Just to be clear: Bill Gates and Microsoft weren't anywhere near inventing this. They bought what was mostly a clone of CP/M and called it PC-DOS/MS-DOS. That's

Just to be clear: Bill Gates and Microsoft weren't anywhere near inventing this. They bought what was mostly a clone of CP/M and called it PC-DOS/MS-DOS. That's where they got the file extension scheme from. Digital Research (the creators of CP/M) also didn't invent this. For more details, see the stackexchange link.