Documentation

The system can keep running long after the reasoning behind it has left. You can’t test it, because the only place it runs is production, so you read the logs and you sit with someone while they do their job with it and build up a picture of what it does from the outside. The customer said it pulls from the billing platform on a schedule, but the logs say it pushes on a trigger, the connection string points at a host that isn’t on the network diagram, and the job everyone calls the nightly sync runs four times a day. At one point the worker does a step that makes no sense, and when you ask why, the answer is that’s just how it’s always done. It takes time and the picture you end up with is nothing like the description, but you get there. ...

A P1 landed mid-morning with no context, the person who’d been handling it was off without a handover, and there were already several people on the call waiting for something to happen. The customer had been sitting with the issue for a while before we got involved, and what I had to work from was basically nothing. I started from scratch, kept it simple and worked up from there, and had it resolved within half an hour. The fix was something I’d documented two years earlier: Windows blocking files downloaded from the internet, unblocked via PowerShell, and I only found it because I’d written it down. ...