field notes
Short notes from real engineering work: one decision, one incident, one reversal at a time. Each one names the shape of the problem, the tension that made it hard, the decision, and what it cost. The internals stay out — the codename is the hint.
If you have five minutes rather than an afternoon: the three case studies condense this material to one problem, one decision and what the decision cost. The notes below are the record those studies cite — and the projects the codenames belong to are on the front page.
A rebuild you have never performed is a hypothesis. The proof is a reset cycle: stop every workload, remove it, resubmit from the repository, and check that the services come back and answer. Running that deliberately, on a quiet day,…
The requirement was absolute: a replayed stream had to be byte-identical to what the live system emitted, or nothing built on the replay could be believed. It nearly was. A full-scale comparison across millions of records showed a small…
Two constraints define reproducibility here, and they arrived years apart. The first is that the executable which ran must be regenerable from a pinned state of the record. So a manifest binds the built artifact's content hash to the exact…
method
Not a changelog entry and not a repository summary. One decision, one incident, one reversal, or one hard-won invariant — the thing an engineer would tell you at a whiteboard.
Prefer records with dates and root causes? Those are on incidents. Live numbers are on stats.