Software architecture

Software architecture underlies the practice of building computer software. In the same way as a building architect sets the principles and goals of a building project as the basis for the draftsman's plans, so too, a software architect sets out the software architecture as a basis for actual system design specifications, per the requirements of the client.

Table of contents

1 History
2 Views
3 Architecture Examples
4 Related Concepts
5 See Also
6 References

History

Software architecture as a concept was touched upon already in the 1960s by (for example) Edsger Dijkstra, but has increased in popularity since the early 1990s, largely due to activity within Rational Software Corporation and within Microsoft.

Views

Software architecture is commonly organised in views, which are analogous to the different types of blueprints made in common architecture. Some possible views are:

Functional/logic view
Code view
Development/structural view
Concurrency/process/thread view
Physical/deployment view
User action/feedback view

Several languages for describing software architectures have been devised, but no consensus has yet been reached on which symbol-set and view-system should be adopted. Some believe that UML will establish a standard for software architecture views. Others believe that effective development of software relies on understanding unique constraints of each problem, and so universal notations are doomed because each provides a notational bias that necessarily makes the notation useless or dangerous for some set of tasks. They point to the proliferation of programming languages and a succession of failed attempts to impose a single 'universal language' on programmers, as proof that software thrives on diversity and not on standards.

Architecture Examples

There are many common ways of designing computer software modules and their communications, among them:

Client-server
Distributed computing
Peer-to-peer system
Monolithic system
Three-tier model
Structured (module-based but usually monolithic within modules)
Component Software (strictly module-based, usually object-oriented programming within modules, slightly less monolithic)

Related Concepts

There are also a number of concepts which have been used in software architecture including

software design patterns
software antipatterns
standard data models

Software ontology is often considered to be a superset of software architecture, i.e. one 'ontologist' co-ordinates several 'architects', 'integrators', 'data modellers', and the usability, technical documentation and trainers. There may even be some control over marketing and sales presentations if the purpose of these is to determine who the products' users are, or to find out their vocabulary or values, to help the product reflect these.

The foundation ontology presently being standardized by the IEEE is intended to simplify and constrain the work of ontologists to a degree, and will to that degree simplify many decisions in software architecture.

References

Software Architecture by Rick Kazman gives a good overview of architectural concepts
Architectural Blueprints - the 4+1 View Model of Software Architecture by Philippe Kruchen (Rational Software)
''Multi-Paradigm Design in C++ - Jim Coplien - outlines all reasonable design approaches possible in C++, which is a particularly rich language but difficult for beginners.