William Nguyen's engineering notes https://zi3t.io/notes/ Short notes about systems software, public experiments, and the boundaries where behaviour changes. en-au Thu, 16 Jul 2026 00:00:00 +1000 At-least-once is a storage problem https://zi3t.io/notes/at-least-once/ https://zi3t.io/notes/at-least-once/ Tue, 14 Jul 2026 00:00:00 +1000 RabbitMQ can deliver a message twice. The hard part is making the second delivery boring. A replay is only useful when it leaves evidence https://zi3t.io/notes/replay-evidence/ https://zi3t.io/notes/replay-evidence/ Tue, 14 Jul 2026 00:00:00 +1000 Random failure looks realistic. Deterministic failure can be reviewed. The system is the path, not the executable https://zi3t.io/systems/ https://zi3t.io/systems/ Sat, 11 Jul 2026 00:00:00 +1000 A command still has to survive queues, translation, transport, a device, and the return path.