The Bucket O' Nothing

My post this year is about someone who I'd not heard of until I started my current job, but whose work was a vital part of the computers I used for most of my school years - the BBC Micro, which we used at junior school, and the Acorn Archimedes, which we used at senior school for the first four years I was there.

Sophie Wilson was not only one of the hardware engineers who designed the BBC Micro and its operating system, she designed the BBC Basic dialect for it and wrote the interpreter .

She designed the instruction set for the first ARM processors, the ones that went into the Acorn Archimedes. I've spent some time looking at the instruction set as it was in ARMv7, and comparing it with the instruction set as it was in the Archimedes it's impressive how similar things are.

(Side note 1: The patents on the version of the instruction set architecture from back then (ARMv2, I believe) have now expired, and so there is an open-source ARMv2-compatible processor project that uses the design from then. It is quite cool.)

(Side note 2: ARMv7 isn't the latest ARM architecture - that's ARMv8, which complicates things by having an extra new ISA. It does still have the original ARM ISA, though. With the extra things that have been added since ARMv2, of course, such as a divide operation, vector instructions, some mnemonic renaming, the entire Thumb (now T32) instruction set, and I could go on. But the basic structure of what's now called A32 - the 32-bit ARM instruction set - has stayed the same in several ways.)

Since Acorn/ARM, she's continued to work in processor design, including designing the FirePath processor that's used for digital signal processing for DSL.

(Side note 3: I found a presentation on FirePath that included the phrase "Viterbi acceleration" which makes me unreasonably excited because oh wow, I remember the Viterbi algorithm from doing statistical language modelling in my MPhil and have only now realised that of course it has more general applications for finding highest probabilities than just state transitions through possible phonemes. Yay, putting disparate bits of knowledge together. :D)

For all the work she's done in processor design, she's been appointed as a Distinguished Engineer at Broadcom (where she currently continues to work on Firepath), a 2012 Fellow of the Computer History Museum in Silicon Valley, and was a finalist in the 2013 European Inventor Award.

EDIT: Correcting something I said initially - winterlove pointed out that she wasn't one of the founding members of ARM the company itself, as she stayed with Acorn when ARM split off. (Wikipedia is the only place I've managed to find an actual list of the founding members - most articles just give a number and no names.)