From owner-freebsd-questions Wed Nov 6 12:51:46 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id MAA24552 for questions-outgoing; Wed, 6 Nov 1996 12:51:46 -0800 (PST) Received: from ghost.mep.ruhr-uni-bochum.de (ghost.mep.ruhr-uni-bochum.de [134.147.6.16]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id MAA24532 for ; Wed, 6 Nov 1996 12:51:25 -0800 (PST) Received: (from roberte@localhost) by ghost.mep.ruhr-uni-bochum.de (8.7.5/8.7.3) id VAA01573; Wed, 6 Nov 1996 21:50:54 +0100 (MET) From: Robert Eckardt Message-Id: <199611062050.VAA01573@ghost.mep.ruhr-uni-bochum.de> Subject: Re: Tape drive problems? maybe? In-Reply-To: <199611041127.MAA00750@freebie.lemis.de> from Greg Lehey at "4. Nov. 96 12:26:48" To: grog@lemis.de (Greg Lehey) Date: Wed, 6 Nov 1996 21:50:52 +0100 (MET) Cc: roberte@mep.ruhr-uni-bochum.de, questions@FreeBSD.org X-Mailer: ELM [version 2.4ME+ PL25 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-questions@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk > >> I am running FreeBSD 2.1.5-RELEASE and have just bought a shiny new > >> Exabyte 8505XLI tape drive. I am attempting to back up several filesystems [...] > > I found with my Wangtek that the tape driver has problems with EOF marks. > > mt -f /dev/nrst0 fsf doesn't work at all (for me) > > -- usually the SCSI bus locks. > > > >> Does anybody know what is going on? > > Robert's on the right track. Streaming tapes, especially helical-scan > versions, aren't very good about positioning on a tape mark, and > *sometimes* you won't find the next file first time: you'll be > positioned somewhere in the tape mark, which on Exabytes are quite > large. Someone once told me that they're the equivalent of a megabyte > or two. Just to add to the confusion: Shouldn't this be OS-independent ? I see this under FreeBSD with 2 Wangteks (500MB, QIC) and a Tandberg (500MB, QIC). However, under ISC 2.2 (which didn't really support these types, but just a generic one) and DOS it works correctly. (ISC also had a generic re-tension command, which I see missing in FreeBSD) Therefore I suspect something being incomplete with the SCSI commands send to the tape, perhaps some argument. Til now I didn't dare to access the tape directly with SCSI commands. May be I should try ... -- however, locking the SCSI-bus is no fun, especially when the system does not recover all files, clearing non-empty inodes instead of reconnecting them in lost+found ... (but I'm digressing) May be someone else has an idea ... Robert -- Robert Eckardt \\ FreeBSD -- solutions for a large universe.(tm) RobertE@MEP.Ruhr-Uni-Bochum.de \\ What do you want to boot tomorrow ?(tm) http://WWW.MEP.Ruhr-Uni-Bochum.de/~roberte For PGP-key finger roberte@gluon.MEP.Ruhr-Uni-Bochum.de