there is something really weird about your particular drive. I can only repeat my experience which is different :/ -- | / o / / _ Arnhem, The Netherlands - Powered by FreeBSD - |/|/ / / /( (_) Bulte WWW : http://www.tcja.nl http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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