IEEE Spectrum April, 2015 - 45

Moore's Law

50 Years

few decades. Almost universally, it has been more rewarding
for them to sit and wait rather than innovate. In particular,
if it takes two years to conceive and implement changes to a
design that doubles its performance, you and your customers
are better served by doing nothing and upgrading to the latest
available ICs two years down the road. It's been a Sisyphean
exercise for the engineers at many small businesses to try to
race against Moore's Law.
Indeed, the exponential growth of Moore's Law works
against them while it favors large businesses, which have the
resources to work on three or four generations of products
simultaneously. And even for large companies, this is hard.
The race manufacturers are in to keep up with
the pace of Moore's Law
has several pernicious
effects. The most relevant one here is that the
small edge (of perhaps a
few months' time) created
by keeping a design proprietary and forcing the
competition to reverse
engineer your products
constitutes a significant
advantage, one that manufacturers are understandably hesitant to squander.
Their reluctance to give
up even the slightest edge
on the competition helps
explain why they rarely
share schematics, code,
or other technical details
about their products.
Thankfully, Moore's Law is slowing, and the dynamics
I've just described are changing.

Since then, CPU makers have been using multicore technology to boost performance, despite the difficulty of implementing such a strategy. [See "The Trouble With Multicore,"
by David Patterson, IEEE Spectrum, July 2010.] But engineers
didn't have much of a choice: Key physical limits prevented
clock speeds from getting any faster, so the only way to use
the increasing number of transistors Moore's Law made available was to create more cores.
Transistor density continues to increase exponentially, as
Moore predicted, but the rate is decelerating. In 1990, transistor
counts were doubling every 18 months; today, that happens every
24 months or more. Soon, transistor density improvements will
slow to a pace of 36 months
per generation, and eventually they will reach an effective standstill.
When will that be? The
short answer is, nobody
really knows. But one study
suggests that it will stop at
an effective gate length of
about 5 nanometers sometime around 2020 or 2030.
Five nanometers is about
the space between 10 silicon atoms, so even if this
guess is wrong, it can't be
wrong by much.
The implications are profound (at least for the kind
of person who reads this
magazine). Someday in the
foreseeable future, you will
not be able to buy a better
computer next year. The
flash drive you purchase next will cost the same and store the
same number of bits as the one you're replacing. And you'll have
to stop looking forward to your next phone being more powerbefore i say how, though, let me defend my assertion that ful and doing more amazing things than your last one.
Rather than expecting that within a few years of its purMoore's Law is slowing. Lots of analysts and commentators
have warned recently that the era of exponential gains in chase you'll just throw out whatever electronic gizmo you
microelectronics is coming to an end. But I do not really buy, you'll be anticipating keeping it for a good long while.
Under such a regime, you'll probably want to purchase
need to hang my argument on their forecasts. The reduction
in size of electronic components, transistors in particular, things that are more nicely made to begin with. The idea of an
has indisputably brought with it an increase in leakage cur- "heirloom laptop" may sound preposterous today, but somerents and waste heat, which in turn has slowed the steady day we may perceive our computers as cherished and useful
progression in digital clock speeds in recent years. Con- looms to hand down to our children, much as some people
sider, for example, the clock speeds of the various Intel today regard wristwatches or antique furniture.
CPUs at the time of their introduction. After making dramatic gains, those speeds essentially stopped increasing this slowing of Moore's law portends a bright future for
about a decade ago.
many small businesses-and likewise | Co nti n u e d o n pag e 58
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Table of Contents for the Digital Edition of IEEE Spectrum April, 2015