> I believe the default setting for version 7.6 was 0.  My guess is that 
the 
> default for version 8 is 10.

I think we have a winner! After my bootstrap job ended (at 10:14AM), I see 
that the tape is unloading ... 10 minutes later, at 10:24! So the tape 
unloading seems to be from the idle drive timeout. And if the previous 
default was zero, then previously it wouldn't unload tapes, which is what 
I am used to.

So that's cleared up. Thanks!