Windows 7, Mac OS X, Ubuntu… Can you identify the differences between the main operating systems?

Most computer users are divided into two camps, PC and Mac. Behind these machines, or rather inside them, lies the soul of these two IT mainstays, the Windows and Mac operating systems, each of which regularly borrows ideas from the other to complement its own unique selling points. And if this wasn’t enough, Ubuntu from Linux throws the cat among the pigeons with its revolutionary scope. But do you think you know everything about these operating systems, from what they have in common to what makes them so different?