Evolutionary development
l Problems • Lack of process visibility • Systems are often poorly structured • Special skills (e.g. in languages for rapid prototyping) may be required l Applicability • For small or medium-size interactive systems • For parts of large systems (e.g. the user interface) • For short-lifetime systems
©Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 1 Slide 13
Formal systems development
l Based on the transformation of a mathematical specification through different representations to an executable program l Transformations are ‘correctness-preserving’ so it is straightforward to show that the program conforms to its specification l Embodied in the ‘Cleanroom’ approach to software development
l Problems • Lack of process visibility • Systems are often poorly structured • Special skills (e.g. in languages for rapid prototyping) may be required l Applicability • For small or medium-size interactive systems • For parts of large systems (e.g. the user interface) • For short-lifetime systems
©Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 1 Slide 13
Formal systems development
l Based on the transformation of a mathematical specification through different representations to an executable program l Transformations are ‘correctness-preserving’ so it is straightforward to show that the program conforms to its specification l Embodied in the ‘Cleanroom’ approach to software development