E-Calc

E-Calc may be the oddest item you will stumble across here, because it is not a game at all — it is an engineering aid. This Dutch DOS program from 1999 does exactly one thing: it works out how thick a cable you need for a DC circuit. You enter the voltage, the power or current, the length of the run and the voltage drop you are willing to accept, and E-Calc recommends a wire cross-section that will carry the load safely.

It sounds trivial, yet it is precisely the kind of calculation people do constantly in the real world: twelve-volt wiring on boats and in caravans, solar panel installations, car batteries, workshop supplies. Anyone can push Ohm's law around on paper, but at low voltages currents climb and losses climb with them, so an undersized cable runs hot while the device at its end is starved. The program simply automates that routine — and the fact that it is entirely in Dutch matters less than you would think, since the quantities and units are international and the forms explain themselves from context.

The date is the interesting part. By 1999 Windows had long ruled the desktop, yet small single-purpose utilities kept being written for DOS: they were tiny, ran on anything including the old box in the corner of the workshop, and could be passed around freely without installers or libraries. E-Calc is a typical specimen of that vanishing culture of one-job programs traded on floppies, bulletin boards and early web archives — a culture soon swallowed whole by web forms.

Nobody will pretend this is an evening's entertainment — it is a calculator. As an exhibit, though, it earns its place, showing what utility software looked like just before the DOS era closed. And if you happen to be wiring up a solar panel, it might even still serve.

You can inspect it on oldgame.cz directly in your browser, no installation required.