Comment by blub

No part of your list was just a detail, but all parts of the list consist of essential properties and details. As I said, many of those details will fall into place when one starts implementing the core architecture.

It also matters a lot what scale one is operating at. Bigger scale will require more effort up front, PoCs, several big iterations, etc.

To give a smaller scale example, I defined a general simple protocol for two local components, picked the IPC and defined the handshake and teardown sequence. The developer defined the message contents. Reviewed together, then it was implemented. Testing showed that component B, which was OSS and had a fixed rate was sending too fast so the developer patched it to do debouncing.

Coding is nothing like changing tires. To abuse an incorrect analogy even more, the architect would prescribe the properties of the tire or even the behaviour of the vehicle and the developer would design and construct the tires/tracks/whatever either from existing parts or from scratch. Possibly going back and forth on the actual means of locomotion.

To wrap it up. Requirements, architecture and design can be changed. When implementing features I always do architecture review with the team and adapt it based on their feedback. We have rejected or negotiated requirements based on PoC or just developer evaluation.

Sometimes that doesn’t work, sure. If it’s a critical feature or there are hard architectural restrictions one puts in the dev work to figure it out and maybe this leads to a non-ideal implementation. Fundamental mistakes at requirements or architecture level do have higher impact, but iterating and having a good arch <-> dev feedback loop is one of the best methods I know to tackle that.

To give another example, I investigated the potential implementations for a feature and prepared a list of technical approaches sorted by specific architectural attributes. The dev team wrote the code to validate them and option 1 turned out to be impossible because of platform constraints. I adjusted the architecture to use option 2.