I remember one time we got a new IBM 3090 mainframe, back in the 80s. About three weeks after it was installed, one evening the night shift operators were surprised by a knock at the door of the ops center; it was an IBM technician who had been tasked with replacing some defective parts. When the operators looked at each other, and asked the technician who had called him, because they had no reports of anything being bad, he said that our computer had let the computer in the local IBM repair center know that some boards were not responding properly, and had been shut down pending a replacement order filed by our computer automatically.
