| |
CISE RESEARCHER: “REVERSIBLE” COMPUTERS MORE ENERGY EFFICIENT, FASTER
GAINESVILLE, Fla. --- As the U.S. Congress continues work on a federal energy bill, a group of
researchers at the Department of Computer and Information Science and Engineering (CISE) at the
University of Florida is to working to make a reality a radical idea for making computers more
energy efficient – as well as smaller and faster.
The goal is to re-engineer the integrated circuits that perform all computing operations to re-use, or
recycle, most of the large amount of wasted energy they currently throw off in the form of heat.
So-called “reversible computing” would not only reduce computer chips’ power consumption, it
also could boost their speed, because these chips are becoming so fast that the heat they
generate limits the speed at which they can operate without overheating and malfunctioning.
The research comes at a time when computers are estimated to consume as much as 10 percent of
electricity in the United States, and chips are rapidly reaching the upper limits of their heat
tolerance, said Michael Frank, an assistant professor at CISE. “The fastest processors available
today dissipate on the order of 100 watts of power in the form of heat,” he said, or about as
much as a large light bulb. “The main reason you can’t run them faster is because they get too
hot. If you could make them produce less heat in the first place, you could end up running them
faster overall, especially if you want to pack a lot of chips together.”
Frank and collaborator Huikai of the ECE department were just awarded a $40K
grant by Semiconductor Research Corporation, a consortium of major
chipmakers to design a resonant MEMS-based power supply for adiabatic
circuits.
Frank, who first worked on reversible computing as a doctoral student at the Massachusetts
Institute of Technology, heads UF’s Reversible & Quantum Computing Research Group. Among other
recent publications and presentations, he presented three papers dealing with topics related to
reversible computing this summer, including “Reversible Computing: Quantum Computing’s Practical
Cousin” at a conference in Stony Brook, N.Y.
Reversible computing, the intellectual seeds of which date back to the early 1960s,
means setting up logic operations – which manipulate the 0s and 1s at the core of digital
computation -- so they can be undone or reversed. The process differs from the current approach,
which performs operations but later discards the result. For example, when a computer “erases”
something, what it does physically is ground one part of a circuit that holds a charge, in
effect converting the charge – and the information it represents -- into heat, Frank said. When
chips perform millions or billions of erasing and other operations in a short time, the total
amount of heat becomes substantial, limiting both the performance of the chip and the number of
chips that can be packed together in a small space, he said.
In fact, unless reversible computing is achieved, computer chips are expected to reach the upper
limit of their performance capabilities within the next three decades, effectively halting the
rapid advances in speed that have driven the information technology revolution, Frank said.
“Reversible computing is absolutely the only possible way to beat this limit,” he said.
Reversible computing seeks to configure integrated circuits in such a way that they can use
their current state to recover previous states – in other words, rather than building up and
tossing away unwanted information, the chips “uncompute” it fluidly, with little power
expenditure or heat generation. Researchers hope to achieve such results by incorporating tiny
oscillators, or spring-like devices, in the circuits. In theory, these oscillators could
recapture most of the energy expended in a calculation and reuse it other calculations. The
concept is somewhat analogous to hybrid cars now on the market that take the energy generated
during braking and recycle it into electricity used to power the car.
“Rather than throwing away all the circuit’s energy constantly, it essentially bounces back
and forth, in a more elastic fashion,” Frank said.
While he was at MIT, Frank worked on a team that built several simple prototypes of reversible
chips. At the Department of Computer and Information Science and Engineering at the University
of Florida, he’s advancing the field through adapting resonators, oscillator-like devices, from
microelectromechanical systems to power computer circuits. Microelectromechanical systems, or
MEMS, are tiny mechanical and electronic devices currently found in cell phones, air bag sensors
and other products. Frank and other researchers he collaborates with at CISE plan to reconfigure
these components, tailoring them to drive reversible logic circuits, he said.
Frank also has been analyzing the extent to which reversible technologies can become more
economical than traditional ones for high-performance computing. One of his most recent
theoretical studies indicated that reversible machines could potentially become thousands of
times faster, more energy efficient, and more cost-effective than other approaches over the
course of the next few decades.
Writer: Aaron Hoover, ahoover@ufl.edu
Source: Michael Frank, 352-392-6888, mpf@cise.ufl.edu
|
| |
|
