Related: What constitutes "retro"?
Which kind of machines and software do we consider on topic?
Are programmable calculators part of this site? What about electronic typewriters (some of them were actually sophisticated)? Punch card mainframes? Jaquard looms (ducks)? What about IoT appliances? Can they eventually become "retrocomputing" material?
The answer might well be "all of them", but I think it's worthwhile making the choice explicit on meta.