I had an old ISA bus 386/486ish thing with linux on it. I was so excited when I got it to run X and I could connect to my other computer and set the DISPLAY and run programs here or there and have them display on this thing just like my X terminal in the office.

Except -- the network only worked when I moved the mouse! It worked fine without X turned on but running X? No soap.

Turns out the network card and the mouse shared an interrupt. Moved some jumpers or moved some teeny tiny switches and everything "worked".

Old time computers only worked because they were extremely simple or someone put a bunch of effort into configuring it for a specific scenario. Heck, in the old-old days even the memory was persistent (core) so turning the computer off "just stopped the clock".

These days everything has a modest computer and a simple network and speaks a simple protocol to allow everything to establish a local topology "on boot".