Architecture vs. Design

When Dr. Dobb's offered me the opportunity me to blog here, we set its scope to include both architecture and design. While I've been covering both themes, I thought that since it was way back in April that I provided a definition for "architecture", it is about time I also define difference between architecture and design.

Two distinct criteria that comes to mind are:

• Design deals with local decisions, where architecture is broader. For instance, you "design" the interfaces for your classes, but you "architect" the division into tiers.
• Design is mostly about the functional requirements, while architecture is mostly about quality attributes. You design how a specific workflow will fulfill a certain use case, but you architect the solution to the system's availability.

It is probably quite evident that this distinction only provides blurry borders between architecture and design; for example, when you have a multi-tier solution and you "architect" the UI and say it will implement MVP pattern. Can this be considered local decision and thus design or is this the overall decision (for the UI) and thus architecture?

The way I see it the exact cross-point from architecture to design is not that important. The point in talking about two distinct activities in the development process is to maintain separation of concern. you need to handle both to make sure a solution will actually work whether you do a little design while architecting or do a little architecture while designing really doesn't matter. Also architects should be involved in both activities anyway.

Posted by Arnon Rotem-Gal-Oz at 08:02 AM  Permalink