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If you’re a PC user, you’ve probably used it: “Control-Alt-Delete.”
The well-known keystroke combo can get you out of a tight
spot when your machine freezes up, but have you ever stopped
to wonder how this technique actually came to be?
Software engineer David J. Bradley is the man behind this
ubiquitous invention. Born in 1949, Bradley received a B.E.E.
degree in 1971 from the University of Dayton, (Ohio). He went
on to Purdue University in West Lafayette, Indiana, where
he completed an M.S. degree in 1972 and Ph.D. in 1975, both
in electrical engineering. Upon graduation he went to work
for IBM in Boca Raton, Florida, as senior associate engineer.
At IBM, Bradley was assigned to work on advanced technology
for IBM’s Series/1 system. In 1978 he transferred into the
entry-level systems department where he developed the I/O
system for the System 23 Datamaster.
In 1980, Bradley became part of a team of 12 engineers who
came to be known as the “Original 12” responsible for building
the IBM Personal Computer. Specifically, his work was to be
on the PC’s ROM BIOS (Basic Input/Output System) code, which
helped to make the modern PC possible. This is the built-in
program containing a computer’s startup commands and operating
directives. For this he was promoted to senior engineer and
began managing BIOS and diagnostics for IBM’s PC XT.
In 1981, Bradley’s team had been looking for a simple way
that computer users could “reboot” the personal computer without
shutting it off should it freeze or fail unexpectedly. After
a computer was “powered down,” the machine needed a few seconds
to “rest” before “powering up” again to avoid damaging the
hardware. This way, it could reboot itself on its own time,
so to speak.
Intending its use only for programmers and those writing
computer documentation, Bradley wrote some code that allowed
the depression of the keys “Control,” “Alt” and “Delete” all
at the same time to accomplish the restart function. He chose
the key combination, which later came to be known as “the
three-finger salute,” because it would be very difficult to
hit these keys together by accident. The inner workings of
the computer also required that he choose two shift keys to
make it work, and with the “delete” key being located at the
other end of the keyboard, this combo was safe and simple.
Bradley has said it only took him a few minutes to come
up with the idea, but he thought at the time it would only
be used internally, or by engineers. This did occur, as the
technique proved helpful to software developers, technical
writers and engineers who needed to restart their machines
many times, but then Microsoft adopted it for the Windows
operating system, for use when software fails. The technique
is still built into the system today. It helps users power
down correctly and also to handle administrative functions
by calling up the “Task Manager” feature.
Though “Control-Alt-Delete” helped make Bradley famous,
his accomplishments over his 28-year career with IBM are numerous
and varied. In 1983 he formed the Personal Systems Architecture
Department and the following year he began managing the Personal
System 2 Model 30. In 1986 he began working on IBM’s Corporate
Development Staff and a year later became manager of advanced
processor design, developing IBM’s 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, Bradley was named manager of architecture for the
PC group in October 1993 and continued in that position after
moving to North Carolina in 1995. Along the way he also taught
electrical and computer engineering at Florida Atlantic and
North Carolina State universities. He wrote the book “Assembly
Language Programming for the IBM Personal Computer” and holds
seven U.S. patents.
In January, 2004, Bradley retired from IBM as Senior Technical
Staff Member; Manager, PC Architecture. As of this writing,
he continues to consult for the company’s facility in Research
Triangle Park, N.C.