After doing a regular CV update, I realised I started coding more than a quarter of a century ago... I then remembered the first command the succeedded on my first PC.

format C:

There was a book that expained how to format a floppy disk (format A:) but it didn't work. At that time I had no idea what floppy is but I knew that C: works, so I thought I'd give it a try...

Oh, was there laughter in the repair shop :)