Hi Rick!
The 3494 uses the library manager (the PC with an customized OS/2, which is
located inside your library control unit frame) to control this. Your AIX
host uses the ATLDD driver to address the library. The library manager
assigns a drive to your mount request and reports this back to your host.
I hope this explains.
Kindest regards,
Eric van Loon
KLM Royal Dutch Airlines