8mm tape media woes

[Yates, John H.]

Argh!! I ordered 10 Sony 8mm tapes from INMAC, $13 apiece. Catalog
misprint I was told, $33 is the real price. They honored the lower
price for the 10, but had only 5 in stock, backordered the second 5.
Ok, I told them, but I won't buy any more 8mm from INMAC. Ok, they said.

The first 5 to come in were: Sony 8mm data cartridge QG-112M.
The next  5 to come in were: Sony Video 8 P6-120MP (metal particle tape).

When doing backups, I tend to get roughly 295 recoverable errors on some
of the tapes of each variety, upon which the system then assumes the end of
volume (just gives up?), and asks for another tape. Argh! Not good for an
overnight script. The data DOES all fit on one GOOD tape.

Questions: 
           Are the two varieties above of high enough quality?
           What is the best tape to use? 
           Should I suspect a hardware problem?
           Should I suspect dirty heads? (this drive is almost brand new!)
             (and how should they be cleaned? I know VCR fanatics on both
              sides of using head cleaner tapes).

Thanks, John
yates at c.chem.upenn.edu

P.S. If anyone is interested, here is the gist of the bru backup file that I
I eventually decided upon. (at least this all made sense once I gave up
on the Backup script). It avoids /tmp, and /scr (a whole 1.2 GB disk on
our machine), and crossing mounted file system boundaries, i.e. gets all
the necessary and none of the unnecessary data.

bru8mm :
#
echo "Starting bru 8mm Backup"
date
df
ps -el
#
mt -t /dev/rmt/tps0d6nr retension
mt -t /dev/rmt/tps0d6nr rewind
#
echo "bru Backup /"
bru -cvmRf /dev/rmt/tps0d6nr /
#
echo "bru Backup /usr"
bru -cvmRf /dev/rmt/tps0d6nr /usr
#
echo "bru Backup /u0"
bru -cvmRf /dev/rmt/tps0d6nr /u0
#
echo "bru Backup /u1"
bru -cvmRf /dev/rmt/tps0d6nr /u1
#
#  (etc. through /u7)
#
echo "Rewind tape."
mt -t /dev/rmt/tps0d6nr rewind
#
echo "List 1st bru backup set (/)"
bru -tvf /dev/rmt/tps0d6nr
#
echo "List 2nd bru backup set (/usr)"
bru -tvf /dev/rmt/tps0d6nr
#
echo "List 3rd bru backup set (/u0)"
bru -tvf /dev/rmt/tps0d6nr
#
echo "List 4th bru backup set (/u1)"
bru -tvf /dev/rmt/tps0d6nr
#
#  (etc. through /u7)
#
mt -t /dev/rmt/tps0d6nr rewind
#
df
ps -el
date
echo "Done."