Software Components

Systems engineers define requirements at various levels, the highest of those levels is the business level, then comes the enterprise level, then the system level, then the component level. For a physical system a component could be easy to identify, how about software?

One way of defining a component in the software world is an active object with clear self-defined interfaces [1]. Active objects are objects with have their own thread of control.

Another definition is that a component is an object written to specification. Components are defined to meet several criteria namely; multi-use, non-context-specific, composable, contained and of independent versioning [2].

So a component level requirement is a requirement that tells the developer the needs that the code shall be able to accomplish.

[1] Hassan Gomma, "Designing Concurrent, Distributed, and Real-Time Applications with UML", Addison Wesley, 2000

[2] http://en.wikipedia.org/wiki/Software_componentry