Have you ever wondered what a security probe of a computer sounded like? I’d guess probably not, because on the face of it that doesn’t make a whole lot of sense. But there was a time when I could very clearly discern the sound of a computer being scanned. It sounded like a small mechanical heart beat: Click-click… click-click… click-click… Prior to 2010, I had a computer under my desk with what at the time were not unheard-of properties: Its storage was based on a stack of spinning metal platters (a now-antiquated device known as a “hard drive”), and it had a publicly routable IPv4 address with an unfiltered connection to the Internet.