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Symposium gathers computing greats to decide whether to go clockless
Is time on their side?
By Tony Fitzpatrick
March 3, 2004 — Computing royalty, including Ivan Sutherland, the
father of computer graphics, and Wesley A. Clark, the designer of the
world's first personal computer, will gather at a computing symposium
Friday, March 26th, 2004, from 1:00-5:30 p.m. at Washington University
in St. Louis's Whitaker Hall Auditorium.
computer chips are getting smaller all the while coordinating the power
of billions of transistors. To meet design and cost challenges,
industry and government are considering clockless computing.|
part of the University's 150th anniversary of its founding,
participants will honor time by contemplating how computing can evade
time as the industry prepares to go clockless.
Department of Computer Science and Engineering at Washington University
will present "Clockless Computing: Coordinating Billions of
Transistors," to honor both the University's sesquicentennial and the
30th anniversary of the completion of the seminal project on
Macromodule Computer Design; work that anticipated current endeavors to
go clockless, or asynchronous.
sort of computing marks an important change from present systems, which
are based on a regularly ticking clock, said symposium organizer Jerome
R. Cox, Sc.D., senior professor in computer science and engineering.
"Clocked technology is inadequate to deal with very large integrated
circuits and systems of the future will certainly have clockless
technology or a blend of clocked and clockless types," Cox said.
key reason that clockless computing is essential to computing's future
is that engineers now are placing literally billions of transistors on
computer chips that are roughly the same size as those that contained
thousands of transistors decades ago.
comprehend clockless computing, consider the analogy of a system of
traffic lights programmed to go green on a regular, clocked schedule.
This would entail many hundreds of lights in synch, say in Manhattan.
Imagine, now, another system of billions of lights (similar to billions
of transistors), some of them far apart, scattered all over the world.
There is no reason to have them all synchronized.
most computer chips today, everything marches to the beat of the same
drummer," Cox explained. "The cost in design time, chip power and
circuit area devoted to clock distribution gets larger and larger as
the number of transistors gets larger. Another way must be found
instead of lockstep throughout billions of transistors."
expect that the symposium will assess the early macromodular work in
the much broader and more difficult context of today's clockless-system
developments," said Clark, a Washington University faculty member from
1964-72 and since then a full-time consultant. "The taming of unplanned
events in enormous 'state-transition spaces' still remains the key
challenge in clockless system design."
designers today are developing chips with diverse clocked domains,
breaking tasks up into multiple domains. Clockless takes that concept a
step farther. Consider the traffic light example again: Imagine sensors
for traffic lights that change the colors according to local
conditions, enabling freedom from the central clock. A clocked system
must wait until the tardiest signal in the whole bunch makes its
transition; a clockless system allows for signals to switch without
unnecessary waiting for others.
computing provides numerous advantages. It facilitates easier power
supply design, reduces noise that a clocked system creates and allows
parts of a system to become idle, reducing power requirements.
"Theoretically, it can lead to faster systems, and we're on the
threshold of being able to realize that theoretical goal," Cox said.
is great interest in clockless computing from both industry and the
Department of Defense perspectives," said Robert Reuss, program manager
with the Defense Advanced Research Projects Agency. "The appeals are
lower operating power, faster performance and reduced electromagnetic
interference on the chips. A challenge is the complexity of designing
very large chips that are approaching one billion transistors.
Clockless logic has the potential to impact these issues. From the
Department of Defense perspective, we are all the more interested
because we do not have the resources to devote to a thorough and long
chip design cycle. So, the DOD is interested in how clockless logic
might help us in regards to economy of scale."
1962 future Washington University computer science engineers Clark and
the late Charles Molnar and others in MIT's Lincoln Laboratory Group
designed the Laboratory Instrument Computer (LINC). With its digital
logic and stored programs, the LINC has been recognized by the IEEE
Computer Society as the world's first interactive personal computer. In
1964, Cox founded the Biomedical Computer Laboratory at the Washington
University School of Medicine. The same year a team of engineers headed
by Clark and Molnar formed the Computer Systems Laboratory at
Washington University. Together, Biomedical Computer Laboratory and
Computer Systems Laboratory engineers brought about profound changes in
the nature of laboratory and clinical computing worldwide.
pioneer Ivan Sutherland, vice president and fellow of Sun Microsystems,
will provide the keynote talk on asynchronous computing research at Sun
Labs. This research has potential for near and medium-term integration
into Sun products. He described the macromodular project at Washington
University as the "design of an entirely asynchronous set of modules
from which one could assemble a complex computing system. Designed from
the mid-1960s into the early 1970s, it is the largest focused
asynchronous research project ever done. Charles E. Molnar and Wesley
Clark, co-directors along with William Papian, of the Computer Systems
Laboratory, conducted the work at Washington University."
1988 Sutherland received the A. M. Turing award, the highest award of
the prestigious Association for Computing Machinery. His acceptance
talk was titled "Micropipelines," in which he described how computer
system designers are constrained by the clocked-logic framework. The
time required to design systems grows annually, but Sutherland's vision
sees micropipelines and clockless computing removing the barriers to
the design of ever larger and more capable systems.
pioneers in clockless computing will also speak at the symposium,
providing a glimpse of future trends in computer engineering. They are:
a principal of Clark, Rockoff and Associates. Clark, along with the
late Charles E. Molnar, directed Washington University's asynchronous
computing research project.
co-founder and vice president of product development of Fulcrum
Microsystems, which has developed the industry's first high-performance
clockless crossbar switch.
professor and associate director of the computer science department at
the University of Utah; Davis has an interest in advanced computer
the ICL Professor of Computer Engineering in the Department of Computer
Science at the University of Manchester (England). Furber's research
focuses on asynchronous logic design.
associate professor of computer science and electrical engineering at
Columbia University. Nowick's research interest is in computer-aided
design of low-power and high-performance asynchronous digital circuits.
The symposium is open to the public and those interested in trends in microelectronic systems are encouraged to attend.