Doug wrote: << OK, I think I have a candidate for the first computer with blinkenlights. This is from David Richie's The Computer Pioneers: << As he sat in his kitchen, one November evening in 1937, [...] Stibitz went into his workshop, took some relays salvaged from Bell Labs' junk pile, [...] and devised a few circuits. Input consisted of strips of metal cut from coffee cans. Output was a pair of flashlights bulbs that lit up or stayed dark to indicate the results of binary calculations. Stibitz is generally credited with creating one of the first digital computers. I think this date is earlier than both Zuse's Z1 (1938) and Atanasoff's ABC (1939), so I guess blinkenlights were there from the start! Now that is really thorough digging! Good find, thank you. John G. Zabolitzky