Howdy,

<a bunch of good stuff from Sr Toback regarding media
  and tape drive head wear patterns snipped>

Yep, different media can cause different wear patterns.

I don't have the owner's/user's manuals for our DAT drives
handy, but I guarantee there is no mention of compatibility
problems dealing with different lengths of media.  So being
as how a 7980 manual wasn't deliverd with our spiffy new
drives and there is a media compatiblity problem...........
what pray tell is a poor country boy to do?  Which I guess
is Jim Phillips question which started this thread.

jt