Subject: Re: scsi tape 'Not Ready to Ready Transition'
To: Andreas Wrede <andreas@planix.com>
From: Jan-Hinrich Fessel <oskar@zippo.unna.ping.de>
List: current-users
Date: 10/21/1997 08:37:30
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In message <26913.877372740@planix.com>you write:
> I get the following scsi check condition on every first access to the tape 
> after a tape change:
> 
> st0(ncr0:4:0):  Check Condition on opcode 0x0
>     SENSE KEY:  Unit Attention
>                 EOM Detected
>      ASC/ASCQ:  Not Ready To Ready Transition (Medium May Have Changed)
> 
> In other words, the sequence 
> 
> $ mt offl
>     <insert new tape and wait for drive to become ready>
> $ mt status
> mt: /dev/nrst0: Input/output error

> st0 at scsibus0 targ 4 lun 0: <EXABYTE, EXB-8500SMBANXH1, 0458> SCSI2 1/sequential removable
> st0: st0(ncr0:4:0): 4.0 MB/s (250 ns, offset 8)

It is the drive, that is set up to report medium changes.  This is correct, as 
I belive, but the driver in NetBSD does not handle this.
I don't have a fix for this problem handy, but I suggest you either 
a) live with it and do mt status after changing tapes before any other action 
or
b) disable the reporting in the drive (which should be possible, at least the 
EXB 8200 had a switch for that) or
c) get a fix for the driver ready or
d) wait til I send-pr a fix or
e) do whatever you like ;-)

c) and d) are not that easy as they look at first shot, because the medium 
change should be visible to software that uses it actively and transparent for 
software knows not how to handle it.  I am not sure if we need another minor 
device node set or if we can get away with ioctl/fcntl style setup or even 
with sysctl and a per drive default.
And I have not looked at how the "others" handle that, so any input on this 
would be nice.

Gruesse
       Oskar

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 					Tragbar ist, was nicht herunterfaellt.
						    oskar@zappa.unna.ping.de
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