WRT architecture: In my experience, you would be lucky if you are free to change the higher level structure of the code without having to dive deeply into the low-level code. Usually, the low-level code is a tangle of pathological dependencies, and you can't do any architectural refactoring without diving in and rooting them out one at a time (I was pulling up ivy this weekend, so I was primed to make this comment!)
> ...you would be lucky if you are free to change the higher level structure of the code without having to dive deeply into the low-level code.
The problem, in my mind, is that code can't be accurately modeled on one axis from "low level" to "high level". You can slice a system in many ways:
- network traffic
- database interactions
- build time dependencies
- run time dependencies
- hardware dependencies
- application level abstractions
...and certainly more. On top of that, the dimensions are not orthogonal. You might need to bump the major version of a library to support a new wire format, for example. Anyway, since there are many ways to slice a project, what is "high level" in on perspective can be "low level" from another. And vice versa.
