Did someone mention dinosaurs?
I still have my original Faber-Castell ENG-II portable. It was lightning fast that old "Ziggy stick" although the processor speed wasn't matched by a decent RAM capacity. It could only store the current operation and there was no cache. This wasn't too much of a disadvantage - you could always do a hard copy data dump at regular intervals. At least it worked anywhere, anytime and had no batteries or power supply to go wrong or die on you at a critical moment. Finally it could be used to draw a decent straight line or even measure things, as long as you were prepared to count in 32nds of an inch - none of that decimal nonsense on the British model of the good old Faber! I can still solve complex trigonometrical functions on it (power calculations generally) faster than most people can type the input data on a keyboard.
Its hard to imagine that until the late seventies, almost all design calculations were done with a slide rule.
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Through difficulties to the cinema