David Bradley (engineer)

David J. Bradley (b. 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" (a.k.a. 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.

Other Achievements

Bradley is the author of Assembly Language Programming for the IBM Personal Computer (Simon & Schuster, ISBN 0130491713, January 1984), also released in French as Assembleur sur IBM PC (Dunod, ISBN 2225806950).

Bradley holds seven U.S. patents.

Bradley has been adjunct professor of electrical and computer engineering at Florida Atlantic and at North Carolina State universities.

Much of Bradley's career has been at IBM. Bradley began at IBM after receiving a Ph.D. 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 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 the personal computer using the PowerPC RISC microprocessor.

In 1993 he returned to manager of architecture in the PC group.

On January 30, 2004, Bradley retired from IBM.

Quote

"I may have invented control-alt-delete, but Bill Gates made it really famous." — at a gathering at the twentieth anniversary of the IBM PC, whilst sitting next to Bill Gates. [1]

Bibliography

• Thank this guy for 'control-alt-delete' - Gannett Online
  • Same text, with Bradley's picture - The Advertiser, 29 Sep 2003
• The History of IBM - about.com
• 1997 Outstanding Electrical Engineer Awards: David J. Bradley - Purdue University School of Electrical and Computer Engineering
• TechTV | Summer PC, Geraldo Rivera, IBM Anniversary
• Ctrl-Alt-Del inventor makes final reboot - The Register, 29 Jan 2004