software process model

A software process model is a simplified description of a software process that presents
one view of that process. Process models may include activities that are part
of the software process, software products and the roles of people involved in software engineering. Some examples of the types of software process model that may
be produced are:
L A workflow model This shows the sequence of activities in the process along
with their inputs, outputs and dependencies. The activities in this model represent
human actions.
2. A dataflow or activity model This represents the process as a set of activities,
each of which carries out some data transformation. It shows how the input to
the process, such as a specification, is transformed to an output, such as a design.
The activities here may represent transfOlmations carried out by people or by
computers.
3. A role/action model This represents the roles of the people involved in the software
process and the activities for which they are responsible.
Most software process models are based on one of three general models or
paradigms of software development:
I. The waterfall approach This takl~S the above activities and represents them as
separate process phases such as requirements specification, software design, implementation,
testing and so on. After each s,tage is defined it is 'signed-off, and
development goes on to the following stage.
2. Iterative development This approach interleaves the activities of specification,
development and validation. An initial system is rapidly developed from very
abstract specifications. This is then refined with customer input to produce a
system that satisfies the customer s needs. The system may then be delivered.
Altematively, it may be reimpkmented using a more structured approach to
produce a more robust and maintainable system.
3. Component-based software engineering (CBSE) This technique assumes that
parts of the system already exist. The system development process focuses on
integrating these parts rather than developing them from scratch.