@alderson @stevel @argv_minus_one
As was the DEC Type 30 on the PDP-1 etc., and the Type 338/339/340 on PDP-8/9/10. The tubes were 16ADP7, with a mix of slow and fast phospors, magnetically deflected. In normal radar use, deflection coils for a single axis would be spun about the neck of the tube by a motor, but for the IBM and DEC displays, there were deflection coils on two fixed orthogonal axes, similar but not identical to a television.