The spirit of Larry Walters . . .
. . . lives on!
https://www.wired.com/2009/07/dayintech-0702/
6 publicly visible posts • joined 17 Dec 2014
.. visiting the Prestwick end of NATS in the 1990's. At that point it was running on PDP11s, with unbelievable amounts of life support. When I asked "Why don't you port it to something modern, like a Z80?" I was told that the problem is that the system has to be ratified by the British CAA, the merkin FAA, the french, spanish, german, yadda yadda. Getting anything agreed is practically impossible. They were looking fwd to the opening of the new Atlantic house, but freely admitted it would be newer tech, but not new tech.