Just in case this ever keeps anyone else from banging their head
against the wall for a few minutes/hours:

Lots of TSM manuals and IBM manuals about using tape libraries with
open systems refer to GC35-0154 as a must-have manual.

It's been superceded by GC27-2130.

I'm sure the rest of you are sharp enough four days a week to figure
that out as soon as you find GC27-2130, but on a Friday, it took me
longer than I expected, thanks in part due to an utter lack of notes
on ibm.com to that effect.

GC27-2130 is on ftp://ftp.software.ibm.com/storage/devdrvr/Doc/ as
IBM_Tape_Driver_IUG.pdf.

For the record,
Nick