We need to be explicit, between physical and virtual, when talking about VTL components.
VTL = the actual physical controller
vlib = a virtual library on the VTL (there could be multiple vlibs on a VTL)
plib = the physical library attached to the VTL (there could be multiple plibs attached to a single VTL)
vtape = virtual tape
ptape = physical tape
EEP = entry/exit port... unfortunately this is ambiguous since there are EEPs on both vlib and plib
Shadow pool = a place where vtapes can reside (vtapes in the shadow pool are not in a vlib)
I'll explain the export process, which I think will then make explaining the import process easier, which will explain how the eep works.
A VERY simplified explanation of how the data flows....
Export process:
0. configure vlib with shadow pool
1. data is written to a vtape
2. the vtape is ejected from vlib by backup app
3. vtape data is copied to ptape
4. vtape is removed from vlib and put into shadow pool
Import process:
0. configure vlib with 'Automatically move Tape from EEP to Slot'
1. Daily Tasks -> Virtual Tapes -> Import Virtual Tape from Shadow Pool (this could be done via CLI)
2. From backup app, re-inventory vlib
Please let me know if you want a similar explanation for ptape and plib interaction with the VTL