On Wed, 7 Aug 2019, Michael Thompson wrote:
can be connected to both 7-track and 9-track drives. The TU20 drive on the PDP-9 at the RICM is a 7-track drive. The only difference between the 7-track and 9-track versions of the TU20 is the tape head. All of the tape drive electronics is the same for both versions.
The same is true for the HP 7970B tape drives, I even have a 9-track 7970B that can be switched between 200, 556 and 800 bpi. I only need a 7-track head...
Christian
