The Magazine of IEEE-Eta Kappa Nu July 2017 - 19

The IEEE Rebooting Computing Initiative

for free online reading), and the March 2017 issue of
Computing in Science and Engineering [4]. RCI also
has an active presence on the web and social media,
and particularly encourages student participation. For
example, the IEEE Rebooting Computing Community is
free to join, and consists of more than 2000 members
who receive monthly emails and newsletters. RCI is
also the sponsor of the Low-Power Image Recognition
Challenge (LPIRC), an annual student-oriented
competition that focuses on optimizing both accuracy
in image recognition and low power consumption in the
same system. For 2017, LPIRC will be held in Hawaii in
July, and participants are now being solicited.
While the technologies being pursued under RCI are
diverse, a set of common themes were identified in
the first RCI Summit in 2013, and are summarized
graphically as the "Three Pillars of Rebooting Computing"
in Fig. 4. These pillars, which connect the devices at
the lowest level (the "engine room") to the algorithms
and architectures at the top levels, consist of security,
energy efficiency, and applications (including humancomputer interfaces). Historically, it was sufficient to
have a universal micro-processor, with these key issues
addressed afterward, but future computer technologies
will need to integrate these in at all levels, to generate
several alternative types of systems optimized for
different applications. The remainder of the article will
focus on the pillar of energy efficiency, and show how
this may be addressed using the different approaches
of superconducting technology and neuromorphic
architectures.

Fig. 4. The three pillars of Rebooting Computing, from the first
Rebooting Computing Summit in 2013.
THE BRIDGE // Issue 2 2017

III. Energy-Efficient Computing
There are two distinct classes of computers: small mobile
computers, and large-scale computing centers. Mobile
computers include smartphones, but also components
of the Internet of Things. The need for reduced power
in mobile computers is obvious; they run on batteries,
and the need for frequent recharging is a major concern.
Large-scale computing centers include internet servers,
centers for cloud computing, and supercomputers.
These are plugged into the electric grid, so the need for
low power is less obvious. But energy efficiency is critical
for these as well, because these computers generate
an enormous amount of heat, and the electrical power
includes not only the direct operating power, but also
the power to run the air conditioning systems to keep
these systems from overheating. In some cases, large
data centers that require 100 MW have been placed in
cold climates, specifically to minimize the cooling power.
Taken collectively, information technology consumes
more than 10% of all electrical power, and this is likely
to increase further.
Consider recent trends in the performance and power
of supercomputers, as shown in Fig 5. A supercomputer
is designed to carry out massively parallel simulations,
and its performance is measured in terms of floatingpoint operations per second (FLOPS). State-of-the-art
supercomputers may have performance approaching
100 petaFLOPS, or 1017 FLOPS. Such a system typically
consists of a large number of identical processors
operating in parallel. For example, one might have 20
million floating-point processors, each running at a
speed of 5 GHz. If the power for each processor if 10
W, the total power dissipated (if they are all operating at
the same time) is 200 MW! Supercomputers also have
a huge footprint, as shown in Fig. 6. Superconducting
computers, discussed below, may provide an alternative.
Such large-scale computing systems are rapidly
approaching technical (Size, Weight, and Power, or SWaP)
and economic limits, and will not be scalable beyond,
or even to achieve, the next milestone, 1 exaFLOPS,
where "exa" is the metric prefix for 1018. Systems of this
magnitude are typically called "Exascale Computing."
Development of exascale computers in the next decade
is a monumental effort that must be planned at the
national level. China, United States, Japan, and Europe
are major players in this area. The US program is being
pursued as part of the National Strategic Computing
Initiative (NSCI), which was announced by the White
House last year.
19

Table of Contents for the Digital Edition of The Magazine of IEEE-Eta Kappa Nu July 2017