Windows users are probably all too familiar with the Ctrl-Alt-Del key sequence. Although it’s commonly associated with closing unresponsive applications through the task manager -- and, in fact, it was originally meant to remain a developer-only tool to reboot a computer -- it is also used as a way to log into Windows.
David Bradley, the designer of the original IBM PC and responsible for coming up with the key combination, famously poked fun at then Microsoft CEO Bill Gates on stage at the 20th anniversary of the IBM PC in 2001. "I may have invented it, but Bill made it famous," Bradley said. The audience laughed and applauded at the clear reference to Windows’ app instability at the time, and though he softened the jab adding that he was merely referencing the Windows NT secure logon procedure, Gates looked far from amused.
Ten years later, in an interview with Cnet, Bradley said he didn't understand why Gates decided to make Ctrl-Alt-Del a login feature, adding that "I guess it made sense for them." Well, not quite.
Speaking at a Harvard fundraising campaign earlier this week Gates was asked about the decision to use the three-finger sequence as a log in command. Funnily, after explaining they needed a low level way of signaling the OS so malicious software could not fake the login screen during boot and steal passwords, and that wanted a single button “but the guy who did the IBM keyboard design” wouldn't give it to them, he just sort of gives up and admits -- much to the audience’s amusement -- that it was a mistake.
I guess that puts the mystery to rest.
The sequence is required in Windows NT, Windows Server 2003 and Windows Server 2008 to gain access to the logon screen securely. Client versions up to Windows 7 won’t see this screen by default but the secure logon option can still be enabled via the Windows Registry or the Local Security Policy Editor.
You can watch the full interview in the video below. His comments on Ctrl-Alt-Del start at around 16:35, but the talk also touches on a number of topics from Gates’ early days at Microsoft to his work at the Foundation, and the decision to spend all their resources within 20 years after Bill's and Melinda's deaths.