barrucadu
I'm Michael Walker. I also go by barrucadu.
It's like the fish, but with the vowels wrong.
What have I done in the past? See my CV.
What am I doing now? See my “now” page.
Sometimes I write things! See my memos.
Work

Currently working on user-driven improvements to search performance and relevancy. Previously lead an upgrade from Elasticsearch 5 to Elasticsearch 6. Line manager to a mid-level developer.
Most of my work for GOV.UK is open source.

I've worked on a variety of evidence-driven improvements to the GOV.UK publishing stack, both performance improvements and also resolving long-standing technical debt. Mostly Ruby and Rails 5 / Sinatra, some Python 2. Also gave regular support to teams which did not merit a full-time developer.
Most of my work for GOV.UK is open source.

Maintained legacy Rails and Java applications by fixing bugs and applying updates.

Marked homeworks and helped students in the undergraduate compilers, discrete maths, and introductory programming modules, and the masters-level software testing module.

Fixed bugs, closed security holes, ported Ruby, and worked on ShareLaTeX code and data analysis after the two companies merged.

Powering realtime with spit and glue! (or so says my mug). I worked on performant and reliable distributed systems for message delivery.

Wrote a parser/renderer for an in-house wiki program using ANTLR in Java, and integrated this with JIRA.
Research
Papers
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Revealing Behaviours of Concurrent Functional Programs by Systematic Testing
University of York. Ph.D thesis. 2018. [bib] -
Cheap Remarks about Concurrent Programs
In Functional and Logic Programming Symposium (FLOPS '18). [bib] [doi] -
Déjà Fu: A Concurrency Testing Library for Haskell
University of York Computer Science Department Technical Report YCS-2016-503. 2016. [bib] -
Déjà Fu: A Concurrency Testing Library for Haskell
In ACM SIGPLAN Symposium on Haskell (Haskell '15). [bib] [doi]
Presentations & Posters
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Cheap Remarks about Concurrent Programs
Presented at Trends in Functional Programming (TFP '17). -
Search Party: a Haskell library for speculative parallelism in generate-and-test searches
Poster at ACM ICFP Student Research Competition (ICFP SRC '15).
Open Source

It's a library for testing concurrent Haskell programs, which came out of my Ph.D research. Pretty much everything is supported, plus a few extras.
Comes with HUnit and Tasty bindings, so you can easily integrate it with your existing testsuite.

I accidentally started a GNU/Hurd distribution based on Arch Linux. This was completely unintentional.
Served my time as project leader from 2010 to 2015, managing a handful of developers around the world porting over Linux software. I also produced installation media and maintained the website and repositories.

I was one of the first few developers, and this is the project that taught me C and Git. It was fun, and I learned a lot. I still host the website and mailing list.
Do not expect good code if you go and dig up my contributions.