TheEconomistOctober 5th 2019 711M
ost microprocessors—the chips
that do the grunt work in comput-
ers—are built around designs, known as
instruction-set architectures (isas), which
are owned either by Intel, an American
giant, or by Arm, a Japanese one. Intel’s
isas power desktop computers, servers and
laptops. Arm’s power phones, watches and
other mobile devices. Together, these two
firms dominate the market. Almost every
one of the 5.1bn mobile phones on the plan-
et, for example, relies on an Arm-designed
isa. The past year, however, has seen a
boomlet in chips made using an isacalled
risc-v. If boomlet becomes boom, it may
change the chip industry dramatically, to
the detriment of Arm and Intel, because
unlike the isas from those two firms,
which are proprietary, risc-vis available to
anyone, anywhere, and is free.
An isais a standardised description of
how a chip works at the most basic level,
and instructions for writing software to
run on it. To draw an analogy, a house
might have two floors or three, five bed-
rooms or six, one bathroom or two. That is
up to the architect. An isa, however, is theequivalent of insisting that the same sorts
of electrical sockets and water inlets and
outlets be put in the same places in every
appropriate room, so that an electrician or
a plumber can find them instantly and car-
ry the correct kit to connect to them.
risc-voffers computer architects a way
to standardise their sockets and plumbing
without having to gain permission from
(and pay royalties to) either of the monopo-
lists—for any company or individual may
download it from the internet. It was origi-
nally written by computer scientists at the
University of California, Berkeley, who
wanted an instruction set that they could
use for publishable research. Commercial
producers of isas were reluctant to make
theirs available, so the academics decidedto buckle down and write their own.
The result, risc-v, made its debut in
2014, at the Hot Chips microprocessor con-
ference in California. It is now governed by
a non-profit foundation. Though there are
no formal royalties, the foundation does
solicit donations as pro bono publicoges-
tures from firms that employ risc-varchi-
tecture—for what was once a tool for aca-
demics is now proliferating commercially.
There are three reasons for this prolifer-
ation. The most obvious is that the lack of
royalties means using risc-vis less costly
than employing a commercial isa. If the fi-
nal product is a high-price object like a
smartphone, that may not be a huge con-
sideration. But for cheaper devices it is.
Moreover, as chips are built into a growing
range of products, such as home appli-
ances, city infrastructure and factory
equipment, it makes business sense to
keep them as cheap as possible.
A second, more subtle advantage is that,
unlike chips based on proprietary designs,
those involving risc-vcan be used without
lengthy and expensive contractual negoti-
ations. It can take between six months and
two years to negotiate a licence to use a
chip design involving a commercial isa. In
the world of computing, especially for a
cash-strapped startup, that is an eternity.
The third reason people are shifting to
risc-vis the nature of open source itself.
Since the instruction set is already pub-
lished online, American export controls do
not apply to it. This has made it particularly
popular with Chinese information-tech-Open-source computingYour own RISC
A new blueprint for microprocessors is challenging the industry’s giantsScience & technology
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