Date: Wed, 6 Nov 1996 21:50:52 +0100 (MET) From: Robert Eckardt <roberte@mep.ruhr-uni-bochum.de> To: grog@lemis.de (Greg Lehey) Cc: roberte@mep.ruhr-uni-bochum.de, questions@FreeBSD.org Subject: Re: Tape drive problems? maybe? Message-ID: <199611062050.VAA01573@ghost.mep.ruhr-uni-bochum.de> In-Reply-To: <199611041127.MAA00750@freebie.lemis.de> from Greg Lehey at "4. Nov. 96 12:26:48"
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> >> 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 <num> 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
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