David J. Bradley - the inventor of "Ctrl-Alt-Delete"

David J. Bradley (born 1949) was one of the twelve engineers who worked on the original IBM PC, developing the computer's ROM BIOS code. He is most famous for inventing the "Control-Alt-Delete" (also known as three-finger salute) key combination that was used to reboot the computer.


Three Finger Salute

Bradley did not intend Control-Alt-Delete to be used by end users — it was meant to be used by people writing programs or documentation, so that they could reboot their computers without powering them down. This was useful since after a computer was powered down, it was necessary to wait a few seconds before powering it up again if one wanted to avoid damaging the hardware. Since software developers and technical writers would need to restart a computer many times, this key combination was a big time-saver. He used this key combination because it is practically impossible to accidentally press this combination of keys on a standard keyboard.

This key combination still exists in the Microsoft Windows operating system. It either gives a list of running programs (in the case of Windows 95 and Windows 98), or gives a list of administative functions, such as to reboot the computer, give a task list, or password protect the computer (in the case of Windows 2000 and Windows XP).

It is used for these functions because only the kernel can respond to this key combination. Other programs are interrupted by it. It is therefore a secure way to assure that the operating system is running, rather than a hostile program that emulates the operating system to record passwords or other sensitive data.