I'm Michael Walker. I also go by barrucadu.
It's like the fish, but with the vowels wrong.

See my CV. I also blog.

I am a Computer Science Ph.D student at the University of York in the Programming Languages and Systems (PLASMA) group, currently thinking about testing distributed systems.

I read a lot of books, I write a lot of code, and I research concurrency.

Places I've Worked



Software Engineering Intern

May–Aug 2016

Powering realtime with spit and glue! (or so says my mug)

I worked on performant and reliable distributed systems for message delivery.

University of York

University of York

Postgraduate Teaching Assistant

Oct 2015–May 2016

Marked homeworks and helped students in the “Theory and Practice of Programming” first-year module.

Oct 2014–May 2015

Marked homeworks and helped students in the “Mathematical Foundations of Computer Science” first-year module.



Software Engineering Intern

Jul–Sep 2014

Wrote a parser/renderer for an in-house wiki program using ANTLR in Java, and integrated this with JIRA.

I Do Research

Concurrency is great as both a design pattern and a performance enhancer, but it can be hard to get right. Testing in particular is hard: you can't just run a program once and see what the result is.

Next I plan to try to apply some of what I've learned to distributed systems.

Conference Papers


Open Source Is Good, Too

Various Projects

Sole/Main Developer

the dawn of time–now

I actively develop a variety of things.

The coolest by far is dejafu, a library for testing concurrent Haskell programs, which came out of my research.

Second place goes to logdb, a performant and reliable log-structured database in Go.

I also maintain a few Haskell IRC libraries which have actual users!

Arch Hurd

Project Leader


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.