> > B.  Because of that, as I said earlier, no tape software ever made,
> > AFAIK, makes such an assumption.
> [...]
> 
> Then you are obviously not as old as me :-(

Might be--cut my teeth on 200bpi, 7-track and rememeber 3-inch-wide
tape. :-)

> Way back, ICL had something called FMS (Filestore Management System,
> IIRC) which did exactly this. It used 'fixed capacity tapes' - which

That's a new one on me (not much ICL in the States), thank you.  I was
excluding file- or block-oriented utilities like Unix cp or dd, or early
tar--things that barf at EOT on the output drive--where you could do
multi-tape output only by guesstimating at an output limit on each tape
and changing media at that point.

We (a vendor) developed elaborate, facetious plans for the "RAT," or
random-access-tapedrive.  2400 feet of tape stretched out over a
railroad track, on which a six-foot tape drive of the day ran on
servos...  too much time on our hands.  I'll quit now, but it has been
fun thinking about sense amps, skew and tracking, 600 feet left on a
2400' reel, chopping off the front of the tape when it wore out, the
fancy trimmers to put a rounded edge on it when autoloaders came out...
They're wheeling me back to the home now.