Date: Sun, 21 Nov 1999 15:40:04 -0800 (PST) From: "Kenneth D. Merry" <ken@kdm.org> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/15025: chio appears to ignore ACCESS field Message-ID: <199911212340.PAA38406@freefall.freebsd.org>
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The following reply was made to PR bin/15025; it has been noted by GNATS. From: "Kenneth D. Merry" <ken@kdm.org> To: mjacob@feral.com Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: bin/15025: chio appears to ignore ACCESS field Date: Sun, 21 Nov 1999 16:37:59 -0700 (MST) Matthew Jacob wrote... > > > > I believe chio *should* have said: "You can't do this because the source > > > element is not accessible". > > > > So what *did* happen? You only say what you think should have happened. > > It allowed the move to occur. Turns out it was 'okay'. So the move actually worked? There wasn't a SCSI error? Some tape changers have the ability to eject a tape if you ask to move it out of a drive and it isn't already ejected. Perhaps that's what yours did? > > I think it's probably better to do state checking in the driver than in > > chio, since the driver has a more persistent view of things. > > That I'm not convinced of as I believe the only reason scsi_ch should > exist is to mediate device ownership. But maybe chio's notion of things > was wrong somehow. I don't think the driver checks to see whether the source or destination are accessible before trying to do the move. The changer will complain if it doesn't like what you're trying to do. The driver does check to make sure what you're asking for fits the device's claimed capabilities, and does some bounds checking to make sure you aren't asking for elements that don't exist. One reason I see for not putting all the smarts into chio is that you want to be able to easily write another program -- like amanda -- that can use the changer ioctls and have a reasonably decent software interface. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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