The Agricultural Age preceded the Industrial Age.
This was followed by the Technological Age, which dawned circa 1960, with the arrival of a somewhat bulky personage named Anita.
Working in the design office, all calculations were conducted on a slide rule or by long-hand calculation, where precision was required for interference fits and so on. The section leader had a wondrous calculator which resembled a pepper mill. This involved the setting of numerous sliding studs around its circular body, before furiously winding a handle on the end. The biggest problem was keeping count of these rotations. Monotony could be avoided by a naive apprentice asking an innocent question at an optimum moment.
Then Anita arrived. Closely chaperoned during the day by the section leader, Anita was ceremonially locked in a cupboard every evening and weekends.
Anita was the name of the first electronic calculator, which was the size of a typewriter. It resembled the comptometers used by an army of girls in the costing department; but those were mechanical in operation. <Sigh - no, not the girls>
Purchased for £360, Anita today would represent an investment of over £6,000; and was accordingly given a high security rating and its own asset account -"electronics".
Values and operands were entered by pressing keys, and the answer appeared in a string of windows along the top of the machine. These contained complex filaments which on heating could display a number. Numbers did not appear instantaneously, but followed several seconds of orange-lit flickering, which added to the mystique.
Anita was used with some apprehension, since data entry was totally silent. No mechanical clicks to register receipt of input, and many calculations were repeated to reassure the operator that the calculation had been correctly entered. A casual but caring enquiry from a bystander ("Are you sure about that?") could produce neurosis.