30. An analytical software design system arranged to receive informal system design specifications of a software system and to convert them into verified design specifications for use in creating source code and carrying out implementation testing of the source code, the software design system being arranged to handle informal system design specifications comprising informal requirement specifications, informal architecture specifications and informal component and specification designs, the software design system comprising: a verified specification generator including a processor to: process the received informal system design specifications; for each component of the software system, create formal design specifications; create formal interface specifications of required run-time interface behavior of each of the components that is visible by its interfaces, the formal interface specifications being specifications of the required run-time interface behavior which captures run-time behavior present at the respective interfaces of the each component with all other components with which the component interacts; generate from the formal design specifications and the formal interface specifications, for each of the components, a mathematical model representing run-time system behavior for the component with all other components with which the component interacts; analyse the mathematical models to determine if the mathematical models have required run-time system behavior; adjust at least one of the formal design specifications or the formal interface specifications until the required run-time system behavior is achieved; and derive the verified design specifications from the mathematical models.
30. An analytical software design system arranged to receive informal system design specifications of a software system and to convert them into verified design specifications for use in creating source code and carrying out implementation testing of the source code, the software design system being arranged to handle informal system design specifications comprising informal requirement specifications, informal architecture specifications and informal component and specification designs, the software design system comprising: a verified specification generator including a processor to: process the received informal system design specifications; for each component of the software system, create formal design specifications; create formal interface specifications of required run-time interface behavior of each of the components that is visible by its interfaces, the formal interface specifications being specifications of the required run-time interface behavior which captures run-time behavior present at the respective interfaces of the each component with all other components with which the component interacts; generate from the formal design specifications and the formal interface specifications, for each of the components, a mathematical model representing run-time system behavior for the component with all other components with which the component interacts; analyse the mathematical models to determine if the mathematical models have required run-time system behavior; adjust at least one of the formal design specifications or the formal interface specifications until the required run-time system behavior is achieved; and derive the verified design specifications from the mathematical models. 33. The software design system according to claim 30 , wherein the specification generator comprises a model verifier for analysing the mathematical models to determine if the mathematical models have the required run-time system behavior.