An unsung heroine of the 21st century

Sophie Wilson

Sophie Wilson, inventor of the ARM processor

Not every technological genius has the profile of Apple's Steve Jobs or Tim Berners-Lee, the inventor of the World Wide Web. But that doesn't make their contributions any less profound. Sophie Wilson is a case in point.
 
There is little doubt that Wilson's groundbreaking work has given her a rightful place among the seminal architects of the modern computer-driven world.


ARM processor In a commercial career spanning 35 years that has generated 59 patents, her credits include the development of some of the world's first commercially successful personal computers and the creation of the original ARM computer processor, whose descendants are now found inside most of the world's mobile computers and smartphones.

Not one to rest on her laurels, Wilson followed up this achievement with the FirePath processor, which powers broadband Internet access equipment. The company she and others founded to develop the FirePath processor was sold a mere two years after its launch for a staggering $594 million.

From cow feeders to slot machines

Sophie Wilson's rise to prominence as one of the most influential women in the history of computing has been anything but conventional. Her first commercial product was an automated cow feeder she developed during a summer holiday in 1979 while studying mathematics and computer science at Cambridge University.

What was so special about this cow feeder? It was constructed around the MOS 6502 processor, a new low-cost microchip built by US manufacturer MOS Technology Inc. The processor was ushering in the dawn of affordable personal computing in the late 1970s, and that would soon propel Wilson to her breakthrough creation immediately after graduating from university.

“In the actual business environment of IT and hardware, patents are decisive to ensure your long-term success.”

Solutions? No problem

Even before she completed her studies, Wilson was presented with an interesting challenge, which would not only allow her to demonstrate her versatility but also introduce her to the man that shaped her early career - Hermann Hauser. Hauser was a 28-year old Cambridge physics graduate who had set up a company called Cambridge Processor Unit.

The company's first contract was for a slot machine manufacturer facing a bizarre-yet-serious technical problem: A new type of electric cigarette lighter was triggering electronic gambling machines to pay out money automatically.

Wilson was tasked with finding a solution, which she did - brilliantly. Her approach was to detect the electric charge produced by the lighter and prevent the unprompted release of winnings by building a wideband radio receiver into the machine's electronics.

Hauser responded swiftly and decisively. He signed Wilson up as lead designer as soon as she graduated and set her up for the challenge of a lifetime: becoming a pioneer in the development of affordable personal computers. 

From small Acorns...

Relaunching his business as Acorn Computers in Cambridge in March 1979, Hauser used Wilson as his secret weapon in developing an affordable personal computer.

Throughout the development process, Wilson took charge of the project. She created the operating system (BBC Basic), designed the hardware, and managed all the people and documentation required to ensure success.

The results were staggering, and by the end of the product's lifecycle in 1989, the company had sold more than 1 million units, compared with a sales target of only 12,000 at inception.

But this was just the precursor to Wilson's crowning achievement.

Wilson’s first commercial product was an automated cow feeder. Hardly the most glamorous start to a computing career.

A new kind of ARM

ARM processor The success of the BBC Micro prompted Hauser to seek in-depth knowledge about chip design in order to choose the right processor to power the machine's successor. Wilson and Furber were tasked with investigating an idea developed by IBM called Reduced Instruction Set Computing (RISC).
This was the moment when Wilson's true genius revealed itself. According to Hauser, while IBM had struggled for months using massive mainframe computing resources to simulate the instruction sets for their RISC processor, Wilson was able to perform the simulations in her own mind. Not only that, she was able to communicate the idea to Furber clearly enough so he could put it into a production-suitable format. Within 18 months, Acorn Computers' first Advanced RISC Machine (ARM) chip was ready for commercial use.

Incidentally, one of the chip's key attributes - low power consumption - had not been one of the project's main objectives and was only discovered by accident.

During the testing phase, a fault prevented current from passing to the computing motherboard and ultimately to the chip, but the chip was still working. It was actually being powered by electricity leaking out of the rest of the circuitry - less than a tenth of a watt.

Thanks to its outstanding efficiency, the descendants of this processor now run many of today's mobile computing devices.

Blazing the FirePath trail

After the dissolution of Acorn Computers in the mid-to-late 1990s, Wilson continued her work in processor design, co-founding Element 14 to create the FirePath processor that now powers today's broadband Digital Subscriber Line (DSL) infrastructure. In 2001, Element 14 was sold to networking equipment manufacturer Broadcom for $594 million.

Wilson says the power of Element 14's portfolio of patents, many of which she developed, helped secure the high price tag.

"In the actual business environment of IT and hardware, patents are decisive to ensure your long-term success. You have to be aware of the chances and understand to invest time and resources to establish and update your patent portfolio," Wilson said.

Today, Wilson continues to work as chief DSL at Broadcom. She plays a leading role in the development of the FirePath instruction set, helping to develop micro-architecture implementations and broaden its use in other non-DSL systems.

Wilson's contributions to the business and the wider world of computing were recognised through an appointment as a Broadcom Distinguished Engineer and as a 2012 Fellow of the Computer History Museum in Silicon Valley.

In 2011, ARM processors powered 95% of all smartphones, 10% of portable computers and 40% of digital TVs and set-top boxes.

Sill going strong

Undoubtedly, Wilson's greatest legacy is her work on the original ARM processor. In 2011, ARM processors powered 95% of all smartphones, 10% of portable computers and 40% of digital TVs and set-top boxes, as well as many printers and other devices.

One of the several spin-offs from Acorn, ARM Holdings, is now the leading specialist for ARM processors and licenses this technology to major computer manufacturers. In 2012, ARM Holdings had annual revenues of £577 million. Licensing revenues and royalties from associated ARM projects made up the bulk of these sales.

Approximately 5 billion ARM chips are sold every year, and this figure is likely to increase significantly as Microsoft's new Windows 8 operating system gains popularity.
In fact, market research firm IHS predicts that, by 2015, 23% of all PCs in the world will use ARM processors.

Overall, Sophie Wilson's inventions have generated revenues of over $30 billion - and counting - and their efficient processing power and low power consumption are largely responsible for the explosion of portable computing. Surely there can be no greater testament to her genius than that.


How it works

Wilson's key invention was to rewrite the instruction set for ARM processors in order to minimise the number and complexity of instructions required for the chip to function, and to simplify their management.

With fewer instructions to process, the chip was able to operate considerably faster and use far fewer transistors than other chips - about 25,000 as opposed to 135,000 for the equivalent chip produced by Intel at the time. Fewer transistors meant far lower energy consumption, an attribute that is essential for the chip's role in today's mobile computing devices.

Another key element of the processor's design was the use of a load/store architecture, meaning that computer memory is only accessed as part of a small number of specific instructions. In addition, Wilson's RISC chip handled instructions as part of a pipeline rather than accessing and processing them individually.

This means one instruction is being processed while the next is being fetched, further accelerating performance.

From ultimate secrecy to licensed technology

From the early days of the development of the ARM processor to Acorn Computers' eventual dissolution into several companies, the secrets of the prized processor were once kept under virtual lock and key.

In 1985, as Italian computer manufacturer Olivetti gradually increased its stake in Acorn to become its major stock holder, proprietary information about the ARM was withheld until long after Olivetti owned a controlling share.

These extensive security measures are in stark contrast to the intellectual property strategies later used at Acorn and now at ARM Holdings. ARM Holdings relies on the strength of its patents and its research and development projects to safeguard its technology.

The company has major licensing agreements with many of the world's top semiconductor and computer manufacturers. ARM develops the processor designs, and these companies are responsible for production and sales.  

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