I'm currently doing my masterthesis in computer science. The project is about the design and development of a software editor in the cloud (a bit like c9.io)
As I started this project I made some choices like which programming language or technologies should I take.
I have to produce some documents a bit like a software engineer should do (not sure if PMSE is the right place to ask this question...). Documents like architecture, class diagram, database diagram ...
I made some important choices before I started to code the project, like programming languages. Obviously they affect the software design. But I'm not sure if thoses choices belongs to the design phases of a software project or to the implementation phase.
Otherwise lots of libraries I needed was chosen during the implementation and does not really affect the design of my software.
Sorry if my question is not clear, I'm not a native English speaker.