

“Work” computers will often have legacy ports because maybe you need it to connect to some old printer.
There are a lot of places still using old-style dot matrix printers or other weird old hardware. Point-of-sale systems made to this day often come with a bunch of serial, or not quite serial, ports.











There’s a Youtube channel called Ben Eater that does a great job of explaining computing from first principles. He built a computer out of discrete components on breadboards. He also has a great series where he wires up a 6502 microprocessor and basically builds a little 8-bit microcomputer around it, again on breadboards, in a way that you’ll get. He sells them as kits, so you can play at home if you want. They’re also just nice educational evening calm time viewing.