​Raspberry Pi stars in UK spy agency's mini supercomputer

Interlinking dozens of the cheap, small electronic brains won't break any computing speed records. But it could help teach people how to program tomorrow's computer systems.

Stephen Shankland principal writer
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Stephen Shankland
2 min read

The GCHQ's Raspberry Pi Bramble cluster has 64 computing nodes and two control nodes.
The GCHQ's Raspberry Pi Bramble cluster has 64 computing nodes and two control nodes. GCHQ

Most people use the $35 Raspberry Pi computer for its intended purpose, as a cheap machine good for education and experimentation. But the UK's Government Communications Headquarters has leveled up by interlinking 66 of the diminutive devices into a single computing cluster.

The spy agency unveiled the GCHQ Raspberry Pi Bramble at the Big Bang Fair for young engineers and scientists -- the target market for the Raspberry Pi project. It consists of eight groups of eight Raspberry Pi machines, all linked over a network and controlled by two central Raspberry Pi machines.

The design is what's known in supercomputing circles as a cluster and, specifically in the Raspberry Pi world, a bramble. Made of the bare-bones Raspberry Pi circuit boards, it's a far cry from the fastest supercomputer today, China's Tianhe-2, which has 3,120,000 processor cores and consumes as much power as 3,400 houses. But fundamentally, the design principles are the same: share a single computing job across many independent nodes.

Thus, although the Bramble itself is an academic curiosity, at a higher level, it's actually quite relevant for computer programmers of the future. Those coders, no longer able to rely on ever-increasing chip speeds for performance improvements, must adjust to the idea that computing jobs can be broken down into simultaneous tasks running in parallel. Those who grasp the idea are more likely to thrive in a world dominated by companies like Google and Facebook that have mastered a computing infrastructure that spans hundreds of thousands of machines.

The GCHQ's Raspberry Pi Bramble cluster is made of eight groups of eight machines called OctaPi.
The GCHQ's Raspberry Pi Bramble cluster is made of eight groups of eight machines called OctaPi. GCHQ

It's neither the first nor the biggest -- several Raspberry Pi clusters have been built, including one 120-node system. But it is notable that it's from the GCHQ -- an agency that has been closely allied with its counterpart in the United States, the NSA, in a years-long digital surveillance effort that's triggered privacy concerns and legal challenges.

The UK agency funds such work to try to keep the pipeline of new employees full. "We fully expect others to beat our record-breaking cluster before too long, but hope that it will inspire young people to get involved in the study of science-based subjects and take advantage of the exciting career opportunities such qualifications can offer," GCHQ said in a statement.

The GCHQ's Bramble is divided into eight boards with eight Pi nodes each -- an "OctaPi." They communicate over gigabit Ethernet links that also supply power. A control system running on the two central Raspberry Pis uses a collection of Web technologies: Node.js, Twitter's Bootstrap and Google's Angular.

GCHQ didn't comment on how much the total system cost or on its performance.