I recently experienced a situation where a tape was mounted
and 'pre-occupied' and mount was still pending when I did a q process

Turned out to be a really bad data corruption that needed 17 minutes for
recovery.   I'm talking about 3590s here.  They have some excellant
recovery capabilites.  But we had just experienced a power-spike with
outage and when we came back up this tape had a bad spot on it.

I thought the tape drive had gone south on me!!!
The only way I could verify what I was seeing was by lookingat errpt
(its AIX) and noting the hardware error and time and then matching it to
the adsm log for the same period.   Then I found a tape recovery message.
Sorry can't remember the msg number.

hope this helps   ...
                     joe.f.

Joseph A Faracchio,  Systems Programmer, UC Berkeley