Woot! I finally got my HP 7970E (yeah, a year in the making!), HP 88780, and Overland Data OD3201 9-track tapes all working at the same time. One on HP-IB, one on SCSI-1, and one on Parallel Port interface. Only my ever finicky Qualstars got jealous and decided not to play ball. Here is a family video: https://youtu.be/eCBxNhEzIfc The DOS computer is a vintage Dolch PAC 65. Thanks for all here who helped with tips, documentation and software.
Marc
