Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 11 Mar 1999 11:20:12 -0500 (EST)
From:      tom@tomqnx.com (Tom Torrance at home)
To:        mjacob@feral.com
Cc:        tom@tomqnx.com, chris@shenton.org, scsi@freebsd.org
Subject:   Re: 3.1-STABLE: nrsa0 T4000 doesn't honor "no rewind"? SCSI errs in  logs
Message-ID:  <m10L8Bw-000I0zC@TomQNX.tomqnx.com>
In-Reply-To: <Pine.LNX.4.04.9903101001010.23447-100000@feral-gw> from Matthew Jacob at "Mar 10, 1999 10:23:42 am"

next in thread | previous in thread | raw e-mail | index | archive | help
Hello, Matt:

I'd like to submit a somewhat more positive suggestion for your
consideration. I don't object to positive action to prevent data
corruption, I just don't like the idea of unilateral action by 
the driver that affects tape positioning.

How about the following?

1) Receive the error.
2) Verify that it is not a harmless device quirk.
3) Map the error back to the application for action.
4) Until the application or the operator does something positive to
   re-establish positioning, greet further attempts to write with a
   media write-protected error. 
5) It might be possible to allow the tape operator a mechanism to
   turn off the condition (the 'ignore' option) in some harmless
   way. Perhaps an 'mt status'?

There might be some actions that would/should be allowable, like
writing tape marks - you would be much better qualified to judge those.

On the face of it, though, this approach might satisfy your concerns
(and mine). The downside is all the queries you might receive from
people puzzled as to why they would suddenly get a media write-
protected error from a tape that they have been happily writing to...
Good explanations/instructions in the error logs would help in 
this regard. Particular care should be taken that only the problem
device/app is affected for systems with multiple tape drives.

Obviously something like this would have to be properly tested with
the most common backup systems to ensure that there is not some
potentially harmful application interaction.

What do you think?

Cheers,
Tom



To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-scsi" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?m10L8Bw-000I0zC>