David Bradley

David J. Bradley (born 4 January 1949) is one of the twelve engineers who worked on the original IBM PC, developing the computer's ROM BIOS code. Bradley is credited for implementing the "Control-Alt-Delete" (Ctrl-Alt-Del) key combination that was used to reboot the computer. Bradley joined IBM in 1975 after earning his doctorate in electrical engineering from Purdue University with a dissertation on computer architectures. Education Bachelors, Electrical Engineering, University of Dayton (Ohio), 1971. Master of Science, Electrical Engineering, Purdue University, 1972. PhD, Electrical Engineering, Purdue University, 1975. Control-Alt-Delete According to Bradley, Control-Alt-Delete was not intended to be used by end users, originally—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 to avoid potential damage to the power supply and hard drive. Since software developers and technical writers would need to restart a computer many times, this key combination was a big time-saver. David Bradley and Mel Hallerman chose this key combination because it is practically impossible to accidentally press this combination of keys on a standard original IBM PC keyboard. However, the key combination was described in IBM's technical reference documentation and thereby revealed to the general public.