David Bradley (engineer)
David Bradley was one of the twelve engineers who worked on the original IBM PC, developing the computer's ROM BIOS code. He is credited[who?] for implementing the "Control-Alt-Delete" key combination that was used to reboot the computer.
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 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 revealed to the public when developers found it useful, and at the 20th anniversary of the IBM PC, while on a panel with Bill Gates, Bradley said, "I may have invented it (control-alt-delete), but I think Bill made it famous".
Bradley is the author of Assembly Language Programming for the IBM Personal Computer (Simon & Schuster, ISBN 0-13-049171-3, January 1984), also released in French as Assembleur sur IBM PC (Dunod, ISBN 2-225-80695-0), Russian ("Radio" Publishing House, Moscow), and Bulgarian ("Technica" Publishing house, 1989).
Bradley holds seven U.S. patents.
Much of Bradley's career has been at IBM. Bradley began at IBM after receiving a PhD from Purdue in 1975. He worked on the Series/1 system. In 1978 he developed the I/O system for the System/23 Datamaster.
In 1980 Bradley was one of twelve engineers developing the first IBM Personal Computer. Bradley developed the ROM BIOS. That got him promoted to manage the BIOS and diagnostics for the IBM PC XT. In 1983 Bradley formed the Personal Systems Architecture Department. In 1984 he helped manage development of the Personal System/2 Model 30.
In November 1987 Bradley became manager of advanced processor design. His group developed the 486/25 Power Platform and the PS/2 Models 90 and 95. In 1991 he became manager of systems architecture for the Entry Systems Technology group. In 1992 he became the architecture manager for the group that developed a personal computer using the PowerPC RISC microprocessor.
In 1993 he returned to be the manager of architecture in the PC group.
On January 30, 2004, Bradley retired from IBM.
Bradley wrote about the development of the IBM PC, including Control-Alt-Delete, in the August 2011 issue of the IEEE Computer magazine.