Stacked dump tapes

[uno%rand-unix at tp3.UUCP]

We are packaging an 11/730 running 4.1BSD with a TU80 and four RL02s.  I'm
setting up a backup system, and am currently planning to stack backups
(using dump/restor) on a single tape (either 2400 or 3600 foot tapes).  My
preliminary testing has gone well.  I've restored full file systems as well
as individual files (using CNTL-Z under the csh when restor prompts for
volume to mount then repositioning the tape and then restarting restor).

I also considered doing multiple partition dumps to a single tape using
dbuf, mounting the tape as a file system to do individual file restores.
Worked just fine, but the system didn't like anything but 1K blocks.
Still, neat if you should need a small extra file system someday, like to
hear that tape drive buzzing or want to develop an empirical sense of how
much buffering actually occurs during file system I/O.  Everyone should
try it once.

Questions:

1) Does anyone have any caveats or horror stories about using multiple
   partition dumps to multiple files on a single tape?
2) Has anyone worked out a way to extract individual files from mag tape
   dbuf or dd copies of file systems with larger than 1K tape blocks?
3) Has anyone managed to get a TU80 into streaming mode?  We don't seem
   to be able to on our 11/730, and I'd appreciate any ideas.

Please reply directly to me unless you think "...that it should be seen
by over 1000 of the most active UNIX people in the world...".

				Thanx,
				   Somewhat actively,
				      Stan Uno

				      uno at RAND-UNIX  (ARPA)
				      decvax!randvax!uno  (uucp)