You are correct. The script is reading the optical disks and copying the data to ESS. After this is all done, we will reconnect the ESS back to TSM, re-register all the nodes that were deleted, and load up the 3995 library with scratch and then copy the data from the ESS over to optical disks. Though it is also possible to restore from the ESS at the moment (once the data is copied to it).
Apparently, it is not taking as long as we had thought initially. It is now doing about 3 disks a day so not too bad.
I think the script should work with other media (such as tapes) because we had to give them details such as type of media (i.e optical) and type of interface (i.e SCSI or FC) and library details