Question

What is software architecture? Why do we need it? Distinguish between architecture and design.

Answer 1

Software architecture refers to the fundamental structures of a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements and relations.

We need architecture because -

1. Communication among stakeholders. Software architecture represents a common abstraction of a system that most if not all of the system's stakeholders can use as a basis for mutual understanding, negotiation, consensus, and communication.

2. Early design decisions. Software architecture manifests the earliest design decisions about a system, and these early bindings carry weight far out of proportion to their individual gravity with respect to the system's remaining development, its deployment, and its maintenance life. It is also the earliest point at which design decisions governing the system to be built can be analyzed.

3. Transferable abstraction of a system. Software architecture constitutes a relatively small, intellectually graspable model for how a system is structured and how its elements work together, and this model is transferable across systems. In particular, it can be applied to other systems exhibiting similar quality attribute and functional requirements and can promote large-scale re-use.

The difference between Software architecture and software design is -

Software Architecture focuses more on the interaction between the externally visible components of the system where as the Design is about how the internal components of the system interact with each other. Software Architecture is more about what we want the system to do and Software Design is about how we want to achieve that. Software Architecture is at a higher level of abstraction than the Software Design. Software Architecture is concerned with issues beyond the data structures and algorithms used in the system.