On Wed, 31 May 2017 18:04:23 -0400 Jed Rothwell <jedrothw...@gmail.com> wrote:
> Data General and the early microcomputers had toggle switches and LED > readouts of processor states. I never saw anyone use these controls, or read > them for any purpose. My boss, Milt Meinck, back in the early seventies did! When designing the chips for the first Singer electonic sewing machine. They had a very early Calma graphics system (Serial #5 or so), based on a DG Nova. The needed to queue up a lot of plots overnight. But the system would pause, waiting for the operator to press the "Enter" key to confirm the next plot. They realized that the LED lights would settle to a particular state. So they rigged a set of photodiodes over the lights, and a bit of logic circuitry to recognise that light configuration and activate a solenoid which depressed the "Enter" key. When we bought a Calma system years later, the specification included an "Electronic finger" capability, for queing plots with no operator intervention. -- Alan Fletcher <a...@well.com>
