Date: Tue, 27 Jun 1995 11:35:11 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: jmb@kryten.Atinc.COM (Jonathan M. Bresler) Cc: msmith@atrad.adelaide.edu.au, sheeme@corpcomm.net, questions@FreeBSD.org Subject: Re: FBSD 2.xR: AIC7xxx driver vs. st() driver vs. tape drives Message-ID: <199506270205.LAA17165@genesis.atrad.adelaide.edu.au> In-Reply-To: <Pine.3.89.9506261011.B1110-0100000@kryten.atinc.com> from "Jonathan M. Bresler" at Jun 26, 95 10:48:30 am
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Jonathan M. Bresler stands accused of saying: > > The two errors here are _very_ different. The first is nasty, the > > second is the 'media changed' "error". > > > > > afterward a 'mt -f /dev/rst0 rewind' is enough to kick the > > > drive/driver so i can use it. strange. > > > > No, normal. Admittedly, the driver could be made smarter about it, but > > that would break other things. In reality, it's a flaw in the SCSI > > spec, and has probably been addressed in later versions. > > i dont follow you, could you explain this somewhat more fully. i > am getting up to speed on scsi now...just read a fujitsi product guide > and i NEED to get a copy of the spec. Sure; when you change the tape in a tape drive, it 'tells' the host by returning a bogus error code. Essentially, it returns a Check Condition status, but Request Sense doesn't show an error. (SCSI gurus please correct me if I'm a little off on terminology here). Adding intelligence to the tape driver to deal with this is generally believed to be a Bad Idea. You can get both SCSI and ATA specification documents from ftp://gatekeeper.dec.com/pub/standards/ > Jonathan M. Bresler jmb@kryten.atinc.com | Analysis & Technology, Inc. -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] My car has "demand start" - Terry Lambert [[
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