APC_Australia_Issue_442_June_2017

technotes » dawn of the accelerators
Google’s ‘tensor
programming unit’ is
aimed at accelerating
machine learning.
DAWN OF THE
ACCELERATORS
THEY’VE POWERED COMPUTERS SINCE THE MID-1970s, BUT IS THE REIGN OF THE CPU
COMING TO AN END? DARREN YATES INVESTIGATES THE ‘POST-CPU’ TECHNOLOGY
CHANGING HOW WE COMPUTE.
Ever thought about the range
of computing devices in
your home? It could be the
odd desktop PC, a couple
of laptops, a games console or two,
smartphones, tablets, media
players, set-top boxes, smart TVs...
the list goes on. What makes these
devices possible is the vast array
of central processing units (CPUs)
now available, chips designed to
run an operating system and
mountains of software code.
But as the sliding fortunes of the
PC collide with rapidly growing
demand for faster artificial
intelligence/machine learning, plus
the threat of high-tech ‘quantum
computers’ waiting tantalisingly on
the horizon, there’s an alternative
computing technology that major
tech companies are taking seriously.
It’s appearing in everything from
retro-gaming consoles to highdemand
applications, such as search
and machine-learning, and in one
particular form, comes with a feature
that CPUs can’t match — the ability to
create your own chips.
ALPHABET SOUP
Our modern lives are filled with digital
technology, virtually all of it run by
small chips or ‘integrated circuits’ that
perform all manner of functions, from
starting your car to powering your
toothbrush. Those chips can be broadly
grouped into three categories that read
like an alphabet soup.
Application-specific integrated
circuits (ASICs) are chips that usually
just have one job — it can be almost
anything, but each chip does just that
one thing. It means they’re
exceptionally fast at what they do
because the required function is
hard-coded into the chip’s electronic
switches or ‘transistors’. This singlefunction
operation also makes them
very power-efficient because only the
transistors required for the job are
included, ideal for when you’re using
ASICs by the thousands in large
installations or on their own in batterypowered
devices. But the drawback of
ASICs is that, once you’ve made the chip,
it can’t do anything else. Need another
function? You need another chip.
At the other end of the scale are
the traditional microprocessor chips
— the CPUs that power your phone, PC,
tablet, games console and seemingly
everything else. Intel made the first
CPU chip, the 4004, back in 1971.
Since then, CPUs have broadly consisted
of separate fixed-function blocks,
programmable through the software
you load to join those blocks together
into everything from spreadsheets to
games. But CPUs also have drawbacks:
because they’re programmable via
software, CPUs are usually much less
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