oh my god, Signalis has literal Aperture Cards in it?
That was NOT on my bingo card of retro media to show up in a scifi game
Here’s an Aperture Card (one of mine). So, they’re a combination of a punch card and microform. They’re basically microfiche that a punch-card sorter/selector can handle.
They were heavily used by the US military, because they’d put entire manuals on these, for every vehicle used by the US and their allies. Then they could quickly pull up info on them by sorting through the punch cards (using sorting machines). It was kind of a searchable database of PDFs long before we had the computer power to do that.
