https://billo.systems/articles/ Careful engineering at serious scale. 2026-06-18T09:00:00Z https://billo.systems/articles/2026/06/supervision-trees/ 2026-06-18T09:00:00Z 2026-06-18T09:00:00Z

Let-it-crash is not carelessness. It's a theory of where responsibility lives — enforced by the runtime rather than by anyone's good intentions.

Duncan McGreggor https://billo.systems/articles/2026/06/bringing-types-to-lfe/ 2026-06-14T10:08:00Z 2026-06-14T10:08:00Z

Why we started building a gradual type system for Lisp Flavoured Erlang — a tour through how Haskell, Go, Rust, Typed Racket, Coalton, and Typed Clojure each spell the same small idea, the ergonomic quibbles that pushed us, and the strategic moves we borrowed from Gleam.

Duncan McGreggor https://billo.systems/articles/2026/06/graph-theory-in-lfe-graffeo-erlang-knowledge/ 2026-06-06T10:08:00Z 2026-06-06T10:08:00Z

A deep, hands-on tour of graph theory in LFE — built on a real corpus of 1,664 Erlang concept cards, driven by the graffeo library, and unfolded slowly enough to teach the mathematics underneath each query.

Duncan McGreggor https://billo.systems/articles/2026/06/lykn-a-lisp-born-from-lfe/ 2026-06-05T18:00:00Z 2026-06-05T18:00:00Z

How fourteen years with Lisp Flavoured Erlang led to a new language — and how that language came home to power lfe.io.

Duncan McGreggor https://billo.systems/articles/2026/05/ai-recap-1-neural-networks-second-winter/ 2026-05-19T09:00:00Z 2026-05-19T09:00:00Z

I left the field when neural networks were a failed research program. I came back to find they had won everything. Part 1 of a catch-up, two decades deep.

Duncan McGreggor https://billo.systems/articles/2026/05/nine-nines/ 2026-05-09T09:00:00Z 2026-05-09T09:00:00Z

Every additional nine is one decimal point away and an order of magnitude harder. The question is never whether you can afford it, but who pays.

Duncan McGreggor https://billo.systems/articles/2026/04/vector-databases/ 2026-04-21T09:00:00Z 2026-04-21T09:00:00Z

Strip the marketing and a vector store is an index that has made peace with being approximately right. That peace is the whole engineering problem.

Duncan McGreggor https://billo.systems/articles/2025/12/raft-in-anger/ 2025-12-15T09:00:00Z 2025-12-15T09:00:00Z

The paper is elegant; production is not. Here is what leader election actually does when the network is having a genuinely bad day.

Duncan McGreggor https://billo.systems/articles/2015/01/translating-sicp-into-lfe/ 2015-01-28T21:12:00Z 2015-01-28T21:12:00Z

The Wizard Book is getting an LFE edition — why I'm porting Abelson and Sussman across, a paragraph at a time, what has to change on the way (procedures, for one), and what must never change.

Duncan McGreggor https://billo.systems/articles/2014/12/scientific-python-on-the-beam/ 2014-12-31T22:00:00Z 2014-12-31T22:00:00Z

The matplotlib book left me wondering how much of the scientific-Python world I could pull onto the Erlang VM. The answer became two projects, a discovery I didn't plan, and line charts drawn in the terminal.

Duncan McGreggor https://billo.systems/articles/2014/12/erlport-using-python-from-erlang-lfe/ 2014-12-03T01:08:00Z 2014-12-03T01:08:00Z

A Quick Introduction to ErlPort via LFE

Duncan McGreggor https://billo.systems/articles/2014/11/mastering-matplotlib/ 2014-11-30T00:33:00Z 2014-11-30T00:33:00Z

A cold email, a move to the Midwest, and a month spent deciding that "mastering" means going down to the architecture — the layers, the event loops, the module graph itself.

Duncan McGreggor https://billo.systems/articles/2014/11/company-site-is-live/ 2014-11-17T11:03:00Z 2014-11-17T11:03:00Z

Announcing the launch of the original Billo Systems company site — a note on the build, the tools that made it painless, and the drafts still to come.

Duncan McGreggor