CTBill wrote:
My client is telling me that I'm nuts.
But ca. 1988, I recall working on an already ancient 3270 terminal that would make a "whunking" sound/feel from the keyboard if I tried to input into a protected field (or invalid screen area), as though a solenoid were being actuated
That's called a "bonk". Kind of the computer's way of saying: "no you can't do that."
In JCL it's called something like "null character echo" where a null character is echoed from the computer. There was a DIP switch in the terminal to disable the bonk.
It's been decades since I messed with IBM mainframes.