Thirty years ago and more, computers didn't have monitors. They always output to paper -- remember those huge piles of fan-folded stripey-green paper? They printed out everything, one letter at time, like a typewriter. And the thing about ever-increasing piles of paper, especially when you have a room full of them, is that paper is easy to ignore, especially if (as was often the case) what the computers were supposed to be doing was printing off great piles of statistical data or payslips or whatever to be read later, if ever.
So in case something went wrong, the printers also had little bells on. And there was a special character -- like a letter, or a punctuation mark -- called "alarm". When the printer received this character, instead of hitting an arm into the paper to print a letter, it would hit an arm on its little bell, and a technician could run over and take care of it.
In computer systems of the 21st century, there is still a character called "alarm" that descended from this character. When this character is encountered, instead of drawing anything on the screen, the computer bypasses all your output settings, any sound cards, in fact just about everything you can put into your computer gets totally ignored. Thirty years of design and re-design are thrown out the window. It goes straight to the core.
And your computer goes "beep".
I think that's wonderful.