Larry W4CSC wrote:

Your DEC/VAX reminded me of her station keeping system which had a
PDP-8 mini tending 4 sonar pingers shot into the bottom over her work
site. It was tape programmed, as I remembered.

Instant flashback! In the late 70's we used a PDP-8 for submersible
tracking by laying an acoustic transponder array, calibrating its
position in UTM's and then tracking another acoustic transponder mounted
on the vehicle. The runs were recorded in real time on a pen plotter.

The PDP was tape programmed. Remember the nightmare of dropping a roll
on the deck? We used to make corrections and enter new parameters by
using the front panel switches which took hours sometimes. Incredibly
primitive by today's standards but that system replaced a Decca unit,
Omega, a surveyor and hours of post processing.

Rick