Fred Lackey -- Commonplace Book

Essay February 14, 2026

The Quiet Architecture of Reliable Systems

There is a particular kind of satisfaction in encountering a system that simply works. Not the flashy, buzzword-laden architecture diagram pinned to a conference talk slide, but the quiet kind -- the service that has been running in production for three years, processing millions of requests, and has needed exactly two deploys in the last six months. Both of which were minor dependency bumps.

I have been thinking about what separates these systems from the rest. It is rarely about the technology choices. It is almost always about the constraints the builders chose to respect.

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Quote February 11, 2026

"Simplicity is prerequisite for reliability."

— Edsger W. Dijkstra

I return to this one constantly. Every time I watch a team reach for a message queue when a cron job would suffice, or introduce a service mesh for three microservices that could be a monolith. The prerequisite framing is what makes it sharp: you cannot get to reliability without passing through simplicity first.

// code February 9, 2026

Tiny utility: debounced async queue

type AsyncFn<T> = () => Promise<T>;

function createAsyncQueue(concurrency = 3) {
  const queue: AsyncFn<any>[] = [];
  let active = 0;

  async function next() {
    if (active >= concurrency || !queue.length) return;
    active++;
    const fn = queue.shift()!;
    try { await fn(); }
    finally { active--; next(); }
  }

  return {
    add<T>(fn: AsyncFn<T>): Promise<T> {
      return new Promise((resolve, reject) => {
        queue.push(() => fn().then(resolve, reject));
        next();
      });
    }
  };
}
    

I keep reaching for this pattern. Useful when you need to rate-limit API calls during batch operations -- say, importing 500 records into a third-party service that throttles at 5 req/s. Drop-in replacement for Promise.all without the thundering herd.

Photo February 7, 2026

A sunlit desk with a mechanical keyboard, a notebook, and a cup of coffee

Morning setup. There is something about the first hour of the day, before Slack wakes up, when the code practically writes itself. This was Wednesday -- the draft of that queue utility above came from this exact session.

Link February 5, 2026

simonwillison.net

Prompt Injection and the Future of LLM Security →

Simon's analysis here is the clearest articulation I have read of why prompt injection is not "just another vulnerability" but a fundamentally new class of problem. The section on the tension between capability and safety is particularly sharp. If you are building anything with LLMs in the loop, this is required reading.

Thought February 3, 2026

The older I get, the more I value boring technology. PostgreSQL. Cron. Bash scripts. Nginx. The kind of tools that do not generate conference talks but do generate uptime. The gap between "interesting to build" and "pleasant to maintain" is where most technical debt lives.