I though this was a brilliant debug. Stan, our experimentalist extraordinaire, had helped considerably by testing the machine over several days and narrowing the fault to this 4k block of memory and noticing the particular address pattern. I was already busy at the back re-reading the address decoding section of your previous core memory blog post... We all said "we wish Ken was here" as we walked towards the machine room, ready for an arduous session of deciphering the "nearly incomprehensible" ALDs. And there you were! You found the faulty card in maybe 10 minutes, using only the power of logic. Usually we use the power of the oscilloscope, the power of trial and error, and the power of arguing around a cup of coffee a lot more. Your in-depth knowledge and detailed reverse engineering of the core memory system paid of big time. It's an asset to have you around!