Re: SCSI Tape hangs when no tape loaded (2.5.6x)

From: Kai Makisara (Kai.Makisara@kolumbus.fi)
Date: Sun Feb 16 2003 - 10:25:22 EST


On Sun, 16 Feb 2003, Ruud Linders wrote:

>
>
> On both 2.5.60 and 2.5.61 when there is no tape loaded in my SCSI DAT
> tape drive, access to the drive blocks for exactly 2 minutes
> before timing out and giving an I/O error.
>
> # mt stat
> ....... < 2 minutes later > ...
> /dev/tape: Input/output error
>
Does you mt open the tape device with the O_NONBLOCK option? If not, this
is what is expected. mt-st version >= 0.6 does use this option. I don't
know about other mt's.

The open() behaviour of st was changed at 2.5.3 to conform with SUS
(blocking) and what the other Unices do (timeout). If the device is opened
without O_NONBLOCK, the driver waits for some time (default 2 minutes) for
the device to become ready. If it does not become ready, an error is returned.

        Kai

P.S. I just tested 2.5.61 and in my system 'mt status' without tape in
the drive works as expected (i.e., prints status immediately).
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