Hello Craig,
thanks for your answer. It helps me a lot.
But I still have a few questions.

1. I think the checkin libvolume would take some time if I specify
checklabel=barcode as  indicated in the README. Is it a good idea to
specify  checklabel=no? I'm quite sure that all necessary volumes are in
the silo. How long would the checkin take in this case?

2. Is there any danger that the checkin command causes loss of data which
is on the volume? What happens if a volume with data on it is checked in as
scratch?

3. What is the difference between devtype CARTRIDGE and ECARTRIDGE? I have
STK 4490 and have used the so far as CARTRIDGE without problems. Should I
change the devtypes?

Many thanks in advance for help!
Gerhard