Implementing a clear room Z80 / ZX Spectrum emulator with Claude Code

- Anthropic recently released a blog post with the description of an experiment in which the last version of Opus, the 4.6, was instructed to write a C compiler in Rust, in a “clean room” setup. The experiment methodology left me dubious about the kind of point they wanted to...

PSA: Your SQLite Connection Pool Might Be Ruining Your Write Performance

- 17 Feb, 2026 Update (Feb 18, 2026): After a productive discussion on Reddit and additional benchmarking, I found that the solutions I originally proposed (batched writes or using a synchronous connection) don't actually help. The real issue is simpler and more fundamental than I...

PSA: Write Transactions are a Footgun with SQLx and SQLite

- Write transactions can lead to lock starvation and serious performance degradation when using SQLite with SQLx, the popular async Rust SQL library. In retrospect, I feel like this should have been obvious, but it took a little more staring at suspiciously consistent "slow...

Running Pydantic's Monty Rust sandboxed Python subset in WebAssembly

- There’s a jargon-filled headline for you! Everyone’s building sandboxes for running untrusted code right now, and Pydantic’s latest attempt, Monty, provides a custom Python-like language (a subset of Python) in …

Rust is Just a Tool

- 2/4/2026 I like Rust. It's versatile enough that it can be used for application and systems programming. It has the best tooling of any language I've seen. It has a fairly pleasant type system. And I think most importantly it does a great job in bringing higher level language...

Wilson Lin on FastRender: a browser built by thousands of parallel agents

- Last week Cursor published Scaling long-running autonomous coding, an article describing their research efforts into coordinating large numbers of autonomous coding agents. One of the projects mentioned in the article …

'Better C' playgrounds

- Playgrounds for C3, Hare, Odin, V, and Zig....

Timing 'Hello, world'

- Compiling and running 'Hello, World!' in 20 programming languages....

What Now? Handling Errors in Large Systems

- What Now? Handling Errors in Large Systems function vote(btn, choice) { const widget = btn.closest('.vote-widget'); widget.querySelector('.user-vote').textContent = choice === 'tick' ? '✅' : '❌'; widget.querySelector('.result').style.display = 'block';...

Messing with bots

- Markov chain babblers, bogus php files, and more!...

The built-in storytelling of Rust

- Although I technically own the game and played it once a decade ago; I had a horrible time playing Rust. Other players called me the N-word several times, I died almost instantly, my frame rates were trash, and after three hours I put it down and never played it again. Despite...

Reverse engineering Codex CLI to get GPT-5-Codex-Mini to draw me a pelican

Building blobd: single-machine object store with sub-millisecond reads and 15 GB/s uploads

- Deep dive into blobd, an object store designed for constant low latency reads using async Rust, io_uring and atomic writes...

What Dynamic Typing Is For

- .languages { grid-template-columns: 1fr 1fr fit-content(60%); } Unplanned Obsolescence is a blog is about writing maintainable, long-lasting software. It also frequently touts—or is, at the very least, not inherently hostile to—writing software in dynamically-typed programming...

Zig Builds Are Getting Faster

A Very Early History of Algebraic Data Types

- Been quiet around here! I’ve been putting almost all of my writing time into Logic for Programmers and my whole brain is book-shaped. Trust me, you do not want to read my 2000-word rant on Sphinx post-build LaTeX customization. But I spent the past week in a historical rabbit...

Are We Chasing Language Hype Over Solving Real Problems?

- Exploring the trend of rewriting existing software in new programming languages, this article delves into the balance between innovation and practicality in software development....

Embedding Wren in Hare

- I’ve been on the lookout for a scripting language which can be neatly embedded into Hare programs. Perhaps the obvious candidate is Lua – but I’m not particularly enthusiastic about it. When I was evaluating the landscape of tools which are “like Lua, but not Lua”, I found an...

Typechecker Zoo

- Typechecker Zoo As a fun side project, I've built four literate Rust implementations spanning 50 years of type theory research, from Milner's Algorithm W to modern dependent type systems. I've tried to make each implementation as readable and understandable as possible, with...

Optimizing My Disk Usage Program

- Increasing performance by reducing thread scheduling overhead and lock contention....

VibeTunnel's first AI-anniversary

- It's been one month since we released the first version of VibeTunnel, and since in the AI world time is so much faster, let's call it VibeTunnel's first anniversary!...

On Reifying Nested Closures in Rust

Fast Tensor Canonicalization in Rust

- Fast Tensor Canonicalization in Rust I recently had a need to do fast tensor canonicalization, but the library ecosystem for this was lacking. In physics and differential geometry, manipulating tensors and especially bringing them into canonical form under their index symmetries...

Projects

- Video games # Pico-8 cartridges # Galactica, a (basic) space shooter # Books # 2017, Mastering Rust, Vesa Kaihlavirta (PACKT) - official reviewer # 2016, Investigating the Energy Impact of Android Smells - accepted to SANER 2017 2015, A Learning Algorithm for Change Impact...