Recommendations for automatic tape switching

IBM® recommends the following when setting up automatic tape switching:

For ease of tape device management, IBM recommends that you use the same device number on all systems to represent an automatically switchable device. If an automatically switchable device is a 3480 or a 3490 without the ‘Read Configuration Data Capable’ function, you must use the same device number.
To support automatic tape switching, you also need to update the GRSRNLxx member of parmlib by adding the following system inclusion RNL:
```
RNLDEF RNL(INCL) TYPE(GENERIC) QNAME(SYSZVOLS)
```
This specification prevents a system from holding a tape device while it waits for a mount of a volume that is in use by another system in the sysplex.