During a talk at Harvard, Gates said that there was an option to make a single button for such a command, but the IBM keyboard designer didn’t want to give Microsoft a single button.

“You want to have something you do with the keyboard that is signaling to a very low-level of the software – actually hard-coded in the hardware – that it really is bringing in the operating system you expect, instead of just a funny piece of software that puts up a screen that looks like a log-in screen, and then it listens to your password and then it’s able to do that,” Mr. Gates said. “It was a mistake.”

David Bradley, a designer of the original IBM PC, invented ‘Control-Alt-Delete.’

“I may have invented it, but Bill made it famous,” Mr. Bradley said.

The command also effectively restarts the computer but Mr. Bradley said “Why they used it for the log-in also, I don’t know.”

This article originally appeared on News.com.au.