Some possible suggestions: Serial line- likely this is a Burroughs Multidrop line - RS485 using a polled protocol. Should be compatible with TD830/TD850/MT983 Burroughs terminals etc. Disk drive control was done by the CPUs - most of the drives were not terribly smart. Best bet is bitsavers as you've already suggested. I've never used a B80 myself, - but am an expert on B1900 stuff. Steve Wilson