I don't know if you are still interest in any of this stuff but I have
copies
of the CS/80 protocol. I actually support a system that was development
in the early 80's and is still in use by British Telecom.
We have prototype and are putting together a proposal to use a PC with a
GPIB card to emulate a disk drive using the CS/80 command set.
Let me know if you have any interest in this.
Regards,
Bruce Gosson
Braddan Bridge Consulting
bgosson(a)cyberus.ca